Move Tie-File out of cpan/ and into dist/

Tie::File has not been changed on CPAN since 2003. It has meanwhile been
actively maintained in p5p.

Signed-off-by: Chris 'BinGOs' Williams <chris@bingosnet.co.uk>

39 files changed, 8960 insertions, 0 deletions

diff --git a/dist/Tie-File/lib/Tie/File.pm b/dist/Tie-File/lib/Tie/File.pm
new file mode 100644
index 0000000000..3862da2367
--- /dev/null
+++ b/dist/Tie-File/lib/Tie/File.pm
@@ -0,0 +1,2633 @@
+
+package Tie::File;
+require 5.005;
+use Carp ':DEFAULT', 'confess';
+use POSIX 'SEEK_SET';
+use Fcntl 'O_CREAT', 'O_RDWR', 'LOCK_EX', 'LOCK_SH', 'O_WRONLY', 'O_RDONLY';
+sub O_ACCMODE () { O_RDONLY | O_RDWR | O_WRONLY }
+
+
+$VERSION = "0.98";
+my $DEFAULT_MEMORY_SIZE = 1<<21;    # 2 megabytes
+my $DEFAULT_AUTODEFER_THRESHHOLD = 3; # 3 records
+my $DEFAULT_AUTODEFER_FILELEN_THRESHHOLD = 65536; # 16 disk blocksful
+
+my %good_opt = map {$_ => 1, "-$_" => 1}
+                 qw(memory dw_size mode recsep discipline 
+                    autodefer autochomp autodefer_threshhold concurrent);
+
+sub TIEARRAY {
+  if (@_ % 2 != 0) {
+    croak "usage: tie \@array, $_[0], filename, [option => value]...";
+  }
+  my ($pack, $file, %opts) = @_;
+
+  # transform '-foo' keys into 'foo' keys
+  for my $key (keys %opts) {
+    unless ($good_opt{$key}) {
+      croak("$pack: Unrecognized option '$key'\n");
+    }
+    my $okey = $key;
+    if ($key =~ s/^-+//) {
+      $opts{$key} = delete $opts{$okey};
+    }
+  }
+
+  if ($opts{concurrent}) {
+    croak("$pack: concurrent access not supported yet\n");
+  }
+
+  unless (defined $opts{memory}) {
+    # default is the larger of the default cache size and the 
+    # deferred-write buffer size (if specified)
+    $opts{memory} = $DEFAULT_MEMORY_SIZE;
+    $opts{memory} = $opts{dw_size}
+      if defined $opts{dw_size} && $opts{dw_size} > $DEFAULT_MEMORY_SIZE;
+    # Dora Winifred Read
+  }
+  $opts{dw_size} = $opts{memory} unless defined $opts{dw_size};
+  if ($opts{dw_size} > $opts{memory}) {
+      croak("$pack: dw_size may not be larger than total memory allocation\n");
+  }
+  # are we in deferred-write mode?
+  $opts{defer} = 0 unless defined $opts{defer};
+  $opts{deferred} = {};         # no records are presently deferred
+  $opts{deferred_s} = 0;        # count of total bytes in ->{deferred}
+  $opts{deferred_max} = -1;     # empty
+
+  # What's a good way to arrange that this class can be overridden?
+  $opts{cache} = Tie::File::Cache->new($opts{memory});
+
+  # autodeferment is enabled by default
+  $opts{autodefer} = 1 unless defined $opts{autodefer};
+  $opts{autodeferring} = 0;     # but is not initially active
+  $opts{ad_history} = [];
+  $opts{autodefer_threshhold} = $DEFAULT_AUTODEFER_THRESHHOLD
+    unless defined $opts{autodefer_threshhold};
+  $opts{autodefer_filelen_threshhold} = $DEFAULT_AUTODEFER_FILELEN_THRESHHOLD
+    unless defined $opts{autodefer_filelen_threshhold};
+
+  $opts{offsets} = [0];
+  $opts{filename} = $file;
+  unless (defined $opts{recsep}) { 
+    $opts{recsep} = _default_recsep();
+  }
+  $opts{recseplen} = length($opts{recsep});
+  if ($opts{recseplen} == 0) {
+    croak "Empty record separator not supported by $pack";
+  }
+
+  $opts{autochomp} = 1 unless defined $opts{autochomp};
+
+  $opts{mode} = O_CREAT|O_RDWR unless defined $opts{mode};
+  $opts{rdonly} = (($opts{mode} & O_ACCMODE) == O_RDONLY);
+  $opts{sawlastrec} = undef;
+
+  my $fh;
+
+  if (UNIVERSAL::isa($file, 'GLOB')) {
+    # We use 1 here on the theory that some systems 
+    # may not indicate failure if we use 0.
+    # MSWin32 does not indicate failure with 0, but I don't know if
+    # it will indicate failure with 1 or not.
+    unless (seek $file, 1, SEEK_SET) {
+      croak "$pack: your filehandle does not appear to be seekable";
+    }
+    seek $file, 0, SEEK_SET;    # put it back
+    $fh = $file;                # setting binmode is the user's problem
+  } elsif (ref $file) {
+    croak "usage: tie \@array, $pack, filename, [option => value]...";
+  } else {
+    # $fh = \do { local *FH };  # XXX this is buggy
+    if ($] < 5.006) {
+	# perl 5.005 and earlier don't autovivify filehandles
+	require Symbol;
+	$fh = Symbol::gensym();
+    }
+    sysopen $fh, $file, $opts{mode}, 0666 or return;
+    binmode $fh;
+    ++$opts{ourfh};
+  }
+  { my $ofh = select $fh; $| = 1; select $ofh } # autoflush on write
+  if (defined $opts{discipline} && $] >= 5.006) {
+    # This avoids a compile-time warning under 5.005
+    eval 'binmode($fh, $opts{discipline})';
+    croak $@ if $@ =~ /unknown discipline/i;
+    die if $@;
+  }
+  $opts{fh} = $fh;
+
+  bless \%opts => $pack;
+}
+
+sub FETCH {
+  my ($self, $n) = @_;
+  my $rec;
+
+  # check the defer buffer
+  $rec = $self->{deferred}{$n} if exists $self->{deferred}{$n};
+  $rec = $self->_fetch($n) unless defined $rec;
+
+  # inlined _chomp1
+  substr($rec, - $self->{recseplen}) = ""
+    if defined $rec && $self->{autochomp};
+  $rec;
+}
+
+# Chomp many records in-place; return nothing useful
+sub _chomp {
+  my $self = shift;
+  return unless $self->{autochomp};
+  if ($self->{autochomp}) {
+    for (@_) {
+      next unless defined;
+      substr($_, - $self->{recseplen}) = "";
+    }
+  }
+}
+
+# Chomp one record in-place; return modified record
+sub _chomp1 {
+  my ($self, $rec) = @_;
+  return $rec unless $self->{autochomp};
+  return unless defined $rec;
+  substr($rec, - $self->{recseplen}) = "";
+  $rec;
+}
+
+sub _fetch {
+  my ($self, $n) = @_;
+
+  # check the record cache
+  { my $cached = $self->{cache}->lookup($n);
+    return $cached if defined $cached;
+  }
+
+  if ($#{$self->{offsets}} < $n) {
+    return if $self->{eof};  # request for record beyond end of file
+    my $o = $self->_fill_offsets_to($n);
+    # If it's still undefined, there is no such record, so return 'undef'
+    return unless defined $o;
+  }
+
+  my $fh = $self->{FH};
+  $self->_seek($n);             # we can do this now that offsets is populated
+  my $rec = $self->_read_record;
+
+# If we happen to have just read the first record, check to see if
+# the length of the record matches what 'tell' says.  If not, Tie::File
+# won't work, and should drop dead.
+#
+#  if ($n == 0 && defined($rec) && tell($self->{fh}) != length($rec)) {
+#    if (defined $self->{discipline}) {
+#      croak "I/O discipline $self->{discipline} not supported";
+#    } else {
+#      croak "File encoding not supported";
+#    }
+#  }
+
+  $self->{cache}->insert($n, $rec) if defined $rec && not $self->{flushing};
+  $rec;
+}
+
+sub STORE {
+  my ($self, $n, $rec) = @_;
+  die "STORE called from _check_integrity!" if $DIAGNOSTIC;
+
+  $self->_fixrecs($rec);
+
+  if ($self->{autodefer}) {
+    $self->_annotate_ad_history($n);
+  }
+
+  return $self->_store_deferred($n, $rec) if $self->_is_deferring;
+
+
+  # We need this to decide whether the new record will fit
+  # It incidentally populates the offsets table 
+  # Note we have to do this before we alter the cache
+  # 20020324 Wait, but this DOES alter the cache.  TODO BUG?
+  my $oldrec = $self->_fetch($n);
+
+  if (not defined $oldrec) {
+    # We're storing a record beyond the end of the file
+    $self->_extend_file_to($n+1);
+    $oldrec = $self->{recsep};
+  }
+#  return if $oldrec eq $rec;    # don't bother
+  my $len_diff = length($rec) - length($oldrec);
+
+  # length($oldrec) here is not consistent with text mode  TODO XXX BUG
+  $self->_mtwrite($rec, $self->{offsets}[$n], length($oldrec));
+  $self->_oadjust([$n, 1, $rec]);
+  $self->{cache}->update($n, $rec);
+}
+
+sub _store_deferred {
+  my ($self, $n, $rec) = @_;
+  $self->{cache}->remove($n);
+  my $old_deferred = $self->{deferred}{$n};
+
+  if (defined $self->{deferred_max} && $n > $self->{deferred_max}) {
+    $self->{deferred_max} = $n;
+  }
+  $self->{deferred}{$n} = $rec;
+
+  my $len_diff = length($rec);
+  $len_diff -= length($old_deferred) if defined $old_deferred;
+  $self->{deferred_s} += $len_diff;
+  $self->{cache}->adj_limit(-$len_diff);
+  if ($self->{deferred_s} > $self->{dw_size}) {
+    $self->_flush;
+  } elsif ($self->_cache_too_full) {
+    $self->_cache_flush;
+  }
+}
+
+# Remove a single record from the deferred-write buffer without writing it
+# The record need not be present
+sub _delete_deferred {
+  my ($self, $n) = @_;
+  my $rec = delete $self->{deferred}{$n};
+  return unless defined $rec;
+
+  if (defined $self->{deferred_max} 
+      && $n == $self->{deferred_max}) {
+    undef $self->{deferred_max};
+  }
+
+  $self->{deferred_s} -= length $rec;
+  $self->{cache}->adj_limit(length $rec);
+}
+
+sub FETCHSIZE {
+  my $self = shift;
+  my $n = $self->{eof} ? $#{$self->{offsets}} : $self->_fill_offsets;
+
+  my $top_deferred = $self->_defer_max;
+  $n = $top_deferred+1 if defined $top_deferred && $n < $top_deferred+1;
+  $n;
+}
+
+sub STORESIZE {
+  my ($self, $len) = @_;
+
+  if ($self->{autodefer}) {
+    $self->_annotate_ad_history('STORESIZE');
+  }
+
+  my $olen = $self->FETCHSIZE;
+  return if $len == $olen;      # Woo-hoo!
+
+  # file gets longer
+  if ($len > $olen) {
+    if ($self->_is_deferring) {
+      for ($olen .. $len-1) {
+        $self->_store_deferred($_, $self->{recsep});
+      }
+    } else {
+      $self->_extend_file_to($len);
+    }
+    return;
+  }
+
+  # file gets shorter
+  if ($self->_is_deferring) {
+    # TODO maybe replace this with map-plus-assignment?
+    for (grep $_ >= $len, keys %{$self->{deferred}}) {
+      $self->_delete_deferred($_);
+    }
+    $self->{deferred_max} = $len-1;
+  }
+
+  $self->_seek($len);
+  $self->_chop_file;
+  $#{$self->{offsets}} = $len;
+#  $self->{offsets}[0] = 0;      # in case we just chopped this
+
+  $self->{cache}->remove(grep $_ >= $len, $self->{cache}->ckeys);
+}
+
+### OPTIMIZE ME
+### It should not be necessary to do FETCHSIZE
+### Just seek to the end of the file.
+sub PUSH {
+  my $self = shift;
+  $self->SPLICE($self->FETCHSIZE, scalar(@_), @_);
+
+  # No need to return:
+  #  $self->FETCHSIZE;  # because av.c takes care of this for me
+}
+
+sub POP {
+  my $self = shift;
+  my $size = $self->FETCHSIZE;
+  return if $size == 0;
+#  print STDERR "# POPPITY POP POP POP\n";
+  scalar $self->SPLICE($size-1, 1);
+}
+
+sub SHIFT {
+  my $self = shift;
+  scalar $self->SPLICE(0, 1);
+}
+
+sub UNSHIFT {
+  my $self = shift;
+  $self->SPLICE(0, 0, @_);
+  # $self->FETCHSIZE; # av.c takes care of this for me
+}
+
+sub CLEAR {
+  my $self = shift;
+
+  if ($self->{autodefer}) {
+    $self->_annotate_ad_history('CLEAR');
+  }
+
+  $self->_seekb(0);
+  $self->_chop_file;
+    $self->{cache}->set_limit($self->{memory});
+    $self->{cache}->empty;
+  @{$self->{offsets}} = (0);
+  %{$self->{deferred}}= ();
+    $self->{deferred_s} = 0;
+    $self->{deferred_max} = -1;
+}
+
+sub EXTEND {
+  my ($self, $n) = @_;
+
+  # No need to pre-extend anything in this case
+  return if $self->_is_deferring;
+
+  $self->_fill_offsets_to($n);
+  $self->_extend_file_to($n);
+}
+
+sub DELETE {
+  my ($self, $n) = @_;
+
+  if ($self->{autodefer}) {
+    $self->_annotate_ad_history('DELETE');
+  }
+
+  my $lastrec = $self->FETCHSIZE-1;
+  my $rec = $self->FETCH($n);
+  $self->_delete_deferred($n) if $self->_is_deferring;
+  if ($n == $lastrec) {
+    $self->_seek($n);
+    $self->_chop_file;
+    $#{$self->{offsets}}--;
+    $self->{cache}->remove($n);
+    # perhaps in this case I should also remove trailing null records?
+    # 20020316
+    # Note that delete @a[-3..-1] deletes the records in the wrong order,
+    # so we only chop the very last one out of the file.  We could repair this
+    # by tracking deleted records inside the object.
+  } elsif ($n < $lastrec) {
+    $self->STORE($n, "");
+  }
+  $rec;
+}
+
+sub EXISTS {
+  my ($self, $n) = @_;
+  return 1 if exists $self->{deferred}{$n};
+  $n < $self->FETCHSIZE;
+}
+
+sub SPLICE {
+  my $self = shift;
+
+  if ($self->{autodefer}) {
+    $self->_annotate_ad_history('SPLICE');
+  }
+
+  $self->_flush if $self->_is_deferring; # move this up?
+  if (wantarray) {
+    $self->_chomp(my @a = $self->_splice(@_));
+    @a;
+  } else {
+    $self->_chomp1(scalar $self->_splice(@_));
+  }
+}
+
+sub DESTROY {
+  my $self = shift;
+  $self->flush if $self->_is_deferring;
+  $self->{cache}->delink if defined $self->{cache}; # break circular link
+  if ($self->{fh} and $self->{ourfh}) {
+      delete $self->{ourfh};
+      close delete $self->{fh};
+  }
+}
+
+sub _splice {
+  my ($self, $pos, $nrecs, @data) = @_;
+  my @result;
+
+  $pos = 0 unless defined $pos;
+
+  # Deal with negative and other out-of-range positions
+  # Also set default for $nrecs 
+  {
+    my $oldsize = $self->FETCHSIZE;
+    $nrecs = $oldsize unless defined $nrecs;
+    my $oldpos = $pos;
+
+    if ($pos < 0) {
+      $pos += $oldsize;
+      if ($pos < 0) {
+        croak "Modification of non-creatable array value attempted, subscript $oldpos";
+      }
+    }
+
+    if ($pos > $oldsize) {
+      return unless @data;
+      $pos = $oldsize;          # This is what perl does for normal arrays
+    }
+
+    # The manual is very unclear here
+    if ($nrecs < 0) {
+      $nrecs = $oldsize - $pos + $nrecs;
+      $nrecs = 0 if $nrecs < 0;
+    }
+
+    # nrecs is too big---it really means "until the end"
+    # 20030507
+    if ($nrecs + $pos > $oldsize) {
+      $nrecs = $oldsize - $pos;
+    }
+  }
+
+  $self->_fixrecs(@data);
+  my $data = join '', @data;
+  my $datalen = length $data;
+  my $oldlen = 0;
+
+  # compute length of data being removed
+  for ($pos .. $pos+$nrecs-1) {
+    last unless defined $self->_fill_offsets_to($_);
+    my $rec = $self->_fetch($_);
+    last unless defined $rec;
+    push @result, $rec;
+
+    # Why don't we just use length($rec) here?
+    # Because that record might have come from the cache.  _splice
+    # might have been called to flush out the deferred-write records,
+    # and in this case length($rec) is the length of the record to be
+    # *written*, not the length of the actual record in the file.  But
+    # the offsets are still true. 20020322
+    $oldlen += $self->{offsets}[$_+1] - $self->{offsets}[$_]
+      if defined $self->{offsets}[$_+1];
+  }
+  $self->_fill_offsets_to($pos+$nrecs);
+
+  # Modify the file
+  $self->_mtwrite($data, $self->{offsets}[$pos], $oldlen);
+  # Adjust the offsets table
+  $self->_oadjust([$pos, $nrecs, @data]);
+
+  { # Take this read cache stuff out into a separate function
+    # You made a half-attempt to put it into _oadjust.  
+    # Finish something like that up eventually.
+    # STORE also needs to do something similarish
+
+    # update the read cache, part 1
+    # modified records
+    for ($pos .. $pos+$nrecs-1) {
+      my $new = $data[$_-$pos];
+      if (defined $new) {
+        $self->{cache}->update($_, $new);
+      } else {
+        $self->{cache}->remove($_);
+      }
+    }
+    
+    # update the read cache, part 2
+    # moved records - records past the site of the change
+    # need to be renumbered
+    # Maybe merge this with the previous block?
+    {
+      my @oldkeys = grep $_ >= $pos + $nrecs, $self->{cache}->ckeys;
+      my @newkeys = map $_-$nrecs+@data, @oldkeys;
+      $self->{cache}->rekey(\@oldkeys, \@newkeys);
+    }
+
+    # Now there might be too much data in the cache, if we spliced out
+    # some short records and spliced in some long ones.  If so, flush
+    # the cache.
+    $self->_cache_flush;
+  }
+
+  # Yes, the return value of 'splice' *is* actually this complicated
+  wantarray ? @result : @result ? $result[-1] : undef;
+}
+
+
+# write data into the file
+# $data is the data to be written.
+# it should be written at position $pos, and should overwrite
+# exactly $len of the following bytes.  
+# Note that if length($data) > $len, the subsequent bytes will have to 
+# be moved up, and if length($data) < $len, they will have to
+# be moved down
+sub _twrite {
+  my ($self, $data, $pos, $len) = @_;
+
+  unless (defined $pos) {
+    die "\$pos was undefined in _twrite";
+  }
+
+  my $len_diff = length($data) - $len;
+
+  if ($len_diff == 0) {          # Woo-hoo!
+    my $fh = $self->{fh};
+    $self->_seekb($pos);
+    $self->_write_record($data);
+    return;                     # well, that was easy.
+  }
+
+  # the two records are of different lengths
+  # our strategy here: rewrite the tail of the file,
+  # reading ahead one buffer at a time
+  # $bufsize is required to be at least as large as the data we're overwriting
+  my $bufsize = _bufsize($len_diff);
+  my ($writepos, $readpos) = ($pos, $pos+$len);
+  my $next_block;
+  my $more_data;
+
+  # Seems like there ought to be a way to avoid the repeated code
+  # and the special case here.  The read(1) is also a little weird.
+  # Think about this.
+  do {
+    $self->_seekb($readpos);
+    my $br = read $self->{fh}, $next_block, $bufsize;
+    $more_data = read $self->{fh}, my($dummy), 1;
+    $self->_seekb($writepos);
+    $self->_write_record($data);
+    $readpos += $br;
+    $writepos += length $data;
+    $data = $next_block;
+  } while $more_data;
+  $self->_seekb($writepos);
+  $self->_write_record($next_block);
+
+  # There might be leftover data at the end of the file
+  $self->_chop_file if $len_diff < 0;
+}
+
+# _iwrite(D, S, E)
+# Insert text D at position S.
+# Let C = E-S-|D|.  If C < 0; die.  
+# Data in [S,S+C) is copied to [S+D,S+D+C) = [S+D,E).
+# Data in [S+C = E-D, E) is returned.  Data in [E, oo) is untouched.
+#
+# In a later version, don't read the entire intervening area into
+# memory at once; do the copying block by block.
+sub _iwrite {
+  my $self = shift;
+  my ($D, $s, $e) = @_;
+  my $d = length $D;
+  my $c = $e-$s-$d;
+  local *FH = $self->{fh};
+  confess "Not enough space to insert $d bytes between $s and $e"
+    if $c < 0;
+  confess "[$s,$e) is an invalid insertion range" if $e < $s;
+
+  $self->_seekb($s);
+  read FH, my $buf, $e-$s;
+
+  $D .= substr($buf, 0, $c, "");
+
+  $self->_seekb($s);
+  $self->_write_record($D);
+
+  return $buf;
+}
+
+# Like _twrite, but the data-pos-len triple may be repeated; you may
+# write several chunks.  All the writing will be done in
+# one pass.   Chunks SHALL be in ascending order and SHALL NOT overlap.
+sub _mtwrite {
+  my $self = shift;
+  my $unwritten = "";
+  my $delta = 0;
+
+  @_ % 3 == 0 
+    or die "Arguments to _mtwrite did not come in groups of three";
+
+  while (@_) {
+    my ($data, $pos, $len) = splice @_, 0, 3;
+    my $end = $pos + $len;  # The OLD end of the segment to be replaced
+    $data = $unwritten . $data;
+    $delta -= length($unwritten);
+    $unwritten  = "";
+    $pos += $delta;             # This is where the data goes now
+    my $dlen = length $data;
+    $self->_seekb($pos);
+    if ($len >= $dlen) {        # the data will fit
+      $self->_write_record($data);
+      $delta += ($dlen - $len); # everything following moves down by this much
+      $data = ""; # All the data in the buffer has been written
+    } else {                    # won't fit
+      my $writable = substr($data, 0, $len - $delta, "");
+      $self->_write_record($writable);
+      $delta += ($dlen - $len); # everything following moves down by this much
+    } 
+
+    # At this point we've written some but maybe not all of the data.
+    # There might be a gap to close up, or $data might still contain a
+    # bunch of unwritten data that didn't fit.
+    my $ndlen = length $data;
+    if ($delta == 0) {
+      $self->_write_record($data);
+    } elsif ($delta < 0) {
+      # upcopy (close up gap)
+      if (@_) {
+        $self->_upcopy($end, $end + $delta, $_[1] - $end);  
+      } else {
+        $self->_upcopy($end, $end + $delta);  
+      }
+    } else {
+      # downcopy (insert data that didn't fit; replace this data in memory
+      # with _later_ data that doesn't fit)
+      if (@_) {
+        $unwritten = $self->_downcopy($data, $end, $_[1] - $end);
+      } else {
+        # Make the file longer to accommodate the last segment that doesn'
+        $unwritten = $self->_downcopy($data, $end);
+      }
+    }
+  }
+}
+
+# Copy block of data of length $len from position $spos to position $dpos
+# $dpos must be <= $spos
+#
+# If $len is undefined, go all the way to the end of the file
+# and then truncate it ($spos - $dpos bytes will be removed)
+sub _upcopy {
+  my $blocksize = 8192;
+  my ($self, $spos, $dpos, $len) = @_;
+  if ($dpos > $spos) {
+    die "source ($spos) was upstream of destination ($dpos) in _upcopy";
+  } elsif ($dpos == $spos) {
+    return;
+  }
+  
+  while (! defined ($len) || $len > 0) {
+    my $readsize = ! defined($len) ? $blocksize
+               : $len > $blocksize ? $blocksize
+               : $len;
+      
+    my $fh = $self->{fh};
+    $self->_seekb($spos);
+    my $bytes_read = read $fh, my($data), $readsize;
+    $self->_seekb($dpos);
+    if ($data eq "") { 
+      $self->_chop_file;
+      last;
+    }
+    $self->_write_record($data);
+    $spos += $bytes_read;
+    $dpos += $bytes_read;
+    $len -= $bytes_read if defined $len;
+  }
+}
+
+# Write $data into a block of length $len at position $pos,
+# moving everything in the block forwards to make room.
+# Instead of writing the last length($data) bytes from the block
+# (because there isn't room for them any longer) return them.
+#
+# Undefined $len means 'until the end of the file'
+sub _downcopy {
+  my $blocksize = 8192;
+  my ($self, $data, $pos, $len) = @_;
+  my $fh = $self->{fh};
+
+  while (! defined $len || $len > 0) {
+    my $readsize = ! defined($len) ? $blocksize 
+      : $len > $blocksize? $blocksize : $len;
+    $self->_seekb($pos);
+    read $fh, my($old), $readsize;
+    my $last_read_was_short = length($old) < $readsize;
+    $data .= $old;
+    my $writable;
+    if ($last_read_was_short) {
+      # If last read was short, then $data now contains the entire rest
+      # of the file, so there's no need to write only one block of it
+      $writable = $data;
+      $data = "";
+    } else {
+      $writable = substr($data, 0, $readsize, "");
+    }
+    last if $writable eq "";
+    $self->_seekb($pos);
+    $self->_write_record($writable);
+    last if $last_read_was_short && $data eq "";
+    $len -= $readsize if defined $len;
+    $pos += $readsize;
+  }
+  return $data;
+}
+
+# Adjust the object data structures following an '_mtwrite'
+# Arguments are
+#  [$pos, $nrecs, @length]  items
+# indicating that $nrecs records were removed at $recpos (a record offset)
+# and replaced with records of length @length...
+# Arguments guarantee that $recpos is strictly increasing.
+# No return value
+sub _oadjust {
+  my $self = shift;
+  my $delta = 0;
+  my $delta_recs = 0;
+  my $prev_end = -1;
+  my %newkeys;
+
+  for (@_) {
+    my ($pos, $nrecs, @data) = @$_;
+    $pos += $delta_recs;
+
+    # Adjust the offsets of the records after the previous batch up
+    # to the first new one of this batch
+    for my $i ($prev_end+2 .. $pos - 1) {
+      $self->{offsets}[$i] += $delta;
+      $newkey{$i} = $i + $delta_recs;
+    }
+
+    $prev_end = $pos + @data - 1; # last record moved on this pass 
+
+    # Remove the offsets for the removed records;
+    # replace with the offsets for the inserted records
+    my @newoff = ($self->{offsets}[$pos] + $delta);
+    for my $i (0 .. $#data) {
+      my $newlen = length $data[$i];
+      push @newoff, $newoff[$i] + $newlen;
+      $delta += $newlen;
+    }
+
+    for my $i ($pos .. $pos+$nrecs-1) {
+      last if $i+1 > $#{$self->{offsets}};
+      my $oldlen = $self->{offsets}[$i+1] - $self->{offsets}[$i];
+      $delta -= $oldlen;
+    }
+
+#    # also this data has changed, so update it in the cache
+#    for (0 .. $#data) {
+#      $self->{cache}->update($pos + $_, $data[$_]);
+#    }
+#    if ($delta_recs) {
+#      my @oldkeys = grep $_ >= $pos + @data, $self->{cache}->ckeys;
+#      my @newkeys = map $_ + $delta_recs, @oldkeys;
+#      $self->{cache}->rekey(\@oldkeys, \@newkeys);
+#    }
+
+    # replace old offsets with new
+    splice @{$self->{offsets}}, $pos, $nrecs+1, @newoff;
+    # What if we just spliced out the end of the offsets table?
+    # shouldn't we clear $self->{eof}?   Test for this XXX BUG TODO
+
+    $delta_recs += @data - $nrecs; # net change in total number of records
+  }
+
+  # The trailing records at the very end of the file
+  if ($delta) {
+    for my $i ($prev_end+2 .. $#{$self->{offsets}}) {
+      $self->{offsets}[$i] += $delta;
+    }
+  }
+
+  # If we scrubbed out all known offsets, regenerate the trivial table
+  # that knows that the file does indeed start at 0.
+  $self->{offsets}[0] = 0 unless @{$self->{offsets}};
+  # If the file got longer, the offsets table is no longer complete
+  # $self->{eof} = 0 if $delta_recs > 0;
+
+  # Now there might be too much data in the cache, if we spliced out
+  # some short records and spliced in some long ones.  If so, flush
+  # the cache.
+  $self->_cache_flush;
+}
+
+# If a record does not already end with the appropriate terminator
+# string, append one.
+sub _fixrecs {
+  my $self = shift;
+  for (@_) {
+    $_ = "" unless defined $_;
+    $_ .= $self->{recsep}
+      unless substr($_, - $self->{recseplen}) eq $self->{recsep};
+  }
+}
+
+
+################################################################
+#
+# Basic read, write, and seek
+#
+
+# seek to the beginning of record #$n
+# Assumes that the offsets table is already correctly populated
+#
+# Note that $n=-1 has a special meaning here: It means the start of
+# the last known record; this may or may not be the very last record
+# in the file, depending on whether the offsets table is fully populated.
+#
+sub _seek {
+  my ($self, $n) = @_;
+  my $o = $self->{offsets}[$n];
+  defined($o)
+    or confess("logic error: undefined offset for record $n");
+  seek $self->{fh}, $o, SEEK_SET
+    or confess "Couldn't seek filehandle: $!";  # "Should never happen."
+}
+
+# seek to byte $b in the file
+sub _seekb {
+  my ($self, $b) = @_;
+  seek $self->{fh}, $b, SEEK_SET
+    or die "Couldn't seek filehandle: $!";  # "Should never happen."
+}
+
+# populate the offsets table up to the beginning of record $n
+# return the offset of record $n
+sub _fill_offsets_to {
+  my ($self, $n) = @_;
+
+  return $self->{offsets}[$n] if $self->{eof};
+
+  my $fh = $self->{fh};
+  local *OFF = $self->{offsets};
+  my $rec;
+
+  until ($#OFF >= $n) {
+    $self->_seek(-1);           # tricky -- see comment at _seek
+    $rec = $self->_read_record;
+    if (defined $rec) {
+      push @OFF, int(tell $fh);  # Tels says that int() saves memory here
+    } else {
+      $self->{eof} = 1;
+      return;                   # It turns out there is no such record
+    }
+  }
+
+  # we have now read all the records up to record n-1,
+  # so we can return the offset of record n
+  $OFF[$n];
+}
+
+sub _fill_offsets {
+  my ($self) = @_;
+
+  my $fh = $self->{fh};
+  local *OFF = $self->{offsets};
+  
+  $self->_seek(-1);           # tricky -- see comment at _seek
+
+  # Tels says that inlining read_record() would make this loop
+  # five times faster. 20030508
+  while ( defined $self->_read_record()) {
+    # int() saves us memory here
+    push @OFF, int(tell $fh);
+  }
+
+  $self->{eof} = 1;
+  $#OFF;
+}
+
+# assumes that $rec is already suitably terminated
+sub _write_record {
+  my ($self, $rec) = @_;
+  my $fh = $self->{fh};
+  local $\ = "";
+  print $fh $rec
+    or die "Couldn't write record: $!";  # "Should never happen."
+#  $self->{_written} += length($rec);
+}
+
+sub _read_record {
+  my $self = shift;
+  my $rec;
+  { local $/ = $self->{recsep};
+    my $fh = $self->{fh};
+    $rec = <$fh>;
+  }
+  return unless defined $rec;
+  if (substr($rec, -$self->{recseplen}) ne $self->{recsep}) {
+    # improperly terminated final record --- quietly fix it.
+#    my $ac = substr($rec, -$self->{recseplen});
+#    $ac =~ s/\n/\\n/g;
+    $self->{sawlastrec} = 1;
+    unless ($self->{rdonly}) {
+      local $\ = "";
+      my $fh = $self->{fh};
+      print $fh $self->{recsep};
+    }
+    $rec .= $self->{recsep};
+  }
+#  $self->{_read} += length($rec) if defined $rec;
+  $rec;
+}
+
+sub _rw_stats {
+  my $self = shift;
+  @{$self}{'_read', '_written'};
+}
+
+################################################################
+#
+# Read cache management
+
+sub _cache_flush {
+  my ($self) = @_;
+  $self->{cache}->reduce_size_to($self->{memory} - $self->{deferred_s});
+}
+
+sub _cache_too_full {
+  my $self = shift;
+  $self->{cache}->bytes + $self->{deferred_s} >= $self->{memory};
+}
+
+################################################################
+#
+# File custodial services
+#
+
+
+# We have read to the end of the file and have the offsets table
+# entirely populated.  Now we need to write a new record beyond
+# the end of the file.  We prepare for this by writing
+# empty records into the file up to the position we want
+#
+# assumes that the offsets table already contains the offset of record $n,
+# if it exists, and extends to the end of the file if not.
+sub _extend_file_to {
+  my ($self, $n) = @_;
+  $self->_seek(-1);             # position after the end of the last record
+  my $pos = $self->{offsets}[-1];
+
+  # the offsets table has one entry more than the total number of records
+  my $extras = $n - $#{$self->{offsets}};
+
+  # Todo : just use $self->{recsep} x $extras here?
+  while ($extras-- > 0) {
+    $self->_write_record($self->{recsep});
+    push @{$self->{offsets}}, int(tell $self->{fh});
+  }
+}
+
+# Truncate the file at the current position
+sub _chop_file {
+  my $self = shift;
+  truncate $self->{fh}, tell($self->{fh});
+}
+
+
+# compute the size of a buffer suitable for moving
+# all the data in a file forward $n bytes
+# ($n may be negative)
+# The result should be at least $n.
+sub _bufsize {
+  my $n = shift;
+  return 8192 if $n <= 0;
+  my $b = $n & ~8191;
+  $b += 8192 if $n & 8191;
+  $b;
+}
+
+################################################################
+#
+# Miscellaneous public methods
+#
+
+# Lock the file
+sub flock {
+  my ($self, $op) = @_;
+  unless (@_ <= 3) {
+    my $pack = ref $self;
+    croak "Usage: $pack\->flock([OPERATION])";
+  }
+  my $fh = $self->{fh};
+  $op = LOCK_EX unless defined $op;
+  my $locked = flock $fh, $op;
+  
+  if ($locked && ($op & (LOCK_EX | LOCK_SH))) {
+    # If you're locking the file, then presumably it's because
+    # there might have been a write access by another process.
+    # In that case, the read cache contents and the offsets table
+    # might be invalid, so discard them.  20030508
+    $self->{offsets} = [0];
+    $self->{cache}->empty;
+  }
+
+  $locked;
+}
+
+# Get/set autochomp option
+sub autochomp {
+  my $self = shift;
+  if (@_) {
+    my $old = $self->{autochomp};
+    $self->{autochomp} = shift;
+    $old;
+  } else {
+    $self->{autochomp};
+  }
+}
+
+# Get offset table entries; returns offset of nth record
+sub offset {
+  my ($self, $n) = @_;
+
+  if ($#{$self->{offsets}} < $n) {
+    return if $self->{eof};     # request for record beyond the end of file
+    my $o = $self->_fill_offsets_to($n);
+    # If it's still undefined, there is no such record, so return 'undef'
+    return unless defined $o;
+   }
+ 
+  $self->{offsets}[$n];
+}
+
+sub discard_offsets {
+  my $self = shift;
+  $self->{offsets} = [0];
+}
+
+################################################################
+#
+# Matters related to deferred writing
+#
+
+# Defer writes
+sub defer {
+  my $self = shift;
+  $self->_stop_autodeferring;
+  @{$self->{ad_history}} = ();
+  $self->{defer} = 1;
+}
+
+# Flush deferred writes
+#
+# This could be better optimized to write the file in one pass, instead
+# of one pass per block of records.  But that will require modifications
+# to _twrite, so I should have a good _twrite test suite first.
+sub flush {
+  my $self = shift;
+
+  $self->_flush;
+  $self->{defer} = 0;
+}
+
+sub _old_flush {
+  my $self = shift;
+  my @writable = sort {$a<=>$b} (keys %{$self->{deferred}});
+
+  while (@writable) {
+    # gather all consecutive records from the front of @writable
+    my $first_rec = shift @writable;
+    my $last_rec = $first_rec+1;
+    ++$last_rec, shift @writable while @writable && $last_rec == $writable[0];
+    --$last_rec;
+    $self->_fill_offsets_to($last_rec);
+    $self->_extend_file_to($last_rec);
+    $self->_splice($first_rec, $last_rec-$first_rec+1, 
+                   @{$self->{deferred}}{$first_rec .. $last_rec});
+  }
+
+  $self->_discard;               # clear out defered-write-cache
+}
+
+sub _flush {
+  my $self = shift;
+  my @writable = sort {$a<=>$b} (keys %{$self->{deferred}});
+  my @args;
+  my @adjust;
+
+  while (@writable) {
+    # gather all consecutive records from the front of @writable
+    my $first_rec = shift @writable;
+    my $last_rec = $first_rec+1;
+    ++$last_rec, shift @writable while @writable && $last_rec == $writable[0];
+    --$last_rec;
+    my $end = $self->_fill_offsets_to($last_rec+1);
+    if (not defined $end) {
+      $self->_extend_file_to($last_rec);
+      $end = $self->{offsets}[$last_rec];
+    }
+    my ($start) = $self->{offsets}[$first_rec];
+    push @args,
+         join("", @{$self->{deferred}}{$first_rec .. $last_rec}), # data
+         $start,                                                  # position
+         $end-$start;                                             # length
+    push @adjust, [$first_rec, # starting at this position...
+                   $last_rec-$first_rec+1,  # this many records...
+                   # are replaced with these...
+                   @{$self->{deferred}}{$first_rec .. $last_rec},
+                  ];
+  }
+
+  $self->_mtwrite(@args);  # write multiple record groups
+  $self->_discard;               # clear out defered-write-cache
+  $self->_oadjust(@adjust);
+}
+
+# Discard deferred writes and disable future deferred writes
+sub discard {
+  my $self = shift;
+  $self->_discard;
+  $self->{defer} = 0;
+}
+
+# Discard deferred writes, but retain old deferred writing mode
+sub _discard {
+  my $self = shift;
+  %{$self->{deferred}} = ();
+  $self->{deferred_s}  = 0;
+  $self->{deferred_max}  = -1;
+  $self->{cache}->set_limit($self->{memory});
+}
+
+# Deferred writing is enabled, either explicitly ($self->{defer})
+# or automatically ($self->{autodeferring})
+sub _is_deferring {
+  my $self = shift;
+  $self->{defer} || $self->{autodeferring};
+}
+
+# The largest record number of any deferred record
+sub _defer_max {
+  my $self = shift;
+  return $self->{deferred_max} if defined $self->{deferred_max};
+  my $max = -1;
+  for my $key (keys %{$self->{deferred}}) {
+    $max = $key if $key > $max;
+  }
+  $self->{deferred_max} = $max;
+  $max;
+}
+
+################################################################
+#
+# Matters related to autodeferment
+#
+
+# Get/set autodefer option
+sub autodefer {
+  my $self = shift;
+  if (@_) {
+    my $old = $self->{autodefer};
+    $self->{autodefer} = shift;
+    if ($old) {
+      $self->_stop_autodeferring;
+      @{$self->{ad_history}} = ();
+    }
+    $old;
+  } else {
+    $self->{autodefer};
+  }
+}
+
+# The user is trying to store record #$n Record that in the history,
+# and then enable (or disable) autodeferment if that seems useful.
+# Note that it's OK for $n to be a non-number, as long as the function
+# is prepared to deal with that.  Nobody else looks at the ad_history.
+#
+# Now, what does the ad_history mean, and what is this function doing?
+# Essentially, the idea is to enable autodeferring when we see that the
+# user has made three consecutive STORE calls to three consecutive records.
+# ("Three" is actually ->{autodefer_threshhold}.)
+# A STORE call for record #$n inserts $n into the autodefer history,
+# and if the history contains three consecutive records, we enable 
+# autodeferment.  An ad_history of [X, Y] means that the most recent
+# STOREs were for records X, X+1, ..., Y, in that order.  
