PATCH: another pattern buglet

PATCH: another pattern buglet

[Peter Stephenson]

Here's an even more subtle bug in pattern.c fixed.  Backtracking over
repeated single characters (other than "?" as ?# is optimised to "*")
was broken by miscounting the number of times it could be done.  This
was quite well hidden.  It's quite likely that the fundamental logical
error existed before the change for multibyte characters, but didn't
show up; I only found it on Solaris during the completion tests.

Index: Src/pattern.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/pattern.c,v
retrieving revision 1.32
diff -u -r1.32 pattern.c
--- Src/pattern.c	25 Apr 2006 13:01:53 -0000	1.32
+++ Src/pattern.c	25 Apr 2006 17:25:30 -0000
@@ -2751,22 +2751,26 @@
 		savglobflags = patglobflags;
 		saverrsfound = errsfound;
 		lastcharstart = charstart + (patinput - start);
-		while (no >= min) {
-		    int charmatch_cache;
-		    if (nextch < 0 ||
-			(patinput < patinend &&
-			 CHARMATCH_EXPR(CHARREF(patinput, patinend),
-					nextch))) {
-			if (patmatch(next))
-			    return 1;
+		if (no >= min) {
+		    for (;;) {
+			int charmatch_cache;
+			if (nextch < 0 ||
+			    (patinput < patinend &&
+			     CHARMATCH_EXPR(CHARREF(patinput, patinend),
+					    nextch))) {
+			    if (patmatch(next))
+				return 1;
+			}
+			if (--no < min)
+			    break;
+			/* find start of previous full character */
+			while (!*--lastcharstart)
+			    DPUTS(lastcharstart < charstart,
+				  "lastcharstart invalid");
+			patinput = start + (lastcharstart-charstart);
+			patglobflags = savglobflags;
+			errsfound = saverrsfound;
 		    }
-		    no--;
-		    /* find start of previous full character */
-		    while (!*--lastcharstart)
-			;
-		    patinput = start + (lastcharstart-charstart);
-		    patglobflags = savglobflags;
-		    errsfound = saverrsfound;
 		}
 	    }
 	    /*

-- 
Peter Stephenson <pws@csr.com>                  Software Engineer
CSR PLC, Churchill House, Cambridge Business Park, Cowley Road
Cambridge, CB4 0WZ, UK                          Tel: +44 (0)1223 692070


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