Revision: 1165
http://www.exim.org/viewvc/pcre2?view=rev&revision=1165
Author: ph10
Date: 2019-09-07 16:16:10 +0100 (Sat, 07 Sep 2019)
Log Message:
-----------
When computing minimum length, don't scan subsequent branches if any branch in
a group has zero minimum length.
Modified Paths:
--------------
code/trunk/ChangeLog
code/trunk/src/pcre2_study.c
Modified: code/trunk/ChangeLog
===================================================================
--- code/trunk/ChangeLog 2019-09-06 16:08:45 UTC (rev 1164)
+++ code/trunk/ChangeLog 2019-09-07 15:16:10 UTC (rev 1165)
@@ -139,7 +139,11 @@
up to that position for an earlier occurrence of the other case. This fix
applies to both interpretive pcre2_match() and to pcre2_dfa_match().
+30. While scanning to find the minimum length of a group, if any branch has
+minimum length zero, there is no need to scan any subsequent branches (a small
+compile-time performance improvement).
+
Version 10.33 16-April-2019
---------------------------
Modified: code/trunk/src/pcre2_study.c
===================================================================
--- code/trunk/src/pcre2_study.c 2019-09-06 16:08:45 UTC (rev 1164)
+++ code/trunk/src/pcre2_study.c 2019-09-07 15:16:10 UTC (rev 1165)
@@ -223,7 +223,9 @@
/* Reached end of a branch; if it's a ket it is the end of a nested
call. If it's ALT it is an alternation in a nested call. If it is END it's
- the end of the outer call. All can be handled by the same code. */
+ the end of the outer call. All can be handled by the same code. If the
+ length of any branch is zero, there is no need to scan any subsequent
+ branches. */
case OP_ALT:
case OP_KET:
@@ -233,7 +235,7 @@
case OP_END:
if (length < 0 || (!had_recurse && branchlength < length))
length = branchlength;
- if (op != OP_ALT) return length;
+ if (op != OP_ALT || length == 0) return length;
nextbranch = cc + GET(cc, 1);
cc += 1 + LINK_SIZE;
branchlength = 0;
