1 | /*
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2 | regexec.c - TRE POSIX compatible matching functions (and more).
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3 |
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4 | Copyright (c) 2001-2009 Ville Laurikari <vl@iki.fi>
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5 | All rights reserved.
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6 |
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7 | Redistribution and use in source and binary forms, with or without
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8 | modification, are permitted provided that the following conditions
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9 | are met:
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10 |
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11 | 1. Redistributions of source code must retain the above copyright
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12 | notice, this list of conditions and the following disclaimer.
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13 |
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14 | 2. Redistributions in binary form must reproduce the above copyright
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15 | notice, this list of conditions and the following disclaimer in the
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16 | documentation and/or other materials provided with the distribution.
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17 |
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18 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS
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19 | ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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20 | LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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21 | A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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22 | HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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23 | SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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24 | LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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25 | DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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26 | THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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27 | (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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28 | OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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29 |
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30 | */
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31 |
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32 | #include <stdlib.h>
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33 | #include <string.h>
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34 | #include <wchar.h>
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35 | #include <wctype.h>
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36 | #include <limits.h>
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37 | #include <stdint.h>
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38 |
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39 | #include <regex.h>
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40 |
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41 | #include "tre.h"
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42 |
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43 | #include <assert.h>
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44 |
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45 | static void
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46 | tre_fill_pmatch(size_t nmatch, regmatch_t pmatch[], int cflags,
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47 | const tre_tnfa_t *tnfa, regoff_t *tags, regoff_t match_eo);
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48 |
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49 | /***********************************************************************
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50 | from tre-match-utils.h
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51 | ***********************************************************************/
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52 |
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53 | #define GET_NEXT_WCHAR() do { \
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54 | prev_c = next_c; pos += pos_add_next; \
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55 | if ((pos_add_next = mbtowc(&next_c, str_byte, MB_LEN_MAX)) <= 0) { \
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56 | if (pos_add_next < 0) { ret = REG_NOMATCH; goto error_exit; } \
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57 | else pos_add_next++; \
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58 | } \
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59 | str_byte += pos_add_next; \
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60 | } while (0)
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61 |
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62 | #define IS_WORD_CHAR(c) ((c) == L'_' || tre_isalnum(c))
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63 |
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64 | #define CHECK_ASSERTIONS(assertions) \
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65 | (((assertions & ASSERT_AT_BOL) \
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66 | && (pos > 0 || reg_notbol) \
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67 | && (prev_c != L'\n' || !reg_newline)) \
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68 | || ((assertions & ASSERT_AT_EOL) \
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69 | && (next_c != L'\0' || reg_noteol) \
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70 | && (next_c != L'\n' || !reg_newline)) \
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71 | || ((assertions & ASSERT_AT_BOW) \
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72 | && (IS_WORD_CHAR(prev_c) || !IS_WORD_CHAR(next_c))) \
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73 | || ((assertions & ASSERT_AT_EOW) \
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74 | && (!IS_WORD_CHAR(prev_c) || IS_WORD_CHAR(next_c))) \
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75 | || ((assertions & ASSERT_AT_WB) \
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76 | && (pos != 0 && next_c != L'\0' \
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77 | && IS_WORD_CHAR(prev_c) == IS_WORD_CHAR(next_c))) \
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78 | || ((assertions & ASSERT_AT_WB_NEG) \
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79 | && (pos == 0 || next_c == L'\0' \
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80 | || IS_WORD_CHAR(prev_c) != IS_WORD_CHAR(next_c))))
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81 |
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82 | #define CHECK_CHAR_CLASSES(trans_i, tnfa, eflags) \
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83 | (((trans_i->assertions & ASSERT_CHAR_CLASS) \
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84 | && !(tnfa->cflags & REG_ICASE) \
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85 | && !tre_isctype((tre_cint_t)prev_c, trans_i->u.class)) \
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86 | || ((trans_i->assertions & ASSERT_CHAR_CLASS) \
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87 | && (tnfa->cflags & REG_ICASE) \
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88 | && !tre_isctype(tre_tolower((tre_cint_t)prev_c),trans_i->u.class) \
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89 | && !tre_isctype(tre_toupper((tre_cint_t)prev_c),trans_i->u.class)) \
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90 | || ((trans_i->assertions & ASSERT_CHAR_CLASS_NEG) \
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91 | && tre_neg_char_classes_match(trans_i->neg_classes,(tre_cint_t)prev_c,\
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92 | tnfa->cflags & REG_ICASE)))
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93 |
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94 |
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95 |
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96 |
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97 | /* Returns 1 if `t1' wins `t2', 0 otherwise. */
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98 | static int
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99 | tre_tag_order(int num_tags, tre_tag_direction_t *tag_directions,
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100 | regoff_t *t1, regoff_t *t2)
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101 | {
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102 | int i;
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103 | for (i = 0; i < num_tags; i++)
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104 | {
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105 | if (tag_directions[i] == TRE_TAG_MINIMIZE)
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106 | {
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107 | if (t1[i] < t2[i])
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108 | return 1;
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109 | if (t1[i] > t2[i])
