Merge commit 'upstream/2.20'

[msp430-binutils.git] / libiberty / memmem.c

diff --git a/libiberty/memmem.c b/libiberty/memmem.c
new file mode 100644 (file)
index 0000000..5d75599
--- /dev/null
+++ b/libiberty/memmem.c
@@ -0,0 +1,70 @@
+/* Copyright (C) 1991,92,93,94,96,97,98,2000,2004,2007 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   This program 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, 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 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+/*
+
+@deftypefn Supplemental void* memmem (const void *@var{haystack}, size_t @var{haystack_len} const void *@var{needle}, size_t @var{needle_len})
+
+Returns a pointer to the first occurrence of @var{needle} (length
+@var{needle_len}) in @var{haystack} (length @var{haystack_len}).
+Returns @code{NULL} if not found.
+
+@end deftypefn
+
+*/
+
+#ifndef _LIBC
+# include <config.h>
+#endif
+
+#include <stddef.h>
+#include <string.h>
+
+#ifndef _LIBC
+# define __builtin_expect(expr, val)   (expr)
+#endif
+
+#undef memmem
+
+/* Return the first occurrence of NEEDLE in HAYSTACK.  */
+void *
+memmem (const void *haystack, size_t haystack_len, const void *needle,
+       size_t needle_len)
+{
+  const char *begin;
+  const char *const last_possible
+    = (const char *) haystack + haystack_len - needle_len;
+
+  if (needle_len == 0)
+    /* The first occurrence of the empty string is deemed to occur at
+       the beginning of the string.  */
+    return (void *) haystack;
+
+  /* Sanity check, otherwise the loop might search through the whole
+     memory.  */
+  if (__builtin_expect (haystack_len < needle_len, 0))
+    return NULL;
+
+  for (begin = (const char *) haystack; begin <= last_possible; ++begin)
+    if (begin[0] == ((const char *) needle)[0] &&
+       !memcmp ((const void *) &begin[1],
+                (const void *) ((const char *) needle + 1),
+                needle_len - 1))
+      return (void *) begin;
+
+  return NULL;
+}