+#
+# Inserting a nonconsecutive number erases the history and starts over.
+#
+# Performing a special operation like SPLICE erases the history.
+#
+# There's one special case: CLEAR means that CLEAR was just called.
+# In this case, we prime the history with [-2, -1] so that if the next
+# write is for record 0, autodeferring goes on immediately.  This is for
+# the common special case of "@a = (...)".
+#
+sub _annotate_ad_history {
+  my ($self, $n) = @_;
+  return unless $self->{autodefer}; # feature is disabled
+  return if $self->{defer};     # already in explicit defer mode
+  return unless $self->{offsets}[-1] >= $self->{autodefer_filelen_threshhold};
+
+  local *H = $self->{ad_history};
+  if ($n eq 'CLEAR') {
+    @H = (-2, -1);              # prime the history with fake records
+    $self->_stop_autodeferring;
+  } elsif ($n =~ /^\d+$/) {
+    if (@H == 0) {
+      @H =  ($n, $n);
+    } else {                    # @H == 2
+      if ($H[1] == $n-1) {      # another consecutive record
+        $H[1]++;
+        if ($H[1] - $H[0] + 1 >= $self->{autodefer_threshhold}) {
+          $self->{autodeferring} = 1;
+        }
+      } else {                  # nonconsecutive- erase and start over
+        @H = ($n, $n);
+        $self->_stop_autodeferring;
+      }
+    }
+  } else {                      # SPLICE or STORESIZE or some such
+    @H = ();
+    $self->_stop_autodeferring;
+  }
+}
+
+# If autodeferring was enabled, cut it out and discard the history
+sub _stop_autodeferring {
+  my $self = shift;
+  if ($self->{autodeferring}) {
+    $self->_flush;
+  }
+  $self->{autodeferring} = 0;
+}
+
+################################################################
+
+
+# This is NOT a method.  It is here for two reasons:
+#  1. To factor a fairly complicated block out of the constructor
+#  2. To provide access for the test suite, which need to be sure
+#     files are being written properly.
+sub _default_recsep {
+  my $recsep = $/;
+  if ($^O eq 'MSWin32') {       # Dos too?
+    # Windows users expect files to be terminated with \r\n
+    # But $/ is set to \n instead
+    # Note that this also transforms \n\n into \r\n\r\n.
+    # That is a feature.
+    $recsep =~ s/\n/\r\n/g;
+  }
+  $recsep;
+}
+
+# Utility function for _check_integrity
+sub _ci_warn {
+  my $msg = shift;
+  $msg =~ s/\n/\\n/g;
+  $msg =~ s/\r/\\r/g;
+  print "# $msg\n";
+}
+
+# Given a file, make sure the cache is consistent with the
+# file contents and the internal data structures are consistent with
+# each other.  Returns true if everything checks out, false if not
+#
+# The $file argument is no longer used.  It is retained for compatibility
+# with the existing test suite.
+sub _check_integrity {
+  my ($self, $file, $warn) = @_;
+  my $rsl = $self->{recseplen};
+  my $rs  = $self->{recsep};
+  my $good = 1; 
+  local *_;                     # local $_ does not work here
+  local $DIAGNOSTIC = 1;
+
+  if (not defined $rs) {
+    _ci_warn("recsep is undef!");
+    $good = 0;
+  } elsif ($rs eq "") {
+    _ci_warn("recsep is empty!");
+    $good = 0;
+  } elsif ($rsl != length $rs) {
+    my $ln = length $rs;
+    _ci_warn("recsep <$rs> has length $ln, should be $rsl");
+    $good = 0;
+  }
+
+  if (not defined $self->{offsets}[0]) {
+    _ci_warn("offset 0 is missing!");
+    $good = 0;
+
+  } elsif ($self->{offsets}[0] != 0) {
+    _ci_warn("rec 0: offset <$self->{offsets}[0]> s/b 0!");
+    $good = 0;
+  }
+
+  my $cached = 0;
+  {
+    local *F = $self->{fh};
+    seek F, 0, SEEK_SET;
+    local $. = 0;
+    local $/ = $rs;
+
+    while (<F>) {
+      my $n = $. - 1;
+      my $cached = $self->{cache}->_produce($n);
+      my $offset = $self->{offsets}[$.];
+      my $ao = tell F;
+      if (defined $offset && $offset != $ao) {
+        _ci_warn("rec $n: offset <$offset> actual <$ao>");
+        $good = 0;
+      }
+      if (defined $cached && $_ ne $cached && ! $self->{deferred}{$n}) {
+        $good = 0;
+        _ci_warn("rec $n: cached <$cached> actual <$_>");
+      }
+      if (defined $cached && substr($cached, -$rsl) ne $rs) {
+        $good = 0;
+        _ci_warn("rec $n in the cache is missing the record separator");
+      }
+      if (! defined $offset && $self->{eof}) {
+        $good = 0;
+        _ci_warn("The offset table was marked complete, but it is missing element $.");
+      }
+    }
+    if (@{$self->{offsets}} > $.+1) {
+        $good = 0;
+        my $n = @{$self->{offsets}};
+        _ci_warn("The offset table has $n items, but the file has only $.");
+    }
+
+    my $deferring = $self->_is_deferring;
+    for my $n ($self->{cache}->ckeys) {
+      my $r = $self->{cache}->_produce($n);
+      $cached += length($r);
+      next if $n+1 <= $.;         # checked this already
+      _ci_warn("spurious caching of record $n");
+      $good = 0;
+    }
+    my $b = $self->{cache}->bytes;
+    if ($cached != $b) {
+      _ci_warn("cache size is $b, should be $cached");
+      $good = 0;
+    }
+  }
+
+  # That cache has its own set of tests
+  $good = 0 unless $self->{cache}->_check_integrity;
+
+  # Now let's check the deferbuffer
+  # Unless deferred writing is enabled, it should be empty
+  if (! $self->_is_deferring && %{$self->{deferred}}) {
+    _ci_warn("deferred writing disabled, but deferbuffer nonempty");
+    $good = 0;
+  }
+
+  # Any record in the deferbuffer should *not* be present in the readcache
+  my $deferred_s = 0;
+  while (my ($n, $r) = each %{$self->{deferred}}) {
+    $deferred_s += length($r);
+    if (defined $self->{cache}->_produce($n)) {
+      _ci_warn("record $n is in the deferbuffer *and* the readcache");
+      $good = 0;
+    }
+    if (substr($r, -$rsl) ne $rs) {
+      _ci_warn("rec $n in the deferbuffer is missing the record separator");
+      $good = 0;
+    }
+  }
+
+  # Total size of deferbuffer should match internal total
+  if ($deferred_s != $self->{deferred_s}) {
+    _ci_warn("buffer size is $self->{deferred_s}, should be $deferred_s");
+    $good = 0;
+  }
+
+  # Total size of deferbuffer should not exceed the specified limit
+  if ($deferred_s > $self->{dw_size}) {
+    _ci_warn("buffer size is $self->{deferred_s} which exceeds the limit of $self->{dw_size}");
+    $good = 0;
+  }
+
+  # Total size of cached data should not exceed the specified limit
+  if ($deferred_s + $cached > $self->{memory}) {
+    my $total = $deferred_s + $cached;
+    _ci_warn("total stored data size is $total which exceeds the limit of $self->{memory}");
+    $good = 0;
+  }
+
+  # Stuff related to autodeferment
+  if (!$self->{autodefer} && @{$self->{ad_history}}) {
+    _ci_warn("autodefer is disabled, but ad_history is nonempty");
+    $good = 0;
+  }
+  if ($self->{autodeferring} && $self->{defer}) {
+    _ci_warn("both autodeferring and explicit deferring are active");
+    $good = 0;
+  }
+  if (@{$self->{ad_history}} == 0) {
+    # That's OK, no additional tests required
+  } elsif (@{$self->{ad_history}} == 2) {
+    my @non_number = grep !/^-?\d+$/, @{$self->{ad_history}};
+    if (@non_number) {
+      my $msg;
+      { local $" = ')(';
+        $msg = "ad_history contains non-numbers (@{$self->{ad_history}})";
+      }
+      _ci_warn($msg);
+      $good = 0;
+    } elsif ($self->{ad_history}[1] < $self->{ad_history}[0]) {
+      _ci_warn("ad_history has nonsensical values @{$self->{ad_history}}");
+      $good = 0;
+    }
+  } else {
+    _ci_warn("ad_history has bad length <@{$self->{ad_history}}>");
+    $good = 0;
+  }
+
+  $good;
+}
+
+################################################################
+#
+# Tie::File::Cache
+#
+# Read cache
+
+package Tie::File::Cache;
+$Tie::File::Cache::VERSION = $Tie::File::VERSION;
+use Carp ':DEFAULT', 'confess';
+
+sub HEAP () { 0 }
+sub HASH () { 1 }
+sub MAX  () { 2 }
+sub BYTES() { 3 }
+#sub STAT () { 4 } # Array with request statistics for each record
+#sub MISS () { 5 } # Total number of cache misses
+#sub REQ  () { 6 } # Total number of cache requests 
+use strict 'vars';
+
+sub new {
+  my ($pack, $max) = @_;
+  local *_;
+  croak "missing argument to ->new" unless defined $max;
+  my $self = [];
+  bless $self => $pack;
+  @$self = (Tie::File::Heap->new($self), {}, $max, 0);
+  $self;
+}
+
+sub adj_limit {
+  my ($self, $n) = @_;
+  $self->[MAX] += $n;
+}
+
+sub set_limit {
+  my ($self, $n) = @_;
+  $self->[MAX] = $n;
+}
+
+# For internal use only
+# Will be called by the heap structure to notify us that a certain 
+# piece of data has moved from one heap element to another.
+# $k is the hash key of the item
+# $n is the new index into the heap at which it is stored
+# If $n is undefined, the item has been removed from the heap.
+sub _heap_move {
+  my ($self, $k, $n) = @_;
+  if (defined $n) {
+    $self->[HASH]{$k} = $n;
+  } else {
+    delete $self->[HASH]{$k};
+  }
+}
+
+sub insert {
+  my ($self, $key, $val) = @_;
+  local *_;
+  croak "missing argument to ->insert" unless defined $key;
+  unless (defined $self->[MAX]) {
+    confess "undefined max" ;
+  }
+  confess "undefined val" unless defined $val;
+  return if length($val) > $self->[MAX];
+
+#  if ($self->[STAT]) {
+#    $self->[STAT][$key] = 1;
+#    return;
+#  }
+
+  my $oldnode = $self->[HASH]{$key};
+  if (defined $oldnode) {
+    my $oldval = $self->[HEAP]->set_val($oldnode, $val);
+    $self->[BYTES] -= length($oldval);
+  } else {
+    $self->[HEAP]->insert($key, $val);
+  }
+  $self->[BYTES] += length($val);
+  $self->flush if $self->[BYTES] > $self->[MAX];
+}
+
+sub expire {
+  my $self = shift;
+  my $old_data = $self->[HEAP]->popheap;
+  return unless defined $old_data;
+  $self->[BYTES] -= length $old_data;
+  $old_data;
+}
+
+sub remove {
+  my ($self, @keys) = @_;
+  my @result;
+
+#  if ($self->[STAT]) {
+#    for my $key (@keys) {
+#      $self->[STAT][$key] = 0;
+#    }
+#    return;
+#  }
+
+  for my $key (@keys) {
+    next unless exists $self->[HASH]{$key};
+    my $old_data = $self->[HEAP]->remove($self->[HASH]{$key});
+    $self->[BYTES] -= length $old_data;
+    push @result, $old_data;
+  }
+  @result;
+}
+
+sub lookup {
+  my ($self, $key) = @_;
+  local *_;
+  croak "missing argument to ->lookup" unless defined $key;
+
+#  if ($self->[STAT]) {
+#    $self->[MISS]++  if $self->[STAT][$key]++ == 0;
+#    $self->[REQ]++;
+#    my $hit_rate = 1 - $self->[MISS] / $self->[REQ];
+#    # Do some testing to determine this threshhold
+#    $#$self = STAT - 1 if $hit_rate > 0.20; 
+#  }
+
+  if (exists $self->[HASH]{$key}) {
+    $self->[HEAP]->lookup($self->[HASH]{$key});
+  } else {
+    return;
+  }
+}
+
+# For internal use only
+sub _produce {
+  my ($self, $key) = @_;
+  my $loc = $self->[HASH]{$key};
+  return unless defined $loc;
+  $self->[HEAP][$loc][2];
+}
+
+# For internal use only
+sub _promote {
+  my ($self, $key) = @_;
+  $self->[HEAP]->promote($self->[HASH]{$key});
+}
+
+sub empty {
+  my ($self) = @_;
+  %{$self->[HASH]} = ();
+    $self->[BYTES] = 0;
+    $self->[HEAP]->empty;
+#  @{$self->[STAT]} = ();
+#    $self->[MISS] = 0;
+#    $self->[REQ] = 0;
+}
+
+sub is_empty {
+  my ($self) = @_;
+  keys %{$self->[HASH]} == 0;
+}
+
+sub update {
+  my ($self, $key, $val) = @_;
+  local *_;
+  croak "missing argument to ->update" unless defined $key;
+  if (length($val) > $self->[MAX]) {
+    my ($oldval) = $self->remove($key);
+    $self->[BYTES] -= length($oldval) if defined $oldval;
+  } elsif (exists $self->[HASH]{$key}) {
+    my $oldval = $self->[HEAP]->set_val($self->[HASH]{$key}, $val);
+    $self->[BYTES] += length($val);
+    $self->[BYTES] -= length($oldval) if defined $oldval;
+  } else {
+    $self->[HEAP]->insert($key, $val);
+    $self->[BYTES] += length($val);
+  }
+  $self->flush;
+}
+
+sub rekey {
+  my ($self, $okeys, $nkeys) = @_;
+  local *_;
+  my %map;
+  @map{@$okeys} = @$nkeys;
+  croak "missing argument to ->rekey" unless defined $nkeys;
+  croak "length mismatch in ->rekey arguments" unless @$nkeys == @$okeys;
+  my %adjusted;                 # map new keys to heap indices
+  # You should be able to cut this to one loop TODO XXX
+  for (0 .. $#$okeys) {
+    $adjusted{$nkeys->[$_]} = delete $self->[HASH]{$okeys->[$_]};
+  }
+  while (my ($nk, $ix) = each %adjusted) {
+    # @{$self->[HASH]}{keys %adjusted} = values %adjusted;
+    $self->[HEAP]->rekey($ix, $nk);
+    $self->[HASH]{$nk} = $ix;
+  }
+}
+
+sub ckeys {
+  my $self = shift;
+  my @a = keys %{$self->[HASH]};
+  @a;
+}
+
+# Return total amount of cached data
+sub bytes {
+  my $self = shift;
+  $self->[BYTES];
+}
+
+# Expire oldest item from cache until cache size is smaller than $max
+sub reduce_size_to {
+  my ($self, $max) = @_;
+  until ($self->[BYTES] <= $max) {
+    # Note that Tie::File::Cache::expire has been inlined here
+    my $old_data = $self->[HEAP]->popheap;
+    return unless defined $old_data;
+    $self->[BYTES] -= length $old_data;
+  }
+}
+
+# Why not just $self->reduce_size_to($self->[MAX])?
+# Try this when things stabilize   TODO XXX
+# If the cache is too full, expire the oldest records
+sub flush {
+  my $self = shift;
+  $self->reduce_size_to($self->[MAX]) if $self->[BYTES] > $self->[MAX];
+}
+
+# For internal use only
+sub _produce_lru {
+  my $self = shift;
+  $self->[HEAP]->expire_order;
+}
+
+BEGIN { *_ci_warn = \&Tie::File::_ci_warn }
+
+sub _check_integrity {          # For CACHE
+  my $self = shift;
+  my $good = 1;
+
+  # Test HEAP
+  $self->[HEAP]->_check_integrity or $good = 0;
+
+  # Test HASH
+  my $bytes = 0;
+  for my $k (keys %{$self->[HASH]}) {
+    if ($k ne '0' && $k !~ /^[1-9][0-9]*$/) {
+      $good = 0;
+      _ci_warn "Cache hash key <$k> is non-numeric";
+    }
+
+    my $h = $self->[HASH]{$k};
+    if (! defined $h) {
+      $good = 0;
+      _ci_warn "Heap index number for key $k is undefined";
+    } elsif ($h == 0) {
+      $good = 0;
+      _ci_warn "Heap index number for key $k is zero";
+    } else {
+      my $j = $self->[HEAP][$h];
+      if (! defined $j) {
+        $good = 0;
+        _ci_warn "Heap contents key $k (=> $h) are undefined";
+      } else {
+        $bytes += length($j->[2]);
+        if ($k ne $j->[1]) {
+          $good = 0;
+          _ci_warn "Heap contents key $k (=> $h) is $j->[1], should be $k";
+        }
+      }
+    }
+  }
+
+  # Test BYTES
+  if ($bytes != $self->[BYTES]) {
+    $good = 0;
+    _ci_warn "Total data in cache is $bytes, expected $self->[BYTES]";
+  }
+
+  # Test MAX
+  if ($bytes > $self->[MAX]) {
+    $good = 0;
+    _ci_warn "Total data in cache is $bytes, exceeds maximum $self->[MAX]";
+  }
+
+  return $good;
+}
+
+sub delink {
+  my $self = shift;
+  $self->[HEAP] = undef;        # Bye bye heap
+}
+
+################################################################
+#
+# Tie::File::Heap
+#
+# Heap data structure for use by cache LRU routines
+
+package Tie::File::Heap;
+use Carp ':DEFAULT', 'confess';
+$Tie::File::Heap::VERSION = $Tie::File::Cache::VERSION;
+sub SEQ () { 0 };
+sub KEY () { 1 };
+sub DAT () { 2 };
+
+sub new {
+  my ($pack, $cache) = @_;
+  die "$pack: Parent cache object $cache does not support _heap_move method"
+    unless eval { $cache->can('_heap_move') };
+  my $self = [[0,$cache,0]];
+  bless $self => $pack;
+}
+
+# Allocate a new sequence number, larger than all previously allocated numbers
+sub _nseq {
+  my $self = shift;
+  $self->[0][0]++;
+}
+
+sub _cache {
+  my $self = shift;
+  $self->[0][1];
+}
+
+sub _nelts {
+  my $self = shift;
+  $self->[0][2];
+}
+
+sub _nelts_inc {
+  my $self = shift;
+  ++$self->[0][2];
+}  
+
+sub _nelts_dec {
+  my $self = shift;
+  --$self->[0][2];
+}  
+
+sub is_empty {
+  my $self = shift;
+  $self->_nelts == 0;
+}
+
+sub empty {
+  my $self = shift;
+  $#$self = 0;
+  $self->[0][2] = 0;
+  $self->[0][0] = 0;            # might as well reset the sequence numbers
+}
+
+# notify the parent cache object that we moved something
+sub _heap_move {
+  my $self = shift;
+  $self->_cache->_heap_move(@_);
+}
+
+# Insert a piece of data into the heap with the indicated sequence number.
+# The item with the smallest sequence number is always at the top.
+# If no sequence number is specified, allocate a new one and insert the
+# item at the bottom.
+sub insert {
+  my ($self, $key, $data, $seq) = @_;
+  $seq = $self->_nseq unless defined $seq;
+  $self->_insert_new([$seq, $key, $data]);
+}
+
+# Insert a new, fresh item at the bottom of the heap
+sub _insert_new {
+  my ($self, $item) = @_;
+  my $i = @$self;
+  $i = int($i/2) until defined $self->[$i/2];
+  $self->[$i] = $item;
+  $self->[0][1]->_heap_move($self->[$i][KEY], $i);
+  $self->_nelts_inc;
+}
+
+# Insert [$data, $seq] pair at or below item $i in the heap.
+# If $i is omitted, default to 1 (the top element.)
+sub _insert {
+  my ($self, $item, $i) = @_;
+#  $self->_check_loc($i) if defined $i;
+  $i = 1 unless defined $i;
+  until (! defined $self->[$i]) {
+    if ($self->[$i][SEQ] > $item->[SEQ]) { # inserted item is older
+      ($self->[$i], $item) = ($item, $self->[$i]);
+      $self->[0][1]->_heap_move($self->[$i][KEY], $i);
+    }
+    # If either is undefined, go that way.  Otherwise, choose at random
+    my $dir;
+    $dir = 0 if !defined $self->[2*$i];
+    $dir = 1 if !defined $self->[2*$i+1];
+    $dir = int(rand(2)) unless defined $dir;
+    $i = 2*$i + $dir;
+  }
+  $self->[$i] = $item;
+  $self->[0][1]->_heap_move($self->[$i][KEY], $i);
+  $self->_nelts_inc;
+}
+
+# Remove the item at node $i from the heap, moving child items upwards.
+# The item with the smallest sequence number is always at the top.
+# Moving items upwards maintains this condition.
+# Return the removed item.  Return undef if there was no item at node $i.
+sub remove {
+  my ($self, $i) = @_;
+  $i = 1 unless defined $i;
+  my $top = $self->[$i];
+  return unless defined $top;
+  while (1) {
+    my $ii;
+    my ($L, $R) = (2*$i, 2*$i+1);
+
+    # If either is undefined, go the other way.
+    # Otherwise, go towards the smallest.
+    last unless defined $self->[$L] || defined $self->[$R];
+    $ii = $R if not defined $self->[$L];
+    $ii = $L if not defined $self->[$R];
+    unless (defined $ii) {
+      $ii = $self->[$L][SEQ] < $self->[$R][SEQ] ? $L : $R;
+    }
+
+    $self->[$i] = $self->[$ii]; # Promote child to fill vacated spot
+    $self->[0][1]->_heap_move($self->[$i][KEY], $i);
+    $i = $ii; # Fill new vacated spot
+  }
+  $self->[0][1]->_heap_move($top->[KEY], undef);
+  undef $self->[$i];
+  $self->_nelts_dec;
+  return $top->[DAT];
+}
+
+sub popheap {
+  my $self = shift;
+  $self->remove(1);
+}
+
+# set the sequence number of the indicated item to a higher number
+# than any other item in the heap, and bubble the item down to the
+# bottom.
+sub promote {
+  my ($self, $n) = @_;
+#  $self->_check_loc($n);
+  $self->[$n][SEQ] = $self->_nseq;
+  my $i = $n;
+  while (1) {
+    my ($L, $R) = (2*$i, 2*$i+1);
+    my $dir;
+    last unless defined $self->[$L] || defined $self->[$R];
+    $dir = $R unless defined $self->[$L];
+    $dir = $L unless defined $self->[$R];
+    unless (defined $dir) {
+      $dir = $self->[$L][SEQ] < $self->[$R][SEQ] ? $L : $R;
+    }
+    @{$self}[$i, $dir] = @{$self}[$dir, $i];
+    for ($i, $dir) {
+      $self->[0][1]->_heap_move($self->[$_][KEY], $_) if defined $self->[$_];
+    }
+    $i = $dir;
+  }
+}
+
+# Return item $n from the heap, promoting its LRU status
+sub lookup {
+  my ($self, $n) = @_;
+#  $self->_check_loc($n);
+  my $val = $self->[$n];
+  $self->promote($n);
+  $val->[DAT];
+}
+
+
+# Assign a new value for node $n, promoting it to the bottom of the heap
+sub set_val {
+  my ($self, $n, $val) = @_;
+#  $self->_check_loc($n);
+  my $oval = $self->[$n][DAT];
+  $self->[$n][DAT] = $val;
+  $self->promote($n);
+  return $oval;
+}
+
+# The hask key has changed for an item;
+# alter the heap's record of the hash key
+sub rekey {
+  my ($self, $n, $new_key) = @_;
+#  $self->_check_loc($n);
+  $self->[$n][KEY] = $new_key;
+}
+
+sub _check_loc {
+  my ($self, $n) = @_;
+  unless (1 || defined $self->[$n]) {
+    confess "_check_loc($n) failed";
+  }
+}
+
+BEGIN { *_ci_warn = \&Tie::File::_ci_warn }
+
+sub _check_integrity {
+  my $self = shift;
+  my $good = 1;
+  my %seq;
+
+  unless (eval {$self->[0][1]->isa("Tie::File::Cache")}) {
+    _ci_warn "Element 0 of heap corrupt";
+    $good = 0;
+  }
+  $good = 0 unless $self->_satisfies_heap_condition(1);
+  for my $i (2 .. $#{$self}) {
+    my $p = int($i/2);          # index of parent node
+    if (defined $self->[$i] && ! defined $self->[$p]) {
+      _ci_warn "Element $i of heap defined, but parent $p isn't";
+      $good = 0;
+    }
+
+    if (defined $self->[$i]) {
+      if ($seq{$self->[$i][SEQ]}) {
+        my $seq = $self->[$i][SEQ];
+        _ci_warn "Nodes $i and $seq{$seq} both have SEQ=$seq";
+        $good = 0;
+      } else {
+        $seq{$self->[$i][SEQ]} = $i;
+      }
+    }
+  }
+
+  return $good;
+}
+
+sub _satisfies_heap_condition {
+  my $self = shift;
+  my $n = shift || 1;
+  my $good = 1;
+  for (0, 1) {
+    my $c = $n*2 + $_;
+    next unless defined $self->[$c];
+    if ($self->[$n][SEQ] >= $self->[$c]) {
+      _ci_warn "Node $n of heap does not predate node $c";
+      $good = 0 ;
+    }
+    $good = 0 unless $self->_satisfies_heap_condition($c);
+  }
+  return $good;
+}
+
+# Return a list of all the values, sorted by expiration order
+sub expire_order {
+  my $self = shift;
+  my @nodes = sort {$a->[SEQ] <=> $b->[SEQ]} $self->_nodes;
+  map { $_->[KEY] } @nodes;
+}
+
+sub _nodes {
+  my $self = shift;
+  my $i = shift || 1;
+  return unless defined $self->[$i];
+  ($self->[$i], $self->_nodes($i*2), $self->_nodes($i*2+1));
+}
+
+"Cogito, ergo sum.";  # don't forget to return a true value from the file
+
+__END__
+
+=head1 NAME
+
+Tie::File - Access the lines of a disk file via a Perl array
+
+=head1 SYNOPSIS
+
+	# This file documents Tie::File version 0.98
+	use Tie::File;
+
+	tie @array, 'Tie::File', filename or die ...;
+
+	$array[13] = 'blah';     # line 13 of the file is now 'blah'
+	print $array[42];        # display line 42 of the file
+
+	$n_recs = @array;        # how many records are in the file?
+	$#array -= 2;            # chop two records off the end
+
+
+	for (@array) {
+	  s/PERL/Perl/g;         # Replace PERL with Perl everywhere in the file
+	}
+
+	# These are just like regular push, pop, unshift, shift, and splice
+	# Except that they modify the file in the way you would expect
+
+	push @array, new recs...;
+	my $r1 = pop @array;
+	unshift @array, new recs...;
+	my $r2 = shift @array;
+	@old_recs = splice @array, 3, 7, new recs...;
+
+	untie @array;            # all finished
+
+
+=head1 DESCRIPTION
+
+C<Tie::File> represents a regular text file as a Perl array.  Each
+element in the array corresponds to a record in the file.  The first
+line of the file is element 0 of the array; the second line is element
+1, and so on.
+
+The file is I<not> loaded into memory, so this will work even for
+gigantic files.
+
+Changes to the array are reflected in the file immediately.
+
+Lazy people and beginners may now stop reading the manual.
+
+=head2 C<recsep>
+
+What is a 'record'?  By default, the meaning is the same as for the
+C<E<lt>...E<gt>> operator: It's a string terminated by C<$/>, which is
+probably C<"\n">.  (Minor exception: on DOS and Win32 systems, a
+'record' is a string terminated by C<"\r\n">.)  You may change the
+definition of "record" by supplying the C<recsep> option in the C<tie>
+call:
+
+	tie @array, 'Tie::File', $file, recsep => 'es';
+
+This says that records are delimited by the string C<es>.  If the file
+contained the following data:
+
+	Curse these pesky flies!\n
+
+then the C<@array> would appear to have four elements:
+
+	"Curse th"
+	"e p"
+	"ky fli"
+	"!\n"
+
+An undefined value is not permitted as a record separator.  Perl's
+special "paragraph mode" semantics (E<agrave> la C<$/ = "">) are not
+emulated.
+
+Records read from the tied array do not have the record separator
+string on the end; this is to allow
+
+	$array[17] .= "extra";
+
+to work as expected.
+
+(See L<"autochomp">, below.)  Records stored into the array will have
+the record separator string appended before they are written to the
+file, if they don't have one already.  For example, if the record
+separator string is C<"\n">, then the following two lines do exactly
+the same thing:
+
+	$array[17] = "Cherry pie";
+	$array[17] = "Cherry pie\n";
+
+The result is that the contents of line 17 of the file will be
+replaced with "Cherry pie"; a newline character will separate line 17
+from line 18.  This means that this code will do nothing:
+
+	chomp $array[17];
+
+Because the C<chomp>ed value will have the separator reattached when
+it is written back to the file.  There is no way to create a file
+whose trailing record separator string is missing.
+
+Inserting records that I<contain> the record separator string is not
+supported by this module.  It will probably produce a reasonable
+result, but what this result will be may change in a future version.
+Use 'splice' to insert records or to replace one record with several.
+
+=head2 C<autochomp>
+
+Normally, array elements have the record separator removed, so that if
+the file contains the text
+
+	Gold
+	Frankincense
+	Myrrh
+
+the tied array will appear to contain C<("Gold", "Frankincense",
+"Myrrh")>.  If you set C<autochomp> to a false value, the record
+separator will not be removed.  If the file above was tied with
+
+	tie @gifts, "Tie::File", $gifts, autochomp => 0;
+
+then the array C<@gifts> would appear to contain C<("Gold\n",
+"Frankincense\n", "Myrrh\n")>, or (on Win32 systems) C<("Gold\r\n",
+"Frankincense\r\n", "Myrrh\r\n")>.
+
+=head2 C<mode>
+
+Normally, the specified file will be opened for read and write access,
+and will be created if it does not exist.  (That is, the flags
+C<O_RDWR | O_CREAT> are supplied in the C<open> call.)  If you want to
+change this, you may supply alternative flags in the C<mode> option.
+See L<Fcntl> for a listing of available flags.
+For example:
+
+	# open the file if it exists, but fail if it does not exist
+	use Fcntl 'O_RDWR';
+	tie @array, 'Tie::File', $file, mode => O_RDWR;
+
+	# create the file if it does not exist
+	use Fcntl 'O_RDWR', 'O_CREAT';
+	tie @array, 'Tie::File', $file, mode => O_RDWR | O_CREAT;
+
+	# open an existing file in read-only mode
+	use Fcntl 'O_RDONLY';
+	tie @array, 'Tie::File', $file, mode => O_RDONLY;
+
+Opening the data file in write-only or append mode is not supported.
+
+=head2 C<memory>
+
+This is an upper limit on the amount of memory that C<Tie::File> will
+consume at any time while managing the file.  This is used for two
+things: managing the I<read cache> and managing the I<deferred write
+buffer>.
+
+Records read in from the file are cached, to avoid having to re-read
+them repeatedly.  If you read the same record twice, the first time it
+will be stored in memory, and the second time it will be fetched from
+the I<read cache>.  The amount of data in the read cache will not
+exceed the value you specified for C<memory>.  If C<Tie::File> wants
+to cache a new record, but the read cache is full, it will make room
+by expiring the least-recently visited records from the read cache.
+
+The default memory limit is 2Mib.  You can adjust the maximum read
+cache size by supplying the C<memory> option.  The argument is the
+desired cache size, in bytes.
+
+	# I have a lot of memory, so use a large cache to speed up access
+	tie @array, 'Tie::File', $file, memory => 20_000_000;
+
+Setting the memory limit to 0 will inhibit caching; records will be
+fetched from disk every time you examine them.
+
+The C<memory> value is not an absolute or exact limit on the memory
+used.  C<Tie::File> objects contains some structures besides the read
+cache and the deferred write buffer, whose sizes are not charged
+against C<memory>. 
+
+The cache itself consumes about 310 bytes per cached record, so if
+your file has many short records, you may want to decrease the cache
+memory limit, or else the cache overhead may exceed the size of the
+cached data.
+
+
+=head2 C<dw_size>
+
+(This is an advanced feature.  Skip this section on first reading.)
+
+If you use deferred writing (See L<"Deferred Writing">, below) then
+data you write into the array will not be written directly to the
+file; instead, it will be saved in the I<deferred write buffer> to be
+written out later.  Data in the deferred write buffer is also charged
+against the memory limit you set with the C<memory> option.
+
+You may set the C<dw_size> option to limit the amount of data that can
+be saved in the deferred write buffer.  This limit may not exceed the
+total memory limit.  For example, if you set C<dw_size> to 1000 and
+C<memory> to 2500, that means that no more than 1000 bytes of deferred
+writes will be saved up.  The space available for the read cache will
+vary, but it will always be at least 1500 bytes (if the deferred write
+buffer is full) and it could grow as large as 2500 bytes (if the
+deferred write buffer is empty.)
+
+If you don't specify a C<dw_size>, it defaults to the entire memory
+limit.
+
+=head2 Option Format
+
+C<-mode> is a synonym for C<mode>.  C<-recsep> is a synonym for
+C<recsep>.  C<-memory> is a synonym for C<memory>.  You get the
+idea.
+
+=head1 Public Methods
+
+The C<tie> call returns an object, say C<$o>.  You may call
+
+	$rec = $o->FETCH($n);
+	$o->STORE($n, $rec);
+
+to fetch or store the record at line C<$n>, respectively; similarly
+the other tied array methods.  (See L<perltie> for details.)  You may
+also call the following methods on this object:
+
+=head2 C<flock>
+
+	$o->flock(MODE)
+
+will lock the tied file.  C<MODE> has the same meaning as the second
+argument to the Perl built-in C<flock> function; for example
+C<LOCK_SH> or C<LOCK_EX | LOCK_NB>.  (These constants are provided by
+the C<use Fcntl ':flock'> declaration.)
+
+C<MODE> is optional; the default is C<LOCK_EX>.
+
+C<Tie::File> maintains an internal table of the byte offset of each
+record it has seen in the file.  
+
+When you use C<flock> to lock the file, C<Tie::File> assumes that the
+read cache is no longer trustworthy, because another process might
+have modified the file since the last time it was read.  Therefore, a
+successful call to C<flock> discards the contents of the read cache
+and the internal record offset table.
+
+C<Tie::File> promises that the following sequence of operations will
+be safe:
+
+	my $o = tie @array, "Tie::File", $filename;
+	$o->flock;
+
+In particular, C<Tie::File> will I<not> read or write the file during
+the C<tie> call.  (Exception: Using C<mode =E<gt> O_TRUNC> will, of
+course, erase the file during the C<tie> call.  If you want to do this
+safely, then open the file without C<O_TRUNC>, lock the file, and use
+C<@array = ()>.)
+
+The best way to unlock a file is to discard the object and untie the
+array.  It is probably unsafe to unlock the file without also untying
+it, because if you do, changes may remain unwritten inside the object.
+That is why there is no shortcut for unlocking.  If you really want to
+unlock the file prematurely, you know what to do; if you don't know
+what to do, then don't do it.
+
+All the usual warnings about file locking apply here.  In particular,
+note that file locking in Perl is B<advisory>, which means that
+holding a lock will not prevent anyone else from reading, writing, or
+erasing the file; it only prevents them from getting another lock at
+the same time.  Locks are analogous to green traffic lights: If you
+have a green light, that does not prevent the idiot coming the other
+way from plowing into you sideways; it merely guarantees to you that
+the idiot does not also have a green light at the same time.
+
+=head2 C<autochomp>
+
+	my $old_value = $o->autochomp(0);    # disable autochomp option
+	my $old_value = $o->autochomp(1);    #  enable autochomp option
+
+	my $ac = $o->autochomp();   # recover current value
+
+See L<"autochomp">, above.
+
+=head2 C<defer>, C<flush>, C<discard>, and C<autodefer>
+
+See L<"Deferred Writing">, below.
+
+=head2 C<offset>
+
+	$off = $o->offset($n);
+
+This method returns the byte offset of the start of the C<$n>th record
+in the file.  If there is no such record, it returns an undefined
+value.
+
+=head1 Tying to an already-opened filehandle
+
+If C<$fh> is a filehandle, such as is returned by C<IO::File> or one
+of the other C<IO> modules, you may use:
+
+	tie @array, 'Tie::File', $fh, ...;
+
+Similarly if you opened that handle C<FH> with regular C<open> or
+C<sysopen>, you may use:
+
+	tie @array, 'Tie::File', \*FH, ...;
+
+Handles that were opened write-only won't work.  Handles that were
+opened read-only will work as long as you don't try to modify the
+array.  Handles must be attached to seekable sources of data---that
+means no pipes or sockets.  If C<Tie::File> can detect that you
+supplied a non-seekable handle, the C<tie> call will throw an
+exception.  (On Unix systems, it can detect this.)
+
+Note that Tie::File will only close any filehandles that it opened
+internally.  If you passed it a filehandle as above, you "own" the
+filehandle, and are responsible for closing it after you have untied
+the @array.
+
+=head1 Deferred Writing
+
+(This is an advanced feature.  Skip this section on first reading.)
+
+Normally, modifying a C<Tie::File> array writes to the underlying file
+immediately.  Every assignment like C<$a[3] = ...> rewrites as much of
+the file as is necessary; typically, everything from line 3 through
+the end will need to be rewritten.  This is the simplest and most
+transparent behavior.  Performance even for large files is reasonably
+good.
+
+However, under some circumstances, this behavior may be excessively
+slow.  For example, suppose you have a million-record file, and you
+want to do:
+
+	for (@FILE) {
+	  $_ = "> $_";
+	}
+
+The first time through the loop, you will rewrite the entire file,
+from line 0 through the end.  The second time through the loop, you
+will rewrite the entire file from line 1 through the end.  The third
+time through the loop, you will rewrite the entire file from line 2 to
+the end.  And so on.
+
+If the performance in such cases is unacceptable, you may defer the
+actual writing, and then have it done all at once.  The following loop
+will perform much better for large files:
+
+	(tied @a)->defer;
+	for (@a) {
+	  $_ = "> $_";
+	}
+	(tied @a)->flush;
+
+If C<Tie::File>'s memory limit is large enough, all the writing will
+done in memory.  Then, when you call C<-E<gt>flush>, the entire file
+will be rewritten in a single pass.
+
+(Actually, the preceding discussion is something of a fib.  You don't
+need to enable deferred writing to get good performance for this
+common case, because C<Tie::File> will do it for you automatically
+unless you specifically tell it not to.  See L<"autodeferring">,
+below.)
+
+Calling C<-E<gt>flush> returns the array to immediate-write mode.  If
+you wish to discard the deferred writes, you may call C<-E<gt>discard>
+instead of C<-E<gt>flush>.  Note that in some cases, some of the data
+will have been written already, and it will be too late for
+C<-E<gt>discard> to discard all the changes.  Support for
+C<-E<gt>discard> may be withdrawn in a future version of C<Tie::File>.
+
+Deferred writes are cached in memory up to the limit specified by the
+C<dw_size> option (see above).  If the deferred-write buffer is full
+and you try to write still more deferred data, the buffer will be
+flushed.  All buffered data will be written immediately, the buffer
+will be emptied, and the now-empty space will be used for future
+deferred writes.
+
+If the deferred-write buffer isn't yet full, but the total size of the
+buffer and the read cache would exceed the C<memory> limit, the oldest
+records will be expired from the read cache until the total size is
+under the limit.
+
+C<push>, C<pop>, C<shift>, C<unshift>, and C<splice> cannot be
+deferred.  When you perform one of these operations, any deferred data
+is written to the file and the operation is performed immediately.
+This may change in a future version.
+
+If you resize the array with deferred writing enabled, the file will
+be resized immediately, but deferred records will not be written.
+This has a surprising consequence: C<@a = (...)> erases the file
+immediately, but the writing of the actual data is deferred.  This
+might be a bug.  If it is a bug, it will be fixed in a future version.
+
+=head2 Autodeferring
+
+C<Tie::File> tries to guess when deferred writing might be helpful,
+and to turn it on and off automatically. 
+
+	for (@a) {
+	  $_ = "> $_";
+	}
+
+In this example, only the first two assignments will be done
+immediately; after this, all the changes to the file will be deferred
+up to the user-specified memory limit.