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110 | return 0;
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111 | }
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112 | else
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113 | {
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114 | if (t1[i] > t2[i])
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115 | return 1;
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116 | if (t1[i] < t2[i])
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117 | return 0;
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118 | }
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119 | }
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120 | /* assert(0);*/
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121 | return 0;
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122 | }
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123 |
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124 | static int
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125 | tre_neg_char_classes_match(tre_ctype_t *classes, tre_cint_t wc, int icase)
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126 | {
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127 | while (*classes != (tre_ctype_t)0)
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128 | if ((!icase && tre_isctype(wc, *classes))
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129 | || (icase && (tre_isctype(tre_toupper(wc), *classes)
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130 | || tre_isctype(tre_tolower(wc), *classes))))
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131 | return 1; /* Match. */
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132 | else
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133 | classes++;
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134 | return 0; /* No match. */
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135 | }
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136 |
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137 |
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138 | /***********************************************************************
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139 | from tre-match-parallel.c
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140 | ***********************************************************************/
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141 |
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142 | /*
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143 | This algorithm searches for matches basically by reading characters
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144 | in the searched string one by one, starting at the beginning. All
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145 | matching paths in the TNFA are traversed in parallel. When two or
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146 | more paths reach the same state, exactly one is chosen according to
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147 | tag ordering rules; if returning submatches is not required it does
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148 | not matter which path is chosen.
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149 |
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150 | The worst case time required for finding the leftmost and longest
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151 | match, or determining that there is no match, is always linearly
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152 | dependent on the length of the text being searched.
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153 |
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154 | This algorithm cannot handle TNFAs with back referencing nodes.
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155 | See `tre-match-backtrack.c'.
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156 | */
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157 |
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158 | typedef struct {
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159 | tre_tnfa_transition_t *state;
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160 | regoff_t *tags;
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161 | } tre_tnfa_reach_t;
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162 |
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163 | typedef struct {
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164 | regoff_t pos;
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165 | regoff_t **tags;
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166 | } tre_reach_pos_t;
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167 |
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168 |
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169 | static reg_errcode_t
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170 | tre_tnfa_run_parallel(const tre_tnfa_t *tnfa, const void *string,
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171 | regoff_t *match_tags, int eflags,
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172 | regoff_t *match_end_ofs)
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173 | {
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174 | /* State variables required by GET_NEXT_WCHAR. */
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175 | tre_char_t prev_c = 0, next_c = 0;
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176 | const char *str_byte = string;
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177 | regoff_t pos = -1;
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178 | regoff_t pos_add_next = 1;
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179 | #ifdef TRE_MBSTATE
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180 | mbstate_t mbstate;
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181 | #endif /* TRE_MBSTATE */
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182 | int reg_notbol = eflags & REG_NOTBOL;
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183 | int reg_noteol = eflags & REG_NOTEOL;
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184 | int reg_newline = tnfa->cflags & REG_NEWLINE;
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185 | reg_errcode_t ret;
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186 |
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187 | char *buf;
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188 | tre_tnfa_transition_t *trans_i;
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189 | tre_tnfa_reach_t *reach, *reach_next, *reach_i, *reach_next_i;
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190 | tre_reach_pos_t *reach_pos;
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191 | int *tag_i;
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192 | int num_tags, i;
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193 |
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194 | regoff_t match_eo = -1; /* end offset of match (-1 if no match found yet) */
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195 | int new_match = 0;
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196 | regoff_t *tmp_tags = NULL;
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197 | regoff_t *tmp_iptr;
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198 |
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199 | #ifdef TRE_MBSTATE
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200 | memset(&mbstate, '\0', sizeof(mbstate));
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201 | #endif /* TRE_MBSTATE */
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202 |
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203 | if (!match_tags)
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204 | num_tags = 0;
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205 | else
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206 | num_tags = tnfa->num_tags;
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207 |
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208 | /* Allocate memory for temporary data required for matching. This needs to
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209 | be done for every matching operation to be thread safe. This allocates
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210 | everything in a single large block with calloc(). */
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211 | {
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212 | size_t tbytes, rbytes, pbytes, xbytes, total_bytes;
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213 | char *tmp_buf;
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214 |
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215 | /* Ensure that tbytes and xbytes*num_states cannot overflow, and that
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216 | * they don't contribute more than 1/8 of SIZE_MAX to total_bytes. */
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217 | if (num_tags > SIZE_MAX/(8 * sizeof(regoff_t) * tnfa->num_states))
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218 | return REG_ESPACE;
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219 |
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220 | /* Likewise check rbytes. */
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221 | if (tnfa->num_states+1 > SIZE_MAX/(8 * sizeof(*reach_next)))
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222 | return REG_ESPACE;
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223 |
