Change 11697 by jhi@alpha on 2001/08/17 01:50:55
Subject: Re: [ID 20010803.016] Possible regex bug in 5.6.1
From: Hugo van der Sanden <[EMAIL PROTECTED]>
Date: Thu, 16 Aug 2001 16:27:49 +0100
Message-Id: <[EMAIL PROTECTED]>
Affected files ...
... //depot/perl/regexec.c#181 edit
... //depot/perl/t/op/re_tests#65 edit
Differences ...
==== //depot/perl/regexec.c#181 (text) ====
Index: perl/regexec.c
--- perl/regexec.c.~1~ Thu Aug 16 20:00:06 2001
+++ perl/regexec.c Thu Aug 16 20:00:06 2001
@@ -3033,12 +3033,15 @@
minmod = 0;
if (ln && regrepeat_hard(scan, ln, &l) < ln)
sayNO;
- if (ln && l == 0 && n >= ln
- /* In fact, this is tricky. If paren, then the
- fact that we did/didnot match may influence
- future execution. */
- && !(paren && ln == 0))
- ln = n;
+ /* if we matched something zero-length we don't need to
+ backtrack - capturing parens are already defined, so
+ the caveat in the maximal case doesn't apply
+
+ XXXX if ln == 0, we can redo this check first time
+ through the following loop
+ */
+ if (ln && l == 0)
+ n = ln; /* don't backtrack */
locinput = PL_reginput;
if (PL_regkind[(U8)OP(next)] == EXACT) {
c1 = (U8)*STRING(next);
@@ -3060,7 +3063,7 @@
UCHARAT(PL_reginput) == c2)
{
if (paren) {
- if (n) {
+ if (ln) {
PL_regstartp[paren] =
HOPc(PL_reginput, -l) - PL_bostr;
PL_regendp[paren] = PL_reginput - PL_bostr;
@@ -3084,12 +3087,13 @@
}
else {
n = regrepeat_hard(scan, n, &l);
- if (n != 0 && l == 0
- /* In fact, this is tricky. If paren, then the
- fact that we did/didnot match may influence
- future execution. */
- && !(paren && ln == 0))
- ln = n;
+ /* if we matched something zero-length we don't need to
+ backtrack, unless the minimum count is zero and we
+ are capturing the result - in that case the capture
+ being defined or not may affect later execution
+ */
+ if (n != 0 && l == 0 && !(paren && ln == 0))
+ ln = n; /* don't backtrack */
locinput = PL_reginput;
DEBUG_r(
PerlIO_printf(Perl_debug_log,
==== //depot/perl/t/op/re_tests#65 (text) ====
Index: perl/t/op/re_tests
--- perl/t/op/re_tests.~1~ Thu Aug 16 20:00:06 2001
+++ perl/t/op/re_tests Thu Aug 16 20:00:06 2001
@@ -792,3 +792,7 @@
^(a(??{"(?!)"})|(a)(?{1}))b ab y $2 a # [ID 20010811.006]
ab(?i)cd AbCd n - - # [ID 20010809.023]
ab(?i)cd abCd y - -
+(A|B)*(?(1)(CD)|(CD)) CD y $2-$3 -CD
+(A|B)*(?(1)(CD)|(CD)) ABCD y $2-$3 CD-
+(A|B)*?(?(1)(CD)|(CD)) CD y $2-$3 -CD # [ID 20010803.016]
+(A|B)*?(?(1)(CD)|(CD)) ABCD y $2-$3 CD-
End of Patch.
