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- /* Return the offset of one string within another.
- Copyright (C) 1994,1996,1997,2000,2001,2003 Free Software Foundation, Inc.
- This file is part of the GNU C Library.
- The GNU C Library 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 2.1 of the License, or (at your option) any later version.
- The GNU C Library 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 the GNU C Library; if not, write to the Free
- Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
- 02111-1307 USA. */
- /*
- * My personal strstr() implementation that beats most other algorithms.
- * Until someone tells me otherwise, I assume that this is the
- * fastest implementation of strstr() in C.
- * I deliberately chose not to comment it. You should have at least
- * as much fun trying to understand it, as I had to write it :-).
- *
- * Stephen R. van den Berg, berg@pool.informatik.rwth-aachen.de */
- #include <string.h>
- typedef unsigned chartype;
- #undef strstr
- char attribute_hidden *__strstr (const char *phaystack, const char *pneedle)
- {
- const unsigned char *haystack, *needle;
- chartype b;
- const unsigned char *rneedle;
- haystack = (const unsigned char *) phaystack;
- if ((b = *(needle = (const unsigned char *) pneedle)))
- {
- chartype c;
- haystack--; /* possible ANSI violation */
- {
- chartype a;
- do
- if (!(a = *++haystack))
- goto ret0;
- while (a != b);
- }
- if (!(c = *++needle))
- goto foundneedle;
- ++needle;
- goto jin;
- for (;;)
- {
- {
- chartype a;
- if (0)
- jin:{
- if ((a = *++haystack) == c)
- goto crest;
- }
- else
- a = *++haystack;
- do
- {
- for (; a != b; a = *++haystack)
- {
- if (!a)
- goto ret0;
- if ((a = *++haystack) == b)
- break;
- if (!a)
- goto ret0;
- }
- }
- while ((a = *++haystack) != c);
- }
- crest:
- {
- chartype a;
- {
- const unsigned char *rhaystack;
- if (*(rhaystack = haystack-- + 1) == (a = *(rneedle = needle)))
- do
- {
- if (!a)
- goto foundneedle;
- if (*++rhaystack != (a = *++needle))
- break;
- if (!a)
- goto foundneedle;
- }
- while (*++rhaystack == (a = *++needle));
- needle = rneedle; /* took the register-poor aproach */
- }
- if (!a)
- break;
- }
- }
- }
- foundneedle:
- return (char *) haystack;
- ret0:
- return 0;
- }
- strong_alias(__strstr, strstr)
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