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224 | /* Likewise check pbytes. */
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225 | if (tnfa->num_states > SIZE_MAX/(8 * sizeof(*reach_pos)))
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226 | return REG_ESPACE;
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227 |
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228 | /* Compute the length of the block we need. */
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229 | tbytes = sizeof(*tmp_tags) * num_tags;
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230 | rbytes = sizeof(*reach_next) * (tnfa->num_states + 1);
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231 | pbytes = sizeof(*reach_pos) * tnfa->num_states;
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232 | xbytes = sizeof(regoff_t) * num_tags;
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233 | total_bytes =
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234 | (sizeof(long) - 1) * 4 /* for alignment paddings */
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235 | + (rbytes + xbytes * tnfa->num_states) * 2 + tbytes + pbytes;
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236 |
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237 | /* Allocate the memory. */
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238 | buf = calloc(total_bytes, 1);
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239 | if (buf == NULL)
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240 | return REG_ESPACE;
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241 |
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242 | /* Get the various pointers within tmp_buf (properly aligned). */
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243 | tmp_tags = (void *)buf;
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244 | tmp_buf = buf + tbytes;
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245 | tmp_buf += ALIGN(tmp_buf, long);
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246 | reach_next = (void *)tmp_buf;
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247 | tmp_buf += rbytes;
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248 | tmp_buf += ALIGN(tmp_buf, long);
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249 | reach = (void *)tmp_buf;
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250 | tmp_buf += rbytes;
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251 | tmp_buf += ALIGN(tmp_buf, long);
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252 | reach_pos = (void *)tmp_buf;
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253 | tmp_buf += pbytes;
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254 | tmp_buf += ALIGN(tmp_buf, long);
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255 | for (i = 0; i < tnfa->num_states; i++)
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256 | {
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257 | reach[i].tags = (void *)tmp_buf;
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258 | tmp_buf += xbytes;
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259 | reach_next[i].tags = (void *)tmp_buf;
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260 | tmp_buf += xbytes;
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261 | }
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262 | }
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263 |
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264 | for (i = 0; i < tnfa->num_states; i++)
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265 | reach_pos[i].pos = -1;
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266 |
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267 | GET_NEXT_WCHAR();
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268 | pos = 0;
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269 |
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270 | reach_next_i = reach_next;
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271 | while (1)
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272 | {
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273 | /* If no match found yet, add the initial states to `reach_next'. */
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274 | if (match_eo < 0)
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275 | {
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276 | trans_i = tnfa->initial;
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277 | while (trans_i->state != NULL)
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278 | {
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279 | if (reach_pos[trans_i->state_id].pos < pos)
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280 | {
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281 | if (trans_i->assertions
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282 | && CHECK_ASSERTIONS(trans_i->assertions))
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283 | {
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284 | trans_i++;
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285 | continue;
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286 | }
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287 |
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288 | reach_next_i->state = trans_i->state;
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289 | for (i = 0; i < num_tags; i++)
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290 | reach_next_i->tags[i] = -1;
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291 | tag_i = trans_i->tags;
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292 | if (tag_i)
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293 | while (*tag_i >= 0)
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294 | {
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295 | if (*tag_i < num_tags)
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296 | reach_next_i->tags[*tag_i] = pos;
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297 | tag_i++;
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298 | }
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299 | if (reach_next_i->state == tnfa->final)
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300 | {
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301 | match_eo = pos;
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302 | new_match = 1;
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303 | for (i = 0; i < num_tags; i++)
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304 | match_tags[i] = reach_next_i->tags[i];
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305 | }
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306 | reach_pos[trans_i->state_id].pos = pos;
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307 | reach_pos[trans_i->state_id].tags = &reach_next_i->tags;
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308 | reach_next_i++;
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309 | }
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310 | trans_i++;
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311 | }
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312 | reach_next_i->state = NULL;
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313 | }
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314 | else
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315 | {
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316 | if (num_tags == 0 || reach_next_i == reach_next)
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317 | /* We have found a match. */
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318 | break;
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319 | }
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320 |
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321 | /* Check for end of string. */
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322 | if (!next_c) break;
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323 |
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324 | GET_NEXT_WCHAR();
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325 |
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326 | /* Swap `reach' and `reach_next'. */
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327 | reach_i = reach;
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328 | reach = reach_next;
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329 | reach_next = reach_i;
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330 |
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331 | /* For each state in `reach', weed out states that don't fulfill the
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332 | minimal matching conditions. */
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333 | if (tnfa->num_minimals && new_match)
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334 | {
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335 | new_match = 0;
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336 | reach_next_i = reach_next;
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337 | for (reach_i = reach; reach_i->state; reach_i++)
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338 | {
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339 | int skip = 0;
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340 | for (i = 0; tnfa->minimal_tags[i] >= 0; i += 2)
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341 | {
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342 | int end = tnfa->minimal_tags[i];
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343 | int start = tnfa->minimal_tags[i + 1];
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344 | if (end >= num_tags)
