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d58ab810a6
calls strcspn, call strcspn directly so we get the end of the token without an extra call to rawmemchr. Also avoid an unnecessary call to strcspn after the last token by adding an early exit for an empty string. Change strtok to tailcall strtok_r to avoid unnecessary code duplication. Remove the special header optimization for strtok_r of a 1-character constant string - both strspn and strcspn contain optimizations for this case. Benchmarking this showed similar performance in the worst case, but up to 5.5x better performance in the "found" case for large inputs. * benchtests/bench-strtok.c (oldstrtok): Add old implementation. * string/strtok.c (strtok): Change to tailcall __strtok_r. * string/strtok_r.c (__strtok_r): Optimize for performance. * string/string-inlines.c (__old_strtok_r_1c): New function. * string/bits/string2.h (__strtok_r): Move to string-inlines.c.
80 lines
2.0 KiB
C
80 lines
2.0 KiB
C
/* Reentrant string tokenizer. Generic version.
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Copyright (C) 1991-2016 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 Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the 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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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#include <string.h>
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#ifndef _LIBC
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/* Get specification. */
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# include "strtok_r.h"
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# define __strtok_r strtok_r
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#endif
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/* Parse S into tokens separated by characters in DELIM.
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If S is NULL, the saved pointer in SAVE_PTR is used as
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the next starting point. For example:
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char s[] = "-abc-=-def";
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char *sp;
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x = strtok_r(s, "-", &sp); // x = "abc", sp = "=-def"
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x = strtok_r(NULL, "-=", &sp); // x = "def", sp = NULL
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x = strtok_r(NULL, "=", &sp); // x = NULL
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// s = "abc\0-def\0"
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*/
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char *
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__strtok_r (char *s, const char *delim, char **save_ptr)
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{
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char *end;
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if (s == NULL)
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s = *save_ptr;
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if (*s == '\0')
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{
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*save_ptr = s;
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return NULL;
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}
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/* Scan leading delimiters. */
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s += strspn (s, delim);
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if (*s == '\0')
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{
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*save_ptr = s;
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return NULL;
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}
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/* Find the end of the token. */
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end = s + strcspn (s, delim);
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if (*end == '\0')
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{
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*save_ptr = end;
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return s;
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}
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/* Terminate the token and make *SAVE_PTR point past it. */
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*end = '\0';
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*save_ptr = end + 1;
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return s;
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}
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#ifdef weak_alias
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libc_hidden_def (__strtok_r)
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weak_alias (__strtok_r, strtok_r)
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#endif
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