From 1e0fa2bf25fc79591bf064ba67744da2398eac0e Mon Sep 17 00:00:00 2001
From: handa <handa>
Date: Fri, 13 Nov 2009 13:12:00 +0000
Subject: [PATCH] (match_ids_backward): New function. (match_chain_ids): Call
 match_ids_backward for backward matching.

---
 src/otfdrive.c |   17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/src/otfdrive.c b/src/otfdrive.c
index 4ae95b8..30081a0 100644
--- a/src/otfdrive.c
+++ b/src/otfdrive.c
@@ -286,6 +286,21 @@ match_ids (OTF_GlyphString *gstring, int gidx, int flag,
 }
 
 static int
+match_ids_backward (OTF_GlyphString *gstring, int gidx, int flag,
+		    int count, OTF_GlyphID *ids)
+{
+  OTF_Glyph *gbeg = gstring->glyphs + gidx;
+  OTF_Glyph *gend = gstring->glyphs;
+  OTF_Glyph *g;
+  int i;
+
+  for (g = gbeg, i = 0; g >= gend && i < count; g--)
+    if (! IGNORED_GLYPH (g, flag) && g->glyph_id != ids[i++])
+      return -1;
+  return (i < count ? -1 : gbeg - g);
+}
+
+static int
 match_chain_ids (OTF_GlyphString *gstring, int gidx, int flag,
 		 OTF_ChainRule *rule)
 {
@@ -301,7 +316,7 @@ match_chain_ids (OTF_GlyphString *gstring, int gidx, int flag,
 	  break;
       if (i > 0)
 	return -1;
-      if (match_ids (gstring, j, flag,
+      if (match_ids_backward (gstring, j, flag,
 		     rule->BacktrackGlyphCount, rule->Backtrack)
 	  < 0)
 	return -1;
-- 
1.7.10.4