+
+You should usually be able to ignore this and just use the module
+without thinking about deferring.  However, special applications may
+require fine control over which writes are deferred, or may require
+that all writes be immediate.  To disable the autodeferment feature,
+use
+
+	(tied @o)->autodefer(0);
+
+or
+
+       	tie @array, 'Tie::File', $file, autodefer => 0;
+
+
+Similarly, C<-E<gt>autodefer(1)> re-enables autodeferment, and 
+C<-E<gt>autodefer()> recovers the current value of the autodefer setting.
+
+
+=head1 CONCURRENT ACCESS TO FILES
+
+Caching and deferred writing are inappropriate if you want the same
+file to be accessed simultaneously from more than one process.  Other
+optimizations performed internally by this module are also
+incompatible with concurrent access.  A future version of this module will
+support a C<concurrent =E<gt> 1> option that enables safe concurrent access.
+
+Previous versions of this documentation suggested using C<memory
+=E<gt> 0> for safe concurrent access.  This was mistaken.  Tie::File
+will not support safe concurrent access before version 0.96.
+
+=head1 CAVEATS
+
+(That's Latin for 'warnings'.)
+
+=over 4
+
+=item *
+
+Reasonable effort was made to make this module efficient.  Nevertheless,
+changing the size of a record in the middle of a large file will
+always be fairly slow, because everything after the new record must be
+moved.
+
+=item *
+
+The behavior of tied arrays is not precisely the same as for regular
+arrays.  For example:
+
+	# This DOES print "How unusual!"
+	undef $a[10];  print "How unusual!\n" if defined $a[10];
+
+C<undef>-ing a C<Tie::File> array element just blanks out the
+corresponding record in the file.  When you read it back again, you'll
+get the empty string, so the supposedly-C<undef>'ed value will be
+defined.  Similarly, if you have C<autochomp> disabled, then
+
+	# This DOES print "How unusual!" if 'autochomp' is disabled
+	undef $a[10];
+        print "How unusual!\n" if $a[10];
+
+Because when C<autochomp> is disabled, C<$a[10]> will read back as
+C<"\n"> (or whatever the record separator string is.)  
+
+There are other minor differences, particularly regarding C<exists>
+and C<delete>, but in general, the correspondence is extremely close.
+
+=item *
+
+I have supposed that since this module is concerned with file I/O,
+almost all normal use of it will be heavily I/O bound.  This means
+that the time to maintain complicated data structures inside the
+module will be dominated by the time to actually perform the I/O.
+When there was an opportunity to spend CPU time to avoid doing I/O, I
+usually tried to take it.
+
+=item *
+
+You might be tempted to think that deferred writing is like
+transactions, with C<flush> as C<commit> and C<discard> as
+C<rollback>, but it isn't, so don't.
+
+=item *
+
+There is a large memory overhead for each record offset and for each
+cache entry: about 310 bytes per cached data record, and about 21 bytes per offset table entry.
+
+The per-record overhead will limit the maximum number of records you
+can access per file. Note that I<accessing> the length of the array
+via C<$x = scalar @tied_file> accesses B<all> records and stores their
+offsets.  The same for C<foreach (@tied_file)>, even if you exit the
+loop early.
+
+=back
+
+=head1 SUBCLASSING
+
+This version promises absolutely nothing about the internals, which
+may change without notice.  A future version of the module will have a
+well-defined and stable subclassing API.
+
+=head1 WHAT ABOUT C<DB_File>?
+
+People sometimes point out that L<DB_File> will do something similar,
+and ask why C<Tie::File> module is necessary.
+
+There are a number of reasons that you might prefer C<Tie::File>.
+A list is available at C<http://perl.plover.com/TieFile/why-not-DB_File>.
+
+=head1 AUTHOR
+
+Mark Jason Dominus
+
+To contact the author, send email to: C<mjd-perl-tiefile+@plover.com>
+
+To receive an announcement whenever a new version of this module is
+released, send a blank email message to
+C<mjd-perl-tiefile-subscribe@plover.com>.
+
+The most recent version of this module, including documentation and
+any news of importance, will be available at
+
+	http://perl.plover.com/TieFile/
+
+
+=head1 LICENSE
+
+C<Tie::File> version 0.96 is copyright (C) 2003 Mark Jason Dominus.
+
+This library is free software; you may redistribute it and/or modify
+it under the same terms as Perl itself.
+
+These terms are your choice of any of (1) the Perl Artistic Licence,
+or (2) version 2 of the GNU General Public License as published by the
+Free Software Foundation, or (3) any later version of the GNU General
+Public License.
+
+This library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this library program; it should be in the file C<COPYING>.
+If not, write to the Free Software Foundation, Inc., 51 Franklin Street,
+Fifth Floor, Boston, MA  02110-1301, USA
+
+For licensing inquiries, contact the author at:
+
+	Mark Jason Dominus
+	255 S. Warnock St.
+	Philadelphia, PA 19107
+
+=head1 WARRANTY
+
+C<Tie::File> version 0.98 comes with ABSOLUTELY NO WARRANTY.
+For details, see the license.
+
+=head1 THANKS
+
+Gigantic thanks to Jarkko Hietaniemi, for agreeing to put this in the
+core when I hadn't written it yet, and for generally being helpful,
+supportive, and competent.  (Usually the rule is "choose any one.")
+Also big thanks to Abhijit Menon-Sen for all of the same things.
+
+Special thanks to Craig Berry and Peter Prymmer (for VMS portability
+help), Randy Kobes (for Win32 portability help), Clinton Pierce and
+Autrijus Tang (for heroic eleventh-hour Win32 testing above and beyond
+the call of duty), Michael G Schwern (for testing advice), and the
+rest of the CPAN testers (for testing generally).
+
+Special thanks to Tels for suggesting several speed and memory
+optimizations.
+
+Additional thanks to:
+Edward Avis /
+Mattia Barbon /
+Tom Christiansen /
+Gerrit Haase /
+Gurusamy Sarathy /
+Jarkko Hietaniemi (again) /
+Nikola Knezevic /
+John Kominetz /
+Nick Ing-Simmons /
+Tassilo von Parseval /
+H. Dieter Pearcey /
+Slaven Rezic /
+Eric Roode /
+Peter Scott /
+Peter Somu /
+Autrijus Tang (again) /
+Tels (again) /
+Juerd Waalboer /
+Todd Rinaldo
+
+=head1 TODO
+
+More tests.  (Stuff I didn't think of yet.)
+
+Paragraph mode?
+
+Fixed-length mode.  Leave-blanks mode.
+
+Maybe an autolocking mode?
+
+For many common uses of the module, the read cache is a liability.
+For example, a program that inserts a single record, or that scans the
+file once, will have a cache hit rate of zero.  This suggests a major
+optimization: The cache should be initially disabled.  Here's a hybrid
+approach: Initially, the cache is disabled, but the cache code
+maintains statistics about how high the hit rate would be *if* it were
+enabled.  When it sees the hit rate get high enough, it enables
+itself.  The STAT comments in this code are the beginning of an
+implementation of this.
+
+Record locking with fcntl()?  Then the module might support an undo
+log and get real transactions.  What a tour de force that would be.
+
+Keeping track of the highest cached record. This would allow reads-in-a-row
+to skip the cache lookup faster (if reading from 1..N with empty cache at
+start, the last cached value will be always N-1).
+
+More tests.
+
+=cut
+
diff --git a/dist/Tie-File/t/00_version.t b/dist/Tie-File/t/00_version.t
new file mode 100644
index 0000000000..84f326d750
--- /dev/null
+++ b/dist/Tie-File/t/00_version.t
@@ -0,0 +1,22 @@
+#!/usr/bin/perl
+
+print "1..1\n";
+
+my $testversion = "0.98";
+use Tie::File;
+
+if ($Tie::File::VERSION != $testversion) {
+  print STDERR "
+
+*** WHOA THERE!!! ***
+
+You seem to be running version $Tie::File::VERSION of the module
+against version $testversion of the test suite!
+
+None of the other test results will be reliable.
+";
+  exit 1;
+}
+
+print "ok 1\n";
+
diff --git a/dist/Tie-File/t/01_gen.t b/dist/Tie-File/t/01_gen.t
new file mode 100644
index 0000000000..202b09c76a
--- /dev/null
+++ b/dist/Tie-File/t/01_gen.t
@@ -0,0 +1,165 @@
+#!/usr/bin/perl
+
+$| = 1;
+my $file = "tf$$.txt";
+1 while unlink $file;
+
+print "1..75\n";
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;
+
+my $o = tie @a, 'Tie::File', $file, autochomp => 0, autodefer => 0;
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+$: = $o->{recsep};
+
+# 3-5 create
+$a[0] = 'rec0';
+check_contents("rec0");
+
+# 6-11 append
+$a[1] = 'rec1';
+check_contents("rec0", "rec1");
+$a[2] = 'rec2';
+check_contents("rec0", "rec1", "rec2");
+
+# 12-20 same-length alterations
+$a[0] = 'new0';
+check_contents("new0", "rec1", "rec2");
+$a[1] = 'new1';
+check_contents("new0", "new1", "rec2");
+$a[2] = 'new2';
+check_contents("new0", "new1", "new2");
+
+# 21-35 lengthening alterations
+$a[0] = 'long0';
+check_contents("long0", "new1", "new2");
+$a[1] = 'long1';
+check_contents("long0", "long1", "new2");
+$a[2] = 'long2';
+check_contents("long0", "long1", "long2");
+$a[1] = 'longer1';
+check_contents("long0", "longer1", "long2");
+$a[0] = 'longer0';
+check_contents("longer0", "longer1", "long2");
+
+# 36-50 shortening alterations, including truncation
+$a[0] = 'short0';
+check_contents("short0", "longer1", "long2");
+$a[1] = 'short1';
+check_contents("short0", "short1", "long2");
+$a[2] = 'short2';
+check_contents("short0", "short1", "short2");
+$a[1] = 'sh1';
+check_contents("short0", "sh1", "short2");
+$a[0] = 'sh0';
+check_contents("sh0", "sh1", "short2");
+
+# (51-56) file with holes
+$a[4] = 'rec4';
+check_contents("sh0", "sh1", "short2", "", "rec4");
+$a[3] = 'rec3';
+check_contents("sh0", "sh1", "short2", "rec3", "rec4");
+
+# (57-59) zero out file
+@a = ();
+check_contents();
+
+# (60-62) insert into the middle of an empty file
+$a[3] = "rec3";
+check_contents("", "", "", "rec3");
+
+# (63-68) 20020326 You thought there would be a bug in STORE where if
+# a cached record was false, STORE wouldn't see it at all.  But you
+# forgot that records always come back from the cache with the record
+# separator attached, so they are unlikely to be false.  The only
+# really weird case is when the cached record is empty and the record
+# separator is "0".  Test that in 09_gen_rs.t.
+$a[1] = "0";
+check_contents("", "0", "", "rec3");
+$a[1] = "whoops";
+check_contents("", "whoops", "", "rec3");
+
+# (69-72) make sure that undefs are treated correctly---they should 
+# be converted to empty records, and should not raise any warnings.
+# (Some of these failed in 0.90.  The change to _fixrec fixed them.)
+# 20020331
+{
+  my $good = 1; my $warn;
+  # If any of these raise warnings, we have a problem.
+  local $SIG{__WARN__} = sub { $good = 0; $warn = shift(); ctrlfix($warn)};
+  local $^W = 1;
+  @a = (1);
+  $a[0] = undef;
+  print $good ? "ok $N\n" : "not ok $N # $warn\n";
+  $N++; $good = 1;
+  print defined($a[0]) ? "ok $N\n" : "not ok $N\n";
+  $N++; $good = 1;
+  $a[3] = '3';
+  print defined($a[1]) ? "ok $N\n" : "not ok $N\n";
+  $N++; $good = 1;
+  undef $a[3];
+  print $good ? "ok $N\n" : "not ok $N # $warn\n";
+  $N++; $good = 1;
+}
+
+# (73-75) What if the user has tampered with $\ ?
+{ {  local $\ = "stop messing with the funny variables!";
+     @a = (0..2);
+   }
+  check_contents(0..2);
+}
+
+use POSIX 'SEEK_SET';
+sub check_contents {
+  my @c = @_;
+  my $x = join $:, @c, '';
+  local *FH = $o->{fh};
+  seek FH, 0, SEEK_SET;
+#  my $open = open FH, "< $file";
+  my $a;
+  { local $/; $a = <FH> }
+  $a = "" unless defined $a;
+  if ($a eq $x) {
+    print "ok $N\n";
+  } else {
+    ctrlfix($a, $x);
+    print "not ok $N\n# expected <$x>, got <$a>\n";
+  }
+  $N++;
+
+  # now check FETCH:
+  my $good = 1;
+  my $msg;
+  for (0.. $#c) {
+    my $aa = $a[$_];
+    unless ($aa eq "$c[$_]$:") {
+      $msg = "expected <$c[$_]$:>, got <$aa>";
+      ctrlfix($msg);
+      $good = 0;
+    }
+  }
+  print $good ? "ok $N\n" : "not ok $N # $msg\n";
+  $N++;
+
+  print $o->_check_integrity($file, $ENV{INTEGRITY}) 
+      ? "ok $N\n" : "not ok $N\n";
+  $N++;
+}
+
+sub ctrlfix {
+  for (@_) {
+    s/\n/\\n/g;
+    s/\r/\\r/g;
+  }
+}
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
diff --git a/dist/Tie-File/t/02_fetchsize.t b/dist/Tie-File/t/02_fetchsize.t
new file mode 100644
index 0000000000..12d2b51cba
--- /dev/null
+++ b/dist/Tie-File/t/02_fetchsize.t
@@ -0,0 +1,53 @@
+#!/usr/bin/perl
+
+my $file = "tf$$.txt";
+$: = Tie::File::_default_recsep();
+my $data = "rec1$:rec2$:rec3$:";
+
+print "1..6\n";
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;
+
+open F, "> $file" or die $!;
+binmode F;
+print F $data;
+close F;
+
+
+my $o = tie @a, 'Tie::File', $file, autochomp => 0;
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+$: = $o->{recsep};
+
+my $n;
+
+# 3  test array element count
+$n = @a;
+print $n == 3 ? "ok $N\n" : "not ok $N # n=$n\n";
+$N++;
+
+# 4 same thing again   
+$n = @a;
+print $n == 3 ? "ok $N\n" : "not ok $N # n=$n\n";
+$N++;
+
+# 5  test $#a notation
+$n = $#a;
+print $n == 2 ? "ok $N\n" : "not ok $N # n=$n\n";
+$N++;
+
+# 6  test looping over array elements
+my $q;
+for (@a) { $q .= $_ }
+print $q eq $data ? "ok $N\n" : "not ok $N # n=$n\n";
+$N++;
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
diff --git a/dist/Tie-File/t/03_longfetch.t b/dist/Tie-File/t/03_longfetch.t
new file mode 100644
index 0000000000..7d5a3886fe
--- /dev/null
+++ b/dist/Tie-File/t/03_longfetch.t
@@ -0,0 +1,54 @@
+#!/usr/bin/perl
+#
+# Make sure we can fetch a record in the middle of the file
+# before we've ever looked at any records before it
+#
+# Make sure fetching past the end of the file returns the undefined value
+#
+# (tests _fill_offsets_to() )
+#
+
+my $file = "tf$$.txt";
+$: = Tie::File::_default_recsep();
+my $data = "rec0$:rec1$:rec2$:";
+
+print "1..8\n";
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;
+
+open F, "> $file" or die $!;
+binmode F;
+print F $data;
+close F;
+
+
+my $o = tie @a, 'Tie::File', $file, autochomp => 0;
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+$: = $o->{recsep};
+
+my $n;
+
+# 3-5
+for (2, 1, 0) {
+  my $rec = $a[$_];
+  print $rec eq "rec$_$:" ? "ok $N\n" : "not ok $N # rec=<$rec> ?\n";
+  $N++;
+}
+
+# 6-8
+for (3, 4, 6) {
+  my $rec = $a[$_];
+  print ((not defined $rec) ? "ok $N\n" : "not ok $N # rec=<$rec> is defined\n");
+  $N++;
+}
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
diff --git a/dist/Tie-File/t/04_splice.t b/dist/Tie-File/t/04_splice.t
new file mode 100644
index 0000000000..b3880b758c
--- /dev/null
+++ b/dist/Tie-File/t/04_splice.t
@@ -0,0 +1,264 @@
+#!/usr/bin/perl
+
+#
+# Check SPLICE function's effect on the file
+# (07_rv_splice.t checks its return value)
+#
+# Each call to 'check_contents' actually performs two tests.
+# First, it calls the tied object's own 'check_integrity' method,
+# which makes sure that the contents of the read cache and offset tables
+# accurately reflect the contents of the file.  
+# Then, it checks the actual contents of the file against the expected
+# contents.
+
+
+$| = 1;
+my $file = "tf$$.txt";
+$: = Tie::File::_default_recsep();
+my $data = "rec0$:rec1$:rec2$:";
+print "1..118\n";
+
+init_file($data);
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;  # partial credit just for showing up
+
+my $o = tie @a, 'Tie::File', $file;
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+$: = $o->{recsep};
+my $n;
+
+# (3-22) splicing at the beginning
+splice(@a, 0, 0, "rec4");
+check_contents("rec4$:$data");
+splice(@a, 0, 1, "rec5");       # same length
+check_contents("rec5$:$data");
+splice(@a, 0, 1, "record5");    # longer
+check_contents("record5$:$data");
+
+splice(@a, 0, 1, "r5");         # shorter
+check_contents("r5$:$data");
+splice(@a, 0, 1);               # removal
+check_contents("$data");
+splice(@a, 0, 0);               # no-op
+check_contents("$data");
+splice(@a, 0, 0, 'r7', 'rec8'); # insert more than one
+check_contents("r7$:rec8$:$data");
+splice(@a, 0, 2, 'rec7', 'record8', 'rec9'); # insert more than delete
+check_contents("rec7$:record8$:rec9$:$data");
+
+splice(@a, 0, 3, 'record9', 'rec10'); # delete more than insert
+check_contents("record9$:rec10$:$data");
+splice(@a, 0, 2);               # delete more than one
+check_contents("$data");
+
+
+# (23-42) splicing in the middle
+splice(@a, 1, 0, "rec4");
+check_contents("rec0$:rec4$:rec1$:rec2$:");
+splice(@a, 1, 1, "rec5");       # same length
+check_contents("rec0$:rec5$:rec1$:rec2$:");
+splice(@a, 1, 1, "record5");    # longer
+check_contents("rec0$:record5$:rec1$:rec2$:");
+
+splice(@a, 1, 1, "r5");         # shorter
+check_contents("rec0$:r5$:rec1$:rec2$:");
+splice(@a, 1, 1);               # removal
+check_contents("$data");
+splice(@a, 1, 0);               # no-op
+check_contents("$data");
+splice(@a, 1, 0, 'r7', 'rec8'); # insert more than one
+check_contents("rec0$:r7$:rec8$:rec1$:rec2$:");
+splice(@a, 1, 2, 'rec7', 'record8', 'rec9'); # insert more than delete
+check_contents("rec0$:rec7$:record8$:rec9$:rec1$:rec2$:");
+
+splice(@a, 1, 3, 'record9', 'rec10'); # delete more than insert
+check_contents("rec0$:record9$:rec10$:rec1$:rec2$:");
+splice(@a, 1, 2);               # delete more than one
+check_contents("$data");
+
+# (43-62) splicing at the end
+splice(@a, 3, 0, "rec4");
+check_contents("$ {data}rec4$:");
+splice(@a, 3, 1, "rec5");       # same length
+check_contents("$ {data}rec5$:");
+splice(@a, 3, 1, "record5");    # longer
+check_contents("$ {data}record5$:");
+
+splice(@a, 3, 1, "r5");         # shorter
+check_contents("$ {data}r5$:");
+splice(@a, 3, 1);               # removal
+check_contents("$data");
+splice(@a, 3, 0);               # no-op
+check_contents("$data");
+splice(@a, 3, 0, 'r7', 'rec8'); # insert more than one
+check_contents("$ {data}r7$:rec8$:");
+splice(@a, 3, 2, 'rec7', 'record8', 'rec9'); # insert more than delete
+check_contents("$ {data}rec7$:record8$:rec9$:");
+
+splice(@a, 3, 3, 'record9', 'rec10'); # delete more than insert
+check_contents("$ {data}record9$:rec10$:");
+splice(@a, 3, 2);               # delete more than one
+check_contents("$data");
+
+# (63-82) splicing with negative subscript
+splice(@a, -1, 0, "rec4");
+check_contents("rec0$:rec1$:rec4$:rec2$:");
+splice(@a, -1, 1, "rec5");       # same length
+check_contents("rec0$:rec1$:rec4$:rec5$:");
+splice(@a, -1, 1, "record5");    # longer
+check_contents("rec0$:rec1$:rec4$:record5$:");
+
+splice(@a, -1, 1, "r5");         # shorter
+check_contents("rec0$:rec1$:rec4$:r5$:");
+splice(@a, -1, 1);               # removal
+check_contents("rec0$:rec1$:rec4$:");
+splice(@a, -1, 0);               # no-op  
+check_contents("rec0$:rec1$:rec4$:");
+splice(@a, -1, 0, 'r7', 'rec8'); # insert more than one
+check_contents("rec0$:rec1$:r7$:rec8$:rec4$:");
+splice(@a, -1, 2, 'rec7', 'record8', 'rec9'); # insert more than delete
+check_contents("rec0$:rec1$:r7$:rec8$:rec7$:record8$:rec9$:");
+
+splice(@a, -3, 3, 'record9', 'rec10'); # delete more than insert
+check_contents("rec0$:rec1$:r7$:rec8$:record9$:rec10$:");
+splice(@a, -4, 3);               # delete more than one
+check_contents("rec0$:rec1$:rec10$:");
+
+# (83-84) scrub it all out
+splice(@a, 0, 3);
+check_contents("");
+
+# (85-86) put some back in
+splice(@a, 0, 0, "rec0", "rec1");
+check_contents("rec0$:rec1$:");
+
+# (87-88) what if we remove too many records?
+splice(@a, 0, 17);
+check_contents("");
+
+# (89-92) In the past, splicing past the end was not correctly detected
+# (1.14)
+splice(@a, 89, 3);
+check_contents("");
+splice(@a, @a, 3);
+check_contents("");
+
+# (93-96) Also we did not emulate splice's freaky behavior when inserting
+# past the end of the array (1.14)
+splice(@a, 89, 0, "I", "like", "pie");
+check_contents("I$:like$:pie$:");
+splice(@a, 89, 0, "pie pie pie");
+check_contents("I$:like$:pie$:pie pie pie$:");
+
+# (97) Splicing with too large a negative number should be fatal
+# This test ignored because it causes 5.6.1 and 5.7.3 to dump core
+# It also garbles the stack under 5.005_03 (20020401)
+# NOT MY FAULT
+if ($] > 5.007003) {
+  eval { splice(@a, -7, 0) };
+  print $@ =~ /^Modification of non-creatable array value attempted, subscript -7/
+      ? "ok $N\n" : "not ok $N \# \$\@ was '$@'\n";
+} else { 
+  print "ok $N \# skipped (versions through 5.7.3 dump core here.)\n";
+}
+$N++;
+       
+# (98-101) Test default arguments
+splice @a, 0, 0, (0..11);
+splice @a, 4;
+check_contents("0$:1$:2$:3$:");
+splice @a;
+check_contents("");
+
+# (102-103) I think there's a bug here---it will fail to clear the EOF flag
+@a = (0..11);
+splice @a, -1, 1000;
+check_contents("0$:1$:2$:3$:4$:5$:6$:7$:8$:9$:10$:");
+
+# (104-106) make sure that undefs are treated correctly---they should
+# be converted to empty records, and should not raise any warnings.
+# (Some of these failed in 0.90.  The change to _fixrec fixed them.)
+# 20020331
+{
+  my $good = 1; my $warn;
+  # If any of these raise warnings, we have a problem.
+  local $SIG{__WARN__} = sub { $good = 0; $warn = shift(); ctrlfix($warn)};
+  local $^W = 1;
+  @a = (1);
+  splice @a, 1, 0, undef, undef, undef;
+  print $good ? "ok $N\n" : "not ok $N # $warn\n";
+  $N++; $good = 1;
+  print defined($a[2]) ? "ok $N\n" : "not ok $N\n";
+  $N++; $good = 1;
+  my @r = splice @a, 2;
+  print defined($r[0]) ? "ok $N\n" : "not ok $N\n";
+  $N++; $good = 1;
+}
+
+# (107-118) splice with negative length was treated wrong
+# 20020402 Reported by Juerd Waalboer
+@a = (0..8) ;
+splice @a, 0, -3;
+check_contents("6$:7$:8$:");
+@a = (0..8) ;
+splice @a, 1, -3;
+check_contents("0$:6$:7$:8$:");
+@a = (0..8) ;
+splice @a, 7, -3;
+check_contents("0$:1$:2$:3$:4$:5$:6$:7$:8$:");
+@a = (0..2) ;
+splice @a, 0, -3;
+check_contents("0$:1$:2$:");
+@a = (0..2) ;
+splice @a, 1, -3;
+check_contents("0$:1$:2$:");
+@a = (0..2) ;
+splice @a, 7, -3;
+check_contents("0$:1$:2$:");
+
+sub init_file {
+  my $data = shift;
+  open F, "> $file" or die $!;
+  binmode F;
+  print F $data;
+  close F;
+}
+
+use POSIX 'SEEK_SET';
+sub check_contents {
+  my $x = shift;
+  my $integrity = $o->_check_integrity($file, $ENV{INTEGRITY});
+  local *FH = $o->{fh};
+  seek FH, 0, SEEK_SET;
+  print $integrity ? "ok $N\n" : "not ok $N\n";
+  $N++;
+  my $a;
+  { local $/; $a = <FH> }
+  $a = "" unless defined $a;
+  if ($a eq $x) {
+    print "ok $N\n";
+  } else {
+    ctrlfix($a, $x);
+    print "not ok $N\n# expected <$x>, got <$a>\n";
+  }
+  $N++;
+}
+
+
+sub ctrlfix {
+  for (@_) {
+    s/\n/\\n/g;
+    s/\r/\\r/g;
+  }
+}
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
diff --git a/dist/Tie-File/t/05_size.t b/dist/Tie-File/t/05_size.t
new file mode 100644
index 0000000000..44c69f910f
--- /dev/null
+++ b/dist/Tie-File/t/05_size.t
@@ -0,0 +1,129 @@
+#!/usr/bin/perl
+#
+# Check FETCHSIZE and SETSIZE functions
+# PUSH POP SHIFT UNSHIFT
+#
+
+use POSIX 'SEEK_SET';
+
+my $file = "tf$$.txt";
+my ($o, $n);
+
+print "1..16\n";
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;
+
+# 2-3 FETCHSIZE 0-length file
+open F, "> $file" or die $!;
+binmode F;
+close F;
+$o = tie @a, 'Tie::File', $file;
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+$: = $o->{recsep};
+
+$n = @a;
+print $n == 0 ? "ok $N\n" : "not ok $N # $n, s/b 0\n";
+$N++;
+
+# Reset everything
+undef $o;
+untie @a;
+
+my $data = "rec0$:rec1$:rec2$:";
+open F, "> $file" or die $!;
+binmode F;
+print F $data;
+close F;
+
+$o = tie @a, 'Tie::File', $file;
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+# 4-5 FETCHSIZE positive-length file
+$n = @a;
+print $n == 3 ? "ok $N\n" : "not ok $N # $n, s/b 0\n";
+$N++;
+
+# STORESIZE
+# (6-7) Make it longer:
+populate();
+$#a = 4;
+check_contents("$data$:$:");
+
+# (8-9) Make it longer again:
+populate();
+$#a = 6;
+check_contents("$data$:$:$:$:");
+
+# (10-11) Make it shorter:
+populate();
+$#a = 4;
+check_contents("$data$:$:");
+
+# (12-13) Make it shorter again:
+populate();
+$#a = 2;
+check_contents($data);
+
+# (14-15) Get rid of it completely:
+populate();
+$#a = -1;
+check_contents('');
+
+# (16) 20020324 I have an idea that shortening the array will not
+# expunge a cached record at the end if one is present.
+$o->defer;
+$a[3] = "record";
+my $r = $a[3];
+$#a = -1;
+$r = $a[3];
+print (! defined $r ? "ok $N\n" : "not ok $N \# was <$r>; should be UNDEF\n");
+# Turns out not to be the case---STORESIZE explicitly removes them later
+# 20020326 Well, but happily, this test did fail today.
+
+# In the past, there was a bug in STORESIZE that it didn't correctly
+# remove deleted records from the cache.  This wasn't detected
+# because these tests were all done with an empty cache.  populate()
+# will ensure that the cache is fully populated.
+sub populate {
+  my $z;
+  $z = $a[$_] for 0 .. $#a;
+}
+
+sub check_contents {
+  my $x = shift;
+  local *FH = $o->{fh};
+  seek FH, 0, SEEK_SET;
+  my $a;
+  { local $/; $a = <FH> }
+  $a = "" unless defined $a;
+  if ($a eq $x) {
+    print "ok $N\n";
+  } else {
+    ctrlfix($a, $x);
+    print "not ok $N\n# expected <$x>, got <$a>\n";
+  }
+  $N++;
+  my $integrity = $o->_check_integrity($file, $ENV{INTEGRITY});
+  print $integrity ? "ok $N\n" : "not ok $N \# integrity\n";
+  $N++;
+}
+
+
+sub ctrlfix {
+  for (@_) {
+    s/\n/\\n/g;
+    s/\r/\\r/g;
+  }
+}
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
diff --git a/dist/Tie-File/t/06_fixrec.t b/dist/Tie-File/t/06_fixrec.t
new file mode 100644
index 0000000000..bf24be1300
--- /dev/null
+++ b/dist/Tie-File/t/06_fixrec.t
@@ -0,0 +1,53 @@
+#!/usr/bin/perl
+
+use POSIX 'SEEK_SET';
+my $file = "tf$$.txt";
+$: = Tie::File::_default_recsep();
+
+print "1..5\n";
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;
+
+my $o = tie @a, 'Tie::File', $file, autodefer => 0;
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+$a[0] = 'rec0';
+check_contents("rec0$:");
+$a[1] = "rec1$:";
+check_contents("rec0$:rec1$:");
+$a[2] = "rec2$:$:";             # should we detect this?
+check_contents("rec0$:rec1$:rec2$:$:");
+
+sub check_contents {
+  my $x = shift;
+  local *FH = $o->{fh};
+  seek FH, 0, SEEK_SET;
+  my $a;
+  { local $/; $a = <FH> }
+  $a = "" unless defined $a;
+  if ($a eq $x) {
+    print "ok $N\n";
+  } else {
+    my $msg = "not ok $N # expected <$x>, got <$a>";
+    ctrlfix($msg);
+    print "$msg\n";
+  }
+  $N++;
+}
+
+sub ctrlfix {
+  for (@_) {
+    s/\n/\\n/g;
+    s/\r/\\r/g;
+  }
+}
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
diff --git a/dist/Tie-File/t/07_rv_splice.t b/dist/Tie-File/t/07_rv_splice.t
new file mode 100644
index 0000000000..e5c09b1a48
--- /dev/null
+++ b/dist/Tie-File/t/07_rv_splice.t
@@ -0,0 +1,205 @@
+#!/usr/bin/perl
+#
+# Check SPLICE function's return value
+# (04_splice.t checks its effect on the file)
+#
+
+
+my $file = "tf$$.txt";
+$: = Tie::File::_default_recsep();
+my $data = "rec0$:rec1$:rec2$:";
+
+print "1..56\n";
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;  # partial credit just for showing up
+
+init_file($data);
+
+my $o = tie @a, 'Tie::File', $file, autochomp => 0;
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+my $n;
+
+# (3-12) splicing at the beginning
+@r = splice(@a, 0, 0, "rec4");
+check_result();
+@r = splice(@a, 0, 1, "rec5");       # same length
+check_result("rec4");
+@r = splice(@a, 0, 1, "record5");    # longer
+check_result("rec5");
+
+@r = splice(@a, 0, 1, "r5");         # shorter
+check_result("record5");
+@r = splice(@a, 0, 1);               # removal
+check_result("r5");
+@r = splice(@a, 0, 0);               # no-op
+check_result();
+@r = splice(@a, 0, 0, 'r7', 'rec8'); # insert more than one
+check_result();
+@r = splice(@a, 0, 2, 'rec7', 'record8', 'rec9'); # insert more than delete
+check_result('r7', 'rec8');
+
+@r = splice(@a, 0, 3, 'record9', 'rec10'); # delete more than insert
+check_result('rec7', 'record8', 'rec9');
+@r = splice(@a, 0, 2);               # delete more than one
+check_result('record9', 'rec10');
+
+
+# (13-22) splicing in the middle
+@r = splice(@a, 1, 0, "rec4");
+check_result();
+@r = splice(@a, 1, 1, "rec5");       # same length
+check_result('rec4');
+@r = splice(@a, 1, 1, "record5");    # longer
+check_result('rec5');
+
+@r = splice(@a, 1, 1, "r5");         # shorter
+check_result("record5");
+@r = splice(@a, 1, 1);               # removal
+check_result("r5");
+@r = splice(@a, 1, 0);               # no-op
+check_result();
+@r = splice(@a, 1, 0, 'r7', 'rec8'); # insert more than one
+check_result();
+@r = splice(@a, 1, 2, 'rec7', 'record8', 'rec9'); # insert more than delete
+check_result('r7', 'rec8');
+
+@r = splice(@a, 1, 3, 'record9', 'rec10'); # delete more than insert
+check_result('rec7', 'record8', 'rec9');
+@r = splice(@a, 1, 2);               # delete more than one
+check_result('record9','rec10');
+
+# (23-32) splicing at the end
+@r = splice(@a, 3, 0, "rec4");
+check_result();
+@r = splice(@a, 3, 1, "rec5");       # same length
+check_result('rec4');
+@r = splice(@a, 3, 1, "record5");    # longer
+check_result('rec5');
+
+@r = splice(@a, 3, 1, "r5");         # shorter
+check_result('record5');
+@r = splice(@a, 3, 1);               # removal
+check_result('r5');
+@r = splice(@a, 3, 0);               # no-op
+check_result();
+@r = splice(@a, 3, 0, 'r7', 'rec8'); # insert more than one
+check_result();
+@r = splice(@a, 3, 2, 'rec7', 'record8', 'rec9'); # insert more than delete
+check_result('r7', 'rec8');
+
+@r = splice(@a, 3, 3, 'record9', 'rec10'); # delete more than insert
+check_result('rec7', 'record8', 'rec9');
+@r = splice(@a, 3, 2);               # delete more than one
+check_result('record9', 'rec10');
+
+# (33-42) splicing with negative subscript
+@r = splice(@a, -1, 0, "rec4");
+check_result();
+@r = splice(@a, -1, 1, "rec5");       # same length
+check_result('rec2');
+@r = splice(@a, -1, 1, "record5");    # longer
+check_result("rec5");
+
+@r = splice(@a, -1, 1, "r5");         # shorter
+check_result("record5");
+@r = splice(@a, -1, 1);               # removal
+check_result("r5");
+@r = splice(@a, -1, 0);               # no-op  
+check_result();
+@r = splice(@a, -1, 0, 'r7', 'rec8'); # insert more than one
+check_result();
+@r = splice(@a, -1, 2, 'rec7', 'record8', 'rec9'); # insert more than delete
+check_result('rec4');
+
+@r = splice(@a, -3, 3, 'record9', 'rec10'); # delete more than insert
+check_result('rec7', 'record8', 'rec9');
+@r = splice(@a, -4, 3);               # delete more than one
+check_result('r7', 'rec8', 'record9');
+
+# (43) scrub it all out
+@r = splice(@a, 0, 3);
+check_result('rec0', 'rec1', 'rec10');
+
+# (44) put some back in
+@r = splice(@a, 0, 0, "rec0", "rec1");
+check_result();
+
+# (45) what if we remove too many records?
+@r = splice(@a, 0, 17);
+check_result('rec0', 'rec1');
+
+# (46-48) Now check the scalar context return
+splice(@a, 0, 0, qw(I like pie));
+my $r;
+$r = splice(@a, 0, 0);
+print !defined($r) ? "ok $N\n" : "not ok $N \# return should have been undef, was <$r>\n";
+$N++;
+
+$r = splice(@a, 2, 1);
+print $r eq "pie$:" ? "ok $N\n" : "not ok $N \# return should have been 'pie\\n', was <$r>\n";
+$N++;
+
+$r = splice(@a, 0, 2);
+print $r eq "like$:" ? "ok $N\n" : "not ok $N \# return should have been 'like\\n', was <$r>\n";
+$N++;
+
+# (49-50) Test default arguments
+splice @a, 0, 0, (0..11);
+@r = splice @a, 4;
+check_result(4..11);
+@r = splice @a;
+check_result(0..3);
+
+# (51-56) splice with negative length was treated wrong
+# 20020402 Reported by Juerd Waalboer
+@a = (0..8) ;
+@r = splice @a, 0, -3;
+check_result(0..5);
+@a = (0..8) ;
+@r = splice @a, 1, -3;
+check_result(1..5);
+@a = (0..8) ;
+@r = splice @a, 7, -3;
+check_result();
+@a = (0..2) ;
+@r = splice @a, 0, -3;
+check_result();
+@a = (0..2) ;
+@r = splice @a, 1, -3;
+check_result();
+@a = (0..2) ;
+@r = splice @a, 7, -3;
+check_result();
+
+sub init_file {
+  my $data = shift;
+  open F, "> $file" or die $!;
+  binmode F;
+  print F $data;
+  close F;
+}
+
+# actual results are in @r.
+# expected results are in @_
+sub check_result {
+  my @x = @_;
+  s/$:$// for @r;
+  my $good = 1;
+  $good = 0 unless @r == @x;
+  for my $i (0 .. $#r) {
+    $good = 0 unless $r[$i] eq $x[$i];
+  }
+  print $good ? "ok $N\n" : "not ok $N \# was (@r); should be (@x)\n";
+  $N++;
+}
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
diff --git a/dist/Tie-File/t/08_ro.t b/dist/Tie-File/t/08_ro.t
new file mode 100644
index 0000000000..5fd8933bf8
--- /dev/null
+++ b/dist/Tie-File/t/08_ro.t
@@ -0,0 +1,86 @@
+#!/usr/bin/perl
+#
+# Make sure it works to open the file in read-only mode
+#
+
+my $file = "tf$$.txt";
+$: = Tie::File::_default_recsep();
+
+print "1..13\n";
+
+my $N = 1;
+use Tie::File;
+use Fcntl 'O_RDONLY';
+print "ok $N\n"; $N++;
+
+my @items = qw(Gold Frankincense Myrrh Ivory Apes Peacocks);
+init_file(join $:, @items, '');
+
+my $o = tie @a, 'Tie::File', $file, mode => O_RDONLY, autochomp => 0;
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+$#a == $#items ? print "ok $N\n" : print "not ok $N\n";
+$N++;
+
+for my $i (0..$#items) {
+  ("$items[$i]$:" eq $a[$i]) ? print "ok $N\n" : print "not ok $N\n";
+  $N++;
+}
+
+sub init_file {
+  my $data = shift;
+  open F, "> $file" or die $!;
+  binmode F;
+  print F $data;
+  close F;
+}
+
+undef $o; untie @a;
+my $badrec = "Malformed";
+# (10-13) When a record lacks the record seprator, we sneakily try
+# to fix it.  How does that work when the file is read-only?
