87aa297030
implementations inspired by the ones in DragonFly. Unlike the DragonFly versions, these have a small data cache footprint, and my tests show that they're never slower than the old code except when the charset or the span is 0 or 1 characters. This implementation is generally faster than DragonFly until either the charset or the span gets in the ballpark of 32 to 64 characters.
73 lines
2.3 KiB
C
73 lines
2.3 KiB
C
/*-
|
|
* Copyright (c) 2005 David Schultz <das@FreeBSD.ORG>
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
__FBSDID("$FreeBSD$");
|
|
|
|
#include <sys/types.h>
|
|
#include <limits.h>
|
|
#include <string.h>
|
|
|
|
#define IDX(c) ((u_char)(c) / LONG_BIT)
|
|
#define BIT(c) ((u_long)1 << ((u_char)(c) % LONG_BIT))
|
|
|
|
size_t
|
|
strcspn(const char *s, const char *charset)
|
|
{
|
|
/*
|
|
* NB: idx and bit are temporaries whose use causes gcc 3.4.2 to
|
|
* generate better code. Without them, gcc gets a little confused.
|
|
*/
|
|
const char *s1;
|
|
u_long bit;
|
|
u_long tbl[(UCHAR_MAX + 1) / LONG_BIT];
|
|
int idx;
|
|
|
|
if(*s == '\0')
|
|
return (0);
|
|
|
|
#if LONG_BIT == 64 /* always better to unroll on 64-bit architectures */
|
|
tbl[0] = 1;
|
|
tbl[3] = tbl[2] = tbl[1] = 0;
|
|
#else
|
|
for (tbl[0] = idx = 1; idx < sizeof(tbl) / sizeof(tbl[0]); idx++)
|
|
tbl[idx] = 0;
|
|
#endif
|
|
for (; *charset != '\0'; charset++) {
|
|
idx = IDX(*charset);
|
|
bit = BIT(*charset);
|
|
tbl[idx] |= bit;
|
|
}
|
|
|
|
for(s1 = s; ; s1++) {
|
|
idx = IDX(*s1);
|
|
bit = BIT(*s1);
|
|
if ((tbl[idx] & bit) != 0)
|
|
break;
|
|
}
|
|
return (s1 - s);
|
|
}
|