From 4ed9aa638088a3dd4865453746330ce239723802 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Tue, 31 Dec 2013 15:05:34 +0530
Subject: [PATCH] Merge upstream bugfix for regex engine

https://code.google.com/p/mrab-regex-hg/source/detail?r=69cdaa98c25506c226717967be7131d06f1d54dd
---
 src/regex/_regex.c | 48 ++++++++++++++++------------------------------
 1 file changed, 16 insertions(+), 32 deletions(-)

diff --git a/src/regex/_regex.c b/src/regex/_regex.c
index f0a4f9a187..43f2135920 100644
--- a/src/regex/_regex.c
+++ b/src/regex/_regex.c
@@ -11767,15 +11767,7 @@ backtrack:
 
                     ch = test->values[0];
 
-                    /* The tail is a character. We don't want to go off the end
-                     * of the slice.
-                     */
-                    limit = RE_MAX(limit, slice_start + 1);
-
                     for (;;) {
-                        if (pos <= limit)
-                            break;
-
                         --pos;
 
                         if ((char_at(text, pos) == ch) == m &&
@@ -11784,6 +11776,10 @@ backtrack:
                             match = TRUE;
                             break;
                         }
+
+                        if (pos == limit)
+                            break;
+
                     }
                     break;
                 }
@@ -11793,15 +11789,7 @@ backtrack:
 
                     ch = test->values[0];
 
-                    /* The tail is a character. We don't want to go off the end
-                     * of the slice.
-                     */
-                    limit = RE_MAX(limit, slice_start + 1);
-
                     for (;;) {
-                        if (pos <= limit)
-                            break;
-
                         --pos;
 
                         if (same_char_ign(encoding, char_at(text, pos), ch) ==
@@ -11810,6 +11798,10 @@ backtrack:
                             match = TRUE;
                             break;
                         }
+
+                        if (pos == limit)
+                            break;
+
                     }
                     break;
                 }
@@ -11819,15 +11811,7 @@ backtrack:
 
                     ch = test->values[0];
 
-                    /* The tail is a character. We don't want to go off the end
-                     * of the slice.
-                     */
-                    limit = RE_MIN(limit, slice_end - 1);
-
                     for (;;) {
-                        if (pos >= limit)
-                            break;
-
                         ++pos;
 
                         if (same_char_ign(encoding, char_at(text, pos - 1), ch)
@@ -11836,6 +11820,10 @@ backtrack:
                             match = TRUE;
                             break;
                         }
+
+                        if (pos == limit)
+                            break;
+
                     }
                     break;
                 }
@@ -11845,15 +11833,7 @@ backtrack:
 
                     ch = test->values[0];
 
-                    /* The tail is a character. We don't want to go off the end
-                     * of the slice.
-                     */
-                    limit = RE_MIN(limit, slice_end - 1);
-
                     for (;;) {
-                        if (pos >= limit)
-                            break;
-
                         ++pos;
 
                         if ((char_at(text, pos - 1) == ch) == m &&
@@ -11862,6 +11842,10 @@ backtrack:
                             match = TRUE;
                             break;
                         }
+
+                        if (pos == limit)
+                            break;
+
                     }
                     break;
                 }