+if (setup_badly_terminated_file(4)) {
+  my $good = 1;
+  my $warn;
+  local $SIG{__WARN__} = sub { $good = 0; ctrlfix($warn = shift); };
+  local $^W = 1;
+  my $o = tie @a, 'Tie::File', $file, mode => O_RDONLY, autochomp => 0
+    or die "Couldn't tie $file: $!";
+
+  print $a[0] eq "Malformed$:" ? "ok $N\n" : "not ok $N\n";  $N++;
+  print $good ? "ok $N\n" : "not ok $N # $warn\n";  $good = 1; $N++;
+  print $a[0] eq "Malformed$:" ? "ok $N\n" : "not ok $N\n";  $N++;
+  print $good ? "ok $N\n" : "not ok $N # $warn\n";  $good = 1; $N++;
+}
+
+sub setup_badly_terminated_file {
+  my $NTESTS = shift;
+  open F, "> $file" or die "Couldn't open $file: $!";
+  binmode F;
+  print F $badrec;
+  close F;
+  unless (-s $file == length $badrec) {
+    for (1 .. $NTESTS) {
+      print "ok $N \# skipped - can't create improperly terminated file\n";
+      $N++;
+    }
+    return;
+  }
+  return 1;
+}
+
+
+sub ctrlfix {
+  for (@_) {
+    s/\n/\\n/g;
+    s/\r/\\r/g;
+  }
+}
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
diff --git a/dist/Tie-File/t/09_gen_rs.t b/dist/Tie-File/t/09_gen_rs.t
new file mode 100644
index 0000000000..e590210335
--- /dev/null
+++ b/dist/Tie-File/t/09_gen_rs.t
@@ -0,0 +1,225 @@
+#!/usr/bin/perl
+
+my $file = "tf$$.txt";
+
+print "1..59\n";
+
+use Fcntl 'O_RDONLY';
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;
+
+$RECSEP = 'blah';
+my $o = tie @a, 'Tie::File', $file, 
+    recsep => $RECSEP, autochomp => 0, autodefer => 0;
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+
+# 3-4 create
+$a[0] = 'rec0';
+check_contents("rec0");
+
+# 5-8 append
+$a[1] = 'rec1';
+check_contents("rec0", "rec1");
+$a[2] = 'rec2';
+check_contents("rec0", "rec1", "rec2");
+
+# 9-14 same-length alterations
+$a[0] = 'new0';
+check_contents("new0", "rec1", "rec2");
+$a[1] = 'new1';
+check_contents("new0", "new1", "rec2");
+$a[2] = 'new2';
+check_contents("new0", "new1", "new2");
+
+# 15-24 lengthening alterations
+$a[0] = 'long0';
+check_contents("long0", "new1", "new2");
+$a[1] = 'long1';
+check_contents("long0", "long1", "new2");
+$a[2] = 'long2';
+check_contents("long0", "long1", "long2");
+$a[1] = 'longer1';
+check_contents("long0", "longer1", "long2");
+$a[0] = 'longer0';
+check_contents("longer0", "longer1", "long2");
+
+# 25-34 shortening alterations, including truncation
+$a[0] = 'short0';
+check_contents("short0", "longer1", "long2");
+$a[1] = 'short1';
+check_contents("short0", "short1", "long2");
+$a[2] = 'short2';
+check_contents("short0", "short1", "short2");
+$a[1] = 'sh1';
+check_contents("short0", "sh1", "short2");
+$a[0] = 'sh0';
+check_contents("sh0", "sh1", "short2");
+
+# (35-38) file with holes
+$a[4] = 'rec4';
+check_contents("sh0", "sh1", "short2", "", "rec4");
+$a[3] = 'rec3';
+check_contents("sh0", "sh1", "short2", "rec3", "rec4");
+
+# (39-40) zero out file
+@a = ();
+check_contents();
+
+# (41-42) insert into the middle of an empty file
+$a[3] = "rec3";
+check_contents("", "", "", "rec3");
+
+# (43-47) 20020326 You thought there would be a bug in STORE where if
+# a cached record was false, STORE wouldn't see it at all.  Yup, there is,
+# and adding the appropriate defined() test fixes the problem.
+undef $o;  untie @a;  1 while unlink $file;
+$RECSEP = '0';
+$o = tie @a, 'Tie::File', $file, 
+    recsep => $RECSEP, autochomp => 0, autodefer => 0;
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+$#a = 2;
+my $z = $a[1];                  # caches "0"
+$a[2] = "oops";
+check_contents("", "", "oops");
+$a[1] = "bah";
+check_contents("", "bah", "oops");
+undef $o; untie @a;
+
+# (48-56) 20020331 Make sure we correctly handle the case where the final
+# record of the file is not properly terminated, Through version 0.90,
+# we would mangle the file.
+my $badrec = "Malformed";
+$: = $RECSEP = Tie::File::_default_recsep();
+# (48-50)
+if (setup_badly_terminated_file(3)) {
+  $o = tie @a, 'Tie::File', $file,
+    recsep => $RECSEP, autochomp => 0, autodefer => 0
+    or die "Couldn't tie file: $!";
+  my $z = $a[0];
+  print $z eq "$badrec$:" ? "ok $N\n" : 
+                        "not ok $N \# got $z, expected $badrec\n";
+  $N++;
+  push @a, "next";
+  check_contents($badrec, "next");
+}
+# (51-52)
+if (setup_badly_terminated_file(2)) {
+  $o = tie @a, 'Tie::File', $file,
+    recsep => $RECSEP, autochomp => 0, autodefer => 0
+    or die "Couldn't tie file: $!";
+  splice @a, 1, 0, "x", "y";
+  check_contents($badrec, "x", "y");
+}
+# (53-56)
+if (setup_badly_terminated_file(4)) {
+  $o = tie @a, 'Tie::File', $file,
+    recsep => $RECSEP, autochomp => 0, autodefer => 0
+    or die "Couldn't tie file: $!";
+  my @r = splice @a, 0, 1, "x", "y";
+  my $n = @r;
+  print $n == 1 ? "ok $N\n" : "not ok $N \# expected 1 elt, got $n\n";
+  $N++;
+  print $r[0] eq "$badrec$:" ? "ok $N\n"
+    : "not ok $N \# expected <$badrec>, got <$r[0]>\n";
+  $N++;
+  check_contents("x", "y");
+}
+
+# (57-58) 20020402 The modification would have failed if $\ were set wrong.
+# I hate $\.
+if (setup_badly_terminated_file(2)) {
+  $o = tie @a, 'Tie::File', $file,
+    recsep => $RECSEP, autochomp => 0, autodefer => 0
+    or die "Couldn't tie file: $!";
+  { local $\ = "I hate \$\\.";
+    my $z = $a[0];
+  }
+  check_contents($badrec);
+}
+
+# (59) 20030527 Tom Christiansen pointed out that FETCH returns the wrong
+# data on the final record of an unterminated file if the file is opened
+# in read-only mode.  Note that the $#a is necessary here.
+# There's special-case code to fix the final record when it is read normally.
+# But the $#a forces it to be read from the cache, which skips the
+# termination.
+$badrec = "world${RECSEP}hello";
+if (setup_badly_terminated_file(1)) {
+  tie(@a, "Tie::File", $file, mode => O_RDONLY, recsep => $RECSEP)
+      or die "Couldn't tie file: $!";
+  my $z = $#a;
+  $z = $a[1];
+  print $z eq "hello" ? "ok $N\n" : 
+      "not ok $N \# got $z, expected hello\n";
+  $N++;
+}
+
+sub setup_badly_terminated_file {
+  my $NTESTS = shift;
+  open F, "> $file" or die "Couldn't open $file: $!";
+  binmode F;
+  print F $badrec;
+  close F;
+  unless (-s $file == length $badrec) {
+    for (1 .. $NTESTS) {
+      print "ok $N \# skipped - can't create improperly terminated file\n";
+      $N++;
+    }
+    return;
+  }
+  return 1;
+}
+
+
+use POSIX 'SEEK_SET';
+sub check_contents {
+  my @c = @_;
+  my $x = join $RECSEP, @c, '';
+  local *FH = $o->{fh};
+  seek FH, 0, SEEK_SET;
+  my $a;
+  { local $/; $a = <FH> }
+
+  $a = "" unless defined $a;
+  if ($a eq $x) {
+    print "ok $N\n";
+  } else {
+    my $msg = "# expected <$x>, got <$a>";
+    ctrlfix($msg);
+    print "not ok $N $msg\n";
+  }
+  $N++;
+
+  # now check FETCH:
+  my $good = 1;
+  for (0.. $#c) {
+    unless ($a[$_] eq "$c[$_]$RECSEP") {
+      $msg = "expected $c[$_]$RECSEP, got $a[$_]";
+      ctrlfix($msg);
+      $good = 0;
+    }
+  }
+  print $good ? "ok $N\n" : "not ok $N # fetch $msg\n";
+  $N++;
+}
+
+
+sub ctrlfix {
+  for (@_) {
+    s/\n/\\n/g;
+    s/\r/\\r/g;
+  }
+}
+
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
diff --git a/dist/Tie-File/t/10_splice_rs.t b/dist/Tie-File/t/10_splice_rs.t
new file mode 100644
index 0000000000..50b8b0a7ee
--- /dev/null
+++ b/dist/Tie-File/t/10_splice_rs.t
@@ -0,0 +1,215 @@
+#!/usr/bin/perl
+#
+# Check SPLICE function's effect on the file
+# (07_rv_splice.t checks its return value)
+#
+# Each call to 'check_contents' actually performs two tests.
+# First, it calls the tied object's own 'check_integrity' method,
+# which makes sure that the contents of the read cache and offset tables
+# accurately reflect the contents of the file.  
+# Then, it checks the actual contents of the file against the expected
+# contents.
+
+use POSIX 'SEEK_SET';
+
+my $file = "tf$$.txt";
+my $data = "rec0blahrec1blahrec2blah";
+
+print "1..101\n";
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;  # partial credit just for showing up
+
+init_file($data);
+
+my $o = tie @a, 'Tie::File', $file, recsep => 'blah';
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+my $n;
+
+# (3-22) splicing at the beginning
+splice(@a, 0, 0, "rec4");
+check_contents("rec4blah$data");
+splice(@a, 0, 1, "rec5");       # same length
+check_contents("rec5blah$data");
+splice(@a, 0, 1, "record5");    # longer
+check_contents("record5blah$data");
+
+splice(@a, 0, 1, "r5");         # shorter
+check_contents("r5blah$data");
+splice(@a, 0, 1);               # removal
+check_contents("$data");
+splice(@a, 0, 0);               # no-op
+check_contents("$data");
+splice(@a, 0, 0, 'r7', 'rec8'); # insert more than one
+check_contents("r7blahrec8blah$data");
+splice(@a, 0, 2, 'rec7', 'record8', 'rec9'); # insert more than delete
+check_contents("rec7blahrecord8blahrec9blah$data");
+
+splice(@a, 0, 3, 'record9', 'rec10'); # delete more than insert
+check_contents("record9blahrec10blah$data");
+splice(@a, 0, 2);               # delete more than one
+check_contents("$data");
+
+
+# (23-42) splicing in the middle
+splice(@a, 1, 0, "rec4");
+check_contents("rec0blahrec4blahrec1blahrec2blah");
+splice(@a, 1, 1, "rec5");       # same length
+check_contents("rec0blahrec5blahrec1blahrec2blah");
+splice(@a, 1, 1, "record5");    # longer
+check_contents("rec0blahrecord5blahrec1blahrec2blah");
+
+splice(@a, 1, 1, "r5");         # shorter
+check_contents("rec0blahr5blahrec1blahrec2blah");
+splice(@a, 1, 1);               # removal
+check_contents("$data");
+splice(@a, 1, 0);               # no-op
+check_contents("$data");
+splice(@a, 1, 0, 'r7', 'rec8'); # insert more than one
+check_contents("rec0blahr7blahrec8blahrec1blahrec2blah");
+splice(@a, 1, 2, 'rec7', 'record8', 'rec9'); # insert more than delete
+check_contents("rec0blahrec7blahrecord8blahrec9blahrec1blahrec2blah");
+
+splice(@a, 1, 3, 'record9', 'rec10'); # delete more than insert
+check_contents("rec0blahrecord9blahrec10blahrec1blahrec2blah");
+splice(@a, 1, 2);               # delete more than one
+check_contents("$data");
+
+# (43-62) splicing at the end
+splice(@a, 3, 0, "rec4");
+check_contents("$ {data}rec4blah");
+splice(@a, 3, 1, "rec5");       # same length
+check_contents("$ {data}rec5blah");
+splice(@a, 3, 1, "record5");    # longer
+check_contents("$ {data}record5blah");
+
+splice(@a, 3, 1, "r5");         # shorter
+check_contents("$ {data}r5blah");
+splice(@a, 3, 1);               # removal
+check_contents("$data");
+splice(@a, 3, 0);               # no-op
+check_contents("$data");
+splice(@a, 3, 0, 'r7', 'rec8'); # insert more than one
+check_contents("$ {data}r7blahrec8blah");
+splice(@a, 3, 2, 'rec7', 'record8', 'rec9'); # insert more than delete
+check_contents("$ {data}rec7blahrecord8blahrec9blah");
+
+splice(@a, 3, 3, 'record9', 'rec10'); # delete more than insert
+check_contents("$ {data}record9blahrec10blah");
+splice(@a, 3, 2);               # delete more than one
+check_contents("$data");
+
+# (63-82) splicing with negative subscript
+splice(@a, -1, 0, "rec4");
+check_contents("rec0blahrec1blahrec4blahrec2blah");
+splice(@a, -1, 1, "rec5");       # same length
+check_contents("rec0blahrec1blahrec4blahrec5blah");
+splice(@a, -1, 1, "record5");    # longer
+check_contents("rec0blahrec1blahrec4blahrecord5blah");
+
+splice(@a, -1, 1, "r5");         # shorter
+check_contents("rec0blahrec1blahrec4blahr5blah");
+splice(@a, -1, 1);               # removal
+check_contents("rec0blahrec1blahrec4blah");
+splice(@a, -1, 0);               # no-op  
+check_contents("rec0blahrec1blahrec4blah");
+splice(@a, -1, 0, 'r7', 'rec8'); # insert more than one
+check_contents("rec0blahrec1blahr7blahrec8blahrec4blah");
+splice(@a, -1, 2, 'rec7', 'record8', 'rec9'); # insert more than delete
+check_contents("rec0blahrec1blahr7blahrec8blahrec7blahrecord8blahrec9blah");
+
+splice(@a, -3, 3, 'record9', 'rec10'); # delete more than insert
+check_contents("rec0blahrec1blahr7blahrec8blahrecord9blahrec10blah");
+splice(@a, -4, 3);               # delete more than one
+check_contents("rec0blahrec1blahrec10blah");
+
+# (83-84) scrub it all out
+splice(@a, 0, 3);
+check_contents("");
+
+# (85-86) put some back in
+splice(@a, 0, 0, "rec0", "rec1");
+check_contents("rec0blahrec1blah");
+
+# (87-88) what if we remove too many records?
+splice(@a, 0, 17);
+check_contents("");
+
+# (89-92) In the past, splicing past the end was not correctly detected
+# (0.14)
+splice(@a, 89, 3);
+check_contents("");
+splice(@a, @a, 3);
+check_contents("");
+
+# (93-96) Also we did not emulate splice's freaky behavior when inserting
+# past the end of the array (1.14)
+splice(@a, 89, 0, "I", "like", "pie");
+check_contents("Iblahlikeblahpieblah");
+splice(@a, 89, 0, "pie pie pie");
+check_contents("Iblahlikeblahpieblahpie pie pieblah");
+
+# (97) Splicing with too large a negative number should be fatal
+# This test ignored because it causes 5.6.1 and 5.7.3 to dump core
+# It also garbles the stack under 5.005_03 (20020401)
+# NOT MY FAULT
+if ($] > 5.007003) {
+  eval { splice(@a, -7, 0) };
+  print $@ =~ /^Modification of non-creatable array value attempted, subscript -7/
+      ? "ok $N\n" : "not ok $N \# \$\@ was '$@'\n";
+} else { 
+  print "ok $N \# skipped (versions through 5.7.3 dump core here.)\n";
+}
+$N++;
+
+# (98-101) Test default arguments
+splice @a, 0, 0, (0..11);
+splice @a, 4;
+check_contents("0blah1blah2blah3blah");
+splice @a;
+check_contents("");
+
+
+sub init_file {
+  my $data = shift;
+  open F, "> $file" or die $!;
+  binmode F;
+  print F $data;
+  close F;
+}
+
+sub check_contents {
+  my $x = shift;
+  my $integrity = $o->_check_integrity($file, $ENV{INTEGRITY});
+  print $integrity ? "ok $N\n" : "not ok $N\n";
+  $N++;
+  local *FH = $o->{fh};
+  seek FH, 0, SEEK_SET;
+  my $a;
+  { local $/; $a = <FH> }
+  $a = "" unless defined $a;
+  if ($a eq $x) {
+    print "ok $N\n";
+  } else {
+    ctrlfix(my $msg = "# expected <$x>, got <$a>");
+    print "not ok $N\n$msg\n";
+  }
+  $N++;
+}
+
+sub ctrlfix {
+  for (@_) {
+    s/\n/\\n/g;
+    s/\r/\\r/g;
+  }
+}
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
diff --git a/dist/Tie-File/t/11_rv_splice_rs.t b/dist/Tie-File/t/11_rv_splice_rs.t
new file mode 100644
index 0000000000..ae1053802a
--- /dev/null
+++ b/dist/Tie-File/t/11_rv_splice_rs.t
@@ -0,0 +1,182 @@
+#!/usr/bin/perl
+#
+# Check SPLICE function's return value
+# (04_splice.t checks its effect on the file)
+#
+
+my $file = "tf$$.txt";
+my $data = "rec0blahrec1blahrec2blah";
+
+print "1..50\n";
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;  # partial credit just for showing up
+
+init_file($data);
+
+my $o = tie @a, 'Tie::File', $file, autochomp => 0, recsep => 'blah';
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+my $n;
+
+# (3-12) splicing at the beginning
+@r = splice(@a, 0, 0, "rec4");
+check_result();
+@r = splice(@a, 0, 1, "rec5");       # same length
+check_result("rec4");
+@r = splice(@a, 0, 1, "record5");    # longer
+check_result("rec5");
+
+@r = splice(@a, 0, 1, "r5");         # shorter
+check_result("record5");
+@r = splice(@a, 0, 1);               # removal
+check_result("r5");
+@r = splice(@a, 0, 0);               # no-op
+check_result();
+@r = splice(@a, 0, 0, 'r7', 'rec8'); # insert more than one
+check_result();
+@r = splice(@a, 0, 2, 'rec7', 'record8', 'rec9'); # insert more than delete
+check_result('r7', 'rec8');
+
+@r = splice(@a, 0, 3, 'record9', 'rec10'); # delete more than insert
+check_result('rec7', 'record8', 'rec9');
+@r = splice(@a, 0, 2);               # delete more than one
+check_result('record9', 'rec10');
+
+
+# (13-22) splicing in the middle
+@r = splice(@a, 1, 0, "rec4");
+check_result();
+@r = splice(@a, 1, 1, "rec5");       # same length
+check_result('rec4');
+@r = splice(@a, 1, 1, "record5");    # longer
+check_result('rec5');
+
+@r = splice(@a, 1, 1, "r5");         # shorter
+check_result("record5");
+@r = splice(@a, 1, 1);               # removal
+check_result("r5");
+@r = splice(@a, 1, 0);               # no-op
+check_result();
+@r = splice(@a, 1, 0, 'r7', 'rec8'); # insert more than one
+check_result();
+@r = splice(@a, 1, 2, 'rec7', 'record8', 'rec9'); # insert more than delete
+check_result('r7', 'rec8');
+
+@r = splice(@a, 1, 3, 'record9', 'rec10'); # delete more than insert
+check_result('rec7', 'record8', 'rec9');
+@r = splice(@a, 1, 2);               # delete more than one
+check_result('record9','rec10');
+
+# (23-32) splicing at the end
+@r = splice(@a, 3, 0, "rec4");
+check_result();
+@r = splice(@a, 3, 1, "rec5");       # same length
+check_result('rec4');
+@r = splice(@a, 3, 1, "record5");    # longer
+check_result('rec5');
+
+@r = splice(@a, 3, 1, "r5");         # shorter
+check_result('record5');
+@r = splice(@a, 3, 1);               # removal
+check_result('r5');
+@r = splice(@a, 3, 0);               # no-op
+check_result();
+@r = splice(@a, 3, 0, 'r7', 'rec8'); # insert more than one
+check_result();
+@r = splice(@a, 3, 2, 'rec7', 'record8', 'rec9'); # insert more than delete
+check_result('r7', 'rec8');
+
+@r = splice(@a, 3, 3, 'record9', 'rec10'); # delete more than insert
+check_result('rec7', 'record8', 'rec9');
+@r = splice(@a, 3, 2);               # delete more than one
+check_result('record9', 'rec10');
+
+# (33-42) splicing with negative subscript
+@r = splice(@a, -1, 0, "rec4");
+check_result();
+@r = splice(@a, -1, 1, "rec5");       # same length
+check_result('rec2');
+@r = splice(@a, -1, 1, "record5");    # longer
+check_result("rec5");
+
+@r = splice(@a, -1, 1, "r5");         # shorter
+check_result("record5");
+@r = splice(@a, -1, 1);               # removal
+check_result("r5");
+@r = splice(@a, -1, 0);               # no-op  
+check_result();
+@r = splice(@a, -1, 0, 'r7', 'rec8'); # insert more than one
+check_result();
+@r = splice(@a, -1, 2, 'rec7', 'record8', 'rec9'); # insert more than delete
+check_result('rec4');
+
+@r = splice(@a, -3, 3, 'record9', 'rec10'); # delete more than insert
+check_result('rec7', 'record8', 'rec9');
+@r = splice(@a, -4, 3);               # delete more than one
+check_result('r7', 'rec8', 'record9');
+
+# (43) scrub it all out
+@r = splice(@a, 0, 3);
+check_result('rec0', 'rec1', 'rec10');
+
+# (44) put some back in
+@r = splice(@a, 0, 0, "rec0", "rec1");
+check_result();
+
+# (45) what if we remove too many records?
+@r = splice(@a, 0, 17);
+check_result('rec0', 'rec1');
+
+# (46-48) Now check the scalar context return
+splice(@a, 0, 0, qw(I like pie));
+my $r;
+$r = splice(@a, 0, 0);
+print !defined($r) ? "ok $N\n" : "not ok $N \# return should have been undef\n";
+$N++;
+
+$r = splice(@a, 2, 1);
+print $r eq "pieblah" ? "ok $N\n" : "not ok $N \# return should have been 'pie'\n";
+$N++;
+
+$r = splice(@a, 0, 2);
+print $r eq "likeblah" ? "ok $N\n" : "not ok $N \# return should have been 'like'\n";
+$N++;
+
+# (49-50) Test default arguments
+splice @a, 0, 0, (0..11);
+@r = splice @a, 4;
+check_result(4..11);
+@r = splice @a;
+check_result(0..3);
+
+sub init_file {
+  my $data = shift;
+  open F, "> $file" or die $!;
+  binmode F;
+  print F $data;
+  close F;
+}
+
+# actual results are in @r.
+# expected results are in @_
+sub check_result {
+  my @x = @_;
+  s/blah$// for @r;
+  my $good = 1;
+  $good = 0 unless @r == @x;
+  for my $i (0 .. $#r) {
+    $good = 0 unless $r[$i] eq $x[$i];
+  }
+  print $good ? "ok $N\n" : "not ok $N \# was (@r); should be (@x)\n";
+  $N++;
+}
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
diff --git a/dist/Tie-File/t/12_longfetch_rs.t b/dist/Tie-File/t/12_longfetch_rs.t
new file mode 100644
index 0000000000..6f1905d6af
--- /dev/null
+++ b/dist/Tie-File/t/12_longfetch_rs.t
@@ -0,0 +1,41 @@
+#!/usr/bin/perl
+#
+# Make sure we can fetch a record in the middle of the file
+# before we've ever looked at any records before it
+#
+# (tests _fill_offsets_to() )
+#
+
+my $file = "tf$$.txt";
+my $data = "rec0blahrec1blahrec2blah";
+
+print "1..5\n";
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;
+
+open F, "> $file" or die $!;
+binmode F;
+print F $data;
+close F;
+
+
+my $o = tie @a, 'Tie::File', $file, autochomp => 0, recsep => 'blah';
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+my $n;
+
+# 3-5
+for (2, 1, 0) {
+  print $a[$_] eq "rec${_}blah" ? "ok $N\n" : "not ok $N # rec=$a[$_] ?\n";
+  $N++;
+}
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
diff --git a/dist/Tie-File/t/13_size_rs.t b/dist/Tie-File/t/13_size_rs.t
new file mode 100644
index 0000000000..a2a8d53bdd
--- /dev/null
+++ b/dist/Tie-File/t/13_size_rs.t
@@ -0,0 +1,95 @@
+#!/usr/bin/perl
+#
+# Check FETCHSIZE and SETSIZE functions
+# PUSH POP SHIFT UNSHIFT
+#
+
+use POSIX 'SEEK_SET';
+
+my $file = "tf$$.txt";
+my $data = "rec0blahrec1blahrec2blah";
+my ($o, $n);
+
+print "1..10\n";
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;
+
+# 2-3 FETCHSIZE 0-length file
+open F, "> $file" or die $!;
+close F;
+$o = tie @a, 'Tie::File', $file, recsep => 'blah';
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+$n = @a;
+print $n == 0 ? "ok $N\n" : "not ok $N # $n, s/b 0\n";
+$N++;
+
+# Reset everything
+undef $o;
+untie @a;
+
+# 4-5 FETCHSIZE positive-length file
+open F, "> $file" or die $!;
+print F $data;
+close F;
+$o = tie @a, 'Tie::File', $file, recsep => 'blah';
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+$n = @a;
+print $n == 3 ? "ok $N\n" : "not ok $N # $n, s/b 0\n";
+$N++;
+
+# STORESIZE
+# 6 Make it longer:
+$#a = 4;
+check_contents("${data}blahblah");
+
+# 7 Make it longer again:
+$#a = 6;
+check_contents("${data}blahblahblahblah");
+
+# 8 Make it shorter:
+$#a = 4;
+check_contents("${data}blahblah");
+
+# 9 Make it shorter again:
+$#a = 2;
+check_contents($data);
+
+# 10 Get rid of it completely:
+$#a = -1;
+check_contents('');
+
+
+sub check_contents {
+  my $x = shift;
+  local *FH = $o->{fh};
+  seek FH, 0, SEEK_SET;
+  my $a;
+  { local $/; $a = <FH> }
+  $a = "" unless defined $a;
+  if ($a eq $x) {
+    print "ok $N\n";
+  } else {
+    ctrlfix(my $msg = "# expected <$x>, got <$a>");
+    print "not ok $N\n$msg\n";
+  }
+  $N++;
+}
+
+
+sub ctrlfix {
+  for (@_) {
+    s/\n/\\n/g;
+    s/\r/\\r/g;
+  }
+}
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
diff --git a/dist/Tie-File/t/14_lock.t b/dist/Tie-File/t/14_lock.t
new file mode 100644
index 0000000000..cab48125b0
--- /dev/null
+++ b/dist/Tie-File/t/14_lock.t
@@ -0,0 +1,50 @@
+#!/usr/bin/perl
+#
+# Check flock() feature
+#
+# This isn't a real test; it just checks to make sure we can call the method.
+# It doesn't even check to make sure that the default behavior
+# (LOCK_EX) is occurring.  This is because I don't know how to write a good
+# portable test for flocking.  I checked the Perl core distribution,
+# and found that Perl doesn't test flock either!
+
+BEGIN {
+  eval { flock STDOUT, 0 };
+  if ($@ && $@ =~ /unimplemented/) {
+    print "1..0\n";
+    exit;
+  }
+}
+
+use Fcntl ':flock';             # This works at least back to 5.004_04
+
+my $file = "tf$$.txt";
+my ($o, $n);
+my @a;
+
+print "1..4\n";
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;
+
+# 2-4  Who the heck knows?
+open F, "> $file" or die $!;
+close F;
+$o = tie @a, 'Tie::File', $file, recsep => 'blah';
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+print $o->flock() ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+print $o->flock(LOCK_UN) ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
diff --git a/dist/Tie-File/t/15_pushpop.t b/dist/Tie-File/t/15_pushpop.t
new file mode 100644
index 0000000000..4b6d1bc959
--- /dev/null
+++ b/dist/Tie-File/t/15_pushpop.t
@@ -0,0 +1,135 @@
+#!/usr/bin/perl
+#
+# Check PUSH, POP, SHIFT, and UNSHIFT 
+#
+# Each call to 'check_contents' actually performs two tests.
+# First, it calls the tied object's own 'check_integrity' method,
+# which makes sure that the contents of the read cache and offset tables
+# accurately reflect the contents of the file.  
+# Then, it checks the actual contents of the file against the expected
+# contents.
+
+use POSIX 'SEEK_SET';
+
+my $file = "tf$$.txt";
+1 while unlink $file;
+$: = Tie::File::_default_recsep();
+my $data = "rec0$:rec1$:rec2$:";
+
+print "1..38\n";
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;  # partial credit just for showing up
+
+my $o = tie @a, 'Tie::File', $file, autochomp => 0;
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+my ($n, @r);
+
+
+# (3-11) PUSH tests
+$n = push @a, "rec0", "rec1", "rec2";
+check_contents($data);
+print $n == 3 ? "ok $N\n" : "not ok $N # size is $n, should be 3\n";
+$N++;
+
+$n = push @a, "rec3", "rec4$:";
+check_contents("$ {data}rec3$:rec4$:");
+print $n == 5 ? "ok $N\n" : "not ok $N # size is $n, should be 5\n";
+$N++;
+
+# Trivial push
+$n = push @a, ();
+check_contents("$ {data}rec3$:rec4$:");
+print $n == 5 ? "ok $N\n" : "not ok $N # size is $n, should be 5\n";
+$N++;
+
+# (12-20) POP tests
+$n = pop @a;
+check_contents("$ {data}rec3$:");
+print $n eq "rec4$:" ? "ok $N\n" : "not ok $N # last rec is $n, should be rec4\n";
+$N++;
+
+# Presumably we have already tested this to death
+splice(@a, 1, 3);
+$n = pop @a;
+check_contents("");
+print $n eq "rec0$:" ? "ok $N\n" : "not ok $N # last rec is $n, should be rec0\n";
+$N++;
+
+$n = pop @a;
+check_contents("");
+print ! defined $n ? "ok $N\n" : "not ok $N # last rec should be undef, is $n\n";
+$N++;
+
+
+# (21-29) UNSHIFT tests
+$n = unshift @a, "rec0", "rec1", "rec2";
+check_contents($data);
+print $n == 3 ? "ok $N\n" : "not ok $N # size is $n, should be 3\n";
+$N++;
+
+$n = unshift @a, "rec3", "rec4$:";
+check_contents("rec3$:rec4$:$data");
+print $n == 5 ? "ok $N\n" : "not ok $N # size is $n, should be 5\n";
+$N++;
+
+# Trivial unshift
+$n = unshift @a, ();
+check_contents("rec3$:rec4$:$data");
+print $n == 5 ? "ok $N\n" : "not ok $N # size is $n, should be 5\n";
+$N++;
+
+# (30-38) SHIFT tests
+$n = shift @a;
+check_contents("rec4$:$data");
+print $n eq "rec3$:" ? "ok $N\n" : "not ok $N # last rec is $n, should be rec3\n";
+$N++;
+
+# Presumably we have already tested this to death
+splice(@a, 1, 3);
+$n = shift @a;
+check_contents("");
+print $n eq "rec4$:" ? "ok $N\n" : "not ok $N # last rec is $n, should be rec4\n";
+$N++;
+
+$n = shift @a;
+check_contents("");
+print ! defined $n ? "ok $N\n" : "not ok $N # last rec should be undef, is $n\n";
+$N++;
+
+
+sub check_contents {
+  my $x = shift;
+  my $integrity = $o->_check_integrity($file, $ENV{INTEGRITY});
+  print $integrity ? "ok $N\n" : "not ok $N\n";
+  $N++;
+
+  local *FH = $o->{fh};
+  seek FH, 0, SEEK_SET;
+  my $a;
+  { local $/; $a = <FH> }
+  $a = "" unless defined $a;
+  if ($a eq $x) {
+    print "ok $N\n";
+  } else {
+    ctrlfix(my $msg = "# expected <$x>, got <$a>");
+    print "not ok $N\n$msg\n";
+  }
+  $N++;
+}
+
+sub ctrlfix {
+  for (@_) {
+    s/\n/\\n/g;
+    s/\r/\\r/g;
+  }
+}
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
diff --git a/dist/Tie-File/t/16_handle.t b/dist/Tie-File/t/16_handle.t
new file mode 100644
index 0000000000..f799496be1
--- /dev/null
+++ b/dist/Tie-File/t/16_handle.t
@@ -0,0 +1,160 @@
+#!/usr/bin/perl
+#
+# Basic operation, initializing the object from an already-open handle
+# instead of from a filename
+
+my $file = "tf$$.txt";
+$: = Tie::File::_default_recsep();
+
+if ($^O =~ /vms/i) {
+  print "1..0\n";
+  exit;
+}
+
+print "1..39\n";
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;
+
+use Fcntl 'O_CREAT', 'O_RDWR';
+sysopen F, $file, O_CREAT | O_RDWR 
+  or die "Couldn't create temp file $file: $!; aborting";
+binmode F;
+
+my $o = tie @a, 'Tie::File', \*F, autochomp => 0, autodefer => 0;
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+# 3-4 create
+$a[0] = 'rec0';
+check_contents("rec0");
+
+# 5-8 append
+$a[1] = 'rec1';
+check_contents("rec0", "rec1");
+$a[2] = 'rec2';
+check_contents("rec0", "rec1", "rec2");
+
+# 9-14 same-length alterations
+$a[0] = 'new0';
+check_contents("new0", "rec1", "rec2");
+$a[1] = 'new1';
+check_contents("new0", "new1", "rec2");
+$a[2] = 'new2';
+check_contents("new0", "new1", "new2");
+
+# 15-24 lengthening alterations
+$a[0] = 'long0';
+check_contents("long0", "new1", "new2");
+$a[1] = 'long1';
+check_contents("long0", "long1", "new2");
+$a[2] = 'long2';
+check_contents("long0", "long1", "long2");
+$a[1] = 'longer1';
+check_contents("long0", "longer1", "long2");
+$a[0] = 'longer0';
+check_contents("longer0", "longer1", "long2");
+
+# 25-38 shortening alterations, including truncation
+$a[0] = 'short0';
+check_contents("short0", "longer1", "long2");
+$a[1] = 'short1';
+check_contents("short0", "short1", "long2");
+$a[2] = 'short2';
+check_contents("short0", "short1", "short2");
+$a[1] = 'sh1';
+check_contents("short0", "sh1", "short2");
+$a[0] = 'sh0';
+check_contents("sh0", "sh1", "short2");
+
+# file with holes
+$a[4] = 'rec4';
+check_contents("sh0", "sh1", "short2", "", "rec4");
+$a[3] = 'rec3';
+check_contents("sh0", "sh1", "short2", "rec3", "rec4");
+
+close F;
+undef $o;
+untie @a;
+
+# (39) Does it correctly detect a non-seekable handle?
+{  if ($^O =~ /^(MSWin32|dos|beos)$/) {
+     print "ok $N # skipped ($^O has broken pipe semantics)\n";
+     last;
+   }
+   if ($] < 5.006) {
+     print "ok $N # skipped - 5.005_03 panics after this test\n";
+     last;
+   }
+   my $pipe_succeeded = eval {pipe *R, *W};
+   if ($@) {
+     chomp $@;
+     print "ok $N # skipped (no pipes: $@)\n";
+     last;
+   } elsif (! $pipe_succeeded) {
+     print "ok $N # skipped (pipe call failed: $!)\n";
+     last;
+   }
+   close R;
+   $o = eval {tie @a, 'Tie::File', \*W};
+   if ($@) {
+     if ($@ =~ /filehandle does not appear to be seekable/) {
+       print "ok $N\n";
+     } else {
+       chomp $@;
+       print "not ok $N \# \$\@ is $@\n";
+     }
+   } else {
+       print "not ok $N \# passing pipe to TIEARRAY didn't abort program\n";
+   }
+   $N++;
+}
+
+use POSIX 'SEEK_SET';
+sub check_contents {
+  my @c = @_;
+  my $x = join $:, @c, '';
+  local *FH = $o->{fh};
+  seek FH, 0, SEEK_SET;
+#  my $open = open FH, "< $file";
+  my $a;
+  { local $/; $a = <FH> }
+  $a = "" unless defined $a;
+  if ($a eq $x) {
+    print "ok $N\n";
+  } else {
+    ctrlfix(my $msg = "# expected <$x>, got <$a>");
+    print "not ok $N\n$msg\n";
+  }
+  $N++;
+
+  # now check FETCH:
+  my $good = 1;
+  my $msg;
+  for (0.. $#c) {
+    unless ($a[$_] eq "$c[$_]$:") {
+      $msg = "expected $c[$_]$:, got $a[$_]";
+      ctrlfix($msg);
+      $good = 0;
+    }
+  }
+  print $good ? "ok $N\n" : "not ok $N # $msg\n";
+  $N++;
+}
+
+
+sub ctrlfix {
+  for (@_) {
+    s/\n/\\n/g;
+    s/\r/\\r/g;
+  }
+}
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
+
diff --git a/dist/Tie-File/t/17_misc_meth.t b/dist/Tie-File/t/17_misc_meth.t
new file mode 100644
index 0000000000..020774bb91
--- /dev/null
+++ b/dist/Tie-File/t/17_misc_meth.t
@@ -0,0 +1,158 @@
+#!/usr/bin/perl
+#
+# Check miscellaneous tied-array interface methods
+# EXTEND, CLEAR, DELETE, EXISTS
+#
+
+my $file = "tf$$.txt";
+$: = Tie::File::_default_recsep();
+1 while unlink $file;
+
+print "1..35\n";
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;
+
+my $o = tie @a, 'Tie::File', $file, autodefer => 0;
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+# (3-8) EXTEND
+$o->EXTEND(3);
+check_contents("$:$:$:");
+$o->EXTEND(4);
+check_contents("$:$:$:$:");
+$o->EXTEND(3);
+check_contents("$:$:$:$:");
+
+# (9-10) CLEAR
+@a = ();
+check_contents("");
+
+# (11-20) EXISTS
+if ($] >= 5.006) {
+  eval << 'TESTS';
+print !exists $a[0] ? "ok $N\n" : "not ok $N\n";
+$N++;
+$a[0] = "I like pie.";
+print exists $a[0] ? "ok $N\n" : "not ok $N\n";
+$N++;
+print !exists $a[1] ? "ok $N\n" : "not ok $N\n";
+$N++;
+$a[2] = "GIVE ME PIE";
+print exists $a[0] ? "ok $N\n" : "not ok $N\n";
+$N++;
+# exists $a[1] is not defined by this module under these circumstances
+print exists $a[1] ? "ok $N\n" : "ok $N\n";
+$N++;
+print exists $a[2] ? "ok $N\n" : "not ok $N\n";
+$N++;
+print exists $a[-1] ? "ok $N\n" : "not ok $N\n";
+$N++;
+print exists $a[-2] ? "ok $N\n" : "not ok $N\n";
+$N++;
+print exists $a[-3] ? "ok $N\n" : "not ok $N\n";
+$N++;
+print !exists $a[-4] ? "ok $N\n" : "not ok $N\n";
+$N++;
+TESTS
+  } else {                      # perl 5.005 doesn't have exists $array[1]
+    for (11..20) {
+      print "ok $_ \# skipped (no exists for arrays)\n";
+          $N++;
+    }
+  }
+
+my $del;
+
+# (21-35) DELETE
+if ($] >= 5.006) {
+  eval << 'TESTS';
+$del = delete $a[0];
+check_contents("$:$:GIVE ME PIE$:");
+# 20020317 Through 0.20, the 'delete' function returned the wrong values.
+expect($del, "I like pie.");
+$del = delete $a[2];
+check_contents("$:$:");
+expect($del, "GIVE ME PIE");
+$del = delete $a[0];
+check_contents("$:$:");
+expect($del, "");
+$del = delete $a[1];
+check_contents("$:");
+expect($del, "");
+
+# 20020317 Through 0.20, we had a bug where deleting an element past the 
+# end of the array would actually extend the array to that length.
