d3496c9f4f
Improve strcspn performance using a much faster algorithm. It is kept simple so it works well on most targets. It is generally at least 10 times faster than the existing implementation on bench-strcspn on a few AArch64 implementations, and for some tests 100 times as fast (repeatedly calling strchr on a small string is extremely slow...). In fact the string/bits/string2.h inlines make no longer sense, as GCC already uses strlen if reject is an empty string, strchrnul is 5 times as fast as __strcspn_c1, while __strcspn_c2 and __strcspn_c3 are slower than the strcspn main loop for large strings (though reject length 2-4 could be special cased in the future to gain even more performance). Tested on x86_64, i686, and aarch64. * string/Version (libc): Add GLIBC_2.24. * string/strcspn.c (strcspn): Rewrite function. * string/bits/string2.h (strcspn): Use __builtin_strcspn. (__strcspn_c1): Remove inline function. (__strcspn_c2): Likewise. (__strcspn_c3): Likewise. * string/string-inline.c [SHLIB_COMPAT(libc, GLIBC_2_1_1, GLIBC_2_24)] (__strcspn_c1): Add compatibility symbol. [SHLIB_COMPAT(libc, GLIBC_2_1_1, GLIBC_2_24)] (__strcspn_c2): Likewise. [SHLIB_COMPAT(libc, GLIBC_2_1_1, GLIBC_2_24)] (__strcspn_c3): Likewise. * sysdeps/i386/string-inlines.c: Include generic string-inlines.c.
75 lines
2.3 KiB
C
75 lines
2.3 KiB
C
/* Copyright (C) 1999-2016 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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/* <bits/string.h> and <bits/string2.h> declare some extern inline
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functions. These functions are declared additionally here if
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inlining is not possible. */
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#undef __USE_STRING_INLINES
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#define __USE_STRING_INLINES
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#define _FORCE_INLINES
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#define __STRING_INLINE /* empty */
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#define __NO_INLINE__
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#include <string.h>
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#undef index
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#undef rindex
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#undef __NO_INLINE__
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#include <bits/string.h>
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#include <bits/string2.h>
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#include "shlib-compat.h"
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#if SHLIB_COMPAT (libc, GLIBC_2_1_1, GLIBC_2_24)
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/* The inline functions are not used from GLIBC 2.24 and forward, however
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they are required to provide the symbols through string-inlines.c
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(if inlining is not possible for compatibility reasons). */
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size_t
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__old_strcspn_c1 (const char *__s, int __reject)
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{
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size_t __result = 0;
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while (__s[__result] != '\0' && __s[__result] != __reject)
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++__result;
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return __result;
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}
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compat_symbol (libc, __old_strcspn_c1, __strcspn_c1, GLIBC_2_1_1);
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size_t
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__old_strcspn_c2 (const char *__s, int __reject1, int __reject2)
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{
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size_t __result = 0;
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while (__s[__result] != '\0' && __s[__result] != __reject1
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&& __s[__result] != __reject2)
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++__result;
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return __result;
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}
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compat_symbol (libc, __old_strcspn_c2, __strcspn_c2, GLIBC_2_1_1);
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size_t
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__old_strcspn_c3 (const char *__s, int __reject1, int __reject2,
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int __reject3)
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{
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size_t __result = 0;
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while (__s[__result] != '\0' && __s[__result] != __reject1
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&& __s[__result] != __reject2 && __s[__result] != __reject3)
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++__result;
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return __result;
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}
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compat_symbol (libc, __old_strcspn_c3, __strcspn_c3, GLIBC_2_1_1);
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#endif
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