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345 | {
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346 | skip = 1;
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347 | break;
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348 | }
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349 | else if (reach_i->tags[start] == match_tags[start]
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350 | && reach_i->tags[end] < match_tags[end])
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351 | {
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352 | skip = 1;
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353 | break;
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354 | }
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355 | }
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356 | if (!skip)
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357 | {
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358 | reach_next_i->state = reach_i->state;
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359 | tmp_iptr = reach_next_i->tags;
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360 | reach_next_i->tags = reach_i->tags;
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361 | reach_i->tags = tmp_iptr;
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362 | reach_next_i++;
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363 | }
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364 | }
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365 | reach_next_i->state = NULL;
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366 |
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367 | /* Swap `reach' and `reach_next'. */
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368 | reach_i = reach;
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369 | reach = reach_next;
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370 | reach_next = reach_i;
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371 | }
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372 |
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373 | /* For each state in `reach' see if there is a transition leaving with
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374 | the current input symbol to a state not yet in `reach_next', and
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375 | add the destination states to `reach_next'. */
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376 | reach_next_i = reach_next;
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377 | for (reach_i = reach; reach_i->state; reach_i++)
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378 | {
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379 | for (trans_i = reach_i->state; trans_i->state; trans_i++)
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380 | {
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381 | /* Does this transition match the input symbol? */
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382 | if (trans_i->code_min <= (tre_cint_t)prev_c &&
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383 | trans_i->code_max >= (tre_cint_t)prev_c)
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384 | {
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385 | if (trans_i->assertions
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386 | && (CHECK_ASSERTIONS(trans_i->assertions)
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387 | || CHECK_CHAR_CLASSES(trans_i, tnfa, eflags)))
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388 | {
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389 | continue;
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390 | }
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391 |
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392 | /* Compute the tags after this transition. */
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393 | for (i = 0; i < num_tags; i++)
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394 | tmp_tags[i] = reach_i->tags[i];
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395 | tag_i = trans_i->tags;
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396 | if (tag_i != NULL)
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397 | while (*tag_i >= 0)
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398 | {
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399 | if (*tag_i < num_tags)
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400 | tmp_tags[*tag_i] = pos;
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401 | tag_i++;
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402 | }
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403 |
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404 | if (reach_pos[trans_i->state_id].pos < pos)
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405 | {
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406 | /* Found an unvisited node. */
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407 | reach_next_i->state = trans_i->state;
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408 | tmp_iptr = reach_next_i->tags;
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409 | reach_next_i->tags = tmp_tags;
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410 | tmp_tags = tmp_iptr;
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411 | reach_pos[trans_i->state_id].pos = pos;
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412 | reach_pos[trans_i->state_id].tags = &reach_next_i->tags;
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413 |
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414 | if (reach_next_i->state == tnfa->final
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415 | && (match_eo == -1
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416 | || (num_tags > 0
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417 | && reach_next_i->tags[0] <= match_tags[0])))
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418 | {
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419 | match_eo = pos;
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420 | new_match = 1;
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421 | for (i = 0; i < num_tags; i++)
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422 | match_tags[i] = reach_next_i->tags[i];
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423 | }
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424 | reach_next_i++;
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425 |
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426 | }
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427 | else
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428 | {
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429 | assert(reach_pos[trans_i->state_id].pos == pos);
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430 | /* Another path has also reached this state. We choose
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431 | the winner by examining the tag values for both
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432 | paths. */
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433 | if (tre_tag_order(num_tags, tnfa->tag_directions,
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434 | tmp_tags,
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435 | *reach_pos[trans_i->state_id].tags))
|
---|
436 | {
|
---|
437 | /* The new path wins. */
|
---|
438 | tmp_iptr = *reach_pos[trans_i->state_id].tags;
|
---|
439 | *reach_pos[trans_i->state_id].tags = tmp_tags;
|
---|
440 | if (trans_i->state == tnfa->final)
|
---|
441 | {
|
---|
442 | match_eo = pos;
|
---|
443 | new_match = 1;
|
---|
444 | for (i = 0; i < num_tags; i++)
|
---|
445 | match_tags[i] = tmp_tags[i];
|
---|
446 | }
|
---|
447 | tmp_tags = tmp_iptr;
|
---|
448 | }
|
---|
449 | }
|
---|
450 | }
|
---|
451 | }
|
---|
452 | }
|
---|
453 | reach_next_i->state = NULL;
|
---|
454 | }
|
---|
455 |
|
---|
456 | *match_end_ofs = match_eo;
|
---|
457 | ret = match_eo >= 0 ? REG_OK : REG_NOMATCH;
|
---|
458 | error_exit:
|
---|
459 | xfree(buf);
|
---|
460 | return ret;
|
---|
461 | }
|
---|
462 |
|
---|
463 |
|
---|
464 |
|
---|
465 | /***********************************************************************
|
---|
466 | from tre-match-backtrack.c
|
---|
467 | ***********************************************************************/
|
---|
468 |
|
---|
469 | /*
|
---|
470 | This matcher is for regexps that use back referencing. Regexp matching
|
---|
471 | with back referencing is an NP-complete problem on the number of back
|
---|
472 | references. The easiest way to match them is to use a backtracking
|
---|
473 | routine which basically goes through all possible paths in the TNFA
|
---|
474 | and chooses the one which results in the best (leftmost and longest)
|
---|
475 | match. This can be spectacularly expensive and may run out of stack
|
---|
476 | space, but there really is no better known generic algorithm. Quoting
|
---|
477 | Henry Spencer from comp.compilers:
|
---|
478 | <URL: http://compilers.iecc.com/comparch/article/93-03-102>
|
---|
479 |
|
---|
480 | POSIX.2 REs require longest match, which is really exciting to
|
---|
481 | implement since the obsolete ("basic") variant also includes
|
---|
482 | \<digit>. I haven't found a better way of tackling this than doing
|
---|
483 | a preliminary match using a DFA (or simulation) on a modified RE
|
---|
484 | that just replicates subREs for \<digit>, and then doing a
|
---|
485 | backtracking match to determine whether the subRE matches were
|
---|
486 | right. This can be rather slow, but I console myself with the
|
---|
487 | thought that people who use \<digit> deserve very slow execution.