+$del = delete $a[4];
+check_contents("$:");
+expect($del, undef);
+
+
+
+TESTS
+  } else {                      # perl 5.005 doesn't have delete $array[1]
+    for (21..35) {
+      print "ok $_ \# skipped (no delete for arrays)\n";
+          $N++;
+    }
+  }
+
+use POSIX 'SEEK_SET';
+sub check_contents {
+  my $x = shift;
+  local *FH = $o->{fh};
+  seek FH, 0, SEEK_SET;
+  my $a;
+  { local $/; $a = <FH> }
+  $a = "" unless defined $a;
+  if ($a eq $x) {
+    print "ok $N\n";
+  } else {
+    ctrlfix(my $msg = "# expected <$x>, got <$a>");
+    print "not ok $N # $msg\n";
+  }
+  $N++;
+  print $o->_check_integrity($file, $ENV{INTEGRITY}) ? "ok $N\n" : "not ok $N\n";
+  $N++;
+}
+
+sub expect {
+  if (@_ == 1) {
+    print $_[0] ? "ok $N\n" : "not ok $N\n";
+  } elsif (@_ == 2) {
+    my ($a, $x) = @_;
+    if    (! defined($a) && ! defined($x)) { print "ok $N\n" }
+    elsif (  defined($a) && ! defined($x)) { 
+      ctrlfix(my $msg = "expected UNDEF, got <$a>");
+      print "not ok $N \# $msg\n";
+    }
+    elsif (! defined($a) &&   defined($x)) { 
+      ctrlfix(my $msg = "expected <$x>, got UNDEF");
+      print "not ok $N \# $msg\n";
+    } elsif ($a eq $x) { print "ok $N\n" }
+    else {
+      ctrlfix(my $msg = "expected <$x>, got <$a>");
+      print "not ok $N \# $msg\n";
+    }
+  } else {
+    die "expect() got ", scalar(@_), " args, should have been 1 or 2";
+  }
+  $N++;
+}
+
+sub ctrlfix {
+  for (@_) {
+    s/\n/\\n/g;
+    s/\r/\\r/g;
+  }
+}
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
+
diff --git a/dist/Tie-File/t/18_rs_fixrec.t b/dist/Tie-File/t/18_rs_fixrec.t
new file mode 100644
index 0000000000..3c2a807e64
--- /dev/null
+++ b/dist/Tie-File/t/18_rs_fixrec.t
@@ -0,0 +1,53 @@
+#!/usr/bin/perl
+
+use POSIX 'SEEK_SET';
+my $file = "tf$$.txt";
+$/ = "blah";
+
+print "1..5\n";
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;
+
+my $o = tie @a, 'Tie::File', $file, autodefer => 0;
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+$a[0] = 'rec0';
+check_contents("rec0blah");
+$a[1] = "rec1blah";
+check_contents("rec0blahrec1blah");
+$a[2] = "rec2blahblah";             # should we detect this?
+check_contents("rec0blahrec1blahrec2blahblah");
+
+sub check_contents {
+  my $x = shift;
+  local *FH = $o->{fh};
+  seek FH, 0, SEEK_SET;
+  my $a;
+  { local $/; $a = <FH> }
+  $a = "" unless defined $a;
+  if ($a eq $x) {
+    print "ok $N\n";
+  } else {
+    my $msg = "not ok $N # expected <$x>, got <$a>";
+    ctrlfix($msg);
+    print "$msg\n";
+  }
+  $N++;
+}
+
+sub ctrlfix {
+  for (@_) {
+    s/\n/\\n/g;
+    s/\r/\\r/g;
+  }
+}
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
diff --git a/dist/Tie-File/t/19_cache.t b/dist/Tie-File/t/19_cache.t
new file mode 100644
index 0000000000..81c693263e
--- /dev/null
+++ b/dist/Tie-File/t/19_cache.t
@@ -0,0 +1,205 @@
+#!/usr/bin/perl
+#
+# Tests for various caching errors
+#
+
+$|=1;
+my $file = "tf$$.txt";
+$: = Tie::File::_default_recsep();
+my $data = join $:, "rec0" .. "rec9", "";
+my $V = $ENV{INTEGRITY};        # Verbose integrity checking?
+
+print "1..55\n";
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;
+
+open F, "> $file" or die $!;
+binmode F;
+print F $data;
+close F;
+
+my $o = tie @a, 'Tie::File', $file;
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+# (3) Through 0.18, this 'splice' call would corrupt the cache.
+my @z = @a;                     # force cache to contain all ten records
+splice @a, 0, 0, "x";
+print $o->_check_integrity($file, $V) ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+# Here we redo *all* the splice tests, with populate()
+# calls before each one, to make sure that splice() does not botch the cache.
+
+# (4-14) splicing at the beginning
+check();
+splice(@a, 0, 0, "rec4");
+check();
+splice(@a, 0, 1, "rec5");       # same length
+check();
+splice(@a, 0, 1, "record5");    # longer
+check();
+splice(@a, 0, 1, "r5");         # shorter
+check();
+splice(@a, 0, 1);               # removal
+check();
+splice(@a, 0, 0);               # no-op
+check();
+
+splice(@a, 0, 0, 'r7', 'rec8'); # insert more than one
+check();
+splice(@a, 0, 2, 'rec7', 'record8', 'rec9'); # insert more than delete
+check();
+splice(@a, 0, 3, 'record9', 'rec10'); # delete more than insert
+check();
+splice(@a, 0, 2);               # delete more than one
+check();
+
+
+# (15-24) splicing in the middle
+splice(@a, 1, 0, "rec4");
+check();
+splice(@a, 1, 1, "rec5");       # same length
+check();
+splice(@a, 1, 1, "record5");    # longer
+check();
+splice(@a, 1, 1, "r5");         # shorter
+check();
+splice(@a, 1, 1);               # removal
+check();
+splice(@a, 1, 0);               # no-op
+check();
+
+splice(@a, 1, 0, 'r7', 'rec8'); # insert more than one
+check();
+splice(@a, 1, 2, 'rec7', 'record8', 'rec9'); # insert more than delete
+check();
+splice(@a, 1, 3, 'record9', 'rec10'); # delete more than insert
+check();
+splice(@a, 1, 2);               # delete more than one
+check();
+
+# (25-34) splicing at the end
+splice(@a, 3, 0, "rec4");
+check();
+splice(@a, 3, 1, "rec5");       # same length
+check();
+splice(@a, 3, 1, "record5");    # longer
+check();
+splice(@a, 3, 1, "r5");         # shorter
+check();
+splice(@a, 3, 1);               # removal
+check();
+splice(@a, 3, 0);               # no-op
+check();
+
+splice(@a, 3, 0, 'r7', 'rec8'); # insert more than one
+check();
+splice(@a, 3, 2, 'rec7', 'record8', 'rec9'); # insert more than delete
+check();
+splice(@a, 3, 3, 'record9', 'rec10'); # delete more than insert
+check();
+splice(@a, 3, 2);               # delete more than one
+check();
+
+# (35-44) splicing with negative subscript
+splice(@a, -1, 0, "rec4");
+check();
+splice(@a, -1, 1, "rec5");       # same length
+check();
+splice(@a, -1, 1, "record5");    # longer
+check();
+splice(@a, -1, 1, "r5");         # shorter
+check();
+splice(@a, -1, 1);               # removal
+check();
+splice(@a, -1, 0);               # no-op  
+check();
+
+splice(@a, -1, 0, 'r7', 'rec8'); # insert more than one
+check();
+splice(@a, -1, 2, 'rec7', 'record8', 'rec9'); # insert more than delete
+check();
+splice(@a, -3, 3, 'record9', 'rec10'); # delete more than insert
+check();
+splice(@a, -4, 3);               # delete more than one
+check();
+
+# (45) scrub it all out
+splice(@a, 0, 3);
+check();
+
+# (46) put some back in
+splice(@a, 0, 0, "rec0", "rec1");
+check();
+
+# (47) what if we remove too many records?
+splice(@a, 0, 17);
+check();
+
+# (48-49) In the past, splicing past the end was not correctly detected
+# (1.14)
+splice(@a, 89, 3);
+check();
+splice(@a, @a, 3);
+check();
+
+# (50-51) Also we did not emulate splice's freaky behavior when inserting
+# past the end of the array (1.14)
+splice(@a, 89, 0, "I", "like", "pie");
+check();
+splice(@a, 89, 0, "pie pie pie");
+check();
+
+# (52-54) Test default arguments
+splice @a, 0, 0, (0..11);
+check();
+splice @a, 4;
+check();
+splice @a;
+check();
+    
+# (55) This was broken on 20030507 when you moved the cache management
+# stuff out of _oadjust back into _splice without also putting it back 
+# into _store.
+@a = (0..11);
+check();
+
+sub init_file {
+  my $data = shift;
+  open F, "> $file" or die $!;
+  binmode F;
+  print F $data;
+  close F;
+}
+
+sub check {
+  my $integrity = $o->_check_integrity($file, $ENV{INTEGRITY});
+  print $integrity ? "ok $N\n" : "not ok $N\n";
+  $N++;
+  repopulate();
+}
+
+
+sub ctrlfix {
+  for (@_) {
+    s/\n/\\n/g;
+    s/\r/\\r/g;
+  }
+}
+
+sub repopulate {
+  $o->{cache}->empty;
+  my @z = @a;                   # refill the cache with correct data
+}
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
+
+
diff --git a/dist/Tie-File/t/20_cache_full.t b/dist/Tie-File/t/20_cache_full.t
new file mode 100644
index 0000000000..8b3bf0b2e0
--- /dev/null
+++ b/dist/Tie-File/t/20_cache_full.t
@@ -0,0 +1,228 @@
+#!/usr/bin/perl
+#
+# Tests for various caching errors
+#
+
+my $file = "tf$$.txt";
+$: = Tie::File::_default_recsep();
+my $data = join $:, "record0" .. "record9", "";
+my $V = $ENV{INTEGRITY};        # Verbose integrity checking?
+
+print "1..111\n";
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;
+
+open F, "> $file" or die $!;
+binmode F;
+print F $data;
+close F;
+
+# Limit cache size to 30 bytes 
+my $MAX = 30;
+#  -- that's enough space for 3 records, but not 4, on both \n and \r\n systems
+my $o = tie @a, 'Tie::File', $file, memory => $MAX, autodefer => 0;
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+# (3-5) Let's see if data was properly expired from the cache
+my @z = @a;                     # force cache to contain all ten records
+# It should now contain only the *last* three records, 7, 8, and 9
+{
+  my $x = "7 8 9";
+  my $a = join " ", sort $o->{cache}->ckeys;
+  if ($a eq $x) { print "ok $N\n" }
+  else { print "not ok $N # cache keys were <$a>; expected <$x>\n" }
+  $N++;
+}
+check();
+
+# Here we redo *all* the splice tests, with populate()
+# calls before each one, to make sure that splice() does not botch the cache.
+
+# (6-25) splicing at the beginning
+splice(@a, 0, 0, "rec4");
+check();
+splice(@a, 0, 1, "rec5");       # same length
+check();
+splice(@a, 0, 1, "record5");    # longer
+check();
+splice(@a, 0, 1, "r5");         # shorter
+check();
+splice(@a, 0, 1);               # removal
+check();
+splice(@a, 0, 0);               # no-op
+check();
+
+splice(@a, 0, 0, 'r7', 'rec8'); # insert more than one
+check();
+splice(@a, 0, 2, 'rec7', 'record8', 'rec9'); # insert more than delete
+check();
+splice(@a, 0, 3, 'record9', 'rec10'); # delete more than insert
+check();
+splice(@a, 0, 2);               # delete more than one
+check();
+
+
+# (26-45) splicing in the middle
+splice(@a, 1, 0, "rec4");
+check();
+splice(@a, 1, 1, "rec5");       # same length
+check();
+splice(@a, 1, 1, "record5");    # longer
+check();
+splice(@a, 1, 1, "r5");         # shorter
+check();
+splice(@a, 1, 1);               # removal
+check();
+splice(@a, 1, 0);               # no-op
+check();
+
+splice(@a, 1, 0, 'r7', 'rec8'); # insert more than one
+check();
+splice(@a, 1, 2, 'rec7', 'record8', 'rec9'); # insert more than delete
+check();
+splice(@a, 1, 3, 'record9', 'rec10'); # delete more than insert
+check();
+splice(@a, 1, 2);               # delete more than one
+check();
+
+# (46-65) splicing at the end
+splice(@a, 3, 0, "rec4");
+check();
+splice(@a, 3, 1, "rec5");       # same length
+check();
+splice(@a, 3, 1, "record5");    # longer
+check();
+splice(@a, 3, 1, "r5");         # shorter
+check();
+splice(@a, 3, 1);               # removal
+check();
+splice(@a, 3, 0);               # no-op
+check();
+
+splice(@a, 3, 0, 'r7', 'rec8'); # insert more than one
+check();
+splice(@a, 3, 2, 'rec7', 'record8', 'rec9'); # insert more than delete
+check();
+splice(@a, 3, 3, 'record9', 'rec10'); # delete more than insert
+check();
+splice(@a, 3, 2);               # delete more than one
+check();
+
+# (66-85) splicing with negative subscript
+splice(@a, -1, 0, "rec4");
+check();
+splice(@a, -1, 1, "rec5");       # same length
+check();
+splice(@a, -1, 1, "record5");    # longer
+check();
+splice(@a, -1, 1, "r5");         # shorter
+check();
+splice(@a, -1, 1);               # removal
+check();
+splice(@a, -1, 0);               # no-op  
+check();
+
+splice(@a, -1, 0, 'r7', 'rec8'); # insert more than one
+check();
+splice(@a, -1, 2, 'rec7', 'record8', 'rec9'); # insert more than delete
+check();
+splice(@a, -3, 3, 'record9', 'rec10'); # delete more than insert
+check();
+splice(@a, -4, 3);               # delete more than one
+check();
+
+# (86-87) scrub it all out
+splice(@a, 0, 3);
+check();
+
+# (88-89) put some back in
+splice(@a, 0, 0, "rec0", "rec1");
+check();
+
+# (90-91) what if we remove too many records?
+splice(@a, 0, 17);
+check();
+
+# (92-95) In the past, splicing past the end was not correctly detected
+# (1.14)
+splice(@a, 89, 3);
+check();
+splice(@a, @a, 3);
+check();
+
+# (96-99) Also we did not emulate splice's freaky behavior when inserting
+# past the end of the array (1.14)
+splice(@a, 89, 0, "I", "like", "pie");
+check();
+splice(@a, 89, 0, "pie pie pie");
+check();
+
+# (100-105) Test default arguments
+splice @a, 0, 0, (0..11);
+check();
+splice @a, 4;
+check();
+splice @a;
+check();
+
+# (106-111) One last set of tests.  I don't know what state the cache
+# is in now.  But if I read any three records, those three records are
+# what should be in the cache, and nothing else.
+@a = "record0" .. "record9";
+check(); # In 0.18 #107 fails here--STORE was not flushing the cache when
+         # replacing an old cached record with a longer one
+for (5, 6, 1) { my $z = $a[$_] }
+{
+  my $x = "5 6 1";
+  my $a = join " ", $o->{cache}->_produce_lru;
+  if ($a eq $x) { print "ok $N\n" }
+  else { print "not ok $N # LRU was <$a>; expected <$x>\n" }
+  $N++;
+  $x = "1 5 6";
+  $a = join " ", sort $o->{cache}->ckeys;
+  if ($a eq $x) { print "ok $N\n" }
+  else { print "not ok $N # cache keys were <$a>; expected <$x>\n" }
+  $N++;
+}
+check();
+
+
+sub init_file {
+  my $data = shift;
+  open F, "> $file" or die $!;
+  binmode F;
+  print F $data;
+  close F;
+}
+
+sub check {
+  my $integrity = $o->_check_integrity($file, $ENV{INTEGRITY});
+  print $integrity ? "ok $N\n" : "not ok $N\n";
+  $N++;
+
+  my $b = $o->{cache}->bytes;
+  print $b <= $MAX 
+    ? "ok $N\n" 
+    : "not ok $N # $b bytes cached, should be <= $MAX\n";
+  $N++;
+}
+
+
+sub ctrlfix {
+  for (@_) {
+    s/\n/\\n/g;
+    s/\r/\\r/g;
+  }
+}
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
+
+
diff --git a/dist/Tie-File/t/21_win32.t b/dist/Tie-File/t/21_win32.t
new file mode 100644
index 0000000000..d06854441b
--- /dev/null
+++ b/dist/Tie-File/t/21_win32.t
@@ -0,0 +1,61 @@
+#!/usr/bin/perl
+#
+# Formerly, on a Win32 system, Tie::File would create files with
+# \n-terminated records instead of \r\n-terminated.  The tests never
+# picked this up because they were using $/ everywhere, and $/ is \n
+# on windows systems.
+#
+# These tests (Win32 only) make sure that the file had \r\n as it should.
+
+my $file = "tf$$.txt";
+
+unless ($^O =~ /^(MSWin32|dos)$/) {
+  print "1..0\n";
+  exit;
+}
+
+
+print "1..3\n";
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;
+
+my $o = tie @a, 'Tie::File', $file, autodefer => 0;
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+my $n;
+
+# (3) Make sure that on Win32 systems, the file is written with \r\n by default
+@a = qw(fish dog carrot);
+undef $o;
+untie @a;
+open F, "< $file" or die "Couldn't open file $file: $!";
+binmode F;
+my $a = do {local $/ ; <F> };
+my $x = "fish\r\ndog\r\ncarrot\r\n" ;
+if ($a eq $x) {
+  print "ok $N\n";
+} else {
+  ctrlfix(my $msg = "expected <$x>, got <$a>");
+  print "not ok $N # $msg\n";
+}
+
+close F;
+
+sub ctrlfix {
+  for (@_) {
+    s/\n/\\n/g;
+    s/\r/\\r/g;
+  }
+}
+
+
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
diff --git a/dist/Tie-File/t/22_autochomp.t b/dist/Tie-File/t/22_autochomp.t
new file mode 100644
index 0000000000..dee07a8ec8
--- /dev/null
+++ b/dist/Tie-File/t/22_autochomp.t
@@ -0,0 +1,175 @@
+#!/usr/bin/perl
+
+my $file = "tf$$.txt";
+$: = Tie::File::_default_recsep();
+
+print "1..71\n";
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;
+
+my $o = tie @a, 'Tie::File', $file, autochomp => 1, autodefer => 0;
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+# 3-5 create
+$a[0] = 'rec0';
+check_contents("rec0");
+
+# 6-11 append
+$a[1] = 'rec1';
+check_contents("rec0", "rec1");
+$a[2] = 'rec2';
+check_contents("rec0", "rec1", "rec2");
+
+# 12-20 same-length alterations
+$a[0] = 'new0';
+check_contents("new0", "rec1", "rec2");
+$a[1] = 'new1';
+check_contents("new0", "new1", "rec2");
+$a[2] = 'new2';
+check_contents("new0", "new1", "new2");
+
+# 21-35 lengthening alterations
+$a[0] = 'long0';
+check_contents("long0", "new1", "new2");
+$a[1] = 'long1';
+check_contents("long0", "long1", "new2");
+$a[2] = 'long2';
+check_contents("long0", "long1", "long2");
+$a[1] = 'longer1';
+check_contents("long0", "longer1", "long2");
+$a[0] = 'longer0';
+check_contents("longer0", "longer1", "long2");
+
+# 36-50 shortening alterations, including truncation
+$a[0] = 'short0';
+check_contents("short0", "longer1", "long2");
+$a[1] = 'short1';
+check_contents("short0", "short1", "long2");
+$a[2] = 'short2';
+check_contents("short0", "short1", "short2");
+$a[1] = 'sh1';
+check_contents("short0", "sh1", "short2");
+$a[0] = 'sh0';
+check_contents("sh0", "sh1", "short2");
+
+# (51-56) file with holes
+$a[4] = 'rec4';
+check_contents("sh0", "sh1", "short2", "", "rec4");
+$a[3] = 'rec3';
+check_contents("sh0", "sh1", "short2", "rec3", "rec4");
+
+# (57-59) zero out file
+@a = ();
+check_contents();
+
+# (60-62) insert into the middle of an empty file
+$a[3] = "rec3";
+check_contents("", "", "", "rec3");
+
+# (63-68) Test the ->autochomp() method
+@a = qw(Gold Frankincense Myrrh);
+my $ac;
+$ac = $o->autochomp();
+expect($ac);
+# See if that accidentally changed it
+$ac = $o->autochomp();
+expect($ac);
+# Now clear it
+$ac = $o->autochomp(0);
+expect($ac);
+expect(join("-", @a), "Gold$:-Frankincense$:-Myrrh$:");
+# Now set it again
+$ac = $o->autochomp(1);
+expect(!$ac);
+expect(join("-", @a), "Gold-Frankincense-Myrrh");
+
+# (69) Does 'splice' work correctly with autochomp?
+my @sr;
+@sr = splice @a, 0, 2;
+expect(join("-", @sr), "Gold-Frankincense");
+
+# (70-71) Didn't you forget that fetch may return an unchomped cached record?
+$a1 = $a[0];                    # populate cache
+$a2 = $a[0];
+expect($a1, "Myrrh");
+expect($a2, "Myrrh");
+# Actually no, you didn't---_fetch might return such a record, but 
+# the chomping is done by FETCH.
+
+use POSIX 'SEEK_SET';
+sub check_contents {
+  my @c = @_;
+  my $x = join $:, @c, '';
+  local *FH = $o->{fh};
+  seek FH, 0, SEEK_SET;
+#  my $open = open FH, "< $file";
+  my $a;
+  { local $/; $a = <FH> }
+  $a = "" unless defined $a;
+  if ($a eq $x) {
+    print "ok $N\n";
+  } else {
+    ctrlfix($a, $x);
+    print "not ok $N\n# expected <$x>, got <$a>\n";
+  }
+  $N++;
+
+  # now check FETCH:
+  my $good = 1;
+  my $msg;
+  for (0.. $#c) {
+    my $aa = $a[$_];
+    unless ($aa eq $c[$_]) {
+      $msg = "expected <$c[$_]>, got <$aa>";
+      ctrlfix($msg);
+      $good = 0;
+    }
+  }
+  print $good ? "ok $N\n" : "not ok $N # $msg\n";
+  $N++;
+
+  print $o->_check_integrity($file, $ENV{INTEGRITY}) 
+      ? "ok $N\n" : "not ok $N\n";
+  $N++;
+}
+
+sub expect {
+  if (@_ == 1) {
+    print $_[0] ? "ok $N\n" : "not ok $N\n";
+  } elsif (@_ == 2) {
+    my ($a, $x) = @_;
+    if    (! defined($a) && ! defined($x)) { print "ok $N\n" }
+    elsif (  defined($a) && ! defined($x)) { 
+      ctrlfix(my $msg = "expected UNDEF, got <$a>");
+      print "not ok $N \# $msg\n";
+    }
+    elsif (! defined($a) &&   defined($x)) { 
+      ctrlfix(my $msg = "expected <$x>, got UNDEF");
+      print "not ok $N \# $msg\n";
+    } elsif ($a eq $x) { print "ok $N\n" }
+    else {
+      ctrlfix(my $msg = "expected <$x>, got <$a>");
+      print "not ok $N \# $msg\n";
+    }
+  } else {
+    die "expect() got ", scalar(@_), " args, should have been 1 or 2";
+  }
+  $N++;
+}
+
+sub ctrlfix {
+  for (@_) {
+    s/\n/\\n/g;
+    s/\r/\\r/g;
+  }
+}
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
diff --git a/dist/Tie-File/t/23_rv_ac_splice.t b/dist/Tie-File/t/23_rv_ac_splice.t
new file mode 100644
index 0000000000..be229574f9
--- /dev/null
+++ b/dist/Tie-File/t/23_rv_ac_splice.t
@@ -0,0 +1,182 @@
+#!/usr/bin/perl
+#
+# Check SPLICE function's return value when autochoping is now
+# (07_rv_splice.t checks it aith autochomping off)
+#
+
+my $file = "tf$$.txt";
+$: = Tie::File::_default_recsep();
+my $data = "rec0$:rec1$:rec2$:";
+
+print "1..50\n";
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;  # partial credit just for showing up
+
+init_file($data);
+
+my $o = tie @a, 'Tie::File', $file, autochomp => 1;
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+my $n;
+
+# (3-12) splicing at the beginning
+@r = splice(@a, 0, 0, "rec4");
+check_result();
+@r = splice(@a, 0, 1, "rec5");       # same length
+check_result("rec4");
+@r = splice(@a, 0, 1, "record5");    # longer
+check_result("rec5");
+
+@r = splice(@a, 0, 1, "r5");         # shorter
+check_result("record5");
+@r = splice(@a, 0, 1);               # removal
+check_result("r5");
+@r = splice(@a, 0, 0);               # no-op
+check_result();
+@r = splice(@a, 0, 0, 'r7', 'rec8'); # insert more than one
+check_result();
+@r = splice(@a, 0, 2, 'rec7', 'record8', 'rec9'); # insert more than delete
+check_result('r7', 'rec8');
+
+@r = splice(@a, 0, 3, 'record9', 'rec10'); # delete more than insert
+check_result('rec7', 'record8', 'rec9');
+@r = splice(@a, 0, 2);               # delete more than one
+check_result('record9', 'rec10');
+
+
+# (13-22) splicing in the middle
+@r = splice(@a, 1, 0, "rec4");
+check_result();
+@r = splice(@a, 1, 1, "rec5");       # same length
+check_result('rec4');
+@r = splice(@a, 1, 1, "record5");    # longer
+check_result('rec5');
+
+@r = splice(@a, 1, 1, "r5");         # shorter
+check_result("record5");
+@r = splice(@a, 1, 1);               # removal
+check_result("r5");
+@r = splice(@a, 1, 0);               # no-op
+check_result();
+@r = splice(@a, 1, 0, 'r7', 'rec8'); # insert more than one
+check_result();
+@r = splice(@a, 1, 2, 'rec7', 'record8', 'rec9'); # insert more than delete
+check_result('r7', 'rec8');
+
+@r = splice(@a, 1, 3, 'record9', 'rec10'); # delete more than insert
+check_result('rec7', 'record8', 'rec9');
+@r = splice(@a, 1, 2);               # delete more than one
+check_result('record9','rec10');
+
+# (23-32) splicing at the end
+@r = splice(@a, 3, 0, "rec4");
+check_result();
+@r = splice(@a, 3, 1, "rec5");       # same length
+check_result('rec4');
+@r = splice(@a, 3, 1, "record5");    # longer
+check_result('rec5');
+
+@r = splice(@a, 3, 1, "r5");         # shorter
+check_result('record5');
+@r = splice(@a, 3, 1);               # removal
+check_result('r5');
+@r = splice(@a, 3, 0);               # no-op
+check_result();
+@r = splice(@a, 3, 0, 'r7', 'rec8'); # insert more than one
+check_result();
+@r = splice(@a, 3, 2, 'rec7', 'record8', 'rec9'); # insert more than delete
+check_result('r7', 'rec8');
+
+@r = splice(@a, 3, 3, 'record9', 'rec10'); # delete more than insert
+check_result('rec7', 'record8', 'rec9');
+@r = splice(@a, 3, 2);               # delete more than one
+check_result('record9', 'rec10');
+
+# (33-42) splicing with negative subscript
+@r = splice(@a, -1, 0, "rec4");
+check_result();
+@r = splice(@a, -1, 1, "rec5");       # same length
+check_result('rec2');
+@r = splice(@a, -1, 1, "record5");    # longer
+check_result("rec5");
+
+@r = splice(@a, -1, 1, "r5");         # shorter
+check_result("record5");
+@r = splice(@a, -1, 1);               # removal
+check_result("r5");
+@r = splice(@a, -1, 0);               # no-op  
+check_result();
+@r = splice(@a, -1, 0, 'r7', 'rec8'); # insert more than one
+check_result();
+@r = splice(@a, -1, 2, 'rec7', 'record8', 'rec9'); # insert more than delete
+check_result('rec4');
+
+@r = splice(@a, -3, 3, 'record9', 'rec10'); # delete more than insert
+check_result('rec7', 'record8', 'rec9');
+@r = splice(@a, -4, 3);               # delete more than one
+check_result('r7', 'rec8', 'record9');
+
+# (43) scrub it all out
+@r = splice(@a, 0, 3);
+check_result('rec0', 'rec1', 'rec10');
+
+# (44) put some back in
+@r = splice(@a, 0, 0, "rec0", "rec1");
+check_result();
+
+# (45) what if we remove too many records?
+@r = splice(@a, 0, 17);
+check_result('rec0', 'rec1');
+
+# (46-48) Now check the scalar context return
+splice(@a, 0, 0, qw(I like pie));
+my $r;
+$r = splice(@a, 0, 0);
+print !defined($r) ? "ok $N\n" : "not ok $N \# return should have been undef, was <$r>\n";
+$N++;
+
+$r = splice(@a, 2, 1);
+print $r eq "pie" ? "ok $N\n" : "not ok $N \# return should have been 'pie', was <$r>\n";
+$N++;
+
+$r = splice(@a, 0, 2);
+print $r eq "like" ? "ok $N\n" : "not ok $N \# return should have been 'like', was <$r>\n";
+$N++;
+
+# (49-50) Test default arguments
+splice @a, 0, 0, (0..11);
+@r = splice @a, 4;
+check_result(4..11);
+@r = splice @a;
+check_result(0..3);
+
+sub init_file {
+  my $data = shift;
+  open F, "> $file" or die $!;
+  binmode F;
+  print F $data;
+  close F;
+}
+
+# actual results are in @r.
+# expected results are in @_
+sub check_result {
+  my @x = @_;
+  my $good = 1;
+  $good = 0 unless @r == @x;
+  for my $i (0 .. $#r) {
+    $good = 0 unless $r[$i] eq $x[$i];
+  }
+  print $good ? "ok $N\n" : "not ok $N \# was (@r); should be (@x)\n";
+  $N++;
+}
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
diff --git a/dist/Tie-File/t/24_cache_loop.t b/dist/Tie-File/t/24_cache_loop.t
new file mode 100644
index 0000000000..0bc66bee2b
--- /dev/null
+++ b/dist/Tie-File/t/24_cache_loop.t
@@ -0,0 +1,55 @@
+#!/usr/bin/perl
+#
+# Tests for various caching errors
+#
+
+use Config;
+my $file = "tf$$.txt";
+unless ($Config{d_alarm}) {
+  print "1..0\n"; exit;
+}
+
+$: = Tie::File::_default_recsep();
+my $data = join $:, "record0" .. "record9", "";
+my $V = $ENV{INTEGRITY};        # Verbose integrity checking?
+
+print "1..3\n";
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;
+
+open F, "> $file" or die $!;
+binmode F;
+print F $data;
+close F;
+
+# Limit cache size to 30 bytes 
+my $MAX = 30;
+#  -- that's enough space for 3 records, but not 4, on both \n and \r\n systems
+my $o = tie @a, 'Tie::File', $file, memory => $MAX, autodefer => 1;
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+# (3) In 0.50 this goes into an infinite loop.  Explanation:
+#
+#   Suppose you overfill the defer buffer by so much that the memory
+#   limit is also exceeded.  You'll go into _splice to prepare to
+#   write out the defer buffer, and _splice will call _fetch, which
+#   will then try to flush the read cache---but the read cache is
+#   already empty, so you're stuck in an infinite loop.
+#
+# Five seconds should be plenty of time for it to complete if it works.
+alarm 5 unless $^P;
+@a = "record0" .. "record9";
+print "ok 3\n";
+alarm 0;
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
+
+
diff --git a/dist/Tie-File/t/25_gen_nocache.t b/dist/Tie-File/t/25_gen_nocache.t
new file mode 100644
index 0000000000..78e5506215
--- /dev/null
+++ b/dist/Tie-File/t/25_gen_nocache.t
@@ -0,0 +1,137 @@
+#!/usr/bin/perl
+#
+# Regular read-write tests with caching disabled
+# (Same as 01_gen.t)
+#
+my $file = "tf$$.txt";
+
+print "1..68\n";
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;
+
+my $o = tie @a, 'Tie::File', $file, autochomp => 0, autodefer => 0, memory => 0;
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+$: = $o->{recsep};
+
+# 3-5 create
+$a[0] = 'rec0';
+check_contents("rec0");
+
+# 6-11 append
+$a[1] = 'rec1';
+check_contents("rec0", "rec1");
+$a[2] = 'rec2';
+check_contents("rec0", "rec1", "rec2");
+
+# 12-20 same-length alterations
+$a[0] = 'new0';
+check_contents("new0", "rec1", "rec2");
+$a[1] = 'new1';
+check_contents("new0", "new1", "rec2");
+$a[2] = 'new2';
+check_contents("new0", "new1", "new2");
+
+# 21-35 lengthening alterations
+$a[0] = 'long0';
+check_contents("long0", "new1", "new2");
+$a[1] = 'long1';
+check_contents("long0", "long1", "new2");
+$a[2] = 'long2';
+check_contents("long0", "long1", "long2");
+$a[1] = 'longer1';
+check_contents("long0", "longer1", "long2");
+$a[0] = 'longer0';
+check_contents("longer0", "longer1", "long2");
+
+# 36-50 shortening alterations, including truncation
+$a[0] = 'short0';
+check_contents("short0", "longer1", "long2");
+$a[1] = 'short1';
+check_contents("short0", "short1", "long2");
+$a[2] = 'short2';
+check_contents("short0", "short1", "short2");
+$a[1] = 'sh1';
+check_contents("short0", "sh1", "short2");
+$a[0] = 'sh0';
+check_contents("sh0", "sh1", "short2");
+
+# (51-56) file with holes
+$a[4] = 'rec4';
+check_contents("sh0", "sh1", "short2", "", "rec4");
+$a[3] = 'rec3';
+check_contents("sh0", "sh1", "short2", "rec3", "rec4");
+
+# (57-59) zero out file
+@a = ();
+check_contents();
+
+# (60-62) insert into the middle of an empty file
+$a[3] = "rec3";
+check_contents("", "", "", "rec3");
+
+# (63-68) 20020326 You thought there would be a bug in STORE where if
+# a cached record was false, STORE wouldn't see it at all.  But you
+# forgot that records always come back from the cache with the record
+# separator attached, so they are unlikely to be false.  The only
+# really weird case is when the cached record is empty and the record
+# separator is "0".  Test that in 09_gen_rs.t.
+$a[1] = "0";
+check_contents("", "0", "", "rec3");
+$a[1] = "whoops";
+check_contents("", "whoops", "", "rec3");
+
+
+use POSIX 'SEEK_SET';
+sub check_contents {
+  my @c = @_;
+  my $x = join $:, @c, '';
+  local *FH = $o->{fh};
+  seek FH, 0, SEEK_SET;
+#  my $open = open FH, "< $file";
+  my $a;
+  { local $/; $a = <FH> }
+  $a = "" unless defined $a;
+  if ($a eq $x) {
+    print "ok $N\n";
+  } else {
+    ctrlfix($a, $x);
+    print "not ok $N\n# expected <$x>, got <$a>\n";
+  }
+  $N++;
+
+  # now check FETCH:
+  my $good = 1;
+  my $msg;
+  for (0.. $#c) {
+    my $aa = $a[$_];
+    unless ($aa eq "$c[$_]$:") {
+      $msg = "expected <$c[$_]$:>, got <$aa>";
+      ctrlfix($msg);
+      $good = 0;
+    }
+  }
+  print $good ? "ok $N\n" : "not ok $N # $msg\n";
+  $N++;
+
+  print $o->_check_integrity($file, $ENV{INTEGRITY}) 
+      ? "ok $N\n" : "not ok $N\n";
+  $N++;
+}
+
+sub ctrlfix {
+  for (@_) {
+    s/\n/\\n/g;
+    s/\r/\\r/g;
+  }
+}
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
diff --git a/dist/Tie-File/t/26_twrite.t b/dist/Tie-File/t/26_twrite.t
new file mode 100644
index 0000000000..e2a925f4e0
--- /dev/null
+++ b/dist/Tie-File/t/26_twrite.t
@@ -0,0 +1,359 @@
+#!/usr/bin/perl
+#
+# Unit tests of _twrite function
+#
+# _twrite($self, $data, $pos, $len)
+#
+# 't' here is for 'tail'.  This writes $data at absolute position $pos
+# in the file, overwriting exactly $len of the bytes at that position.
+# Everything else is moved down or up, dependong on whether
+# length($data) > $len or length($data) < $len.
+# $len == 0 is a pure insert; $len == length($data) is a simple overwrite.
+#
+
+my $file = "tf$$.txt";
+
+print "1..181\n";
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;
+
+$: = Tie::File::_default_recsep();
+
+# (2) Peter Scott sent this one.  It fails in 0.51 and works in 0.90
+# <4.3.2.7.2.20020331102819.00b913d0@shell2.webquarry.com>
+#
+# The problem was premature termination in the inner loop
+# because you had $more_data scoped *inside* the block instead of outside.
+# 20020331
+open F, "> $file" or die "Couldn't open $file: $!";
+binmode F;
+for (1..100) {
+  print F "$_ ", 'a'x150, $: ;
+}
+close F;
+# The file is now 15292 characters long on Unix, 15392 on Win32
+die -s $file unless -s $file == 15292 + 100 * length($:);
+
+tie my @lines, 'Tie::File', $file or die $!;
+push @lines, "1001 ".('a' x 100);
+splice @lines, 0, 1;
+untie @lines;
+
+my $s = -s $file;
+my $x = 15292 - 152 + 105 + 100*length($:);
+print $s == $x
+  ? "ok $N\n" : "not ok $N # expected $x, got $s\n";
+$N++;
+
+my @subtests = qw(x <x x> x><x <x> <x><x x><x> <x><x> <x><x><x> 0);
+
+# (3-73) These were generated by 'gentests.pl' to cover all possible cases
+# (I hope)
+# Legend:
+#         x: data is entirely contained within one block
+#        x>: data runs from the middle to the end of the block
+#        <x: data runs from the start to the middle of the block
+#       <x>: data occupies precisely one block
+#      x><x: data overlaps one block boundary
+#     <x><x: data runs from the start of one block into the middle of the next
+#     x><x>: data runs from the middle of one block to the end of the next
+#    <x><x>: data occupies two blocks exactly
+# <x><x><x>: data occupies three blocks exactly
+#         0: data is null
+#
+# For each possible alignment of the old and new data, we investigate
+# up to three situations: old data is shorter, old and new data are the
+# same length, and new data is shorter.
+#
+# try($pos, $old, $new) means to run a test where the data starts at 
+# position $pos, the old data has length $old,
+# and the new data has length $new.
