Fix Math::BigInt's bnok($k) for $k==0 and $k==$n-1

Signed-off-by: Florian Ragwitz <rafl@debian.org>
[rafl@debian.org: fixed bigflt tests and test plans]

11 files changed, 37 insertions, 33 deletions

diff --git a/dist/Math-BigInt/lib/Math/BigInt.pm b/dist/Math-BigInt/lib/Math/BigInt.pm
index 9f1f983ae3..a775afa66d 100644
--- a/dist/Math-BigInt/lib/Math/BigInt.pm
+++ b/dist/Math-BigInt/lib/Math/BigInt.pm
@@ -1320,18 +1320,17 @@ sub bnok
     }
   else
     {
-    # ( 7 )    7!          7*6*5 * 4*3*2*1   7 * 6 * 5
-    # ( - ) = --------- =  --------------- = ---------
-    # ( 3 )   3! (7-3)!    3*2*1 * 4*3*2*1   3 * 2 * 1 
+    # ( 7 )       7!       1*2*3*4 * 5*6*7   5 * 6 * 7       6   7
+    # ( - ) = --------- =  --------------- = --------- = 5 * - * -
+    # ( 3 )   (7-3)! 3!    1*2*3*4 * 1*2*3   1 * 2 * 3       2   3
 
-    # compute n - k + 2 (so we start with 5 in the example above)
-    my $z = $x - $y;
-    if (!$z->is_one())
+    if (!$y->is_zero())
       {
+      my $z = $x - $y;
       $z->binc();
       my $r = $z->copy(); $z->binc();
       my $d = $self->new(2);
-      while ($z->bacmp($x) <= 0)		# f < x ?
+      while ($z->bacmp($x) <= 0)		# f <= x ?
         {
         $r->bmul($z); $r->bdiv($d);
         $z->binc(); $d->binc();
diff --git a/dist/Math-BigInt/lib/Math/BigInt/Calc.pm b/dist/Math-BigInt/lib/Math/BigInt/Calc.pm
index 52e33d232a..aa374ff881 100644
--- a/dist/Math-BigInt/lib/Math/BigInt/Calc.pm
+++ b/dist/Math-BigInt/lib/Math/BigInt/Calc.pm
@@ -1264,8 +1264,8 @@ sub _is_even
 
 sub _is_odd
   {
-  # return true if arg is even
-  (($_[1]->[0] & 1)) <=> 0; 
+  # return true if arg is odd
+  (($_[1]->[0] & 1)) <=> 0;
   }
 
 sub _is_one
@@ -1536,28 +1536,26 @@ sub _nok
   # ref to array, return ref to array
   my ($c,$n,$k) = @_;
 
-  # ( 7 )    7!          7*6*5 * 4*3*2*1   7 * 6 * 5
-  # ( - ) = --------- =  --------------- = ---------
-  # ( 3 )   3! (7-3)!    3*2*1 * 4*3*2*1   3 * 2 * 1 
-
-  # compute n - k + 2 (so we start with 5 in the example above)
-  my $x = _copy($c,$n);
+  # ( 7 )       7!       1*2*3*4 * 5*6*7   5 * 6 * 7       6   7
+  # ( - ) = --------- =  --------------- = --------- = 5 * - * -
+  # ( 3 )   (7-3)! 3!    1*2*3*4 * 1*2*3   1 * 2 * 3       2   3
 
-  _sub($c,$n,$k);
-  if (!_is_one($c,$n))
+  if (!_is_zero($c,$k))
     {
+    my $x = _copy($c,$n);
+    _sub($c,$n,$k);
     _inc($c,$n);
     my $f = _copy($c,$n); _inc($c,$f);		# n = 5, f = 6, d = 2
     my $d = _two($c);
-    while (_acmp($c,$f,$x) <= 0)		# f < n ?
+    while (_acmp($c,$f,$x) <= 0)		# f <= n ?
       {
-      # n = (n * f / d) == 5 * 6 / 2 => n == 3
+      # n = (n * f / d) == 5 * 6 / 2
       $n = _mul($c,$n,$f); $n = _div($c,$n,$d);
       # f = 7, d = 3
       _inc($c,$f); _inc($c,$d);
       }
     }
-  else 
+  else
     {
     # keep ref to $n and set it to 1
     splice (@$n,1); $n->[0] = 1;
diff --git a/dist/Math-BigInt/t/bare_mbf.t b/dist/Math-BigInt/t/bare_mbf.t
index 44792064ac..d5c186045c 100644
--- a/dist/Math-BigInt/t/bare_mbf.t
+++ b/dist/Math-BigInt/t/bare_mbf.t
@@ -22,7 +22,7 @@ BEGIN
     }
   print "# INC = @INC\n";
 