|
---|
488 | (Pun unintentional but very appropriate.)
|
---|
489 |
|
---|
490 | */
|
---|
491 |
|
---|
492 | typedef struct {
|
---|
493 | regoff_t pos;
|
---|
494 | const char *str_byte;
|
---|
495 | tre_tnfa_transition_t *state;
|
---|
496 | int state_id;
|
---|
497 | int next_c;
|
---|
498 | regoff_t *tags;
|
---|
499 | #ifdef TRE_MBSTATE
|
---|
500 | mbstate_t mbstate;
|
---|
501 | #endif /* TRE_MBSTATE */
|
---|
502 | } tre_backtrack_item_t;
|
---|
503 |
|
---|
504 | typedef struct tre_backtrack_struct {
|
---|
505 | tre_backtrack_item_t item;
|
---|
506 | struct tre_backtrack_struct *prev;
|
---|
507 | struct tre_backtrack_struct *next;
|
---|
508 | } *tre_backtrack_t;
|
---|
509 |
|
---|
510 | #ifdef TRE_MBSTATE
|
---|
511 | #define BT_STACK_MBSTATE_IN stack->item.mbstate = (mbstate)
|
---|
512 | #define BT_STACK_MBSTATE_OUT (mbstate) = stack->item.mbstate
|
---|
513 | #else /* !TRE_MBSTATE */
|
---|
514 | #define BT_STACK_MBSTATE_IN
|
---|
515 | #define BT_STACK_MBSTATE_OUT
|
---|
516 | #endif /* !TRE_MBSTATE */
|
---|
517 |
|
---|
518 | #define tre_bt_mem_new tre_mem_new
|
---|
519 | #define tre_bt_mem_alloc tre_mem_alloc
|
---|
520 | #define tre_bt_mem_destroy tre_mem_destroy
|
---|
521 |
|
---|
522 |
|
---|
523 | #define BT_STACK_PUSH(_pos, _str_byte, _str_wide, _state, _state_id, _next_c, _tags, _mbstate) \
|
---|
524 | do \
|
---|
525 | { \
|
---|
526 | int i; \
|
---|
527 | if (!stack->next) \
|
---|
528 | { \
|
---|
529 | tre_backtrack_t s; \
|
---|
530 | s = tre_bt_mem_alloc(mem, sizeof(*s)); \
|
---|
531 | if (!s) \
|
---|
532 | { \
|
---|
533 | tre_bt_mem_destroy(mem); \
|
---|
534 | if (tags) \
|
---|
535 | xfree(tags); \
|
---|
536 | if (pmatch) \
|
---|
537 | xfree(pmatch); \
|
---|
538 | if (states_seen) \
|
---|
539 | xfree(states_seen); \
|
---|
540 | return REG_ESPACE; \
|
---|
541 | } \
|
---|
542 | s->prev = stack; \
|
---|
543 | s->next = NULL; \
|
---|
544 | s->item.tags = tre_bt_mem_alloc(mem, \
|
---|
545 | sizeof(*tags) * tnfa->num_tags); \
|
---|
546 | if (!s->item.tags) \
|
---|
547 | { \
|
---|
548 | tre_bt_mem_destroy(mem); \
|
---|
549 | if (tags) \
|
---|
550 | xfree(tags); \
|
---|
551 | if (pmatch) \
|
---|
552 | xfree(pmatch); \
|
---|
553 | if (states_seen) \
|
---|
554 | xfree(states_seen); \
|
---|
555 | return REG_ESPACE; \
|
---|
556 | } \
|
---|
557 | stack->next = s; \
|
---|
558 | stack = s; \
|
---|
559 | } \
|
---|
560 | else \
|
---|
561 | stack = stack->next; \
|
---|
562 | stack->item.pos = (_pos); \
|
---|
563 | stack->item.str_byte = (_str_byte); \
|
---|
564 | stack->item.state = (_state); \
|
---|
565 | stack->item.state_id = (_state_id); \
|
---|
566 | stack->item.next_c = (_next_c); \
|
---|
567 | for (i = 0; i < tnfa->num_tags; i++) \
|
---|
568 | stack->item.tags[i] = (_tags)[i]; \
|
---|
569 | BT_STACK_MBSTATE_IN; \
|
---|
570 | } \
|
---|
571 | while (0)
|
---|
572 |
|
---|
573 | #define BT_STACK_POP() \
|
---|
574 | do \
|
---|
575 | { \
|
---|
576 | int i; \
|
---|
577 | assert(stack->prev); \
|
---|
578 | pos = stack->item.pos; \
|
---|
579 | str_byte = stack->item.str_byte; \
|
---|
580 | state = stack->item.state; \
|
---|
581 | next_c = stack->item.next_c; \
|
---|