+try( 9659,  6635,  6691);  # old=x        , new=x        ; old < new
+try( 8605,  2394,  2394);  # old=x        , new=x        ; old = new
+try( 9768,  1361,   664);  # old=x        , new=x        ; old > new
+try( 9955,  6429,  6429);  # old=x>       , new=x        ; old = new
+try(10550,  5834,  4123);  # old=x>       , new=x        ; old > new
+try(14580,  6158,   851);  # old=x><x     , new=x        ; old > new
+try(13442, 11134,  1572);  # old=x><x>    , new=x        ; old > new
+try( 8394,     0,  5742);  # old=0        , new=x        ; old < new
+try( 8192,  2819,  6738);  # old=<x       , new=<x       ; old < new
+try( 8192,   514,   514);  # old=<x       , new=<x       ; old = new
+try( 8192,  2196,   858);  # old=<x       , new=<x       ; old > new
+try( 8192,  8192,  8192);  # old=<x>      , new=<x       ; old = new
+try( 8192,  8192,  1290);  # old=<x>      , new=<x       ; old > new
+try( 8192, 10575,  6644);  # old=<x><x    , new=<x       ; old > new
+try( 8192, 16384,  5616);  # old=<x><x>   , new=<x       ; old > new
+try( 8192, 24576,  6253);  # old=<x><x><x>, new=<x       ; old > new
+try( 8192,     0,  6870);  # old=0        , new=<x       ; old < new
+try( 8478,  6259,  7906);  # old=x        , new=x>       ; old < new
+try( 9965,  6419,  6419);  # old=x>       , new=x>       ; old = new
+try(16059,  6102,   325);  # old=x><x     , new=x>       ; old > new
+try( 9503, 15073,  6881);  # old=x><x>    , new=x>       ; old > new
+try( 9759,     0,  6625);  # old=0        , new=x>       ; old < new
+try( 8525,  2081,  8534);  # old=x        , new=x><x     ; old < new
+try(15550,   834,  1428);  # old=x>       , new=x><x     ; old < new
+try(14966,  1668,  3479);  # old=x><x     , new=x><x     ; old < new
+try(16316,  1605,  1605);  # old=x><x     , new=x><x     ; old = new
+try(16093,  4074,   993);  # old=x><x     , new=x><x     ; old > new
+try(14739,  9837,  9837);  # old=x><x>    , new=x><x     ; old = new
+try(14071, 10505,  7344);  # old=x><x>    , new=x><x     ; old > new
+try(12602,     0,  8354);  # old=0        , new=x><x     ; old < new
+try( 8192,  2767,  8192);  # old=<x       , new=<x>      ; old < new
+try( 8192,  8192,  8192);  # old=<x>      , new=<x>      ; old = new
+try( 8192, 14817,  8192);  # old=<x><x    , new=<x>      ; old > new
+try( 8192, 16384,  8192);  # old=<x><x>   , new=<x>      ; old > new
+try( 8192, 24576,  8192);  # old=<x><x><x>, new=<x>      ; old > new
+try( 8192,     0,  8192);  # old=0        , new=<x>      ; old < new
+try( 8192,  6532, 10882);  # old=<x       , new=<x><x    ; old < new
+try( 8192,  8192, 16044);  # old=<x>      , new=<x><x    ; old < new
+try( 8192,  9555, 11020);  # old=<x><x    , new=<x><x    ; old < new
+try( 8192,  9001,  9001);  # old=<x><x    , new=<x><x    ; old = new
+try( 8192, 11760, 10274);  # old=<x><x    , new=<x><x    ; old > new
+try( 8192, 16384, 10781);  # old=<x><x>   , new=<x><x    ; old > new
+try( 8192, 24576,  9284);  # old=<x><x><x>, new=<x><x    ; old > new
+try( 8192,     0, 12488);  # old=0        , new=<x><x    ; old < new
+try( 8222,  6385, 16354);  # old=x        , new=x><x>    ; old < new
+try(13500,  2884, 11076);  # old=x>       , new=x><x>    ; old < new
+try(14069,  4334, 10507);  # old=x><x     , new=x><x>    ; old < new
+try(14761,  9815,  9815);  # old=x><x>    , new=x><x>    ; old = new
+try(10469,     0, 14107);  # old=0        , new=x><x>    ; old < new
+try( 8192,  4181, 16384);  # old=<x       , new=<x><x>   ; old < new
+try( 8192,  8192, 16384);  # old=<x>      , new=<x><x>   ; old < new
+try( 8192, 12087, 16384);  # old=<x><x    , new=<x><x>   ; old < new
+try( 8192, 16384, 16384);  # old=<x><x>   , new=<x><x>   ; old = new
+try( 8192, 24576, 16384);  # old=<x><x><x>, new=<x><x>   ; old > new
+try( 8192,     0, 16384);  # old=0        , new=<x><x>   ; old < new
+try( 8192,  4968, 24576);  # old=<x       , new=<x><x><x>; old < new
+try( 8192,  8192, 24576);  # old=<x>      , new=<x><x><x>; old < new
+try( 8192, 14163, 24576);  # old=<x><x    , new=<x><x><x>; old < new
+try( 8192, 16384, 24576);  # old=<x><x>   , new=<x><x><x>; old < new
+try( 8192, 24576, 24576);  # old=<x><x><x>, new=<x><x><x>; old = new
+try( 8192,     0, 24576);  # old=0        , new=<x><x><x>; old < new
+try( 8771,   776,     0);  # old=x        , new=0        ; old > new
+try( 8192,  2813,     0);  # old=<x       , new=0        ; old > new
+try(13945,  2439,     0);  # old=x>       , new=0        ; old > new
+try(14493,  6090,     0);  # old=x><x     , new=0        ; old > new
+try( 8192,  8192,     0);  # old=<x>      , new=0        ; old > new
+try( 8192, 10030,     0);  # old=<x><x    , new=0        ; old > new
+try(14983,  9593,     0);  # old=x><x>    , new=0        ; old > new
+try( 8192, 16384,     0);  # old=<x><x>   , new=0        ; old > new
+try( 8192, 24576,     0);  # old=<x><x><x>, new=0        ; old > new
+try(10489,     0,     0);  # old=0        , new=0        ; old = new
+
+# (74-114)
+# These tests all take place at the start of the file
+try(    0,   771,  1593);  # old=<x       , new=<x       ; old < new
+try(    0,  4868,  4868);  # old=<x       , new=<x       ; old = new
+try(    0,   147,   118);  # old=<x       , new=<x       ; old > new
+try(    0,  8192,  8192);  # old=<x>      , new=<x       ; old = new
+try(    0,  8192,  4574);  # old=<x>      , new=<x       ; old > new
+try(    0, 11891,  1917);  # old=<x><x    , new=<x       ; old > new
+try(    0, 16384,  5155);  # old=<x><x>   , new=<x       ; old > new
+try(    0, 24576,  2953);  # old=<x><x><x>, new=<x       ; old > new
+try(    0,     0,  1317);  # old=0        , new=<x       ; old < new
+try(    0,  5609,  8192);  # old=<x       , new=<x>      ; old < new
+try(    0,  8192,  8192);  # old=<x>      , new=<x>      ; old = new
+try(    0, 11083,  8192);  # old=<x><x    , new=<x>      ; old > new
+try(    0, 16384,  8192);  # old=<x><x>   , new=<x>      ; old > new
+try(    0, 24576,  8192);  # old=<x><x><x>, new=<x>      ; old > new
+try(    0,     0,  8192);  # old=0        , new=<x>      ; old < new
+try(    0,  6265,  9991);  # old=<x       , new=<x><x    ; old < new
+try(    0,  8192, 16119);  # old=<x>      , new=<x><x    ; old < new
+try(    0, 10218, 11888);  # old=<x><x    , new=<x><x    ; old < new
+try(    0, 14126, 14126);  # old=<x><x    , new=<x><x    ; old = new
+try(    0, 12002,  9034);  # old=<x><x    , new=<x><x    ; old > new
+try(    0, 16384, 13258);  # old=<x><x>   , new=<x><x    ; old > new
+try(    0, 24576, 14367);  # old=<x><x><x>, new=<x><x    ; old > new
+try(    0,     0, 10881);  # old=0        , new=<x><x    ; old < new
+try(    0,  6448, 16384);  # old=<x       , new=<x><x>   ; old < new
+try(    0,  8192, 16384);  # old=<x>      , new=<x><x>   ; old < new
+try(    0, 15082, 16384);  # old=<x><x    , new=<x><x>   ; old < new
+try(    0, 16384, 16384);  # old=<x><x>   , new=<x><x>   ; old = new
+try(    0, 24576, 16384);  # old=<x><x><x>, new=<x><x>   ; old > new
+try(    0,     0, 16384);  # old=0        , new=<x><x>   ; old < new
+try(    0,  2421, 24576);  # old=<x       , new=<x><x><x>; old < new
+try(    0,  8192, 24576);  # old=<x>      , new=<x><x><x>; old < new
+try(    0, 11655, 24576);  # old=<x><x    , new=<x><x><x>; old < new
+try(    0, 16384, 24576);  # old=<x><x>   , new=<x><x><x>; old < new
+try(    0, 24576, 24576);  # old=<x><x><x>, new=<x><x><x>; old = new
+try(    0,     0, 24576);  # old=0        , new=<x><x><x>; old < new
+try(    0,  6530,     0);  # old=<x       , new=0        ; old > new
+try(    0,  8192,     0);  # old=<x>      , new=0        ; old > new
+try(    0, 14707,     0);  # old=<x><x    , new=0        ; old > new
+try(    0, 16384,     0);  # old=<x><x>   , new=0        ; old > new
+try(    0, 24576,     0);  # old=<x><x><x>, new=0        ; old > new
+try(    0,     0,     0);  # old=0        , new=0        ; old = new
+
+# (115-141)
+# These tests all take place at the end of the file
+$FLEN = 40960;  # Force the file to be exactly 40960 bytes long
+try(32768,  8192,  8192);  # old=<x>      , new=<x       ; old = new
+try(32768,  8192,  4026);  # old=<x>      , new=<x       ; old > new
+try(24576, 16384,  1917);  # old=<x><x>   , new=<x       ; old > new
+try(16384, 24576,  3818);  # old=<x><x><x>, new=<x       ; old > new
+try(40960,     0,  2779);  # old=0        , new=<x       ; old < new
+try(32768,  8192,  8192);  # old=<x>      , new=<x>      ; old = new
+try(24576, 16384,  8192);  # old=<x><x>   , new=<x>      ; old > new
+try(16384, 24576,  8192);  # old=<x><x><x>, new=<x>      ; old > new
+try(40960,     0,  8192);  # old=0        , new=<x>      ; old < new
+try(32768,  8192, 10724);  # old=<x>      , new=<x><x    ; old < new
+try(24576, 16384, 12221);  # old=<x><x>   , new=<x><x    ; old > new
+try(16384, 24576, 15030);  # old=<x><x><x>, new=<x><x    ; old > new
+try(40960,     0, 11752);  # old=0        , new=<x><x    ; old < new
+try(32768,  8192, 16384);  # old=<x>      , new=<x><x>   ; old < new
+try(24576, 16384, 16384);  # old=<x><x>   , new=<x><x>   ; old = new
+try(16384, 24576, 16384);  # old=<x><x><x>, new=<x><x>   ; old > new
+try(40960,     0, 16384);  # old=0        , new=<x><x>   ; old < new
+try(32768,  8192, 24576);  # old=<x>      , new=<x><x><x>; old < new
+try(24576, 16384, 24576);  # old=<x><x>   , new=<x><x><x>; old < new
+try(16384, 24576, 24576);  # old=<x><x><x>, new=<x><x><x>; old = new
+try(40960,     0, 24576);  # old=0        , new=<x><x><x>; old < new
+try(35973,  4987,     0);  # old=x>       , new=0        ; old > new
+try(32768,  8192,     0);  # old=<x>      , new=0        ; old > new
+try(29932, 11028,     0);  # old=x><x>    , new=0        ; old > new
+try(24576, 16384,     0);  # old=<x><x>   , new=0        ; old > new
+try(16384, 24576,     0);  # old=<x><x><x>, new=0        ; old > new
+try(40960,     0,     0);  # old=0        , new=0        ; old = new
+
+# (142-181)
+# These tests all take place at the end of the file
+$FLEN = 42000;  # Force the file to be exactly 42000 bytes long
+try(41275,   725,  4059);  # old=x        , new=x        ; old < new
+try(41683,   317,   317);  # old=x        , new=x        ; old = new
+try(41225,   775,   405);  # old=x        , new=x        ; old > new
+try(35709,  6291,   284);  # old=x><x     , new=x        ; old > new
+try(42000,     0,  2434);  # old=0        , new=x        ; old < new
+try(40960,  1040,  1608);  # old=<x       , new=<x       ; old < new
+try(40960,  1040,  1040);  # old=<x       , new=<x       ; old = new
+try(40960,  1040,   378);  # old=<x       , new=<x       ; old > new
+try(32768,  9232,  5604);  # old=<x><x    , new=<x       ; old > new
+try(42000,     0,  6637);  # old=0        , new=<x       ; old < new
+try(41022,   978,  8130);  # old=x        , new=x>       ; old < new
+try(39994,  2006,   966);  # old=x><x     , new=x>       ; old > new
+try(42000,     0,  7152);  # old=0        , new=x>       ; old < new
+try(41613,   387, 10601);  # old=x        , new=x><x     ; old < new
+try(38460,  3540,  3938);  # old=x><x     , new=x><x     ; old < new
+try(36725,  5275,  5275);  # old=x><x     , new=x><x     ; old = new
+try(37990,  4010,  3199);  # old=x><x     , new=x><x     ; old > new
+try(42000,     0,  9189);  # old=0        , new=x><x     ; old < new
+try(40960,  1040,  8192);  # old=<x       , new=<x>      ; old < new
+try(32768,  9232,  8192);  # old=<x><x    , new=<x>      ; old > new
+try(42000,     0,  8192);  # old=0        , new=<x>      ; old < new
+try(40960,  1040, 11778);  # old=<x       , new=<x><x    ; old < new
+try(32768,  9232, 13792);  # old=<x><x    , new=<x><x    ; old < new
+try(32768,  9232,  9232);  # old=<x><x    , new=<x><x    ; old = new
+try(32768,  9232,  8795);  # old=<x><x    , new=<x><x    ; old > new
+try(42000,     0,  8578);  # old=0        , new=<x><x    ; old < new
+try(41531,   469, 15813);  # old=x        , new=x><x>    ; old < new
+try(39618,  2382,  9534);  # old=x><x     , new=x><x>    ; old < new
+try(42000,     0, 15344);  # old=0        , new=x><x>    ; old < new
+try(40960,  1040, 16384);  # old=<x       , new=<x><x>   ; old < new
+try(32768,  9232, 16384);  # old=<x><x    , new=<x><x>   ; old < new
+try(42000,     0, 16384);  # old=0        , new=<x><x>   ; old < new
+try(40960,  1040, 24576);  # old=<x       , new=<x><x><x>; old < new
+try(32768,  9232, 24576);  # old=<x><x    , new=<x><x><x>; old < new
+try(42000,     0, 24576);  # old=0        , new=<x><x><x>; old < new
+try(41500,   500,     0);  # old=x        , new=0        ; old > new
+try(40960,  1040,     0);  # old=<x       , new=0        ; old > new
+try(35272,  6728,     0);  # old=x><x     , new=0        ; old > new
+try(32768,  9232,     0);  # old=<x><x    , new=0        ; old > new
+try(42000,     0,     0);  # old=0        , new=0        ; old = new
+
+sub try {
+  my ($pos, $len, $newlen) = @_;
+  open F, "> $file" or die "Couldn't open file $file: $!";
+  binmode F;
+
+  # The record has exactly 17 characters.  This will help ensure that
+  # even if _twrite screws up, the data doesn't coincidentally
+  # look good because the remainder accidentally lines up.
+  my $d = substr("0123456789abcdef$:", -17);
+  my $recs = defined($FLEN) ?
+    int($FLEN/length($d))+1 : # enough to make up at least $FLEN
+    int(8192*5/length($d))+1; # at least 5 blocks' worth
+  my $oldfile = $d x $recs;
+  my $flen = defined($FLEN) ? $FLEN : $recs * 17;
+  substr($oldfile, $FLEN) = "" if defined $FLEN;  # truncate
+  print F $oldfile;
+  close F;
+
+  die "wrong length!" unless -s $file == $flen;
+
+  my $newdata = "-" x $newlen;
+  my $expected = $oldfile;
+  substr($expected, $pos, $len) = $newdata;
+
+  my $o = tie my @lines, 'Tie::File', $file or die $!;
+  $o->_twrite($newdata, $pos, $len);
+  undef $o; untie @lines;
+
+  open F, "< $file" or die "Couldn't open file $file: $!";
+  binmode F;
+  my $actual;
+  { local $/;
+    $actual = <F>;
+  }
+  close F;
+
+  my ($alen, $xlen) = (length $actual, length $expected);
+  unless ($alen == $xlen) {
+    print "# try(@_) expected file length $xlen, actual $alen!\n";
+  }
+  print $actual eq $expected ? "ok $N\n" : "not ok $N\n";
+  $N++;
+}
+
+
+
+use POSIX 'SEEK_SET';
+sub check_contents {
+  my @c = @_;
+  my $x = join $:, @c, '';
+  local *FH = $o->{fh};
+  seek FH, 0, SEEK_SET;
+#  my $open = open FH, "< $file";
+  my $a;
+  { local $/; $a = <FH> }
+  $a = "" unless defined $a;
+  if ($a eq $x) {
+    print "ok $N\n";
+  } else {
+    ctrlfix($a, $x);
+    print "not ok $N\n# expected <$x>, got <$a>\n";
+  }
+  $N++;
+
+  # now check FETCH:
+  my $good = 1;
+  my $msg;
+  for (0.. $#c) {
+    my $aa = $a[$_];
+    unless ($aa eq "$c[$_]$:") {
+      $msg = "expected <$c[$_]$:>, got <$aa>";
+      ctrlfix($msg);
+      $good = 0;
+    }
+  }
+  print $good ? "ok $N\n" : "not ok $N # $msg\n";
+  $N++;
+
+  print $o->_check_integrity($file, $ENV{INTEGRITY}) 
+      ? "ok $N\n" : "not ok $N\n";
+  $N++;
+}
+
+sub ctrlfix {
+  for (@_) {
+    s/\n/\\n/g;
+    s/\r/\\r/g;
+  }
+}
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
diff --git a/dist/Tie-File/t/27_iwrite.t b/dist/Tie-File/t/27_iwrite.t
new file mode 100644
index 0000000000..db591a81ba
--- /dev/null
+++ b/dist/Tie-File/t/27_iwrite.t
@@ -0,0 +1,235 @@
+#!/usr/bin/perl
+#
+# Unit tests of _iwrite function
+#
+# _iwrite($self, $data, $start, $end)
+#
+# 'i' here is for 'insert'.  This writes $data at absolute position $start
+# in the file, copying the data at that position downwards---
+# but only down to position $end.  Data at or past $end is not moved
+# or even examined.    Since there isn't enough room for the full copy
+# (Because we inserted $data at the beginning) we copy as much as possible
+# and return a string containing the remainder.
+
+my $file = "tf$$.txt";
+$| = 1;
+
+print "1..203\n";
+
+my $N = 1;
+my $oldfile;
+use Tie::File;
+print "ok $N\n"; $N++;
+
+$: = Tie::File::_default_recsep();
+
+$FLEN = 40970;   # Use files of this length
+$oldfile = mkrand($FLEN);
+print "# MOF tests\n";
+# (2-85) These were generated by 'gentests.pl' to cover all possible cases
+# (I hope)
+# Legend:
+#         x: data is entirely contained within one block
+#        x>: data runs from the middle to the end of the block
+#        <x: data runs from the start to the middle of the block
+#       <x>: data occupies precisely one block
+#      x><x: data overlaps one block boundary
+#     <x><x: data runs from the start of one block into the middle of the next
+#     x><x>: data runs from the middle of one block to the end of the next
+#    <x><x>: data occupies two blocks exactly
+# <x><x><x>: data occupies three blocks exactly
+#         0: data is null
+#
+# For each possible alignment of the old and new data, we investigate
+# up to three situations: old data is shorter, old and new data are the
+# same length, and new data is shorter.
+#
+# try($pos, $old, $new) means to run a test where the area being
+# written into starts at position $pos, the area being written into
+# has length $old, and and the new data has length $new.
+try( 8605,  2394,  2394);  # old=x        , new=x        ; old = new
+try( 9768,  1361,   664);  # old=x        , new=x        ; old > new
+try( 9955,  6429,  6429);  # old=x>       , new=x        ; old = new
+try(10550,  5834,  4123);  # old=x>       , new=x        ; old > new
+try(14580,  6158,   851);  # old=x><x     , new=x        ; old > new
+try(13442, 11134,  1572);  # old=x><x>    , new=x        ; old > new
+try( 8192,   514,   514);  # old=<x       , new=<x       ; old = new
+try( 8192,  2196,   858);  # old=<x       , new=<x       ; old > new
+try( 8192,  8192,  8192);  # old=<x>      , new=<x       ; old = new
+try( 8192,  8192,  1290);  # old=<x>      , new=<x       ; old > new
+try( 8192, 10575,  6644);  # old=<x><x    , new=<x       ; old > new
+try( 8192, 16384,  5616);  # old=<x><x>   , new=<x       ; old > new
+try( 8192, 24576,  6253);  # old=<x><x><x>, new=<x       ; old > new
+try( 9965,  6419,  6419);  # old=x>       , new=x>       ; old = new
+try(16059,  6102,   325);  # old=x><x     , new=x>       ; old > new
+try( 9503, 15073,  6881);  # old=x><x>    , new=x>       ; old > new
+try(16316,  1605,  1605);  # old=x><x     , new=x><x     ; old = new
+try(16093,  4074,   993);  # old=x><x     , new=x><x     ; old > new
+try(14739,  9837,  9837);  # old=x><x>    , new=x><x     ; old = new
+try(14071, 10505,  7344);  # old=x><x>    , new=x><x     ; old > new
+try( 8192,  8192,  8192);  # old=<x>      , new=<x>      ; old = new
+try( 8192, 14817,  8192);  # old=<x><x    , new=<x>      ; old > new
+try( 8192, 16384,  8192);  # old=<x><x>   , new=<x>      ; old > new
+try( 8192, 24576,  8192);  # old=<x><x><x>, new=<x>      ; old > new
+try( 8192,  9001,  9001);  # old=<x><x    , new=<x><x    ; old = new
+try( 8192, 11760, 10274);  # old=<x><x    , new=<x><x    ; old > new
+try( 8192, 16384, 10781);  # old=<x><x>   , new=<x><x    ; old > new
+try( 8192, 24576,  9284);  # old=<x><x><x>, new=<x><x    ; old > new
+try(14761,  9815,  9815);  # old=x><x>    , new=x><x>    ; old = new
+try( 8192, 16384, 16384);  # old=<x><x>   , new=<x><x>   ; old = new
+try( 8192, 24576, 16384);  # old=<x><x><x>, new=<x><x>   ; old > new
+try( 8192, 24576, 24576);  # old=<x><x><x>, new=<x><x><x>; old = new
+try( 8771,   776,     0);  # old=x        , new=0        ; old > new
+try( 8192,  2813,     0);  # old=<x       , new=0        ; old > new
+try(13945,  2439,     0);  # old=x>       , new=0        ; old > new
+try(14493,  6090,     0);  # old=x><x     , new=0        ; old > new
+try( 8192,  8192,     0);  # old=<x>      , new=0        ; old > new
+try( 8192, 10030,     0);  # old=<x><x    , new=0        ; old > new
+try(14983,  9593,     0);  # old=x><x>    , new=0        ; old > new
+try( 8192, 16384,     0);  # old=<x><x>   , new=0        ; old > new
+try( 8192, 24576,     0);  # old=<x><x><x>, new=0        ; old > new
+try(10489,     0,     0);  # old=0        , new=0        ; old = new
+
+print "# SOF tests\n";
+# (86-133)
+# These tests all take place at the start of the file
+try(    0,  4868,  4868);  # old=<x       , new=<x       ; old = new
+try(    0,   147,   118);  # old=<x       , new=<x       ; old > new
+try(    0,  8192,  8192);  # old=<x>      , new=<x       ; old = new
+try(    0,  8192,  4574);  # old=<x>      , new=<x       ; old > new
+try(    0, 11891,  1917);  # old=<x><x    , new=<x       ; old > new
+try(    0, 16384,  5155);  # old=<x><x>   , new=<x       ; old > new
+try(    0, 24576,  2953);  # old=<x><x><x>, new=<x       ; old > new
+try(    0,  8192,  8192);  # old=<x>      , new=<x>      ; old = new
+try(    0, 11083,  8192);  # old=<x><x    , new=<x>      ; old > new
+try(    0, 16384,  8192);  # old=<x><x>   , new=<x>      ; old > new
+try(    0, 24576,  8192);  # old=<x><x><x>, new=<x>      ; old > new
+try(    0, 14126, 14126);  # old=<x><x    , new=<x><x    ; old = new
+try(    0, 12002,  9034);  # old=<x><x    , new=<x><x    ; old > new
+try(    0, 16384, 13258);  # old=<x><x>   , new=<x><x    ; old > new
+try(    0, 24576, 14367);  # old=<x><x><x>, new=<x><x    ; old > new
+try(    0, 16384, 16384);  # old=<x><x>   , new=<x><x>   ; old = new
+try(    0, 24576, 16384);  # old=<x><x><x>, new=<x><x>   ; old > new
+try(    0, 24576, 24576);  # old=<x><x><x>, new=<x><x><x>; old = new
+try(    0,  6530,     0);  # old=<x       , new=0        ; old > new
+try(    0,  8192,     0);  # old=<x>      , new=0        ; old > new
+try(    0, 14707,     0);  # old=<x><x    , new=0        ; old > new
+try(    0, 16384,     0);  # old=<x><x>   , new=0        ; old > new
+try(    0, 24576,     0);  # old=<x><x><x>, new=0        ; old > new
+try(    0,     0,     0);  # old=0        , new=0        ; old = new
+
+print "# EOF tests 1\n";
+# (134-169)
+# These tests all take place at the end of the file
+$FLEN = 40960;  # Force the file to be exactly 40960 bytes long
+$oldfile = mkrand($FLEN);
+try(32768,  8192,  8192);  # old=<x>      , new=<x       ; old = new
+try(32768,  8192,  4026);  # old=<x>      , new=<x       ; old > new
+try(24576, 16384,  1917);  # old=<x><x>   , new=<x       ; old > new
+try(16384, 24576,  3818);  # old=<x><x><x>, new=<x       ; old > new
+try(32768,  8192,  8192);  # old=<x>      , new=<x>      ; old = new
+try(24576, 16384,  8192);  # old=<x><x>   , new=<x>      ; old > new
+try(16384, 24576,  8192);  # old=<x><x><x>, new=<x>      ; old > new
+try(24576, 16384, 12221);  # old=<x><x>   , new=<x><x    ; old > new
+try(16384, 24576, 15030);  # old=<x><x><x>, new=<x><x    ; old > new
+try(24576, 16384, 16384);  # old=<x><x>   , new=<x><x>   ; old = new
+try(16384, 24576, 16384);  # old=<x><x><x>, new=<x><x>   ; old > new
+try(16384, 24576, 24576);  # old=<x><x><x>, new=<x><x><x>; old = new
+try(35973,  4987,     0);  # old=x>       , new=0        ; old > new
+try(32768,  8192,     0);  # old=<x>      , new=0        ; old > new
+try(29932, 11028,     0);  # old=x><x>    , new=0        ; old > new
+try(24576, 16384,     0);  # old=<x><x>   , new=0        ; old > new
+try(16384, 24576,     0);  # old=<x><x><x>, new=0        ; old > new
+try(40960,     0,     0);  # old=0        , new=0        ; old = new
+
+print "# EOF tests 2\n";
+# (170-203)
+# These tests all take place at the end of the file
+$FLEN = 42000;  # Force the file to be exactly 42000 bytes long
+$oldfile = mkrand($FLEN);
+try(41683,   317,   317);  # old=x        , new=x        ; old = new
+try(41225,   775,   405);  # old=x        , new=x        ; old > new
+try(35709,  6291,   284);  # old=x><x     , new=x        ; old > new
+try(40960,  1040,  1040);  # old=<x       , new=<x       ; old = new
+try(40960,  1040,   378);  # old=<x       , new=<x       ; old > new
+try(32768,  9232,  5604);  # old=<x><x    , new=<x       ; old > new
+try(39994,  2006,   966);  # old=x><x     , new=x>       ; old > new
+try(36725,  5275,  5275);  # old=x><x     , new=x><x     ; old = new
+try(37990,  4010,  3199);  # old=x><x     , new=x><x     ; old > new
+try(32768,  9232,  8192);  # old=<x><x    , new=<x>      ; old > new
+try(32768,  9232,  9232);  # old=<x><x    , new=<x><x    ; old = new
+try(32768,  9232,  8795);  # old=<x><x    , new=<x><x    ; old > new
+try(41500,   500,     0);  # old=x        , new=0        ; old > new
+try(40960,  1040,     0);  # old=<x       , new=0        ; old > new
+try(35272,  6728,     0);  # old=x><x     , new=0        ; old > new
+try(32768,  9232,     0);  # old=<x><x    , new=0        ; old > new
+try(42000,     0,     0);  # old=0        , new=0        ; old = new
+
+sub mkrand {
+  my $len = shift;
+  srand $len;
+  my @c = ('a' .. 'z', 'A' .. 'Z', 0..9, $:);
+  my $d = "";
+  $d .= $c[rand @c] until length($d) >= $len;
+  substr($d, $len) = ""; # chop it off to the proper length
+  $d;
+}
+
+sub try {
+  my ($s, $len, $newlen) = @_;
+  my $e = $s + $len;
+
+  open F, "> $file" or die "Couldn't open file $file: $!";
+  binmode F;
+
+  print F $oldfile;
+  close F;
+
+  die "wrong length!" unless -s $file == $FLEN;
+
+  my $newdata = "-" x $newlen;
+  my $expected = $oldfile;
+
+  my $expected_return = substr($expected, $e - $newlen, $newlen, "");
+  substr($expected, $s, 0, $newdata);
+
+  my $o = tie my @lines, 'Tie::File', $file or die $!;
+  my $actual_return = $o->_iwrite($newdata, $s, $e);
+  undef $o; untie @lines;
+
+  open F, "< $file" or die "Couldn't open file $file: $!";
+  binmode F;
+  my $actual;
+  { local $/;
+    $actual = <F>;
+  }
+  close F;
+
+  my ($alen, $xlen) = (length $actual, length $expected);
+  unless ($alen == $xlen) {
+    print "# try(@_) expected file length $xlen, actual $alen!\n";
+  }
+  print $actual eq $expected ? "ok $N\n" : "not ok $N\n";
+  $N++;
+
+  if (! defined $actual_return && ! defined $expected_return) {
+    print "ok $N\n";
+  } elsif (! defined $actual_return || ! defined $expected_return) {
+    print "not ok $N\n";
+  } else {
+    print $actual_return eq $expected_return ? "ok $N\n" : "not ok $N\n";
+  }
+  $N++;
+}
+
+sub ctrlfix {
+  for (@_) {
+    s/\n/\\n/g;
+    s/\r/\\r/g;
+  }
+}
+
+END {
+  1 while unlink $file;
+}
+
diff --git a/dist/Tie-File/t/28_mtwrite.t b/dist/Tie-File/t/28_mtwrite.t
new file mode 100644
index 0000000000..50e306d3b6
--- /dev/null
+++ b/dist/Tie-File/t/28_mtwrite.t
@@ -0,0 +1,295 @@
+#!/usr/bin/perl
+#
+# Unit tests of _mtwrite function
+#
+# _mtwrite($self, $d1, $s1, $l1, $d2, $s2, $l2, ...)
+#
+# 'm' here is for 'multiple'.  This writes data $d1 at position $s1
+# over a block of space $l1, moving subsequent data up or down as necessary.
+
+my $file = "tf$$.txt";
+$| = 1;
+
+print "1..2252\n";
+
+my $N = 1;
+my $oldfile;
+use Tie::File;
+print "ok $N\n"; $N++;
+
+$: = Tie::File::_default_recsep();
+
+# Only these are used for the triple-region tests
+@BASE_TRIES = (
+               [10, 20, 30], 
+               [10, 30, 20], 
+               [100, 30, 20],
+               [100, 20, 30], 
+               [100, 40, 20], 
+               [100, 20, 40], 
+               [200, 20, 30],
+               [200, 30, 20],
+               [200, 20, 60],
+               [200, 60, 20],
+               );
+
+@TRIES = @BASE_TRIES;
+
+$FLEN = 40970;   # Use files of this length
+$oldfile = mkrand($FLEN);
+print "# MOF tests\n";
+# These were generated by 'gentests.pl' to cover all possible cases
+# (I hope)
+# Legend:
+#         x: data is entirely contained within one block
+#        x>: data runs from the middle to the end of the block
+#        <x: data runs from the start to the middle of the block
+#       <x>: data occupies precisely one block
+#      x><x: data overlaps one block boundary
+#     <x><x: data runs from the start of one block into the middle of the next
+#     x><x>: data runs from the middle of one block to the end of the next
+#    <x><x>: data occupies two blocks exactly
+# <x><x><x>: data occupies three blocks exactly
+#         0: data is null
+#
+# For each possible alignment of the old and new data, we investigate
+# up to three situations: old data is shorter, old and new data are the
+# same length, and new data is shorter.
+#
+# try($pos, $old, $new) means to run a test where the area being
+# written into starts at position $pos, the area being written into
+# has length $old, and and the new data has length $new.
+try( 8605,  2394,  2394);  # old=x        , new=x        ; old = new
+try( 9768,  1361,   664);  # old=x        , new=x        ; old > new
+try( 9955,  6429,  6429);  # old=x>       , new=x        ; old = new
+try(10550,  5834,  4123);  # old=x>       , new=x        ; old > new
+try(14580,  6158,   851);  # old=x><x     , new=x        ; old > new
+try(13442, 11134,  1572);  # old=x><x>    , new=x        ; old > new
+try( 8192,   514,   514);  # old=<x       , new=<x       ; old = new
+try( 8192,  2196,   858);  # old=<x       , new=<x       ; old > new
+try( 8192,  8192,  8192);  # old=<x>      , new=<x       ; old = new
+try( 8192,  8192,  1290);  # old=<x>      , new=<x       ; old > new
+try( 8192, 10575,  6644);  # old=<x><x    , new=<x       ; old > new
+try( 8192, 16384,  5616);  # old=<x><x>   , new=<x       ; old > new
+try( 8192, 24576,  6253);  # old=<x><x><x>, new=<x       ; old > new
+try( 9965,  6419,  6419);  # old=x>       , new=x>       ; old = new
+try(16059,  6102,   325);  # old=x><x     , new=x>       ; old > new
+try( 9503, 15073,  6881);  # old=x><x>    , new=x>       ; old > new
+try(16316,  1605,  1605);  # old=x><x     , new=x><x     ; old = new
+try(16093,  4074,   993);  # old=x><x     , new=x><x     ; old > new
+try(14739,  9837,  9837);  # old=x><x>    , new=x><x     ; old = new
+try(14071, 10505,  7344);  # old=x><x>    , new=x><x     ; old > new
+try( 8192,  8192,  8192);  # old=<x>      , new=<x>      ; old = new
+try( 8192, 14817,  8192);  # old=<x><x    , new=<x>      ; old > new
+try( 8192, 16384,  8192);  # old=<x><x>   , new=<x>      ; old > new
+try( 8192, 24576,  8192);  # old=<x><x><x>, new=<x>      ; old > new
+try( 8192,  9001,  9001);  # old=<x><x    , new=<x><x    ; old = new
+try( 8192, 11760, 10274);  # old=<x><x    , new=<x><x    ; old > new
+try( 8192, 16384, 10781);  # old=<x><x>   , new=<x><x    ; old > new
+try( 8192, 24576,  9284);  # old=<x><x><x>, new=<x><x    ; old > new
+try(14761,  9815,  9815);  # old=x><x>    , new=x><x>    ; old = new
+try( 8192, 16384, 16384);  # old=<x><x>   , new=<x><x>   ; old = new
+try( 8192, 24576, 16384);  # old=<x><x><x>, new=<x><x>   ; old > new
+try( 8192, 24576, 24576);  # old=<x><x><x>, new=<x><x><x>; old = new
+try( 8771,   776,     0);  # old=x        , new=0        ; old > new
+try( 8192,  2813,     0);  # old=<x       , new=0        ; old > new
+try(13945,  2439,     0);  # old=x>       , new=0        ; old > new
+try(14493,  6090,     0);  # old=x><x     , new=0        ; old > new
+try( 8192,  8192,     0);  # old=<x>      , new=0        ; old > new
+try( 8192, 10030,     0);  # old=<x><x    , new=0        ; old > new
+try(14983,  9593,     0);  # old=x><x>    , new=0        ; old > new
+try( 8192, 16384,     0);  # old=<x><x>   , new=0        ; old > new
+try( 8192, 24576,     0);  # old=<x><x><x>, new=0        ; old > new
+try(10489,     0,     0);  # old=0        , new=0        ; old = new
+
+print "# SOF tests\n";
+# These tests all take place at the start of the file
+try(    0,  4868,  4868);  # old=<x       , new=<x       ; old = new
+try(    0,   147,   118);  # old=<x       , new=<x       ; old > new
+try(    0,  8192,  8192);  # old=<x>      , new=<x       ; old = new
+try(    0,  8192,  4574);  # old=<x>      , new=<x       ; old > new
+try(    0, 11891,  1917);  # old=<x><x    , new=<x       ; old > new
+try(    0, 16384,  5155);  # old=<x><x>   , new=<x       ; old > new
+try(    0, 24576,  2953);  # old=<x><x><x>, new=<x       ; old > new
+try(    0,  8192,  8192);  # old=<x>      , new=<x>      ; old = new
+try(    0, 11083,  8192);  # old=<x><x    , new=<x>      ; old > new
+try(    0, 16384,  8192);  # old=<x><x>   , new=<x>      ; old > new
+try(    0, 24576,  8192);  # old=<x><x><x>, new=<x>      ; old > new
+try(    0, 14126, 14126);  # old=<x><x    , new=<x><x    ; old = new
+try(    0, 12002,  9034);  # old=<x><x    , new=<x><x    ; old > new
+try(    0, 16384, 13258);  # old=<x><x>   , new=<x><x    ; old > new
+try(    0, 24576, 14367);  # old=<x><x><x>, new=<x><x    ; old > new
+try(    0, 16384, 16384);  # old=<x><x>   , new=<x><x>   ; old = new
+try(    0, 24576, 16384);  # old=<x><x><x>, new=<x><x>   ; old > new
+try(    0, 24576, 24576);  # old=<x><x><x>, new=<x><x><x>; old = new
+try(    0,  6530,     0);  # old=<x       , new=0        ; old > new
+try(    0,  8192,     0);  # old=<x>      , new=0        ; old > new
+try(    0, 14707,     0);  # old=<x><x    , new=0        ; old > new
+try(    0, 16384,     0);  # old=<x><x>   , new=0        ; old > new
+try(    0, 24576,     0);  # old=<x><x><x>, new=0        ; old > new
+try(    0,     0,     0);  # old=0        , new=0        ; old = new
+
+print "# EOF tests 1\n";
+# These tests all take place at the end of the file
+$FLEN = 40960;  # Force the file to be exactly 40960 bytes long
+$oldfile = mkrand($FLEN);
+try(32768,  8192,  8192);  # old=<x>      , new=<x       ; old = new
+try(32768,  8192,  4026);  # old=<x>      , new=<x       ; old > new
+try(24576, 16384,  1917);  # old=<x><x>   , new=<x       ; old > new
+try(16384, 24576,  3818);  # old=<x><x><x>, new=<x       ; old > new
+try(32768,  8192,  8192);  # old=<x>      , new=<x>      ; old = new
+try(24576, 16384,  8192);  # old=<x><x>   , new=<x>      ; old > new
+try(16384, 24576,  8192);  # old=<x><x><x>, new=<x>      ; old > new
+try(24576, 16384, 12221);  # old=<x><x>   , new=<x><x    ; old > new
+try(16384, 24576, 15030);  # old=<x><x><x>, new=<x><x    ; old > new
+try(24576, 16384, 16384);  # old=<x><x>   , new=<x><x>   ; old = new
+try(16384, 24576, 16384);  # old=<x><x><x>, new=<x><x>   ; old > new
+try(16384, 24576, 24576);  # old=<x><x><x>, new=<x><x><x>; old = new
+try(35973,  4987,     0);  # old=x>       , new=0        ; old > new
+try(32768,  8192,     0);  # old=<x>      , new=0        ; old > new
+try(29932, 11028,     0);  # old=x><x>    , new=0        ; old > new
+try(24576, 16384,     0);  # old=<x><x>   , new=0        ; old > new
+try(16384, 24576,     0);  # old=<x><x><x>, new=0        ; old > new
+try(40960,     0,     0);  # old=0        , new=0        ; old = new
+
+print "# EOF tests 2\n";
+# These tests all take place at the end of the file
+$FLEN = 42000;  # Force the file to be exactly 42000 bytes long
+$oldfile = mkrand($FLEN);
+try(41683,   317,   317);  # old=x        , new=x        ; old = new
+try(41225,   775,   405);  # old=x        , new=x        ; old > new
+try(35709,  6291,   284);  # old=x><x     , new=x        ; old > new
+try(40960,  1040,  1040);  # old=<x       , new=<x       ; old = new
+try(40960,  1040,   378);  # old=<x       , new=<x       ; old > new
+try(32768,  9232,  5604);  # old=<x><x    , new=<x       ; old > new
+try(39994,  2006,   966);  # old=x><x     , new=x>       ; old > new
+try(36725,  5275,  5275);  # old=x><x     , new=x><x     ; old = new
+try(37990,  4010,  3199);  # old=x><x     , new=x><x     ; old > new
+try(32768,  9232,  8192);  # old=<x><x    , new=<x>      ; old > new
+try(32768,  9232,  9232);  # old=<x><x    , new=<x><x    ; old = new
+try(32768,  9232,  8795);  # old=<x><x    , new=<x><x    ; old > new
+try(41500,   500,     0);  # old=x        , new=0        ; old > new
+try(40960,  1040,     0);  # old=<x       , new=0        ; old > new
+try(35272,  6728,     0);  # old=x><x     , new=0        ; old > new
+try(32768,  9232,     0);  # old=<x><x    , new=0        ; old > new
+try(42000,     0,     0);  # old=0        , new=0        ; old = new
+
+# Now the REAL tests 
+# Make sure mtwrite can properly write sequences of several intervals
+# The intervals tested above were accumulated into @TRIES.
