49 lines
1.7 KiB
C
49 lines
1.7 KiB
C
/* Copyright (C) 1991, 1992, 1993, 1994, 1996 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library 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
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If
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not, write to the Free Software Foundation, Inc., 675 Mass Ave,
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Cambridge, MA 02139, USA. */
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#include <ansidecl.h>
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#include <stddef.h>
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#include <string.h>
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/* Return the first occurrence of NEEDLE in HAYSTACK. */
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PTR
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DEFUN(memmem, (haystack, haystack_len,
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needle, needle_len),
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CONST PTRCONST haystack AND CONST size_t haystack_len AND
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CONST PTRCONST needle AND CONST size_t needle_len)
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{
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register CONST char *begin;
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register CONST char *CONST last_possible
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= (CONST char *) haystack + haystack_len - needle_len;
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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 end of the string. */
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return (PTR) &((CONST char *) haystack)[haystack_len - 1];
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for (begin = (CONST char *) haystack; begin <= last_possible; ++begin)
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if (begin[0] == ((CONST char *) needle)[0] &&
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!memcmp ((CONST PTR) &begin[1],
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(CONST PTR) ((CONST char *) needle + 1),
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needle_len - 1))
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return (PTR) begin;
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return NULL;
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}
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