582 | for (i = 0; i < tnfa->num_tags; i++) \
|
---|
583 | tags[i] = stack->item.tags[i]; \
|
---|
584 | BT_STACK_MBSTATE_OUT; \
|
---|
585 | stack = stack->prev; \
|
---|
586 | } \
|
---|
587 | while (0)
|
---|
588 |
|
---|
589 | #undef MIN
|
---|
590 | #define MIN(a, b) ((a) <= (b) ? (a) : (b))
|
---|
591 |
|
---|
592 | static reg_errcode_t
|
---|
593 | tre_tnfa_run_backtrack(const tre_tnfa_t *tnfa, const void *string,
|
---|
594 | regoff_t *match_tags, int eflags, regoff_t *match_end_ofs)
|
---|
595 | {
|
---|
596 | /* State variables required by GET_NEXT_WCHAR. */
|
---|
597 | tre_char_t prev_c = 0, next_c = 0;
|
---|
598 | const char *str_byte = string;
|
---|
599 | regoff_t pos = 0;
|
---|
600 | regoff_t pos_add_next = 1;
|
---|
601 | #ifdef TRE_MBSTATE
|
---|
602 | mbstate_t mbstate;
|
---|
603 | #endif /* TRE_MBSTATE */
|
---|
604 | int reg_notbol = eflags & REG_NOTBOL;
|
---|
605 | int reg_noteol = eflags & REG_NOTEOL;
|
---|
606 | int reg_newline = tnfa->cflags & REG_NEWLINE;
|
---|
607 |
|
---|
608 | /* These are used to remember the necessary values of the above
|
---|
609 | variables to return to the position where the current search
|
---|
610 | started from. */
|
---|
611 | int next_c_start;
|
---|
612 | const char *str_byte_start;
|
---|
613 | regoff_t pos_start = -1;
|
---|
614 | #ifdef TRE_MBSTATE
|
---|
615 | mbstate_t mbstate_start;
|
---|
616 | #endif /* TRE_MBSTATE */
|
---|
617 |
|
---|
618 | /* End offset of best match so far, or -1 if no match found yet. */
|
---|
619 | regoff_t match_eo = -1;
|
---|
620 | /* Tag arrays. */
|
---|
621 | int *next_tags;
|
---|
622 | regoff_t *tags = NULL;
|
---|
623 | /* Current TNFA state. */
|
---|
624 | tre_tnfa_transition_t *state;
|
---|
625 | int *states_seen = NULL;
|
---|
626 |
|
---|
627 | /* Memory allocator to for allocating the backtracking stack. */
|
---|
628 | tre_mem_t mem = tre_bt_mem_new();
|
---|
629 |
|
---|
630 | /* The backtracking stack. */
|
---|
631 | tre_backtrack_t stack;
|
---|
632 |
|
---|
633 | tre_tnfa_transition_t *trans_i;
|
---|
634 | regmatch_t *pmatch = NULL;
|
---|
635 | int ret;
|
---|
636 |
|
---|
637 | #ifdef TRE_MBSTATE
|
---|
638 | memset(&mbstate, '\0', sizeof(mbstate));
|
---|
639 | #endif /* TRE_MBSTATE */
|
---|
640 |
|
---|
641 | if (!mem)
|
---|
642 | return REG_ESPACE;
|
---|
643 | stack = tre_bt_mem_alloc(mem, sizeof(*stack));
|
---|
644 | if (!stack)
|
---|
645 | {
|
---|
646 | ret = REG_ESPACE;
|
---|
647 | goto error_exit;
|
---|
648 | }
|
---|
649 | stack->prev = NULL;
|
---|
650 | stack->next = NULL;
|
---|
651 |
|
---|
652 | if (tnfa->num_tags)
|
---|
653 | {
|
---|
654 | tags = xmalloc(sizeof(*tags) * tnfa->num_tags);
|
---|
655 | if (!tags)
|
---|
656 | {
|
---|
657 | ret = REG_ESPACE;
|
---|
658 | goto error_exit;
|
---|
659 | }
|
---|
660 | }
|
---|
661 | if (tnfa->num_submatches)
|
---|
662 | {
|
---|
663 | pmatch = xmalloc(sizeof(*pmatch) * tnfa->num_submatches);
|
---|
664 | if (!pmatch)
|
---|
665 | {
|
---|
666 | ret = REG_ESPACE;
|
---|
667 | goto error_exit;
|
---|
668 | }
|
---|
669 | }
|
---|
670 | if (tnfa->num_states)
|
---|
671 | {
|
---|
672 | states_seen = xmalloc(sizeof(*states_seen) * tnfa->num_states);
|
---|
