X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2Fbigint.pl;h=4044f7f6348379e67a01adafaca46578697c18b8;hb=ad1ebafb1ecaed58230ed26d371e08c109ae3ac4;hp=45ffe1d4026da2e05b088b5fa79cb6533d95fbe3;hpb=ed6116ce9b9d13712ea252ee248b0400653db7f9;p=p5sagit%2Fp5-mst-13.2.git

diff --git a/lib/bigint.pl b/lib/bigint.pl
index 45ffe1d..4044f7f 100644
--- a/lib/bigint.pl
+++ b/lib/bigint.pl
@@ -1,5 +1,13 @@
 package bigint;
-
+#
+# This library is no longer being maintained, and is included for backward
+# compatibility with Perl 4 programs which may require it.
+#
+# In particular, this should not be used as an example of modern Perl
+# programming techniques.
+#
+# Suggested alternative:  Math::BigInt
+#
 # arbitrary size integer math package
 #
 # by Mark Biggar
@@ -33,10 +41,14 @@ package bigint;
 #   bgcd(BINT,BINT) return BINT         greatest common divisor
 #   bnorm(BINT) return BINT             normalization
 #
+
+$zero = 0;
+
 
 # normalize string form of number.   Strip leading zeros.  Strip any
 #   white space and add a sign, if missing.
 # Strings that are not numbers result the value 'NaN'.
+
 sub main'bnorm { #(num_str) return num_str
     local($_) = @_;
     s/\s+//g;                           # strip white space
@@ -70,7 +82,7 @@ sub external { #(int_num_array) return num_str
 sub main'bneg { #(num_str) return num_str
     local($_) = &'bnorm(@_);
     vec($_,0,8) ^= ord('+') ^ ord('-') unless $_ eq '+0';
-    s/^H/N/;
+    s/^./N/ unless /^[-+]/; # works both in ASCII and EBCDIC
     $_;
 }
 
@@ -99,13 +111,23 @@ sub main'bcmp { #(num_str, num_str) return cond_code
 
 sub cmp { # post-normalized compare for internal use
     local($cx, $cy) = @_;
-    $cx cmp $cy
-    &&
-    (
-	ord($cy) <=> ord($cx)
-	||
-	($cx cmp ',') * (length($cy) <=> length($cx) || $cy cmp $cx)
-    );
+    return 0 if ($cx eq $cy);
+
+    local($sx, $sy) = (substr($cx, 0, 1), substr($cy, 0, 1));
+    local($ld);
+
+    if ($sx eq '+') {
+      return  1 if ($sy eq '-' || $cy eq '+0');
+      $ld = length($cx) - length($cy);
+      return $ld if ($ld);
+      return $cx cmp $cy;
+    } else { # $sx eq '-'
+      return -1 if ($sy eq '+');
+      $ld = length($cy) - length($cx);
+      return $ld if ($ld);
+      return $cy cmp $cx;
+    }
+
 }
 
 sub main'badd { #(num_str, num_str) return num_str
@@ -154,11 +176,11 @@ sub add { #(int_num_array, int_num_array) return int_num_array
     $car = 0;
     for $x (@x) {
 	last unless @y || $car;
-	$x -= 1e5 if $car = (($x += shift(@y) + $car) >= 1e5);
+	$x -= 1e5 if $car = (($x += shift(@y) + $car) >= 1e5) ? 1 : 0;
     }
     for $y (@y) {
 	last unless $car;
-	$y -= 1e5 if $car = (($y += $car) >= 1e5);
+	$y -= 1e5 if $car = (($y += $car) >= 1e5) ? 1 : 0;
     }
     (@x, @y, $car);
 }
@@ -263,7 +285,7 @@ sub main'bdiv { #(dividend: num_str, divisor: num_str) return num_str
 	else {
 	    @d = @x;
 	}
-	(&external($sr, @q), &external($srem, @d, 0));
+	(&external($sr, @q), &external($srem, @d, $zero));
     } else {
 	&external($sr, @q);
     }