? g_utf8_offset_to_pointer-optimize.patch
Index: glib/gutf8.c
===================================================================
RCS file: /cvs/gnome/glib/glib/gutf8.c,v
retrieving revision 1.43.2.2
diff -u -p -r1.43.2.2 gutf8.c
--- glib/gutf8.c	30 Oct 2005 03:07:24 -0000	1.43.2.2
+++ glib/gutf8.c	3 Nov 2005 00:15:33 -0000
@@ -290,11 +290,51 @@ gchar *
 g_utf8_offset_to_pointer  (const gchar *str,
 			   glong        offset)    
 {
-  const gchar *s = str;
-  while (offset--)
-    s = g_utf8_next_char (s);
-  
-  return (gchar *)s;
+  union
+  {
+    const guint32 *p32;
+    const gchar   *p8;
+  }
+  pt;
+
+  pt.p8 = str;
+
+  while (offset >= 4)
+    {
+      guint32 seg    = *pt.p32;
+      guint32 seg_hi = seg & 0x80808080;
+
+      if (!seg_hi)
+        {
+          pt.p32++;
+          offset -= 4;
+          continue;
+        }
+      else if G_LIKELY (seg_hi == 0x80808080)
+        {
+          if ((seg & 0x80e080e0) == 0x80c080c0)
+	    {
+              pt.p32++;
+              offset -= 2;
+              continue;
+            }
+
+          if ((seg & 0xf08080f0) == 0xe08080e0)
+            {
+              pt.p8 += 6;
+              offset -= 2;
+              continue;
+            }
+        }
+
+      pt.p8 += g_utf8_skip [(guchar) seg];
+      offset--;
+    }
+
+  for ( ; offset; offset--)
+    pt.p8 = g_utf8_next_char (pt.p8);
+
+  return (gchar *) pt.p8;
 }
 
 /**