--- ../../grep-2.5.orig/src/search.c	2001-04-19 05:42:14.000000000 +0200
+++ src/search.c	2003-04-24 16:25:22.000000000 +0200
@@ -147,6 +147,32 @@
    are not singlebyte character nor the first byte of a multibyte
    character.  Caller must free the array.  */
 static char*
+check_multibyte_string_stateful(char const *buf, size_t size, char *mb_properties, int *from, int *to, mbstate_t *cur_state)
+{
+  int i;
+  int j;
+  
+  for (i = *from; i <= *to ;)
+    {
+      size_t mbclen;
+      mbclen = mbrlen(buf + i, size - i, cur_state);
+
+      if (mbclen == (size_t) -1 || mbclen == (size_t) -2 || mbclen == 0)
+	{
+	  /* An invalid sequence, or a truncated multibyte character.
+	     We treat it as a singlebyte character.  */
+	  mbclen = 1;
+	}
+      mb_properties[i] = mbclen;
+      for (j = i+1; j < i + mbclen; j++)
+        mb_properties[j] = 0;
+      i += mbclen;
+    }
+  *to = i-1;
+
+  return mb_properties;
+}
+static char*
 check_multibyte_string(char const *buf, size_t size)
 {
   char *mb_properties = malloc(size);
@@ -332,6 +358,14 @@
   kwsmusts ();
 }
 
+static int maxInt(int m, int n) {
+  return ((m>n)?m:n);
+}
+
+static int minInt(int m, int n) {
+  return ((m<n)?m:n);
+}
+
 static size_t
 EGexecute (char const *buf, size_t size, size_t *match_size, int exact)
 {
@@ -343,10 +377,18 @@
 #ifdef MBS_SUPPORT
   char *mb_properties = NULL;
 #endif /* MBS_SUPPORT */
+  mbstate_t cur_state;
+  int startpos;
+  int stoppos;
 
 #ifdef MBS_SUPPORT
-  if (MB_CUR_MAX > 1 && kwset)
-    mb_properties = check_multibyte_string(buf, size);
+  if (MB_CUR_MAX > 1 && kwset) {
+    memset(&cur_state, 0, sizeof(mbstate_t));
+    mb_properties = malloc(size);
+    startpos = 0;
+    stoppos = minInt(size-1, 100);
+    check_multibyte_string_stateful(buf, size, mb_properties, &startpos, &stoppos, &cur_state);
+  }
 #endif /* MBS_SUPPORT */
 
   buflim = buf + size;
@@ -373,8 +415,15 @@
 	      end = memchr(beg, eol, buflim - beg);
 	      end++;
 #ifdef MBS_SUPPORT
-	      if (MB_CUR_MAX > 1 && mb_properties[beg - buf] == 0)
-		continue;
+	      if (MB_CUR_MAX > 1) {
+                if ((beg-buf) > stoppos) {
+                  startpos = stoppos + 1;
+                  stoppos = minInt(size-1, beg-buf + 100);
+                  check_multibyte_string_stateful(buf, size, mb_properties, &startpos, &stoppos, &cur_state);
+                }
+                if (mb_properties[beg - buf] == 0)
+                  continue;
+              }
 #endif
 	      while (beg > buf && beg[-1] != eol)
 		--beg;