utf8_heavy.pl: Skip unnecessary work for official properties

The tables that mktables generates are well behaved, and so the checks
and sorting that are done for user-defined properties may be skipped.

tainting needs to be preserved because $list can be passed in already
tainted.

This is also in preparation for Unicode 6.1, in which one table will
legitimately have duplicate entries that the old code removed.

1 files changed, 20 insertions, 2 deletions

diff --git a/lib/utf8_heavy.pl b/lib/utf8_heavy.pl
index 699a26f1dd..84a81676f0 100644
--- a/lib/utf8_heavy.pl
+++ b/lib/utf8_heavy.pl
@@ -525,9 +525,10 @@ sub _loose_name ($) {
         if ($list) {
             my $taint = substr($list,0,0); # maintain taint
 
-            # Separate the extras from the code point list, and 
-            # make sure the latter are well-behaved
+            # Separate the extras from the code point list, and for
+            # user-defined properties, make sure the latter are well-behaved
             # for downstream code.
+            if ($user_defined) {
                 my @tmp = split(/^/m, $list);
                 my %seen;
                 no warnings;
@@ -543,6 +544,23 @@ sub _loose_name ($) {
                         sort { $a->[0] <=> $b->[0] }
                         map  { /^([0-9a-fA-F]+)/; [ CORE::hex($1), $_ ] }
                         grep { /^([0-9a-fA-F]+)/ and not $seen{$1}++ } @tmp; # XXX doesn't do ranges right
+            }
+            else {
+                # mktables has gone to some trouble to make non-user defined
+                # properties well-behaved, so we can skip the effort we do for
+                # user-defined ones.  Any extras are at the very beginning of
+                # the string.
+
+                # This regex splits out the first lines of $list into $1 and
+                # strips them off from $list, until we get one that begins
+                # with a hex number, alone on the line, or followed by a tab.
+                # Either portion may be empty.
+                $list =~ s/ \A ( .*? )
+                            (?: \z | (?= ^ [0-9a-fA-F]+ (?: \t | $) ) )
+                          //msx;
+
+                $extras = "$taint$1";
+            }
         }
 
         if ($none) {