| 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 | |