1 files changed, 46 insertions, 0 deletions
diff --git a/util/memrchr.c b/util/memrchr.c
new file mode 100644
index 000000000..009ae8ec4
--- /dev/null
+++ b/util/memrchr.c
@@ -0,0 +1,46 @@
+/* memrchr.c - libc replacement function
+ * Copyright (C) 2005 Free Software Foundation, Inc.
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuPG 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+/*
+  memrchr() is a GNU function that might not be available everywhere.
+  It's basically the inverse of memchr() - search backwards in a
+  memory block for a particular character.
+*/
+
+#include <config.h>
+#include <string.h>
+
+/* There are many ways to optimize this, but this is a simple
+   unoptimized implementation. */
+void *
+memrchr(const void *s, int c, size_t n)
+{
+  const unsigned char *start=s,*end=s+n-1;
+
+  while(end>=start)
+    {
+      if(*end==c)
+	return (void *)end;
+      else
+	end--;
+    }
+
+  return NULL;
+}