1 files changed, 101 insertions, 0 deletions
diff --git a/lib/unistr/u8-strrchr.c b/lib/unistr/u8-strrchr.c
new file mode 100644
index 00000000..309f3234
--- /dev/null
+++ b/lib/unistr/u8-strrchr.c
@@ -0,0 +1,101 @@
+/* Search character in UTF-8 string.
+   Copyright (C) 1999, 2002, 2006-2007 Free Software Foundation, Inc.
+   Written by Bruno Haible <bruno@clisp.org>, 2002.
+
+   This program is free software: you can redistribute it and/or modify it
+   under the terms of the GNU Lesser General Public License as published
+   by the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include "unistr.h"
+
+uint8_t *
+u8_strrchr (const uint8_t *s, ucs4_t uc)
+{
+  /* Calling u8_strlen and then searching from the other end would cause more
+     memory accesses. Avoid that, at the cost of a few more comparisons.  */
+  uint8_t *result = NULL;
+  uint8_t c[6];
+
+  if (uc < 0x80)
+    {
+      uint8_t c0 = uc;
+
+      for (;; s++)
+	{
+	  if (*s == c0)
+	    result = (uint8_t *) s;
+	  if (*s == 0)
+	    break;
+	}
+    }
+  else
+    switch (u8_uctomb_aux (c, uc, 6))
+      {
+      case 2:
+	if (*s)
+	  {
+	    uint8_t c0 = c[0];
+	    uint8_t c1 = c[1];
+
+	    /* FIXME: Maybe walking the string via u8_mblen is a win?  */
+	    for (;; s++)
+	      {
+		if (s[1] == 0)
+		  break;
+		if (*s == c0 && s[1] == c1)
+		  result = (uint8_t *) s;
+	      }
+	  }
+	break;
+
+      case 3:
+	if (*s && s[1])
+	  {
+	    uint8_t c0 = c[0];
+	    uint8_t c1 = c[1];
+	    uint8_t c2 = c[2];
+
+	    /* FIXME: Maybe walking the string via u8_mblen is a win?  */
+	    for (;; s++)
+	      {
+		if (s[2] == 0)
+		  break;
+		if (*s == c0 && s[1] == c1 && s[2] == c2)
+		  result = (uint8_t *) s;
+	      }
+	  }
+	break;
+
+      case 4:
+	if (*s && s[1] && s[2])
+	  {
+	    uint8_t c0 = c[0];
+	    uint8_t c1 = c[1];
+	    uint8_t c2 = c[2];
+	    uint8_t c3 = c[3];
+
+	    /* FIXME: Maybe walking the string via u8_mblen is a win?  */
+	    for (;; s++)
+	      {
+		if (s[3] == 0)
+		  break;
+		if (*s == c0 && s[1] == c1 && s[2] == c2 && s[3] == c3)
+		  result = (uint8_t *) s;
+	      }
+	  }
+	break;
+      }
+  return result;
+}