-  plan tests => 2308;
+  plan tests => 2316;
   }
 
 use Math::BigFloat lib => 'BareCalc';
@@ -30,5 +30,5 @@ use Math::BigFloat lib => 'BareCalc';
 use vars qw ($class $try $x $y $f @args $ans $ans1 $ans1_str $setup $CL);
 $class = "Math::BigFloat";
 $CL = "Math::BigInt::BareCalc";
-   
+
 require 'bigfltpm.inc';	# all tests here for sharing
diff --git a/dist/Math-BigInt/t/bare_mbi.t b/dist/Math-BigInt/t/bare_mbi.t
index f005edeccd..0a5d7314c7 100644
--- a/dist/Math-BigInt/t/bare_mbi.t
+++ b/dist/Math-BigInt/t/bare_mbi.t
@@ -21,7 +21,7 @@ BEGIN
     }
   print "# INC = @INC\n";
 
-  plan tests => 3273;
+  plan tests => 3279;
   }
 
 use Math::BigInt lib => 'BareCalc';
diff --git a/dist/Math-BigInt/t/bigfltpm.inc b/dist/Math-BigInt/t/bigfltpm.inc
index 7d650e5cba..309b86e25c 100644
--- a/dist/Math-BigInt/t/bigfltpm.inc
+++ b/dist/Math-BigInt/t/bigfltpm.inc
@@ -495,8 +495,12 @@ NaN:1:NaN
 1:-2:0
 # 7 over 3 = 35
 7:3:35
-7:6:1
+7:6:7
 100:90:17310309456440
+100:95:75287520
+2:0:1
+7:0:1
+2:1:2
 &flog
 0::NaN
 -1::NaN
diff --git a/dist/Math-BigInt/t/bigfltpm.t b/dist/Math-BigInt/t/bigfltpm.t
index 50b47afac4..dbd36ac90a 100644
--- a/dist/Math-BigInt/t/bigfltpm.t
+++ b/dist/Math-BigInt/t/bigfltpm.t
@@ -21,7 +21,7 @@ BEGIN
     }
   print "# INC = @INC\n";
 
-  plan tests => 2308
+  plan tests => 2316
 	+ 5;		# own tests
   }
 
diff --git a/dist/Math-BigInt/t/bigintpm.inc b/dist/Math-BigInt/t/bigintpm.inc
index 87140ba44d..317e5ed8ab 100644
--- a/dist/Math-BigInt/t/bigintpm.inc
+++ b/dist/Math-BigInt/t/bigintpm.inc
@@ -2346,9 +2346,12 @@ NaN:1:NaN
 1:-2:0
 # 7 over 3 = 35
 7:3:35
-7:6:1
+7:6:7
 100:90:17310309456440
 100:95:75287520
+2:0:1
+7:0:1
+2:1:2
 &bround
 $round_mode('trunc')
 0:12:0
diff --git a/dist/Math-BigInt/t/bigintpm.t b/dist/Math-BigInt/t/bigintpm.t
index b4f5bf2fb1..4f33c9f905 100644
--- a/dist/Math-BigInt/t/bigintpm.t
+++ b/dist/Math-BigInt/t/bigintpm.t
@@ -10,7 +10,7 @@ BEGIN
   my $location = $0; $location =~ s/bigintpm.t//;
   unshift @INC, $location; # to locate the testing files
   chdir 't' if -d 't';
-  plan tests => 3273 + 6;
+  plan tests => 3279 + 6;
   }
 
 use Math::BigInt lib => 'Calc';
diff --git a/dist/Math-BigInt/t/sub_mbf.t b/dist/Math-BigInt/t/sub_mbf.t
index 94375b6998..95911940aa 100644
--- a/dist/Math-BigInt/t/sub_mbf.t
+++ b/dist/Math-BigInt/t/sub_mbf.t
@@ -19,9 +19,9 @@ BEGIN
     {
     unshift @INC, $location;
     }
-  print "# INC = @INC\n"; 
-  
-  plan tests => 2308
+  print "# INC = @INC\n";
+
+  plan tests => 2316
     + 6;	# + our own tests
   }
 
diff --git a/dist/Math-BigInt/t/sub_mbi.t b/dist/Math-BigInt/t/sub_mbi.t
index edb4daf058..fe89ba407e 100644
--- a/dist/Math-BigInt/t/sub_mbi.t
+++ b/dist/Math-BigInt/t/sub_mbi.t
@@ -21,7 +21,7 @@ BEGIN
     }
   print "# INC = @INC\n";
 
-  plan tests => 3273
+  plan tests => 3279
     + 5;	# +5 own tests
   }
 
@@ -37,7 +37,7 @@ require 'bigintpm.inc';	# perform same tests as bigintpm
 
 ###############################################################################
 # Now do custom tests for Subclass itself
- 
+
 my $ms = $class->new(23);
 print "# Missing custom attribute \$ms->{_custom}" if !ok (1, $ms->{_custom});
 
diff --git a/dist/Math-BigInt/t/with_sub.t b/dist/Math-BigInt/t/with_sub.t
index d34d9fb885..eecc0e17a2 100644
--- a/dist/Math-BigInt/t/with_sub.t
+++ b/dist/Math-BigInt/t/with_sub.t
@@ -23,7 +23,7 @@ BEGIN
     }
   print "# INC = @INC\n";
 
-  plan tests => 2308
+  plan tests => 2316
 	+ 1;
   }