Avoid loop caused by (*SKIP) with an argument.

git-svn-id: svn://vcs.exim.org/pcre/code/trunk@543 2f5784b3-3f2a-0410-8824-cb99058d5e15

3 files changed, 30 insertions, 10 deletions

diff --git a/pcre_exec.c b/pcre_exec.c
index cdd66ce..8b5bae2 100644
--- a/pcre_exec.c
+++ b/pcre_exec.c
@@ -6069,13 +6069,28 @@ for(;;)
 
   switch(rc)
     {
-    /* NOMATCH and PRUNE advance by one character. If MATCH_SKIP_ARG reaches
-    this level it means that a MARK that matched the SKIP's arg was not found.
-    We treat this as NOMATCH. THEN at this level acts exactly like PRUNE. */
+    /* SKIP passes back the next starting point explicitly, but if it is the 
+    same as the match we have just done, treat it as NOMATCH. */
+
+    case MATCH_SKIP:
+    if (md->start_match_ptr != start_match)
+      {  
+      new_start_match = md->start_match_ptr;
+      break;
+      }
+    /* Fall through */
+    
+    /* If MATCH_SKIP_ARG reaches this level it means that a MARK that matched
+    the SKIP's arg was not found. We also treat this as NOMATCH. */
+     
+    case MATCH_SKIP_ARG:
+    /* Fall through */ 
+
+    /* NOMATCH and PRUNE advance by one character. THEN at this level acts
+    exactly like PRUNE. */
 
     case MATCH_NOMATCH:
     case MATCH_PRUNE:
-    case MATCH_SKIP_ARG:
     case MATCH_THEN:
     new_start_match = start_match + 1;
 #ifdef SUPPORT_UTF8
@@ -6085,12 +6100,6 @@ for(;;)
 #endif
     break;
 
-    /* SKIP passes back the next starting point explicitly. */
-
-    case MATCH_SKIP:
-    new_start_match = md->start_match_ptr;
-    break;
-
     /* COMMIT disables the bumpalong, but otherwise behaves as NOMATCH. */
 
     case MATCH_COMMIT:
diff --git a/testdata/testinput11 b/testdata/testinput11
index 43d08f3..c074176 100644
--- a/testdata/testinput11
+++ b/testdata/testinput11
@@ -435,6 +435,11 @@ with the handling of backtracking verbs. ---/
 /A(*:A)A+(*SKIP:A)(B|Z) | AC/xK
     AAAC
 
+/--- Don't loop! ---/
+
+/(*:A)A+(*SKIP:A)(B|Z)/K
+    AAAC
+
 /--- This should succeed, as a non-existent skip name disables the skip ---/ 
 
 /A(*MARK:A)A+(*SKIP:B)(B|Z) | AC/xK
diff --git a/testdata/testoutput11 b/testdata/testoutput11
index 5821d44..8b0f111 100644
--- a/testdata/testoutput11
+++ b/testdata/testoutput11
@@ -864,6 +864,12 @@ with the handling of backtracking verbs. ---/
     AAAC
  0: AC
 
+/--- Don't loop! ---/
+
+/(*:A)A+(*SKIP:A)(B|Z)/K
+    AAAC
+No match, mark = A
+
 /--- This should succeed, as a non-existent skip name disables the skip ---/ 
 
 /A(*MARK:A)A+(*SKIP:B)(B|Z) | AC/xK