The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/libkern/strcspn.c

Version: -  FREEBSD  -  FREEBSD11  -  FREEBSD10  -  FREEBSD9  -  FREEBSD92  -  FREEBSD91  -  FREEBSD90  -  FREEBSD8  -  FREEBSD82  -  FREEBSD81  -  FREEBSD80  -  FREEBSD7  -  FREEBSD74  -  FREEBSD73  -  FREEBSD72  -  FREEBSD71  -  FREEBSD70  -  FREEBSD6  -  FREEBSD64  -  FREEBSD63  -  FREEBSD62  -  FREEBSD61  -  FREEBSD60  -  FREEBSD5  -  FREEBSD55  -  FREEBSD54  -  FREEBSD53  -  FREEBSD52  -  FREEBSD51  -  FREEBSD50  -  FREEBSD4  -  FREEBSD3  -  FREEBSD22  -  linux-2.6  -  linux-2.4.22  -  MK83  -  MK84  -  PLAN9  -  DFBSD  -  NETBSD  -  NETBSD5  -  NETBSD4  -  NETBSD3  -  NETBSD20  -  OPENBSD  -  xnu-517  -  xnu-792  -  xnu-792.6.70  -  xnu-1228  -  xnu-1456.1.26  -  xnu-1699.24.8  -  xnu-2050.18.24  -  OPENSOLARIS  -  minix-3-1-1 
SearchContext: -  none  -  3  -  10 

    1 /*-
    2  * Copyright (c) 2005 David Schultz <das@FreeBSD.ORG>
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  *
   14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   24  * SUCH DAMAGE.
   25  */
   26 
   27 #include <sys/cdefs.h>
   28 __FBSDID("$FreeBSD: stable/11/sys/libkern/strcspn.c 181748 2008-08-15 04:07:22Z kmacy $");
   29 
   30 #include <sys/libkern.h>
   31 #include <sys/types.h>
   32 #include <sys/limits.h>
   33 
   34 #define IDX(c)  ((u_char)(c) / LONG_BIT)
   35 #define BIT(c)  ((u_long)1 << ((u_char)(c) % LONG_BIT))
   36 
   37 size_t 
   38 strcspn(const char * __restrict s, const char * __restrict charset) 
   39 {
   40         /*
   41          * NB: idx and bit are temporaries whose use causes gcc 3.4.2 to
   42          * generate better code.  Without them, gcc gets a little confused.
   43          */
   44         const char *s1;
   45         u_long bit;
   46         u_long tbl[(UCHAR_MAX + 1) / LONG_BIT];
   47         int idx;
   48 
   49         if(*s == '\0')
   50                 return (0);
   51 
   52 #if LONG_BIT == 64      /* always better to unroll on 64-bit architectures */
   53         tbl[0] = 1;
   54         tbl[3] = tbl[2] = tbl[1] = 0;
   55 #else
   56         for (tbl[0] = idx = 1; idx < sizeof(tbl) / sizeof(tbl[0]); idx++)
   57                 tbl[idx] = 0;
   58 #endif
   59         for (; *charset != '\0'; charset++) {
   60                 idx = IDX(*charset);
   61                 bit = BIT(*charset);
   62                 tbl[idx] |= bit;
   63         }
   64 
   65         for(s1 = s; ; s1++) {
   66                 idx = IDX(*s1);
   67                 bit = BIT(*s1);
   68                 if ((tbl[idx] & bit) != 0)
   69                         break;
   70         }
   71         return (s1 - s);
   72 }

Cache object: 6feab445bfd37b0730da7c8eaef60ab7


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.