small lookbehind fix

Message-Id: <200105172307.AAA06142@crypt.compulink.co.uk>

p4raw-id: //depot/perl@10152

diff --git a/regexec.c b/regexec.c
index d3e347e..d60e7c7 100644 (file)
--- a/regexec.c
+++ b/regexec.c
@@ -116,6 +116,15 @@
 #define HOPc(pos,off) ((char*)HOP(pos,off))
 #define HOPMAYBEc(pos,off) ((char*)HOPMAYBE(pos,off))
 
+#define HOPBACK(pos, off) (            \
+    (UTF && DO_UTF8(PL_reg_sv))                \
+       ? reghopmaybe((U8*)pos, -off)   \
+    : (pos - off >= PL_bostr)          \
+       ? (U8*)(pos - off)              \
+    : (U8*)NULL                                \
+)
+#define HOPBACKc(pos, off) (char*)HOPBACK(pos, off)
+
 #define reghop3_c(pos,off,lim) ((char*)reghop3((U8*)pos, off, (U8*)lim))
 #define reghopmaybe3_c(pos,off,lim) ((char*)reghopmaybe3((U8*)pos, off, (U8*)lim))
 #define HOP3(pos,off,lim) (DO_UTF8(PL_reg_sv) ? reghop3((U8*)pos, off, (U8*)lim) : (U8*)(pos + off))
@@ -3368,20 +3377,10 @@ S_regmatch(pTHX_ regnode *prog)
        case UNLESSM:
            n = 0;
            if (scan->flags) {
-               if (UTF) {              /* XXXX This is absolutely
-                                          broken, we read before
-                                          start of string. */
-                   s = HOPMAYBEc(locinput, -scan->flags);
-                   if (!s)
-                       goto say_yes;
-                   PL_reginput = s;
-               }
-               else {
-                   if (locinput < PL_bostr + scan->flags)
-                       goto say_yes;
-                   PL_reginput = locinput - scan->flags;
-                   goto do_ifmatch;
-               }
+               s = HOPBACKc(locinput, scan->flags);
+               if (!s)
+                   goto say_yes;
+               PL_reginput = s;
            }
            else
                PL_reginput = locinput;
@@ -3389,20 +3388,10 @@ S_regmatch(pTHX_ regnode *prog)
        case IFMATCH:
            n = 1;
            if (scan->flags) {
-               if (UTF) {              /* XXXX This is absolutely
-                                          broken, we read before
-                                          start of string. */
-                   s = HOPMAYBEc(locinput, -scan->flags);
-                   if (!s || s < PL_bostr)
-                       goto say_no;
-                   PL_reginput = s;
-               }
-               else {
-                   if (locinput < PL_bostr + scan->flags)
-                       goto say_no;
-                   PL_reginput = locinput - scan->flags;
-                   goto do_ifmatch;
-               }
+               s = HOPBACKc(locinput, scan->flags);
+               if (!s)
+                   goto say_no;
+               PL_reginput = s;
            }
            else
                PL_reginput = locinput;