673 | if (!states_seen)
|
---|
674 | {
|
---|
675 | ret = REG_ESPACE;
|
---|
676 | goto error_exit;
|
---|
677 | }
|
---|
678 | }
|
---|
679 |
|
---|
680 | retry:
|
---|
681 | {
|
---|
682 | int i;
|
---|
683 | for (i = 0; i < tnfa->num_tags; i++)
|
---|
684 | {
|
---|
685 | tags[i] = -1;
|
---|
686 | if (match_tags)
|
---|
687 | match_tags[i] = -1;
|
---|
688 | }
|
---|
689 | for (i = 0; i < tnfa->num_states; i++)
|
---|
690 | states_seen[i] = 0;
|
---|
691 | }
|
---|
692 |
|
---|
693 | state = NULL;
|
---|
694 | pos = pos_start;
|
---|
695 | GET_NEXT_WCHAR();
|
---|
696 | pos_start = pos;
|
---|
697 | next_c_start = next_c;
|
---|
698 | str_byte_start = str_byte;
|
---|
699 | #ifdef TRE_MBSTATE
|
---|
700 | mbstate_start = mbstate;
|
---|
701 | #endif /* TRE_MBSTATE */
|
---|
702 |
|
---|
703 | /* Handle initial states. */
|
---|
704 | next_tags = NULL;
|
---|
705 | for (trans_i = tnfa->initial; trans_i->state; trans_i++)
|
---|
706 | {
|
---|
707 | if (trans_i->assertions && CHECK_ASSERTIONS(trans_i->assertions))
|
---|
708 | {
|
---|
709 | continue;
|
---|
710 | }
|
---|
711 | if (state == NULL)
|
---|
712 | {
|
---|
713 | /* Start from this state. */
|
---|
714 | state = trans_i->state;
|
---|
715 | next_tags = trans_i->tags;
|
---|
716 | }
|
---|
717 | else
|
---|
718 | {
|
---|
719 | /* Backtrack to this state. */
|
---|
720 | BT_STACK_PUSH(pos, str_byte, 0, trans_i->state,
|
---|
721 | trans_i->state_id, next_c, tags, mbstate);
|
---|
722 | {
|
---|
723 | int *tmp = trans_i->tags;
|
---|
724 | if (tmp)
|
---|
725 | while (*tmp >= 0)
|
---|
726 | stack->item.tags[*tmp++] = pos;
|
---|
727 | }
|
---|
728 | }
|
---|
729 | }
|
---|
730 |
|
---|
731 | if (next_tags)
|
---|
732 | for (; *next_tags >= 0; next_tags++)
|
---|
733 | tags[*next_tags] = pos;
|
---|
734 |
|
---|
735 |
|
---|
736 | if (state == NULL)
|
---|
737 | goto backtrack;
|
---|
738 |
|
---|
739 | while (1)
|
---|
740 | {
|
---|
741 | tre_tnfa_transition_t *next_state;
|
---|
742 | int empty_br_match;
|
---|
743 |
|
---|
744 | if (state == tnfa->final)
|
---|
745 | {
|
---|
746 | if (match_eo < pos
|
---|
747 | || (match_eo == pos
|
---|
748 | && match_tags
|
---|
749 | && tre_tag_order(tnfa->num_tags, tnfa->tag_directions,
|
---|
750 | tags, match_tags)))
|
---|
751 | {
|
---|
752 | int i;
|
---|
753 | /* This match wins the previous match. */
|
---|
754 | match_eo = pos;
|
---|
755 | if (match_tags)
|
---|
756 | for (i = 0; i < tnfa->num_tags; i++)
|
---|
757 | match_tags[i] = tags[i];
|
---|
758 | }
|
---|
759 | /* Our TNFAs never have transitions leaving from the final state,
|
---|
760 | so we jump right to backtracking. */
|
---|
761 | goto backtrack;
|
---|
762 | }
|
---|
763 |
|
---|
764 | /* Go to the next character in the input string. */
|
---|
765 | empty_br_match = 0;
|
---|
766 | trans_i = state;
|
---|
767 | if (trans_i->state && trans_i->assertions & ASSERT_BACKREF)
|
---|
768 | {
|
---|
769 | /* This is a back reference state. All transitions leaving from
|
---|
770 | this state have the same back reference "assertion". Instead
|
---|
771 | of reading the next character, we match the back reference. */
|
---|
772 | regoff_t so, eo;
|
---|
773 | int bt = trans_i->u.backref;
