glibc/string/string-inlines.c
Adhemerval Zanella 91f3b75f47 Improve generic strspn performance
As for strcspn, this patch improves strspn performance using a much
faster algorithm.  It first constructs a 256-entry table based on
the accept string and then uses it as a lookup table for the
input string.  As for strcspn optimization, it is generally at least
10 times faster than the existing implementation on bench-strspn
on a few AArch64 implementations.

Also the string/bits/string2.h inlines make no longer sense, as current
implementation will already implement most of the optimizations.

Tested on x86_64, i686, and aarch64.

	* string/strspn.c (strcspn): Rewrite function.
	* string/bits/string2.h (strspn): Use __builtin_strcspn.
	(__strspn_c1): Remove inline function.
	(__strspn_c2): Likewise.
	(__strspn_c3): Likewise.
	* string/string-inlines.c
	[SHLIB_COMPAT(libc, GLIBC_2_1_1, GLIBC_2_24)] (__strspn_c1): Add
	compatibility symbol.
	[SHLIB_COMPAT(libc, GLIBC_2_1_1, GLIBC_2_24)] (__strspn_c2):
	Likewise.
	[SHLIB_COMPAT(libc, GLIBC_2_1_1, GLIBC_2_24)] (__strspn_c3):
	Likewise.
2016-04-01 10:44:44 -03:00

111 lines
3.3 KiB
C

/* Copyright (C) 1999-2016 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, see
<http://www.gnu.org/licenses/>. */
/* <bits/string.h> and <bits/string2.h> declare some extern inline
functions. These functions are declared additionally here if
inlining is not possible. */
#undef __USE_STRING_INLINES
#define __USE_STRING_INLINES
#define _FORCE_INLINES
#define __STRING_INLINE /* empty */
#define __NO_INLINE__
#include <string.h>
#undef index
#undef rindex
#undef __NO_INLINE__
#include <bits/string.h>
#include <bits/string2.h>
#include "shlib-compat.h"
#if SHLIB_COMPAT (libc, GLIBC_2_1_1, GLIBC_2_24)
/* The inline functions are not used from GLIBC 2.24 and forward, however
they are required to provide the symbols through string-inlines.c
(if inlining is not possible for compatibility reasons). */
size_t
__old_strcspn_c1 (const char *__s, int __reject)
{
size_t __result = 0;
while (__s[__result] != '\0' && __s[__result] != __reject)
++__result;
return __result;
}
compat_symbol (libc, __old_strcspn_c1, __strcspn_c1, GLIBC_2_1_1);
size_t
__old_strcspn_c2 (const char *__s, int __reject1, int __reject2)
{
size_t __result = 0;
while (__s[__result] != '\0' && __s[__result] != __reject1
&& __s[__result] != __reject2)
++__result;
return __result;
}
compat_symbol (libc, __old_strcspn_c2, __strcspn_c2, GLIBC_2_1_1);
size_t
__old_strcspn_c3 (const char *__s, int __reject1, int __reject2,
int __reject3)
{
size_t __result = 0;
while (__s[__result] != '\0' && __s[__result] != __reject1
&& __s[__result] != __reject2 && __s[__result] != __reject3)
++__result;
return __result;
}
compat_symbol (libc, __old_strcspn_c3, __strcspn_c3, GLIBC_2_1_1);
size_t
__old_strspn_c1 (const char *__s, int __accept)
{
size_t __result = 0;
/* Please note that __accept never can be '\0'. */
while (__s[__result] == __accept)
++__result;
return __result;
}
compat_symbol (libc, __old_strspn_c1, __strspn_c1, GLIBC_2_1_1);
size_t
__old_strspn_c2 (const char *__s, int __accept1, int __accept2)
{
size_t __result = 0;
/* Please note that __accept1 and __accept2 never can be '\0'. */
while (__s[__result] == __accept1 || __s[__result] == __accept2)
++__result;
return __result;
}
compat_symbol (libc, __old_strspn_c2, __strspn_c2, GLIBC_2_1_1);
size_t
__old_strspn_c3 (const char *__s, int __accept1, int __accept2,
int __accept3)
{
size_t __result = 0;
/* Please note that __accept1 to __accept3 never can be '\0'. */
while (__s[__result] == __accept1 || __s[__result] == __accept2
|| __s[__result] == __accept3)
++__result;
return __result;
}
compat_symbol (libc, __old_strspn_c3, __strspn_c3, GLIBC_2_1_1);
#endif