1 | /* |
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2 | FUNCTION |
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3 | <<strcasestr>>---case-insensitive character string search |
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4 | |
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5 | INDEX |
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6 | strcasestr |
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7 | |
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8 | SYNOPSIS |
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9 | #include <string.h> |
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10 | char *strcasestr(const char *<[s]>, const char *<[find]>); |
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11 | |
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12 | DESCRIPTION |
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13 | <<strcasestr>> searchs the string <[s]> for |
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14 | the first occurrence of the sequence <[find]>. <<strcasestr>> |
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15 | is identical to <<strstr>> except the search is |
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16 | case-insensitive. |
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17 | |
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18 | RETURNS |
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19 | |
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20 | A pointer to the first case-insensitive occurrence of the sequence |
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21 | <[find]> or <<NULL>> if no match was found. |
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22 | |
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23 | PORTABILITY |
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24 | <<strcasestr>> is in the Berkeley Software Distribution. |
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25 | |
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26 | <<strcasestr>> requires no supporting OS subroutines. It uses |
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27 | tolower() from elsewhere in this library. |
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28 | |
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29 | QUICKREF |
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30 | strcasestr |
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31 | */ |
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32 | |
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33 | /*- |
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34 | * Copyright (c) 1990, 1993 |
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35 | * The Regents of the University of California. All rights reserved. |
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36 | * |
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37 | * The quadratic code is derived from software contributed to Berkeley by |
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38 | * Chris Torek. |
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39 | * |
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40 | * Redistribution and use in source and binary forms, with or without |
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41 | * modification, are permitted provided that the following conditions |
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42 | * are met: |
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43 | * 1. Redistributions of source code must retain the above copyright |
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44 | * notice, this list of conditions and the following disclaimer. |
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45 | * 2. Redistributions in binary form must reproduce the above copyright |
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46 | * notice, this list of conditions and the following disclaimer in the |
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47 | * documentation and/or other materials provided with the distribution. |
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48 | * 4. Neither the name of the University nor the names of its contributors |
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49 | * may be used to endorse or promote products derived from this software |
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50 | * without specific prior written permission. |
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51 | * |
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52 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
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53 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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54 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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55 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
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56 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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57 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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58 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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59 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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60 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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61 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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62 | * SUCH DAMAGE. |
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63 | */ |
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64 | /* Linear algorithm Copyright (C) 2008 Eric Blake |
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65 | * Permission to use, copy, modify, and distribute the linear portion of |
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66 | * software is freely granted, provided that this notice is preserved. |
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67 | */ |
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68 | |
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69 | #include <sys/cdefs.h> |
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70 | |
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71 | #include <ctype.h> |
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72 | #include <string.h> |
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73 | #include <strings.h> |
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74 | |
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75 | #if !defined(PREFER_SIZE_OVER_SPEED) && !defined(__OPTIMIZE_SIZE__) |
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76 | # define RETURN_TYPE char * |
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77 | # define AVAILABLE(h, h_l, j, n_l) \ |
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78 | (!memchr ((h) + (h_l), '\0', (j) + (n_l) - (h_l)) \ |
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79 | && ((h_l) = (j) + (n_l))) |
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80 | # define CANON_ELEMENT(c) tolower (c) |
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81 | #if __GNUC_PREREQ (4, 2) |
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82 | /* strncasecmp uses signed char, CMP_FUNC is expected to use unsigned char. */ |
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83 | #pragma GCC diagnostic ignored "-Wpointer-sign" |
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84 | #endif |
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85 | # define CMP_FUNC strncasecmp |
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86 | # include "str-two-way.h" |
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87 | #endif |
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88 | |
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89 | /* |
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90 | * Find the first occurrence of find in s, ignore case. |
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91 | */ |
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92 | char * |
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93 | strcasestr (const char *s, |
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94 | const char *find) |
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95 | { |
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96 | #if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__) |
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97 | |
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98 | /* Less code size, but quadratic performance in the worst case. */ |
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99 | char c, sc; |
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100 | size_t len; |
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101 | |
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102 | if ((c = *find++) != 0) { |
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103 | c = tolower((unsigned char)c); |
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104 | len = strlen(find); |
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105 | do { |
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106 | do { |
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107 | if ((sc = *s++) == 0) |
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108 | return (NULL); |
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109 | } while ((char)tolower((unsigned char)sc) != c); |
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110 | } while (strncasecmp(s, find, len) != 0); |
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111 | s--; |
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112 | } |
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113 | return ((char *)s); |
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114 | |
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115 | #else /* compilation for speed */ |
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116 | |
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117 | /* Larger code size, but guaranteed linear performance. */ |
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118 | const char *haystack = s; |
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119 | const char *needle = find; |
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120 | size_t needle_len; /* Length of NEEDLE. */ |
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121 | size_t haystack_len; /* Known minimum length of HAYSTACK. */ |
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122 | int ok = 1; /* True if NEEDLE is prefix of HAYSTACK. */ |
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123 | |
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124 | /* Determine length of NEEDLE, and in the process, make sure |
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125 | HAYSTACK is at least as long (no point processing all of a long |
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126 | NEEDLE if HAYSTACK is too short). */ |
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127 | while (*haystack && *needle) |
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128 | ok &= (tolower ((unsigned char) *haystack++) |
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129 | == tolower ((unsigned char) *needle++)); |
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130 | if (*needle) |
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131 | return NULL; |
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132 | if (ok) |
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133 | return (char *) s; |
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134 | needle_len = needle - find; |
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135 | haystack = s + 1; |
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136 | haystack_len = needle_len - 1; |
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137 | |
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138 | /* Perform the search. */ |
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139 | if (needle_len < LONG_NEEDLE_THRESHOLD) |
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140 | return two_way_short_needle ((const unsigned char *) haystack, |
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141 | haystack_len, |
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142 | (const unsigned char *) find, needle_len); |
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143 | return two_way_long_needle ((const unsigned char *) haystack, haystack_len, |
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144 | (const unsigned char *) find, needle_len); |
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145 | #endif /* compilation for speed */ |
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146 | } |
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