1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2005 David Schultz <das@FreeBSD.ORG> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include <sys/libkern.h> 33 #include <sys/limits.h> 34 #include <sys/types.h> 35 36 #define IDX(c) ((u_char)(c) / LONG_BIT) 37 #define BIT(c) ((u_long)1 << ((u_char)(c) % LONG_BIT)) 38 39 size_t 40 strspn(const char *s, const char *charset) 41 { 42 /* 43 * NB: idx and bit are temporaries whose use causes gcc 3.4.2 to 44 * generate better code. Without them, gcc gets a little confused. 45 */ 46 const char *s1; 47 u_long bit; 48 u_long tbl[(UCHAR_MAX + 1) / LONG_BIT]; 49 int idx; 50 51 if(*s == '\0') 52 return (0); 53 54 #if LONG_BIT == 64 /* always better to unroll on 64-bit architectures */ 55 tbl[3] = tbl[2] = tbl[1] = tbl[0] = 0; 56 #else 57 for (idx = 0; idx < sizeof(tbl) / sizeof(tbl[0]); idx++) 58 tbl[idx] = 0; 59 #endif 60 for (; *charset != '\0'; charset++) { 61 idx = IDX(*charset); 62 bit = BIT(*charset); 63 tbl[idx] |= bit; 64 } 65 66 for(s1 = s; ; s1++) { 67 idx = IDX(*s1); 68 bit = BIT(*s1); 69 if ((tbl[idx] & bit) == 0) 70 break; 71 } 72 return (s1 - s); 73 } 74