+# try_all_doubles() tries every possible sensible pair of those intervals.
+# try_all_triples() tries every possible sensible group of 
+#  tree intervals from the more restrictive set @BASE_TRIES.
+$FLEN = 40970;
+$oldfile = mkrand($FLEN);
+try_all_doubles();
+try_all_triples();
+
+sub mkrand {
+  my $len = shift;
+  srand $len;
+  my @c = ('a' .. 'z', 'A' .. 'Z', 0..9, $:);
+  my $d = "";
+  $d .= $c[rand @c] until length($d) >= $len;
+  substr($d, $len) = ""; # chop it off to the proper length
+  $d;
+}
+
+sub try {
+  push @TRIES, [@_] if @_ == 3;
+
+  open F, "> $file" or die "Couldn't open file $file: $!";
+  binmode F;
+  print F $oldfile;
+  close F;
+  die "wrong length!" unless -s $file == $FLEN;
+
+  my @mt_args; 
+  my $expected = $oldfile;
+  { my @a = @_;
+    my $c = "a";
+    while (@a) {
+      my ($s, $len, $newlen) = splice @a, -3;
+      my $newdata = $c++ x $newlen;
+      substr($expected, $s, $len, $newdata);
+      unshift @mt_args, $newdata, $s, $len;
+    }
+  }
+
+  my $o = tie my @lines, 'Tie::File', $file or die $!;
+  my $actual_return = $o->_mtwrite(@mt_args);
+  undef $o; untie @lines;
+
+  open F, "< $file" or die "Couldn't open file $file: $!";
+  binmode F;
+  my $actual;
+  { local $/;
+    $actual = <F>;
+  }
+  close F;
+
+  my ($alen, $xlen) = (length $actual, length $expected);
+  unless ($alen == $xlen) {
+    print "# try(@_) expected file length $xlen, actual $alen!\n";
+  }
+  print $actual eq $expected ? "ok $N\n" : "not ok $N\n";
+  $N++;
+
+#  if (! defined $actual_return && ! defined $expected_return) {
+#    print "ok $N\n";
+#  } elsif (! defined $actual_return || ! defined $expected_return) {
+#    print "not ok $N\n";
+#  } else {
+#    print $actual_return eq $expected_return ? "ok $N\n" : "not ok $N\n";
+#  }
+#  $N++;
+}
+
+sub try_all_doubles {
+  print "# Trying double regions.\n";
+  for my $a (@TRIES) {
+    next if $a->[0] + $a->[1] >= $FLEN;
+    next if $a->[0] + $a->[2] >= $FLEN;
+    for my $b (@TRIES) {
+      next if $b->[0] + $b->[1] >= $FLEN;
+      next if $b->[0] + $b->[2] >= $FLEN;
+
+      next if $b->[0] < $a->[0] + $a->[1]; # Overlapping regions
+      try(@$a, @$b);
+    }
+  }
+}
+
+sub try_all_triples {
+  print "# Trying triple regions.\n";
+  for my $a (@BASE_TRIES) {
+    next if $a->[0] + $a->[1] >= $FLEN;
+    next if $a->[0] + $a->[2] >= $FLEN;
+    for my $b (@BASE_TRIES) {
+      next if $b->[0] + $b->[1] >= $FLEN;
+      next if $b->[0] + $b->[2] >= $FLEN;
+
+      next if $b->[0] < $a->[0] + $a->[1]; # Overlapping regions
+
+      for my $c (@BASE_TRIES) {
+        next if $c->[0] + $c->[1] >= $FLEN;
+        next if $c->[0] + $c->[2] >= $FLEN;
+
+        next if $c->[0] < $b->[0] + $b->[1]; # Overlapping regions
+        try(@$a, @$b, @$c);
+      }
+    }
+  }
+}
+
+sub ctrlfix {
+  for (@_) {
+    s/\n/\\n/g;
+    s/\r/\\r/g;
+  }
+}
+
+END {
+  1 while unlink $file;
+}
+
diff --git a/dist/Tie-File/t/29_downcopy.t b/dist/Tie-File/t/29_downcopy.t
new file mode 100644
index 0000000000..d75806d5b2
--- /dev/null
+++ b/dist/Tie-File/t/29_downcopy.t
@@ -0,0 +1,363 @@
+#!/usr/bin/perl
+#
+# Unit tests of _downcopy function
+#
+# _downcopy($self, $data, $pos, $len)
+# Write $data into a block of length $len at position $pos,
+# moving everything in the block forwards to make room.
+# Instead of writing the last length($data) bytes from the block
+# (because there isn't room for them any longer) return them.
+#
+#
+
+my $file = "tf$$.txt";
+
+print "1..718\n";
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;
+
+$: = Tie::File::_default_recsep();
+
+my @subtests = qw(x <x x> x><x <x> <x><x x><x> <x><x> <x><x><x> 0);
+print "ok $N\n"; $N++;
+
+# (3-144) These were generated by 'gentests.pl' to cover all possible cases
+# (I hope)
+# Legend:
+#         x: data is entirely contained within one block
+#        x>: data runs from the middle to the end of the block
+#        <x: data runs from the start to the middle of the block
+#       <x>: data occupies precisely one block
+#      x><x: data overlaps one block boundary
+#     <x><x: data runs from the start of one block into the middle of the next
+#     x><x>: data runs from the middle of one block to the end of the next
+#    <x><x>: data occupies two blocks exactly
+# <x><x><x>: data occupies three blocks exactly
+#         0: data is null
+#
+# For each possible alignment of the old and new data, we investigate
+# up to three situations: old data is shorter, old and new data are the
+# same length, and new data is shorter.
+#
+# try($pos, $old, $new) means to run a test where the data starts at 
+# position $pos, the old data has length $old,
+# and the new data has length $new.
+try( 9659,  6635,  6691);  # old=x        , new=x        ; old < new
+try( 8605,  2394,  2394);  # old=x        , new=x        ; old = new
+try( 9768,  1361,   664);  # old=x        , new=x        ; old > new
+try( 9955,  6429,  6429);  # old=x>       , new=x        ; old = new
+try(10550,  5834,  4123);  # old=x>       , new=x        ; old > new
+try(14580,  6158,   851);  # old=x><x     , new=x        ; old > new
+try(13442, 11134,  1572);  # old=x><x>    , new=x        ; old > new
+try( 8394,     0,  5742);  # old=0        , new=x        ; old < new
+try( 8192,  2819,  6738);  # old=<x       , new=<x       ; old < new
+try( 8192,   514,   514);  # old=<x       , new=<x       ; old = new
+try( 8192,  2196,   858);  # old=<x       , new=<x       ; old > new
+try( 8192,  8192,  8192);  # old=<x>      , new=<x       ; old = new
+try( 8192,  8192,  1290);  # old=<x>      , new=<x       ; old > new
+try( 8192, 10575,  6644);  # old=<x><x    , new=<x       ; old > new
+try( 8192, 16384,  5616);  # old=<x><x>   , new=<x       ; old > new
+try( 8192, 24576,  6253);  # old=<x><x><x>, new=<x       ; old > new
+try( 8192,     0,  6870);  # old=0        , new=<x       ; old < new
+try( 8478,  6259,  7906);  # old=x        , new=x>       ; old < new
+try( 9965,  6419,  6419);  # old=x>       , new=x>       ; old = new
+try(16059,  6102,   325);  # old=x><x     , new=x>       ; old > new
+try( 9503, 15073,  6881);  # old=x><x>    , new=x>       ; old > new
+try( 9759,     0,  6625);  # old=0        , new=x>       ; old < new
+try( 8525,  2081,  8534);  # old=x        , new=x><x     ; old < new
+try(15550,   834,  1428);  # old=x>       , new=x><x     ; old < new
+try(14966,  1668,  3479);  # old=x><x     , new=x><x     ; old < new
+try(16316,  1605,  1605);  # old=x><x     , new=x><x     ; old = new
+try(16093,  4074,   993);  # old=x><x     , new=x><x     ; old > new
+try(14739,  9837,  9837);  # old=x><x>    , new=x><x     ; old = new
+try(14071, 10505,  7344);  # old=x><x>    , new=x><x     ; old > new
+try(12602,     0,  8354);  # old=0        , new=x><x     ; old < new
+try( 8192,  2767,  8192);  # old=<x       , new=<x>      ; old < new
+try( 8192,  8192,  8192);  # old=<x>      , new=<x>      ; old = new
+try( 8192, 14817,  8192);  # old=<x><x    , new=<x>      ; old > new
+try( 8192, 16384,  8192);  # old=<x><x>   , new=<x>      ; old > new
+try( 8192, 24576,  8192);  # old=<x><x><x>, new=<x>      ; old > new
+try( 8192,     0,  8192);  # old=0        , new=<x>      ; old < new
+try( 8192,  6532, 10882);  # old=<x       , new=<x><x    ; old < new
+try( 8192,  8192, 16044);  # old=<x>      , new=<x><x    ; old < new
+try( 8192,  9555, 11020);  # old=<x><x    , new=<x><x    ; old < new
+try( 8192,  9001,  9001);  # old=<x><x    , new=<x><x    ; old = new
+try( 8192, 11760, 10274);  # old=<x><x    , new=<x><x    ; old > new
+try( 8192, 16384, 10781);  # old=<x><x>   , new=<x><x    ; old > new
+try( 8192, 24576,  9284);  # old=<x><x><x>, new=<x><x    ; old > new
+try( 8192,     0, 12488);  # old=0        , new=<x><x    ; old < new
+try( 8222,  6385, 16354);  # old=x        , new=x><x>    ; old < new
+try(13500,  2884, 11076);  # old=x>       , new=x><x>    ; old < new
+try(14069,  4334, 10507);  # old=x><x     , new=x><x>    ; old < new
+try(14761,  9815,  9815);  # old=x><x>    , new=x><x>    ; old = new
+try(10469,     0, 14107);  # old=0        , new=x><x>    ; old < new
+try( 8192,  4181, 16384);  # old=<x       , new=<x><x>   ; old < new
+try( 8192,  8192, 16384);  # old=<x>      , new=<x><x>   ; old < new
+try( 8192, 12087, 16384);  # old=<x><x    , new=<x><x>   ; old < new
+try( 8192, 16384, 16384);  # old=<x><x>   , new=<x><x>   ; old = new
+try( 8192, 24576, 16384);  # old=<x><x><x>, new=<x><x>   ; old > new
+try( 8192,     0, 16384);  # old=0        , new=<x><x>   ; old < new
+try( 8192,  4968, 24576);  # old=<x       , new=<x><x><x>; old < new
+try( 8192,  8192, 24576);  # old=<x>      , new=<x><x><x>; old < new
+try( 8192, 14163, 24576);  # old=<x><x    , new=<x><x><x>; old < new
+try( 8192, 16384, 24576);  # old=<x><x>   , new=<x><x><x>; old < new
+try( 8192, 24576, 24576);  # old=<x><x><x>, new=<x><x><x>; old = new
+try( 8192,     0, 24576);  # old=0        , new=<x><x><x>; old < new
+try( 8771,   776,     0);  # old=x        , new=0        ; old > new
+try( 8192,  2813,     0);  # old=<x       , new=0        ; old > new
+try(13945,  2439,     0);  # old=x>       , new=0        ; old > new
+try(14493,  6090,     0);  # old=x><x     , new=0        ; old > new
+try( 8192,  8192,     0);  # old=<x>      , new=0        ; old > new
+try( 8192, 10030,     0);  # old=<x><x    , new=0        ; old > new
+try(14983,  9593,     0);  # old=x><x>    , new=0        ; old > new
+try( 8192, 16384,     0);  # old=<x><x>   , new=0        ; old > new
+try( 8192, 24576,     0);  # old=<x><x><x>, new=0        ; old > new
+try(10489,     0,     0);  # old=0        , new=0        ; old = new
+
+# (142-223)
+# These tests all take place at the start of the file
+try(    0,   771,  1593);  # old=<x       , new=<x       ; old < new
+try(    0,  4868,  4868);  # old=<x       , new=<x       ; old = new
+try(    0,   147,   118);  # old=<x       , new=<x       ; old > new
+try(    0,  8192,  8192);  # old=<x>      , new=<x       ; old = new
+try(    0,  8192,  4574);  # old=<x>      , new=<x       ; old > new
+try(    0, 11891,  1917);  # old=<x><x    , new=<x       ; old > new
+try(    0, 16384,  5155);  # old=<x><x>   , new=<x       ; old > new
+try(    0, 24576,  2953);  # old=<x><x><x>, new=<x       ; old > new
+try(    0,     0,  1317);  # old=0        , new=<x       ; old < new
+try(    0,  5609,  8192);  # old=<x       , new=<x>      ; old < new
+try(    0,  8192,  8192);  # old=<x>      , new=<x>      ; old = new
+try(    0, 11083,  8192);  # old=<x><x    , new=<x>      ; old > new
+try(    0, 16384,  8192);  # old=<x><x>   , new=<x>      ; old > new
+try(    0, 24576,  8192);  # old=<x><x><x>, new=<x>      ; old > new
+try(    0,     0,  8192);  # old=0        , new=<x>      ; old < new
+try(    0,  6265,  9991);  # old=<x       , new=<x><x    ; old < new
+try(    0,  8192, 16119);  # old=<x>      , new=<x><x    ; old < new
+try(    0, 10218, 11888);  # old=<x><x    , new=<x><x    ; old < new
+try(    0, 14126, 14126);  # old=<x><x    , new=<x><x    ; old = new
+try(    0, 12002,  9034);  # old=<x><x    , new=<x><x    ; old > new
+try(    0, 16384, 13258);  # old=<x><x>   , new=<x><x    ; old > new
+try(    0, 24576, 14367);  # old=<x><x><x>, new=<x><x    ; old > new
+try(    0,     0, 10881);  # old=0        , new=<x><x    ; old < new
+try(    0,  6448, 16384);  # old=<x       , new=<x><x>   ; old < new
+try(    0,  8192, 16384);  # old=<x>      , new=<x><x>   ; old < new
+try(    0, 15082, 16384);  # old=<x><x    , new=<x><x>   ; old < new
+try(    0, 16384, 16384);  # old=<x><x>   , new=<x><x>   ; old = new
+try(    0, 24576, 16384);  # old=<x><x><x>, new=<x><x>   ; old > new
+try(    0,     0, 16384);  # old=0        , new=<x><x>   ; old < new
+try(    0,  2421, 24576);  # old=<x       , new=<x><x><x>; old < new
+try(    0,  8192, 24576);  # old=<x>      , new=<x><x><x>; old < new
+try(    0, 11655, 24576);  # old=<x><x    , new=<x><x><x>; old < new
+try(    0, 16384, 24576);  # old=<x><x>   , new=<x><x><x>; old < new
+try(    0, 24576, 24576);  # old=<x><x><x>, new=<x><x><x>; old = new
+try(    0,     0, 24576);  # old=0        , new=<x><x><x>; old < new
+try(    0,  6530,     0);  # old=<x       , new=0        ; old > new
+try(    0,  8192,     0);  # old=<x>      , new=0        ; old > new
+try(    0, 14707,     0);  # old=<x><x    , new=0        ; old > new
+try(    0, 16384,     0);  # old=<x><x>   , new=0        ; old > new
+try(    0, 24576,     0);  # old=<x><x><x>, new=0        ; old > new
+try(    0,     0,     0);  # old=0        , new=0        ; old = new
+
+# (224-277)
+# These tests all take place at the end of the file
+$FLEN = 40960;  # Force the file to be exactly 40960 bytes long
+try(32768,  8192,  8192);  # old=<x>      , new=<x       ; old = new
+try(32768,  8192,  4026);  # old=<x>      , new=<x       ; old > new
+try(24576, 16384,  1917);  # old=<x><x>   , new=<x       ; old > new
+try(16384, 24576,  3818);  # old=<x><x><x>, new=<x       ; old > new
+try(40960,     0,  2779);  # old=0        , new=<x       ; old < new
+try(32768,  8192,  8192);  # old=<x>      , new=<x>      ; old = new
+try(24576, 16384,  8192);  # old=<x><x>   , new=<x>      ; old > new
+try(16384, 24576,  8192);  # old=<x><x><x>, new=<x>      ; old > new
+try(40960,     0,  8192);  # old=0        , new=<x>      ; old < new
+try(32768,  8192, 10724);  # old=<x>      , new=<x><x    ; old < new
+try(24576, 16384, 12221);  # old=<x><x>   , new=<x><x    ; old > new
+try(16384, 24576, 15030);  # old=<x><x><x>, new=<x><x    ; old > new
+try(40960,     0, 11752);  # old=0        , new=<x><x    ; old < new
+try(32768,  8192, 16384);  # old=<x>      , new=<x><x>   ; old < new
+try(24576, 16384, 16384);  # old=<x><x>   , new=<x><x>   ; old = new
+try(16384, 24576, 16384);  # old=<x><x><x>, new=<x><x>   ; old > new
+try(40960,     0, 16384);  # old=0        , new=<x><x>   ; old < new
+try(32768,  8192, 24576);  # old=<x>      , new=<x><x><x>; old < new
+try(24576, 16384, 24576);  # old=<x><x>   , new=<x><x><x>; old < new
+try(16384, 24576, 24576);  # old=<x><x><x>, new=<x><x><x>; old = new
+try(40960,     0, 24576);  # old=0        , new=<x><x><x>; old < new
+try(35973,  4987,     0);  # old=x>       , new=0        ; old > new
+try(32768,  8192,     0);  # old=<x>      , new=0        ; old > new
+try(29932, 11028,     0);  # old=x><x>    , new=0        ; old > new
+try(24576, 16384,     0);  # old=<x><x>   , new=0        ; old > new
+try(16384, 24576,     0);  # old=<x><x><x>, new=0        ; old > new
+try(40960,     0,     0);  # old=0        , new=0        ; old = new
+
+# (278-357)
+# These tests all take place at the end of the file
+$FLEN = 42000;  # Force the file to be exactly 42000 bytes long
+try(41275,   725,  4059);  # old=x        , new=x        ; old < new
+try(41683,   317,   317);  # old=x        , new=x        ; old = new
+try(41225,   775,   405);  # old=x        , new=x        ; old > new
+try(35709,  6291,   284);  # old=x><x     , new=x        ; old > new
+try(42000,     0,  2434);  # old=0        , new=x        ; old < new
+try(40960,  1040,  1608);  # old=<x       , new=<x       ; old < new
+try(40960,  1040,  1040);  # old=<x       , new=<x       ; old = new
+try(40960,  1040,   378);  # old=<x       , new=<x       ; old > new
+try(32768,  9232,  5604);  # old=<x><x    , new=<x       ; old > new
+try(42000,     0,  6637);  # old=0        , new=<x       ; old < new
+try(41022,   978,  8130);  # old=x        , new=x>       ; old < new
+try(39994,  2006,   966);  # old=x><x     , new=x>       ; old > new
+try(42000,     0,  7152);  # old=0        , new=x>       ; old < new
+try(41613,   387, 10601);  # old=x        , new=x><x     ; old < new
+try(38460,  3540,  3938);  # old=x><x     , new=x><x     ; old < new
+try(36725,  5275,  5275);  # old=x><x     , new=x><x     ; old = new
+try(37990,  4010,  3199);  # old=x><x     , new=x><x     ; old > new
+try(42000,     0,  9189);  # old=0        , new=x><x     ; old < new
+try(40960,  1040,  8192);  # old=<x       , new=<x>      ; old < new
+try(32768,  9232,  8192);  # old=<x><x    , new=<x>      ; old > new
+try(42000,     0,  8192);  # old=0        , new=<x>      ; old < new
+try(40960,  1040, 11778);  # old=<x       , new=<x><x    ; old < new
+try(32768,  9232, 13792);  # old=<x><x    , new=<x><x    ; old < new
+try(32768,  9232,  9232);  # old=<x><x    , new=<x><x    ; old = new
+try(32768,  9232,  8795);  # old=<x><x    , new=<x><x    ; old > new
+try(42000,     0,  8578);  # old=0        , new=<x><x    ; old < new
+try(41531,   469, 15813);  # old=x        , new=x><x>    ; old < new
+try(39618,  2382,  9534);  # old=x><x     , new=x><x>    ; old < new
+try(42000,     0, 15344);  # old=0        , new=x><x>    ; old < new
+try(40960,  1040, 16384);  # old=<x       , new=<x><x>   ; old < new
+try(32768,  9232, 16384);  # old=<x><x    , new=<x><x>   ; old < new
+try(42000,     0, 16384);  # old=0        , new=<x><x>   ; old < new
+try(40960,  1040, 24576);  # old=<x       , new=<x><x><x>; old < new
+try(32768,  9232, 24576);  # old=<x><x    , new=<x><x><x>; old < new
+try(42000,     0, 24576);  # old=0        , new=<x><x><x>; old < new
+try(41500,   500,     0);  # old=x        , new=0        ; old > new
+try(40960,  1040,     0);  # old=<x       , new=0        ; old > new
+try(35272,  6728,     0);  # old=x><x     , new=0        ; old > new
+try(32768,  9232,     0);  # old=<x><x    , new=0        ; old > new
+try(42000,     0,     0);  # old=0        , new=0        ; old = new
+
+sub try {
+  my ($pos, $len, $newlen) = @_;
+  open F, "> $file" or die "Couldn't open file $file: $!";
+  binmode F;
+
+  # The record has exactly 17 characters.  This will help ensure that
+  # even if _downcoopy screws up, the data doesn't coincidentally
+  # look good because the remainder accidentally lines up.
+  my $d = substr("0123456789abcdef$:", -17);
+  my $recs = defined($FLEN) ?
+    int($FLEN/length($d))+1 : # enough to make up at least $FLEN
+    int(8192*5/length($d))+1; # at least 5 blocks' worth
+  my $oldfile = $d x $recs;
+  my $flen = defined($FLEN) ? $FLEN : $recs * 17;
+  substr($oldfile, $FLEN) = "" if defined $FLEN;  # truncate
+  print F $oldfile;
+  close F;
+
+  die "wrong length!" unless -s $file == $flen;
+
+  my $newdata = "-" x $newlen;
+  my $expected = $oldfile;
+  my $old = defined $len ? substr($expected, $pos, $len) 
+                         : substr($expected, $pos);
+  $old = "$newdata$old";
+  my $x_retval;
+  if (defined $len) {
+    substr($expected, $pos, $len, substr($old, 0, $len, ""));
+    $x_retval = $old;
+  } else {
+    substr($expected, $pos) = $old;
+    $x_retval = "";
+  }
+
+  my $o = tie my @lines, 'Tie::File', $file or die $!;
+  local $SIG{ALRM} = sub { die "Alarm clock" };
+  my $a_retval = eval { alarm(5) unless $^P; $o->_downcopy($newdata, $pos, $len) };
+  my $err = $@;
+  undef $o; untie @lines; alarm(0);
+  if ($err) {
+    if ($err =~ /^Alarm clock/) {
+      print "# Timeout\n";
+      print "not ok $N\n"; $N++;
+      print "not ok $N\n"; $N++;
+      return;
+    } else {
+      $@ = $err;
+      die;
+    }
+  }
+
+  open F, "< $file" or die "Couldn't open file $file: $!";
+  binmode F;
+  my $actual;
+  { local $/;
+    $actual = <F>;
+  }
+  close F;
+
+  my ($alen, $xlen) = (length $actual, length $expected);
+  unless ($alen == $xlen) {
+    my @ARGS = @_;
+    for (@ARGS) { $_ = "UNDEF" unless defined }
+    print "# try(@ARGS) expected file length $xlen, actual $alen!\n";
+  }
+  print $actual eq $expected ? "ok $N\n" : "not ok $N\n";
+  $N++;
+  print $a_retval eq $x_retval ? "ok $N\n" : "not ok $N\n";
+  $N++;
+
+  if (defined $len) {
+    try($pos, undef, $newlen);
+  }
+}
+
+
+
+use POSIX 'SEEK_SET';
+sub check_contents {
+  my @c = @_;
+  my $x = join $:, @c, '';
+  local *FH = $o->{fh};
+  seek FH, 0, SEEK_SET;
+#  my $open = open FH, "< $file";
+  my $a;
+  { local $/; $a = <FH> }
+  $a = "" unless defined $a;
+  if ($a eq $x) {
+    print "ok $N\n";
+  } else {
+    ctrlfix($a, $x);
+    print "not ok $N\n# expected <$x>, got <$a>\n";
+  }
+  $N++;
+
+  # now check FETCH:
+  my $good = 1;
+  my $msg;
+  for (0.. $#c) {
+    my $aa = $a[$_];
+    unless ($aa eq "$c[$_]$:") {
+      $msg = "expected <$c[$_]$:>, got <$aa>";
+      ctrlfix($msg);
+      $good = 0;
+    }
+  }
+  print $good ? "ok $N\n" : "not ok $N # $msg\n";
+  $N++;
+
+  print $o->_check_integrity($file, $ENV{INTEGRITY}) 
+      ? "ok $N\n" : "not ok $N\n";
+  $N++;
+}
+
+sub ctrlfix {
+  for (@_) {
+    s/\n/\\n/g;
+    s/\r/\\r/g;
+  }
+}
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
diff --git a/dist/Tie-File/t/29a_upcopy.t b/dist/Tie-File/t/29a_upcopy.t
new file mode 100644
index 0000000000..1130615f37
--- /dev/null
+++ b/dist/Tie-File/t/29a_upcopy.t
@@ -0,0 +1,211 @@
+#!/usr/bin/perl
+#
+# Unit tests of _upcopy function
+#
+# _upcopy($self, $source, $dest, $len)
+#
+# Take a block of data of leength $len at $source and copy it
+# to $dest, which must be <= $source but which need not be <= $source - $len
+# (That is, this will only copy a block to a position earlier in the file,
+# but the source and destination regions may overlap.)
+
+
+my $file = "tf$$.txt";
+
+print "1..55\n";
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;
+
+$: = Tie::File::_default_recsep();
+
+my @subtests = qw(x <x x> x><x <x> <x><x x><x> <x><x> <x><x><x> 0);
+
+$FLEN = 40970;  # 2410 records of 17 chars each
+
+# (2-7) Trivial non-moves at start of file
+try(0, 0, 0);
+try(0, 0, 10);
+try(0, 0, 100);
+try(0, 0, 1000);
+try(0, 0, 10000);
+try(0, 0, 20000);
+
+# (8-13) Trivial non-moves in middle of file
+try(100, 100, 0);
+try(100, 100, 10);
+try(100, 100, 100);
+try(100, 100, 1000);
+try(100, 100, 10000);
+try(100, 100, 20000);
+
+# (14) Trivial non-move at end of file
+try($FLEN, $FLEN, 0);
+
+# (15-17) Trivial non-move of tail of file
+try(0, 0, undef);
+try(100, 100, undef);
+try($FLEN, $FLEN, undef);
+
+# (18-24) Moves to start of file
+try(100, 0, 0);
+try(100, 0, 10);
+try(100, 0, 100);
+try(100, 0, 1000);
+try(100, 0, 10000);
+try(100, 0, 20000);
+try(100, 0, undef);
+
+# (25-31) Moves in middle of file
+try(200, 100, 0);
+try(200, 100, 10);
+try(200, 100, 100);
+try(200, 100, 1000);
+try(200, 100, 10000);
+try(200, 100, 20000);
+try(200, 100, undef);
+
+# (32-43) Moves from end of file
+try($FLEN, 10000, 0);
+try($FLEN-10, 10000, 10);
+try($FLEN-100, 10000, 100);
+try($FLEN-1000, 200, 1000);
+try($FLEN-10000, 200, 10000);
+try($FLEN-20000, 200, 20000);
+try($FLEN, 10000, undef);
+try($FLEN-10, 10000, undef);
+try($FLEN-100, 10000, undef);
+try($FLEN-1000, 200, undef);
+try($FLEN-10000, 200, undef);
+try($FLEN-20000, 200, undef);
+
+$FLEN = 40960;
+
+# (44-55) Moves from end of file when file ends on a block boundary
+try($FLEN, 10000, 0);
+try($FLEN-10, 10000, 10);
+try($FLEN-100, 10000, 100);
+try($FLEN-1000, 200, 1000);
+try($FLEN-10000, 200, 10000);
+try($FLEN-20000, 200, 20000);
+try($FLEN, 10000, undef);
+try($FLEN-10, 10000, undef);
+try($FLEN-100, 10000, undef);
+try($FLEN-1000, 200, undef);
+try($FLEN-10000, 200, undef);
+try($FLEN-20000, 200, undef);
+
+sub try {
+  my ($src, $dst, $len) = @_;
+  open F, "> $file" or die "Couldn't open file $file: $!";
+  binmode F;
+
+  # The record has exactly 17 characters.  This will help ensure that
+  # even if _upcopy screws up, the data doesn't coincidentally
+  # look good because the remainder accidentally lines up.
+  my $d = substr("0123456789abcdef$:", -17);
+  my $recs = defined($FLEN) ?
+    int($FLEN/length($d))+1 : # enough to make up at least $FLEN
+    int(8192*5/length($d))+1; # at least 5 blocks' worth
+  my $oldfile = $d x $recs;
+  my $flen = defined($FLEN) ? $FLEN : $recs * 17;
+  substr($oldfile, $FLEN) = "" if defined $FLEN;  # truncate
+  print F $oldfile;
+  close F;
+
+  die "wrong length!" unless -s $file == $flen;
+
+  # If len is specified, use that.  If it's undef,
+  # then behave *as if* we had specified the whole rest of the file
+  my $expected = $oldfile;
+  if (defined $len) {
+    substr($expected, $dst, $len) = substr($expected, $src, $len);
+  } else {
+    substr($expected, $dst) = substr($expected, $src);
+  }
+
+  my $o = tie my @lines, 'Tie::File', $file or die $!;
+  local $SIG{ALRM} = sub { die "Alarm clock" };
+  my $a_retval = eval { alarm(5) unless $^P; $o->_upcopy($src, $dst, $len) };
+  my $err = $@;
+  undef $o; untie @lines; alarm(0);
+  if ($err) {
+    if ($err =~ /^Alarm clock/) {
+      print "# Timeout\n";
+      print "not ok $N\n"; $N++;
+      return;
+    } else {
+      $@ = $err;
+      die;
+    }
+  }
+
+  open F, "< $file" or die "Couldn't open file $file: $!";
+  binmode F;
+  my $actual;
+  { local $/;
+    $actual = <F>;
+  }
+  close F;
+
+  my ($alen, $xlen) = (length $actual, length $expected);
+  unless ($alen == $xlen) {
+    print "# try(@_) expected file length $xlen, actual $alen!\n";
+  }
+  print $actual eq $expected ? "ok $N\n" : "not ok $N\n";
+  $N++;
+}
+
+
+
+use POSIX 'SEEK_SET';
+sub check_contents {
+  my @c = @_;
+  my $x = join $:, @c, '';
+  local *FH = $o->{fh};
+  seek FH, 0, SEEK_SET;
+#  my $open = open FH, "< $file";
+  my $a;
+  { local $/; $a = <FH> }
+  $a = "" unless defined $a;
+  if ($a eq $x) {
+    print "ok $N\n";
+  } else {
+    ctrlfix($a, $x);
+    print "not ok $N\n# expected <$x>, got <$a>\n";
+  }
+  $N++;
+
+  # now check FETCH:
+  my $good = 1;
+  my $msg;
+  for (0.. $#c) {
+    my $aa = $a[$_];
+    unless ($aa eq "$c[$_]$:") {
+      $msg = "expected <$c[$_]$:>, got <$aa>";
+      ctrlfix($msg);
+      $good = 0;
+    }
+  }
+  print $good ? "ok $N\n" : "not ok $N # $msg\n";
+  $N++;
+
+  print $o->_check_integrity($file, $ENV{INTEGRITY}) 
+      ? "ok $N\n" : "not ok $N\n";
+  $N++;
+}
+
+sub ctrlfix {
+  for (@_) {
+    s/\n/\\n/g;
+    s/\r/\\r/g;
+  }
+}
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
diff --git a/dist/Tie-File/t/30_defer.t b/dist/Tie-File/t/30_defer.t
new file mode 100644
index 0000000000..063b3a7090
--- /dev/null
+++ b/dist/Tie-File/t/30_defer.t
@@ -0,0 +1,328 @@
+#!/usr/bin/perl
+#
+# Check ->defer and ->flush methods
+#
+# This is the old version, which you used in the past when
+# there was a defer buffer separate from the read cache.  
+# There isn't any longer.
+#
+
+use POSIX 'SEEK_SET';
+my $file = "tf$$.txt";
+$: = Tie::File::_default_recsep();
+my $data = "rec0$:rec1$:rec2$:";
+my ($o, $n);
+
+print "1..79\n";
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;
+
+open F, "> $file" or die $!;
+binmode F;
+print F $data;
+close F;
+$o = tie @a, 'Tie::File', $file;
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+# (3-6) Deferred storage
+$o->defer;
+$a[3] = "rec3";
+check_contents($data);          # nothing written yet
+$a[4] = "rec4";
+check_contents($data);          # nothing written yet
+
+# (7-8) Flush
+$o->flush;
+check_contents($data . "rec3$:rec4$:");          # now it's written
+
+# (9-12) Deferred writing disabled?
+$a[3] = "rec9";
+check_contents("${data}rec9$:rec4$:");
+$a[4] = "rec8";
+check_contents("${data}rec9$:rec8$:");
+
+# (13-18) Now let's try two batches of records
+$#a = 2;
+$o->defer;
+$a[0] = "record0";
+check_contents($data);          # nothing written yet
+$a[2] = "record2";
+check_contents($data);          # nothing written yet
+$o->flush;
+check_contents("record0$:rec1$:record2$:");
+
+# (19-22) Deferred writing past the end of the file
+$o->defer;
+$a[4] = "record4";
+check_contents("record0$:rec1$:record2$:");
+$o->flush;
+check_contents("record0$:rec1$:record2$:$:record4$:");
+
+
+# (23-26) Now two long batches
+$o->defer;
+for (0..2, 4..6) {
+  $a[$_] = "r$_";
+}
+check_contents("record0$:rec1$:record2$:$:record4$:");
+$o->flush;
+check_contents(join $:, "r0".."r2", "", "r4".."r6", "");
+
+# (27-30) Now let's make sure that discarded writes are really discarded
+# We have a 2Mib buffer here, so we can be sure that we aren't accidentally
+# filling it up
+$o->defer;
+for (0, 3, 7) {
+  $a[$_] = "discarded$_";
+}
+check_contents(join $:, "r0".."r2", "", "r4".."r6", "");
+$o->discard;
+check_contents(join $:, "r0".."r2", "", "r4".."r6", "");
+
+################################################################
+#
+# Now we're going to test the results of a small memory limit
+#
+# 
+undef $o;  untie @a;
+$data = join "$:", map("record$_", 0..7), "";  # records are 8 or 9 bytes long
+open F, "> $file" or die $!;
+binmode F;
+print F $data;
+close F;
+
+# Limit cache+buffer size to 47 bytes 
+my $MAX = 47;
+#  -- that's enough space for 5 records, but not 6, on both \n and \r\n systems
+my $BUF = 20;
+#  -- that's enough space for 2 records, but not 3, on both \n and \r\n systems
+$o = tie @a, 'Tie::File', $file, memory => $MAX, dw_size => $BUF;
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+# (31-32) Fill up the read cache
+my @z;
+@z = @a;                        
+# the cache now contains records 3,4,5,6,7.
+check_caches({map(($_ => "record$_$:"), 3..7)}, 
+             {});
+
+# (33-44) See if overloading the defer starts by flushing the read cache
+# and then flushes out the defer
+$o->defer;
+$a[0] = "recordA";              # That should flush record 3 from the cache
+check_caches({map(($_ => "record$_$:"), 4..7)}, 
+             {0 => "recordA$:"});
+check_contents($data);
+
+$a[1] = "recordB";              # That should flush record 4 from the cache
+check_caches({map(($_ => "record$_$:"), 5..7)}, 
+             {0 => "recordA$:",
+              1 => "recordB$:"});
+check_contents($data);
+
+$a[2] = "recordC";              # That should flush the whole darn defer
+# This shouldn't change the cache contents
+check_caches({map(($_ => "record$_$:"), 5..7)}, 
+             {});               # URRRP
+check_contents(join("$:", qw(recordA recordB recordC 
+                             record3 record4 record5 record6 record7)) . "$:");
+
+$a[3] = "recordD";         # even though we flushed, deferring is STILL ENABLED
+check_caches({map(($_ => "record$_$:"), 5..7)},
+             {3 => "recordD$:"}); 
+check_contents(join("$:", qw(recordA recordB recordC 
+                             record3 record4 record5 record6 record7)) . "$:");
+
+# Check readcache-deferbuffer interactions
+
+# (45-47) This should remove outdated data from the read cache
+$a[5] = "recordE";
+check_caches({6 => "record6$:", 7 => "record7$:"},
+             {3 => "recordD$:", 5 => "recordE$:"}); 
+check_contents(join("$:", qw(recordA recordB recordC 
+                             record3 record4 record5 record6 record7)) . "$:");
+
+# (48-51) This should read back out of the defer buffer
+# without adding anything to the read cache
+my $z;
+$z = $a[5];
+print $z eq "recordE" ? "ok $N\n" : "not ok $N\n";  $N++;
+check_caches({6 => "record6$:", 7 => "record7$:"},
+             {3 => "recordD$:", 5 => "recordE$:"}); 
+check_contents(join("$:", qw(recordA recordB recordC 
+                             record3 record4 record5 record6 record7)) . "$:");
+
+# (52-55) This should repopulate the read cache with a new record
+$z = $a[0];
+print $z eq "recordA" ? "ok $N\n" : "not ok $N\n";  $N++;
+check_caches({0 => "recordA$:", 6 => "record6$:", 7 => "record7$:"},
+             {3 => "recordD$:", 5 => "recordE$:"}); 
+check_contents(join("$:", qw(recordA recordB recordC 
+                             record3 record4 record5 record6 record7)) . "$:");
+
+# (56-59) This should flush the LRU record from the read cache
+$z = $a[4];
+print $z eq "record4" ? "ok $N\n" : "not ok $N\n";  $N++;
+check_caches({7 => "record7$:", 0 => "recordA$:", 4 => "record4$:"},
+             {3 => "recordD$:", 5 => "recordE$:"}); 
+check_contents(join("$:", qw(recordA recordB recordC 
+                             record3 record4 record5 record6 record7)) . "$:");
+
+# (60-63) This should FLUSH the deferred buffer
+$z = splice @a, 3, 1, "recordZ";
+print $z eq "recordD" ? "ok $N\n" : "not ok $N\n";  $N++;
+check_caches({7 => "record7$:", 0 => "recordA$:", 4 => "record4$:", 3 => "recordZ$:"},
+             {}); 
+check_contents(join("$:", qw(recordA recordB recordC 
+                             recordZ record4 recordE record6 record7)) . "$:");
+
+# (64-66) We should STILL be in deferred writing mode
+$a[5] = "recordX";
+check_caches({7 => "record7$:", 0 => "recordA$:", 4 => "record4$:", 3 => "recordZ$:"},
+             {5 => "recordX$:"}); 
+check_contents(join("$:", qw(recordA recordB recordC 
+                             recordZ record4 recordE record6 record7)) . "$:");
+
+# Fill up the defer buffer again
+$a[4] = "recordP";
+# (67-69) This should OVERWRITE the existing deferred record 
+# and NOT flush the buffer
+$a[5] = "recordQ";   
+check_caches({7 => "record7$:", 0 => "recordA$:", 3 => "recordZ$:"},
+             {5 => "recordQ$:", 4 => "recordP$:"}); 
+check_contents(join("$:", qw(recordA recordB recordC 
+                             recordZ record4 recordE record6 record7)) . "$:");
+
+# (70-72) Discard should just dump the whole deferbuffer
+$o->discard;
+check_caches({7 => "record7$:", 0 => "recordA$:", 3 => "recordZ$:"},
+             {}); 
+check_contents(join("$:", qw(recordA recordB recordC 
+                             recordZ record4 recordE record6 record7)) . "$:");
+
+# (73-75) NOW we are out of deferred writing mode
+$a[0] = "recordF";
+check_caches({7 => "record7$:", 0 => "recordF$:", 3 => "recordZ$:"},
+             {}); 
+check_contents(join("$:", qw(recordF recordB recordC
+                             recordZ record4 recordE record6 record7)) . "$:");
+
+# (76-79) Last call--untying the array should flush the deferbuffer
+$o->defer;
+$a[0] = "flushed";
+check_caches({7 => "record7$:",                   3 => "recordZ$:"},
+             {0 => "flushed$:" }); 
+check_contents(join("$:", qw(recordF recordB recordC
+                             recordZ record4 recordE record6 record7)) . "$:");
+undef $o;
+untie @a;
+# (79) We can't use check_contents any more, because the object is dead
+open F, "< $file" or die;
+binmode F;
+{ local $/ ; $z = <F> }
+close F;
+my $x = join("$:", qw(flushed recordB recordC
+                      recordZ record4 recordE record6 record7)) . "$:";
+if ($z eq $x) {
+  print "ok $N\n";
+} else {
+  my $msg = ctrlfix("expected <$x>, got <$z>");
+  print "not ok $N \# $msg\n";
+}
+$N++;
+
+################################################################
+
+
+sub check_caches {
+  my ($xcache, $xdefer) = @_;
+
+#  my $integrity = $o->_check_integrity($file, $ENV{INTEGRITY});
+#  print $integrity ? "ok $N\n" : "not ok $N\n";
+#  $N++;
+
+  my $good = 1;
+
+  # Copy the contents of the cache into a regular hash
+  my %cache;
+  for my $k ($o->{cache}->ckeys) {
+    $cache{$k} = $o->{cache}->_produce($k);
+  }
+
+  $good &&= hash_equal(\%cache, $xcache, "true cache", "expected cache");
+  $good &&= hash_equal($o->{deferred}, $xdefer, "true defer", "expected defer");
+  print $good ? "ok $N\n" : "not ok $N\n";
+  $N++;
+}
+
+sub hash_equal {
+  my ($a, $b, $ha, $hb) = @_;
+  $ha = 'first hash'  unless defined $ha;
+  $hb = 'second hash' unless defined $hb;
+
+  my $good = 1;
+  my %b_seen;
+
+  for my $k (keys %$a) {
+    if (! exists $b->{$k}) {
+      print ctrlfix("# Key $k is in $ha but not $hb"), "\n";
+      $good = 0;
+    } elsif ($b->{$k} ne $a->{$k}) {
+      print ctrlfix("# Key $k is <$a->{$k}> in $ha but <$b->{$k}> in $hb"), "\n";
+      $b_seen{$k} = 1;
+      $good = 0;
+    } else {
+      $b_seen{$k} = 1;
+    }
+  }
+
+  for my $k (keys %$b) {
+    unless ($b_seen{$k}) {
+      print ctrlfix("# Key $k is in $hb but not $ha"), "\n";
+      $good = 0;
+    }
+  }
+
+  $good;
+}
+
+
+sub check_contents {
+  my $x = shift;
+
+  my $integrity = $o->_check_integrity($file, $ENV{INTEGRITY});
+  print $integrity ? "ok $N\n" : "not ok $N\n";
+  $N++;
+
+  local *FH = $o->{fh};
+  seek FH, 0, SEEK_SET;
+
+  my $a;
+  { local $/; $a = <FH> }
+  $a = "" unless defined $a;
+  if ($a eq $x) {
+    print "ok $N\n";
+  } else {
+    my $msg = ctrlfix("# expected <$x>, got <$a>");
+    print "not ok $N\n$msg\n";
+  }
+  $N++;
+}
+
+sub ctrlfix {
+  local $_ = shift;
+  s/\n/\\n/g;
+  s/\r/\\r/g;
+  $_;
+}
+
+END {
+  undef $o;
+  untie @a if tied @a;
+  1 while unlink $file;
+}
+
diff --git a/dist/Tie-File/t/31_autodefer.t b/dist/Tie-File/t/31_autodefer.t
new file mode 100644
index 0000000000..ea929a4097
--- /dev/null
+++ b/dist/Tie-File/t/31_autodefer.t
@@ -0,0 +1,182 @@
+#!/usr/bin/perl
+#
+# Check behavior of 'autodefer' feature
+# Mostly this isn't implemented yet
+# This file is primarily here to make sure that the promised ->autodefer
+# method doesn't croak.
