2 files changed, 15 insertions, 4 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 7809565de87..44c55252b62 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,8 @@
+2010-03-30  Eli Zaretskii  <eliz@gnu.org>
+
+        * bidi.c (bidi_cache_iterator_state): Invalidate the cache if we
+        are outside the range of cached character positions.
+
 2010-03-30  Juanma Barranquero  <lekktu@gmail.com>
 
         * makefile.w32-in ($(BLD)/bidi.$(O)): Add dependency on w32gui.h.
diff --git a/src/bidi.c b/src/bidi.c
index d5e28cd2d8a..ea47cd33fec 100644
--- a/src/bidi.c
+++ b/src/bidi.c
@@ -671,10 +671,16 @@ bidi_cache_iterator_state (struct bidi_it *bidi_it, int resolved)
       /* Don't overrun the cache limit.  */
       if (idx > sizeof (bidi_cache) / sizeof (bidi_cache[0]) - 1)
         abort ();
-      /* Don't violate cache integrity: character positions should
-         correspond to cache positions 1:1.  */
-      if (idx > 0 && bidi_it->charpos != bidi_cache[idx - 1].charpos + 1)
-        abort ();
+      /* Character positions should correspond to cache positions 1:1.
+         If we are outside the range of cached positions, the cache is
+         useless and must be reset.  */
+      if (idx > 0 &&
+          (bidi_it->charpos > bidi_cache[idx - 1].charpos + 1
+           || bidi_it->charpos < bidi_cache[0].charpos))
+        {
+          bidi_cache_reset ();
+          idx = 0;
+        }
       bidi_copy_it (&bidi_cache[idx], bidi_it);
       if (!resolved)
         bidi_cache[idx].resolved_level = -1;