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("$FreeBSD$"); 29 30 #include <sys/types.h> 31 #include <limits.h> 32 #include <string.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 strspn(const char *s, const char *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[3] = tbl[2] = tbl[1] = tbl[0] = 0; 54 #else 55 for (idx = 0; idx < sizeof(tbl) / sizeof(tbl[0]); idx++) 56 tbl[idx] = 0; 57 #endif 58 for (; *charset != '\0'; charset++) { 59 idx = IDX(*charset); 60 bit = BIT(*charset); 61 tbl[idx] |= bit; 62 } 63 64 for(s1 = s; ; s1++) { 65 idx = IDX(*s1); 66 bit = BIT(*s1); 67 if ((tbl[idx] & bit) == 0) 68 break; 69 } 70 return (s1 - s); 71 } 72