+#
+
+use POSIX 'SEEK_SET';
+
+my $file = "tf$$.txt";
+$: = Tie::File::_default_recsep();
+my $data = "rec0$:rec1$:rec2$:";
+my ($o, $n, @a);
+
+print "1..65\n";
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;
+
+open F, "> $file" or die $!;
+binmode F;
+print F $data;
+close F;
+$o = tie @a, 'Tie::File', $file;
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+# I am an undocumented feature
+$o->{autodefer_filelen_threshhold} = 0;
+# Normally autodeferring only works on large files.  This disables that.
+
+# (3-22) Deferred storage
+$a[3] = "rec3";
+check_autodeferring('OFF');
+$a[4] = "rec4";
+check_autodeferring('OFF');
+$a[5] = "rec5";
+check_autodeferring('ON');
+check_contents($data . "rec3$:rec4$:"); # only the first two were written
+$a[6] = "rec6";
+check_autodeferring('ON');
+check_contents($data . "rec3$:rec4$:"); # still nothing written
+$a[7] = "rec7";
+check_autodeferring('ON');
+check_contents($data . "rec3$:rec4$:"); # still nothing written
+$a[0] = "recX";
+check_autodeferring('OFF');
+check_contents("recX$:rec1$:rec2$:rec3$:rec4$:rec5$:rec6$:rec7$:");
+$a[1] = "recY";
+check_autodeferring('OFF');
+check_contents("recX$:recY$:rec2$:rec3$:rec4$:rec5$:rec6$:rec7$:");
+$a[2] = "recZ";                 # it kicks in here
+check_autodeferring('ON');
+check_contents("recX$:recY$:rec2$:rec3$:rec4$:rec5$:rec6$:rec7$:");
+
+# (23-26) Explicitly enabling deferred writing deactivates autodeferring
+$o->defer;
+check_autodeferring('OFF');
+check_contents("recX$:recY$:recZ$:rec3$:rec4$:rec5$:rec6$:rec7$:");
+$o->discard;
+check_autodeferring('OFF');
+
+# (27-32) Now let's try the CLEAR special case
+@a = ("r0" .. "r4");
+check_autodeferring('ON');
+# The file was extended to the right length, but nothing was actually written.
+check_contents("$:$:$:$:$:");
+$a[2] = "fish";
+check_autodeferring('OFF');
+check_contents("r0$:r1$:fish$:r3$:r4$:");
+
+# (33-47) Now let's try the originally intended application:  a 'for' loop.
+my $it = 0;
+for (@a) {
+  $_ = "##$_";
+  if ($it == 0) {
+    check_autodeferring('OFF');
+    check_contents("##r0$:r1$:fish$:r3$:r4$:");
+  } elsif ($it == 1) {
+    check_autodeferring('OFF');
+    check_contents("##r0$:##r1$:fish$:r3$:r4$:");
+  } else {
+    check_autodeferring('ON');
+    check_contents("##r0$:##r1$:fish$:r3$:r4$:");
+  }
+  $it++;
+}
+
+# (48-56) Autodeferring should not become active during explicit defer mode
+$o->defer();  # This should flush the pending autodeferred records
+              # and deactivate autodeferring
+check_autodeferring('OFF');
+check_contents("##r0$:##r1$:##fish$:##r3$:##r4$:");
+@a = ("s0" .. "s4");
+check_autodeferring('OFF');
+check_contents("");
+$o->flush;
+check_autodeferring('OFF');
+check_contents("s0$:s1$:s2$:s3$:s4$:");
+
+undef $o; untie @a;
+
+# Limit cache+buffer size to 47 bytes 
+my $MAX = 47;
+#  -- that's enough space for 5 records, but not 6, on both \n and \r\n systems
+my $BUF = 20;
+#  -- that's enough space for 2 records, but not 3, on both \n and \r\n systems
+# Re-tie the object for more tests
+$o = tie @a, 'Tie::File', $file, autodefer => 0;
+die $! unless $o;
+# I am an undocumented feature
+$o->{autodefer_filelen_threshhold} = 0;
+# Normally autodeferring only works on large files.  This disables that.
+
+# (57-59) Did the autodefer => 0 option work?
+# (If it doesn't, a whole bunch of the other test files will fail.)
+@a = (0..3);
+check_autodeferring('OFF');
+check_contents(join("$:", qw(0 1 2 3), ""));
+
+# (60-62) Does the ->autodefer method work?
+$o->autodefer(1);
+@a = (10..13);
+check_autodeferring('ON');
+check_contents("$:$:$:$:");  # This might be unfortunate.
+
+# (63-65) Does the ->autodefer method work?
+$o->autodefer(0);
+check_autodeferring('OFF');
+check_contents(join("$:", qw(10 11 12 13), ""));
+
+
+sub check_autodeferring {
+  my ($x) = shift;
+  my $a = $o->{autodeferring} ? 'ON' : 'OFF';
+  if ($x eq $a) {
+    print "ok $N\n";
+  } else {
+    print "not ok $N \# Autodeferring was $a, expected it to be $x\n";
+  }
+  $N++;
+}
+
+
+sub check_contents {
+  my $x = shift;
+#  for (values %{$o->{cache}}) {
+#    print "# cache=$_";    
+#  }
+  
+  my $integrity = $o->_check_integrity($file, $ENV{INTEGRITY});
+  local *FH = $o->{fh};
+  seek FH, 0, SEEK_SET;
+  print $integrity ? "ok $N\n" : "not ok $N\n";
+  $N++;
+  my $a;
+  { local $/; $a = <FH> }
+  $a = "" unless defined $a;
+  if ($a eq $x) {
+    print "ok $N\n";
+  } else {
+    ctrlfix(my $msg = "# expected <$x>, got <$a>");
+    print "not ok $N\n$msg\n";
+  }
+  $N++;
+}
+
+sub ctrlfix {
+  for (@_) {
+    s/\n/\\n/g;
+    s/\r/\\r/g;
+  }
+}
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
diff --git a/dist/Tie-File/t/32_defer_misc.t b/dist/Tie-File/t/32_defer_misc.t
new file mode 100644
index 0000000000..e0e3f15bb8
--- /dev/null
+++ b/dist/Tie-File/t/32_defer_misc.t
@@ -0,0 +1,232 @@
+#!/usr/bin/perl
+#
+# Check interactions of deferred writing
+# with miscellaneous methods like DELETE, EXISTS,
+# FETCHSIZE, STORESIZE, CLEAR, EXTEND
+#
+
+use POSIX 'SEEK_SET';
+my $file = "tf$$.txt";
+$: = Tie::File::_default_recsep();
+my $data = "rec0$:rec1$:rec2$:";
+my ($o, $n);
+
+print "1..53\n";
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;
+
+open F, "> $file" or die $!;
+binmode F;
+print F $data;
+close F;
+$o = tie @a, 'Tie::File', $file;
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+# (3-6) EXISTS
+if ($] >= 5.006) {
+  eval << 'TESTS';
+$o->defer;
+expect(not exists $a[4]);
+$a[4] = "rec4";
+expect(exists $a[4]);
+check_contents($data);          # nothing written yet
+$o->discard;
+TESTS
+} else {
+    for (3..6) {
+      print "ok $_ \# skipped (no exists for arrays)\n";
+          $N++;
+    }
+}
+
+# (7-10) FETCHSIZE
+$o->defer;
+expect($#a, 2);
+$a[4] = "rec4";
+expect($#a, 4);
+check_contents($data);          # nothing written yet
+$o->discard;
+
+# (11-21) STORESIZE
+$o->defer;
+$#a = 4;
+check_contents($data);          # nothing written yet
+expect($#a, 4);
+$o->flush;
+expect($#a, 4);
+check_contents("$data$:$:");    # two extra empty records
+
+$o->defer;
+$a[4] = "rec4";
+$#a = 2;
+expect($a[4], undef);
+check_contents($data);          # written data was unwritten
+$o->flush;
+check_contents($data);          # nothing left to write
+
+# (22-28) CLEAR
+$o->defer;
+$a[9] = "rec9";
+check_contents($data);          # nothing written yet
+@a = ();
+check_contents("");             # this happens right away
+expect($a[9], undef);
+$o->flush;
+check_contents("");             # nothing left to write
+
+# (29-34) EXTEND
+# Actually it's not real clear what these tests are for
+# since EXTEND has no defined semantics
+$o->defer;
+@a = (0..3);
+check_contents("");             # nothing happened yet
+expect($a[3], "3");
+expect($a[4], undef);
+$o->flush;
+check_contents("0$:1$:2$:3$:"); # file now 4 records long
+
+# (35-53) DELETE
+if ($] >= 5.006) {
+  eval << 'TESTS';
+my $del;
+$o->defer;
+$del = delete $a[2];
+check_contents("0$:1$:2$:3$:"); # nothing happened yet
+expect($a[2], "");
+expect($del, "2");
+$del = delete $a[3];            # shortens file!
+check_contents("0$:1$:2$:");    # deferred writes NOT flushed
+expect($a[3], undef);
+expect($a[2], "");
+expect($del, "3");
+$a[2] = "cookies";
+$del = delete $a[2];            # shortens file!
+expect($a[2], undef);
+expect($del, 'cookies');
+check_contents("0$:1$:");
+$a[0] = "crackers";
+$del = delete $a[0];            # file unchanged
+expect($a[0], "");
+expect($del, 'crackers');
+check_contents("0$:1$:");       # no change yet
+$o->flush;
+check_contents("$:1$:");        # record 0 is NOT 'cookies';
+TESTS
+} else {
+    for (35..53) {
+      print "ok $_ \# skipped (no delete for arrays)\n";
+          $N++;
+    }
+}
+
+################################################################
+
+
+sub check_caches {
+  my ($xcache, $xdefer) = @_;
+
+#  my $integrity = $o->_check_integrity($file, $ENV{INTEGRITY});
+#  print $integrity ? "ok $N\n" : "not ok $N\n";
+#  $N++;
+
+  my $good = 1;
+  $good &&= hash_equal($o->{cache}, $xcache, "true cache", "expected cache");
+  $good &&= hash_equal($o->{deferred}, $xdefer, "true defer", "expected defer");
+  print $good ? "ok $N\n" : "not ok $N\n";
+  $N++;
+}
+
+sub hash_equal {
+  my ($a, $b, $ha, $hb) = @_;
+  $ha = 'first hash'  unless defined $ha;
+  $hb = 'second hash' unless defined $hb;
+
+  my $good = 1;
+  my %b_seen;
+
+  for my $k (keys %$a) {
+    if (! exists $b->{$k}) {
+      print ctrlfix("# Key $k is in $ha but not $hb"), "\n";
+      $good = 0;
+    } elsif ($b->{$k} ne $a->{$k}) {
+      print ctrlfix("# Key $k is <$a->{$k}> in $ha but <$b->{$k}> in $hb"), "\n";
+      $b_seen{$k} = 1;
+      $good = 0;
+    } else {
+      $b_seen{$k} = 1;
+    }
+  }
+
+  for my $k (keys %$b) {
+    unless ($b_seen{$k}) {
+      print ctrlfix("# Key $k is in $hb but not $ha"), "\n";
+      $good = 0;
+    }
+  }
+
+  $good;
+}
+
+
+sub check_contents {
+  my $x = shift;
+
+  my $integrity = $o->_check_integrity($file, $ENV{INTEGRITY});
+  print $integrity ? "ok $N\n" : "not ok $N\n";
+  $N++;
+
+  local *FH = $o->{fh};
+  seek FH, 0, SEEK_SET;
+
+  my $a;
+  { local $/; $a = <FH> }
+  $a = "" unless defined $a;
+  if ($a eq $x) {
+    print "ok $N\n";
+  } else {
+    my $msg = ctrlfix("# expected <$x>, got <$a>");
+    print "not ok $N\n$msg\n";
+  }
+  $N++;
+}
+
+sub expect {
+  if (@_ == 1) {
+    print $_[0] ? "ok $N\n" : "not ok $N\n";
+  } elsif (@_ == 2) {
+    my ($a, $x) = @_;
+    if    (! defined($a) && ! defined($x)) { print "ok $N\n" }
+    elsif (  defined($a) && ! defined($x)) { 
+      ctrlfix(my $msg = "expected UNDEF, got <$a>");
+      print "not ok $N \# $msg\n";
+    }
+    elsif (! defined($a) &&   defined($x)) { 
+      ctrlfix(my $msg = "expected <$x>, got UNDEF");
+      print "not ok $N \# $msg\n";
+    } elsif ($a eq $x) { print "ok $N\n" }
+    else {
+      ctrlfix(my $msg = "expected <$x>, got <$a>");
+      print "not ok $N \# $msg\n";
+    }
+  } else {
+    die "expect() got ", scalar(@_), " args, should have been 1 or 2";
+  }
+  $N++;
+}
+
+sub ctrlfix {
+  local $_ = shift;
+  s/\n/\\n/g;
+  s/\r/\\r/g;
+  $_;
+}
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
diff --git a/dist/Tie-File/t/33_defer_vs.t b/dist/Tie-File/t/33_defer_vs.t
new file mode 100644
index 0000000000..071af77a68
--- /dev/null
+++ b/dist/Tie-File/t/33_defer_vs.t
@@ -0,0 +1,125 @@
+#!/usr/bin/perl
+#
+# Deferred caching of varying size records
+#
+# 30_defer.t always uses records that are 8 bytes long
+# (9 on \r\n machines.)  We might miss some sort of
+# length-calculation bug as a result.  This file will run some of the same
+# tests, but with with varying-length records.
+#
+
+use POSIX 'SEEK_SET';
+my $file = "tf$$.txt";
+# print "1..0\n"; exit;
+$: = Tie::File::_default_recsep();
+my $data = "$:1$:22$:";
+my ($o, $n);
+
+print "1..30\n";
+
+my $N = 1;
+use Tie::File;
+print "ok $N\n"; $N++;
+
+open F, "> $file" or die $!;
+binmode F;
+print F $data;
+close F;
+$o = tie @a, 'Tie::File', $file;
+print $o ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+# (3-6) Deferred storage
+$o->defer;
+$a[3] = "333";
+check_contents($data);          # nothing written yet
+$a[4] = "4444";
+check_contents($data);          # nothing written yet
+
+# (7-8) Flush
+$o->flush;
+check_contents($data . "333$:4444$:");          # now it's written
+
+# (9-12) Deferred writing disabled?
+$a[3] = "999999999";
+check_contents("${data}999999999$:4444$:");
+$a[4] = "88888888";
+check_contents("${data}999999999$:88888888$:");
+
+# (13-18) Now let's try two batches of records
+$#a = 2;
+$o->defer;
+$a[0] = "55555";
+check_contents($data);          # nothing written yet
+$a[2] = "aaaaaaaaaa";
+check_contents($data);          # nothing written yet
+$o->flush;
+check_contents("55555$:1$:aaaaaaaaaa$:");
+
+# (19-22) Deferred writing past the end of the file
+$o->defer;
+$a[4] = "7777777";
+check_contents("55555$:1$:aaaaaaaaaa$:");
+$o->flush;
+check_contents("55555$:1$:aaaaaaaaaa$:$:7777777$:");
+
+
+# (23-26) Now two long batches
+$o->defer;
+%l = qw(0 2  1 3  2 4  4 5  5 4  6 3);
+for (0..2, 4..6) {
+  $a[$_] = $_ x $l{$_};
+}
+check_contents("55555$:1$:aaaaaaaaaa$:$:7777777$:");
+$o->flush;
+check_contents(join $:, "00", "111", "2222", "", "44444", "5555", "666", "");
+
+# (27-30) Now let's make sure that discarded writes are really discarded
+# We have a 2Mib buffer here, so we can be sure that we aren't accidentally
+# filling it up
+$o->defer;
+for (0, 3, 7) {
+  $a[$_] = "discarded" . $_ x $_;
+}
+check_contents(join $:, "00", "111", "2222", "", "44444", "5555", "666", "");
+$o->discard;
+check_contents(join $:, "00", "111", "2222", "", "44444", "5555", "666", "");
+
+################################################################
+
+
+sub check_contents {
+  my $x = shift;
+
+  my $integrity = $o->_check_integrity($file, $ENV{INTEGRITY});
+  print $integrity ? "ok $N\n" : "not ok $N\n";
+  $N++;
+
+  local *FH = $o->{fh};
+  seek FH, 0, SEEK_SET;
+
+  my $a;
+  { local $/; $a = <FH> }
+  $a = "" unless defined $a;
+  if ($a eq $x) {
+    print "ok $N\n";
+  } else {
+    my $msg = ctrlfix("# expected <$x>, got <$a>");
+    print "not ok $N\n$msg\n";
+  }
+  $N++;
+}
+
+sub ctrlfix {
+  local $_ = shift;
+  s/\n/\\n/g;
+  s/\r/\\r/g;
+  $_;
+}
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}
+
diff --git a/dist/Tie-File/t/40_abs_cache.t b/dist/Tie-File/t/40_abs_cache.t
new file mode 100644
index 0000000000..137c9bb78d
--- /dev/null
+++ b/dist/Tie-File/t/40_abs_cache.t
@@ -0,0 +1,281 @@
+#!/usr/bin/perl
+#
+# Unit tests for abstract cache implementation
+#
+# Test the following methods:
+# * new()
+# * is_empty()
+# * empty()
+# * lookup(key)
+# * remove(key)
+# * insert(key,val)
+# * update(key,val)
+# * rekey(okeys,nkeys)
+# * expire()
+# * keys()
+# * bytes()
+# DESTROY()
+#
+# 20020327 You somehow managed to miss:
+# * reduce_size_to(bytes)
+#
+
+# print "1..0\n"; exit;
+print "1..42\n";
+
+my ($N, @R, $Q, $ar) = (1);
+
+use Tie::File;
+print "ok $N\n";
+$N++;
+
+my $h = Tie::File::Cache->new(10000) or die;
+print "ok $N\n";
+$N++;
+
+# (3) Are all the methods there?
+{
+  my $good = 1;
+  for my $meth (qw(new is_empty empty lookup remove
+                 insert update rekey expire ckeys bytes
+                   set_limit adj_limit flush  reduce_size_to
+                   _produce _produce_lru )) {
+    unless ($h->can($meth)) {
+      print STDERR "# Method '$meth' is missing.\n";
+      $good = 0;
+    }
+  }
+  print $good ? "ok $N\n" : "not ok $N\n";
+  $N++;
+}
+
+# (4-5) Straight insert and removal FIFO test
+$ar = 'a0';
+for (1..10) {
+  $h->insert($_, $ar++);
+}
+1;
+for (1..10) {
+  push @R, $h->expire;
+}
+$iota = iota('a',9);
+print "@R" eq $iota
+  ? "ok $N\n" : "not ok $N \# expected ($iota), got (@R)\n";
+$N++;
+check($h);
+
+# (6-7) Remove from empty heap
+$n = $h->expire;
+print ! defined $n ? "ok $N\n" : "not ok $N \# expected UNDEF, got $n";
+$N++;
+check($h);
+
+# (8-9) Interleaved insert and removal
+$Q = 0;
+@R = ();
+for my $i (1..4) {
+  for my $j (1..$i) {
+    $h->insert($Q, "b$Q");
+    $Q++;
+  }
+  for my $j (1..$i) {
+    push @R, $h->expire;
+  }
+}
+$iota = iota('b', 9);
+print "@R" eq $iota ? "ok $N\n" : "not ok $N \# expected ($iota), got (@R)\n";
+$N++;
+check($h);
+
+# (10) It should be empty now
+print $h->is_empty ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+# (11-12) Insert and delete
+$Q = 1;
+for (1..10) {
+  $h->insert($_, "c$Q");
+  $Q++;
+}
+for (2, 4, 6, 8, 10) {
+  $h->remove($_);
+}
+@R = ();
+push @R, $n while defined ($n = $h->expire);
+print "@R" eq "c1 c3 c5 c7 c9" ? 
+  "ok $N\n" : "not ok $N \# expected (c1 c3 c5 c7 c9), got (@R)\n";
+$N++;
+check($h);
+
+# (13-14) Interleaved insert and delete
+$Q = 1; my $QQ = 1;
+@R = ();
+for my $i (1..4) {
+  for my $j (1..$i) {
+    $h->insert($Q, "d$Q");
+    $Q++;
+  }
+  for my $j (1..$i) {
+    $h->remove($QQ) if $QQ % 2 == 0;
+    $QQ++;
+  }
+}
+push @R, $n while defined ($n = $h->expire);
+print "@R" eq "d1 d3 d5 d7 d9" ? 
+  "ok $N\n" : "not ok $N \# expected (d1 d3 d5 d7 d9), got (@R)\n";
+$N++;
+check($h);
+
+# (15-16) Promote
+$h->empty;
+$Q = 1;
+for (1..10) {
+  $h->insert($_, "e$Q");
+  unless ($h->_check_integrity) {
+    die "Integrity failed after inserting ($_, e$Q)\n";
+  }
+  $Q++;
+}
+1;
+for (2, 4, 6, 8, 10) {
+  $h->_promote($_);
+}
+@R = ();
+push @R, $n while defined ($n = $h->expire);
+print "@R" eq "e1 e3 e5 e7 e9 e2 e4 e6 e8 e10" ? 
+    "ok $N\n" : 
+    "not ok $N \# expected (e1 e3 e5 e7 e9 e2 e4 e6 e8 e10), got (@R)\n";
+$N++;
+check($h);
+
+# (17-22) Lookup
+$Q = 1;
+for (1..10) {
+  $h->insert($_, "f$Q");
+  $Q++;
+}
+1;
+for (2, 4, 6, 4, 8) {
+  my $r = $h->lookup($_);
+  print $r eq "f$_" ? "ok $N\n" : "not ok $N \# expected f$_, got $r\n";
+  $N++;
+}
+check($h);
+
+# (23) It shouldn't be empty
+print ! $h->is_empty ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+# (24-25) Lookup should have promoted the looked-up records
+@R = ();
+push @R, $n while defined ($n = $h->expire);
+print "@R" eq "f1 f3 f5 f7 f9 f10 f2 f6 f4 f8" ?
+  "ok $N\n" : 
+  "not ok $N \# expected (f1 f3 f5 f7 f9 f10 f2 f6 f4 f8), got (@R)\n";
+$N++;
+check($h);
+
+# (26-29) Typical 'rekey' operation
+$Q = 1;
+for (1..10) {
+  $h->insert($_, "g$Q");
+  $Q++;
+}
+$h->rekey([6,7,8,9,10], [8,9,10,11,12]);
+my %x = qw(1 g1 2 g2  3 g3  4 g4  5 g5
+           8 g6 9 g7 10 g8 11 g9 12 g10);
+{
+  my $good = 1;
+  for my $k (keys %x) {
+    my $v = $h->lookup($k);
+    $v = "UNDEF" unless defined $v;
+    unless ($v eq $x{$k}) {
+      print "# looked up $k, got $v, expected $x{$k}\n";
+      $good = 0;
+    }
+  }
+  print $good ? "ok $N\n" : "not ok $N\n";
+  $N++;
+}
+check($h);
+{
+  my $good = 1;
+  for my $k (6, 7) {
+    my $v = $h->lookup($k);
+    if (defined $v) {
+      print "# looked up $k, got $v, should have been undef\n";
+      $good = 0;
+    }
+  }
+  print $good ? "ok $N\n" : "not ok $N\n";
+  $N++;
+}
+check($h);
+
+# (30-31) ckeys
+@R = sort { $a <=> $b } $h->ckeys;
+print "@R" eq "1 2 3 4 5 8 9 10 11 12" ?
+  "ok $N\n" : 
+  "not ok $N \# expected (1 2 3 4 5 8 9 10 11 12) got (@R)\n";
+$N++;
+check($h);
+1;
+# (32-33) update
+for (1..5, 8..12) {
+  $h->update($_, "h$_");
+}
+@R = ();
+for (sort { $a <=> $b } $h->ckeys) {
+  push @R, $h->lookup($_);
+}
+print "@R" eq "h1 h2 h3 h4 h5 h8 h9 h10 h11 h12" ?
+  "ok $N\n" : 
+  "not ok $N \# expected (h1 h2 h3 h4 h5 h8 h9 h10 h11 h12) got (@R)\n";
+$N++;
+check($h);
+
+# (34-37) bytes
+my $B;
+$B = $h->bytes;
+print $B == 23 ? "ok $N\n" : "not ok $N \# expected 23, got $B\n";
+$N++;
+check($h);
+$h->update('12', "yobgorgle");
+$B = $h->bytes;
+print $B == 29 ? "ok $N\n" : "not ok $N \# expected 29, got $B\n";
+$N++;
+check($h);
+
+# (38-41) empty
+$h->empty;
+print $h->is_empty ? "ok $N\n" : "not ok $N\n";
+$N++;
+check($h);
+$n = $h->expire;
+print ! defined $n ? "ok $N\n" : "not ok $N \# expected UNDEF, got $n";
+$N++;
+check($h);
+
+# (42) very weak testing of DESTROY
+undef $h;
+# are we still alive?
+print "ok $N\n";
+$N++;
+
+sub check {
+  my $h = shift;
+  print $h->_check_integrity ? "ok $N\n" : "not ok $N\n";
+  $N++;
+}
+
+sub iota {
+  my ($p, $n) = @_;
+  my $r;
+  my $i = 0;
+  while ($i <= $n) {
+    $r .= "$p$i ";
+    $i++;
+  }
+  chop $r;
+  $r;
+}
diff --git a/dist/Tie-File/t/41_heap.t b/dist/Tie-File/t/41_heap.t
new file mode 100644
index 0000000000..9e7ad2516c
--- /dev/null
+++ b/dist/Tie-File/t/41_heap.t
@@ -0,0 +1,259 @@
+#!/usr/bin/perl
+#
+# Unit tests for heap implementation
+#
+# Test the following methods:
+# new
+# is_empty
+# empty
+# insert
+# remove
+# popheap
+# promote
+# lookup
+# set_val
+# rekey
+# expire_order
+
+
+# Finish these later.
+
+# They're nonurgent because the important heap stuff is extensively
+# tested by tests 19, 20, 24, 30, 32, 33, and 40, as well as by pretty
+# much everything else.
+print "1..1\n";
+
+
+my ($N, @R, $Q, $ar) = (1);
+
+use Tie::File;
+print "ok $N\n";
+$N++;
+exit;
+
+__END__
+
+my @HEAP_MOVE;
+sub Fake::Cache::_heap_move { push @HEAP_MOVE, @_ }
+
+my $h = Tie::File::Heap->new(bless [] => 'Fake::Cache');
+print "ok $N\n";
+$N++;
+
+# (3) Are all the methods there?
+{
+  my $good = 1;
+  for my $meth (qw(new is_empty empty lookup insert remove popheap
+                   promote set_val rekey expire_order)) {
+    unless ($h->can($meth)) {
+      print STDERR "# Method '$meth' is missing.\n";
+      $good = 0;
+    }
+  }
+  print $good ? "ok $N\n" : "not ok $N\n";
+  $N++;
+}
+
+# (4) Straight insert and removal FIFO test
+$ar = 'a0';
+for (1..10) {
+  $h->insert($_, $ar++);
+}
+for (1..10) {
+  push @R, $h->popheap;
+}
+$iota = iota('a',9);
+print "@R" eq $iota
+  ? "ok $N\n" : "not ok $N \# expected ($iota), got (@R)\n";
+$N++;
+
+# (5) Remove from empty heap
+$n = $h->popheap;
+print ! defined $n ? "ok $N\n" : "not ok $N \# expected UNDEF, got $n";
+$N++;
+
+# (6) Interleaved insert and removal
+$Q = 0;
+@R = ();
+for my $i (1..4) {
+  for my $j (1..$i) {
+    $h->insert($Q, "b$Q");
+    $Q++;
+  }
+  for my $j (1..$i) {
+    push @R, $h->popheap;
+  }
+}
+$iota = iota('b', 9);
+print "@R" eq $iota ? "ok $N\n" : "not ok $N \# expected ($iota), got (@R)\n";
+$N++;
+
+# (7) It should be empty now
+print $h->is_empty ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+# (8) Insert and delete
+$Q = 1;
+for (1..10) {
+  $h->insert($_, "c$Q");
+  $Q++;
+}
+for (2, 4, 6, 8, 10) {
+  $h->remove($_);
+}
+@R = ();
+push @R, $n while defined ($n = $h->popheap);
+print "@R" eq "c1 c3 c5 c7 c9" ? 
+  "ok $N\n" : "not ok $N \# expected (c1 c3 c5 c7 c9), got (@R)\n";
+$N++;
+
+# (9) Interleaved insert and delete
+$Q = 1; my $QQ = 1;
+@R = ();
+for my $i (1..4) {
+  for my $j (1..$i) {
+    $h->insert($Q, "d$Q");
+    $Q++;
+  }
+  for my $j (1..$i) {
+    $h->remove($QQ) if $QQ % 2 == 0;
+    $QQ++;
+  }
+}
+push @R, $n while defined ($n = $h->popheap);
+print "@R" eq "d1 d3 d5 d7 d9" ? 
+  "ok $N\n" : "not ok $N \# expected (d1 d3 d5 d7 d9), got (@R)\n";
+$N++;
+
+# (10) Promote
+$Q = 1;
+for (1..10) {
+  $h->insert($_, "e$Q");
+  $Q++;
+}
+for (2, 4, 6, 8, 10) {
+  $h->promote($_);
+}
+@R = ();
+push @R, $n while defined ($n = $h->popheap);
+print "@R" eq "e1 e3 e5 e7 e9 e2 e4 e6 e8 e10" ? 
+  "ok $N\n" : 
+  "not ok $N \# expected (e1 e3 e5 e7 e9 e2 e4 e6 e8 e10), got (@R)\n";
+$N++;
+
+# (11-15) Lookup
+$Q = 1;
+for (1..10) {
+  $h->insert($_, "f$Q");
+  $Q++;
+}
+for (2, 4, 6, 4, 8) {
+  my $r = $h->lookup($_);
+  print $r eq "f$_" ? "ok $N\n" : "not ok $N \# expected f$_, got $r\n";
+  $N++;
+}
+
+# (16) It shouldn't be empty
+print ! $h->is_empty ? "ok $N\n" : "not ok $N\n";
+$N++;
+
+# (17) Lookup should have promoted the looked-up records
+@R = ();
+push @R, $n while defined ($n = $h->popheap);
+print "@R" eq "f1 f3 f5 f7 f9 f10 f2 f6 f4 f8" ?
+  "ok $N\n" : 
+  "not ok $N \# expected (f1 f3 f5 f7 f9 f10 f2 f6 f4 f8), got (@R)\n";
+$N++;
+
+# (18-19) Typical 'rekey' operation
+$Q = 1;
+for (1..10) {
+  $h->insert($_, "g$Q");
+  $Q++;
+}
+
+$h->rekey([6,7,8,9,10], [8,9,10,11,12]);
+my %x = qw(1 g1 2 g2  3 g3  4 g4  5 g5
+           8 g6 9 g7 10 g8 11 g9 12 g10);
+{
+  my $good = 1;
+  for my $k (keys %x) {
+    my $v = $h->lookup($k);
+    $v = "UNDEF" unless defined $v;
+    unless ($v eq $x{$k}) {
+      print "# looked up $k, got $v, expected $x{$k}\n";
+      $good = 0;
+    }
+  }
+  print $good ? "ok $N\n" : "not ok $N\n";
+  $N++;
+}
+{
+  my $good = 1;
+  for my $k (6, 7) {
+    my $v = $h->lookup($k);
+    if (defined $v) {
+      print "# looked up $k, got $v, should have been undef\n";
+      $good = 0;
+    }
+  }
+  print $good ? "ok $N\n" : "not ok $N\n";
+  $N++;
+}
+
+# (20) keys
+@R = sort { $a <=> $b } $h->keys;
+print "@R" eq "1 2 3 4 5 8 9 10 11 12" ?
+  "ok $N\n" : 
+  "not ok $N \# expected (1 2 3 4 5 8 9 10 11 12) got (@R)\n";
+$N++;
+
+# (21) update
+for (1..5, 8..12) {
+  $h->update($_, "h$_");
+}
+@R = ();
+for (sort { $a <=> $b } $h->keys) {
+  push @R, $h->lookup($_);
+}
+print "@R" eq "h1 h2 h3 h4 h5 h8 h9 h10 h11 h12" ?
+  "ok $N\n" : 
+  "not ok $N \# expected (h1 h2 h3 h4 h5 h8 h9 h10 h11 h12) got (@R)\n";
+$N++;
+
+# (22-23) bytes
+my $B;
+$B = $h->bytes;
+print $B == 23 ? "ok $N\n" : "not ok $N \# expected 23, got $B\n";
+$N++;
+$h->update('12', "yobgorgle");
+$B = $h->bytes;
+print $B == 29 ? "ok $N\n" : "not ok $N \# expected 29, got $B\n";
+$N++;
+
+# (24-25) empty
+$h->empty;
+print $h->is_empty ? "ok $N\n" : "not ok $N\n";
+$N++;
+$n = $h->popheap;
+print ! defined $n ? "ok $N\n" : "not ok $N \# expected UNDEF, got $n";
+$N++;
+
+# (26) very weak testing of DESTROY
+undef $h;
+# are we still alive?
+print "ok $N\n";
+$N++;
+
+
+sub iota {
+  my ($p, $n) = @_;
+  my $r;
+  my $i = 0;
+  while ($i <= $n) {
+    $r .= "$p$i ";
+    $i++;
+  }
+  chop $r;
+  $r;
+}
diff --git a/dist/Tie-File/t/42_offset.t b/dist/Tie-File/t/42_offset.t
new file mode 100644
index 0000000000..8c628325d9
--- /dev/null
+++ b/dist/Tie-File/t/42_offset.t
@@ -0,0 +1,69 @@
+#!/usr/bin/perl
+
+# 2003-04-09 Tels: test the offset method from 0.94
+
+use Test::More;
+use strict;
+use File::Spec;
+
+use POSIX 'SEEK_SET';
+my $file = "tf$$.txt";
+
+BEGIN
+  {
+  $| = 1;
+  unshift @INC, File::Spec->catdir(File::Spec->updir, 'lib');
+  chdir 't' if -d 't';
+  print "# INC = @INC\n";
+
+  plan tests => 24;
+
+  use_ok ('Tie::File');
+  }
+
+$/ = "#";	# avoid problems with \n\r vs. \n
+
+my @a;
+my $o = tie @a, 'Tie::File', $file, autodefer => 0;
+
+is (ref($o), 'Tie::File');
+
+is ($o->offset(0), 0, 'first one always there');
+is ($o->offset(1), undef, 'no offsets yet');
+
+$a[0] = 'Bourbon';
+is ($o->offset(0), 0, 'first is ok');
+is ($o->offset(1), 8, 'and second ok');
+is ($o->offset(2), undef, 'third undef');
+
+$a[1] = 'makes';
+is ($o->offset(0), 0, 'first is ok');
+is ($o->offset(1), 8, 'and second ok');
+is ($o->offset(2), 14, 'and third ok');
+is ($o->offset(3), undef, 'fourth undef');
+
+$a[2] = 'the baby';
+is ($o->offset(0), 0, 'first is ok');
+is ($o->offset(1), 8, 'and second ok');
+is ($o->offset(2), 14, 'and third ok');
+is ($o->offset(3), 23, 'and fourth ok');
+is ($o->offset(4), undef, 'fourth undef');
+
+$a[3] = 'grin';
+is ($o->offset(0), 0, 'first is ok');
+is ($o->offset(1), 8, 'and second ok');
+is ($o->offset(2), 14, 'and third ok');
+is ($o->offset(3), 23, 'and fourth ok');
+is ($o->offset(4), 28, 'and fifth ok');
+
+$a[4] = '!';
+is ($o->offset(5), 30, 'and fifth ok');
+$a[3] = 'water';
+is ($o->offset(4), 29, 'and fourth changed ok');
+is ($o->offset(5), 31, 'and fifth ok');
+
+END {
+  undef $o;
+  untie @a;
+  1 while unlink $file;
+}