1 /* $NetBSD: strspn.c,v 1.1 2014/07/19 18:38:33 lneto Exp $ */ 2 3 /*- 4 * Copyright (c) 2008 Joerg Sonnenberger 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(S) ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #include <sys/cdefs.h> 29 __RCSID("$NetBSD: strspn.c,v 1.1 2014/07/19 18:38:33 lneto Exp $"); 30 31 #if !defined(_KERNEL) && !defined(_STANDALONE) 32 #include <assert.h> 33 #include <inttypes.h> 34 #include <limits.h> 35 #include <string.h> 36 #else 37 #include <lib/libkern/libkern.h> 38 #endif 39 40 #if ULONG_MAX != 0xffffffffffffffffull 41 42 size_t 43 strspn(const char *s, const char *charset) 44 { 45 static const uint8_t idx[8] = { 1, 2, 4, 8, 16, 32, 64, 128 }; 46 uint8_t set[32]; 47 const char *t; 48 #define UC(a) ((unsigned int)(unsigned char)(a)) 49 50 _DIAGASSERT(s != NULL); 51 _DIAGASSERT(charset != NULL); 52 53 if (charset[0] == '\0') 54 return 0; 55 if (charset[1] == '\0') { 56 for (t = s; *t != '\0'; ++t) { 57 if (*t != *charset) 58 break; 59 } 60 return t - s; 61 } 62 63 (void)memset(set, 0, sizeof(set)); 64 65 for (; *charset != '\0'; ++charset) 66 set[UC(*charset) >> 3] |= idx[UC(*charset) & 7]; 67 68 for (t = s; *t != '\0'; ++t) 69 if ((set[UC(*t) >> 3] & idx[UC(*t) & 7]) == 0) 70 break; 71 return t - s; 72 } 73 74 #else 75 76 /* 64 bit system, use four 64 bits registers for bitmask */ 77 78 static size_t 79 strspn_x(const char *s_s, const char *charset_s, unsigned long invert) 80 { 81 const unsigned char *s = (const unsigned char *)s_s; 82 const unsigned char *charset = (const unsigned char *)charset_s; 83 unsigned long m_0, m_4, m_8, m_c; 84 unsigned char ch, next_ch; 85 unsigned long bit; 86 unsigned long check; 87 size_t count; 88 89 /* Four 64bit registers have one bit for each character value */ 90 m_0 = 0; 91 m_4 = 0; 92 m_8 = 0; 93 m_c = 0; 94 95 for (ch = *charset; ch != 0; ch = next_ch) { 96 next_ch = *++charset; 97 bit = 1ul << (ch & 0x3f); 98 if (__predict_true(ch < 0x80)) { 99 if (ch < 0x40) 100 m_0 |= bit; 101 else 102 m_4 |= bit; 103 } else { 104 if (ch < 0xc0) 105 m_8 |= bit; 106 else 107 m_c |= bit; 108 } 109 } 110 111 /* For strcspn() we just invert the validity set */ 112 m_0 ^= invert; 113 m_4 ^= invert; 114 m_8 ^= invert; 115 m_c ^= invert; 116 117 /* 118 * We could do remove the lsb from m_0 to terminate at the 119 * end of the input string. 120 * However prefetching the next char is benifitial and we must 121 * not read the byte after the \0 - as it might fault! 122 * So we take the 'hit' of the compare against 0. 123 */ 124 125 ch = *s++; 126 for (count = 0; ch != 0; ch = next_ch) { 127 next_ch = s[count]; 128 if (__predict_true(ch < 0x80)) { 129 check = m_0; 130 if (ch >= 0x40) 131 check = m_4; 132 } else { 133 check = m_8; 134 if (ch >= 0xc0) 135 check = m_c; 136 } 137 if (!((check >> (ch & 0x3f)) & 1)) 138 break; 139 count++; 140 } 141 return count; 142 } 143 144 size_t 145 strspn(const char *s, const char *charset) 146 { 147 return strspn_x(s, charset, 0); 148 } 149 150 size_t 151 strcspn(const char *s, const char *charset) 152 { 153 return strspn_x(s, charset, ~0ul); 154 } 155 #endif 156