+
−/* Copyright (C) 1991-1994, 1996-1998, 2000, 2004, 2007-2011 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,
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−   but WITHOUT ANY WARRANTY; without even the implied warranty of
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−   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.  */
+
−
+
−/* This particular implementation was written by Eric Blake, 2008.  */
+
−
+
−#ifndef _LIBC
+
−# include <config.h>
+
−#endif
+
−
+
−/* Specification of memmem.  */
+
−#include <string.h>
+
−
+
−#ifndef _LIBC
+
−# define __builtin_expect(expr, val)   (expr)
+
−#endif
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−
+
−#define RETURN_TYPE void *
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−#define AVAILABLE(h, h_l, j, n_l) ((j) <= (h_l) - (n_l))
+
−#include "str-two-way.h"
+
−
+
−/* Return the first occurrence of NEEDLE in HAYSTACK.  Return HAYSTACK
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−   if NEEDLE_LEN is 0, otherwise NULL if NEEDLE is not found in
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−   HAYSTACK.  */
+
−void *
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−memmem (const void *haystack_start, size_t haystack_len,
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−        const void *needle_start, size_t needle_len)
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−{
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−  /* Abstract memory is considered to be an array of 'unsigned char' values,
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−     not an array of 'char' values.  See ISO C 99 section 6.2.6.1.  */
+
−  const unsigned char *haystack = (const unsigned char *) haystack_start;
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−  const unsigned char *needle = (const unsigned char *) needle_start;
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−
+
−  if (needle_len == 0)
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−    /* The first occurrence of the empty string is deemed to occur at
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−       the beginning of the string.  */
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−    return (void *) haystack;
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−
+
−  /* Sanity check, otherwise the loop might search through the whole
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−     memory.  */
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−  if (__builtin_expect (haystack_len < needle_len, 0))
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−    return NULL;
+
−
+
−  /* Use optimizations in memchr when possible, to reduce the search
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−     size of haystack using a linear algorithm with a smaller
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−     coefficient.  However, avoid memchr for long needles, since we
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−     can often achieve sublinear performance.  */
+
−  if (needle_len < LONG_NEEDLE_THRESHOLD)
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−    {
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−      haystack = memchr (haystack, *needle, haystack_len);
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−      if (!haystack || __builtin_expect (needle_len == 1, 0))
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−        return (void *) haystack;
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−      haystack_len -= haystack - (const unsigned char *) haystack_start;
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−      if (haystack_len < needle_len)
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−        return NULL;
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−      return two_way_short_needle (haystack, haystack_len, needle, needle_len);
+
−    }
+
−  else
+
−    return two_way_long_needle (haystack, haystack_len, needle, needle_len);
+
−}
+
−
+
−#undef LONG_NEEDLE_THRESHOLD