|
---|
774 | regoff_t bt_len;
|
---|
775 | int result;
|
---|
776 |
|
---|
777 | /* Get the substring we need to match against. Remember to
|
---|
778 | turn off REG_NOSUB temporarily. */
|
---|
779 | tre_fill_pmatch(bt + 1, pmatch, tnfa->cflags & ~REG_NOSUB,
|
---|
780 | tnfa, tags, pos);
|
---|
781 | so = pmatch[bt].rm_so;
|
---|
782 | eo = pmatch[bt].rm_eo;
|
---|
783 | bt_len = eo - so;
|
---|
784 |
|
---|
785 | result = strncmp((const char*)string + so, str_byte - 1,
|
---|
786 | (size_t)bt_len);
|
---|
787 |
|
---|
788 | if (result == 0)
|
---|
789 | {
|
---|
790 | /* Back reference matched. Check for infinite loop. */
|
---|
791 | if (bt_len == 0)
|
---|
792 | empty_br_match = 1;
|
---|
793 | if (empty_br_match && states_seen[trans_i->state_id])
|
---|
794 | {
|
---|
795 | goto backtrack;
|
---|
796 | }
|
---|
797 |
|
---|
798 | states_seen[trans_i->state_id] = empty_br_match;
|
---|
799 |
|
---|
800 | /* Advance in input string and resync `prev_c', `next_c'
|
---|
801 | and pos. */
|
---|
802 | str_byte += bt_len - 1;
|
---|
803 | pos += bt_len - 1;
|
---|
804 | GET_NEXT_WCHAR();
|
---|
805 | }
|
---|
806 | else
|
---|
807 | {
|
---|
808 | goto backtrack;
|
---|
809 | }
|
---|
810 | }
|
---|
811 | else
|
---|
812 | {
|
---|
813 | /* Check for end of string. */
|
---|
814 | if (next_c == L'\0')
|
---|
815 | goto backtrack;
|
---|
816 |
|
---|
817 | /* Read the next character. */
|
---|
818 | GET_NEXT_WCHAR();
|
---|
819 | }
|
---|
820 |
|
---|
821 | next_state = NULL;
|
---|
822 | for (trans_i = state; trans_i->state; trans_i++)
|
---|
823 | {
|
---|
824 | if (trans_i->code_min <= (tre_cint_t)prev_c
|
---|
825 | && trans_i->code_max >= (tre_cint_t)prev_c)
|
---|
826 | {
|
---|
827 | if (trans_i->assertions
|
---|
828 | && (CHECK_ASSERTIONS(trans_i->assertions)
|
---|
829 | || CHECK_CHAR_CLASSES(trans_i, tnfa, eflags)))
|
---|
830 | {
|
---|
831 | continue;
|
---|
832 | }
|
---|
833 |
|
---|
834 | if (next_state == NULL)
|
---|
835 | {
|
---|
836 | /* First matching transition. */
|
---|
837 | next_state = trans_i->state;
|
---|
838 | next_tags = trans_i->tags;
|
---|
839 | }
|
---|
840 | else
|
---|
841 | {
|
---|
842 | /* Second matching transition. We may need to backtrack here
|
---|
843 | to take this transition instead of the first one, so we
|
---|
844 | push this transition in the backtracking stack so we can
|
---|
845 | jump back here if needed. */
|
---|
846 | BT_STACK_PUSH(pos, str_byte, 0, trans_i->state,
|
---|
847 | trans_i->state_id, next_c, tags, mbstate);
|
---|
848 | {
|
---|
849 | int *tmp;
|
---|
850 | for (tmp = trans_i->tags; tmp && *tmp >= 0; tmp++)
|
---|
851 | stack->item.tags[*tmp] = pos;
|
---|
852 | }
|
---|
853 | #if 0 /* XXX - it's important not to look at all transitions here to keep
|
---|
854 | the stack small! */
|
---|
855 | break;
|
---|
856 | #endif
|
---|
857 | }
|
---|
858 | }
|
---|
859 | }
|
---|
860 |
|
---|
861 | if (next_state != NULL)
|
---|
862 | {
|
---|
863 | /* Matching transitions were found. Take the first one. */
|
---|
864 | state = next_state;
|
---|
865 |
|
---|
866 | /* Update the tag values. */
|
---|
867 | if (next_tags)
|
---|
868 | while (*next_tags >= 0)
|
---|
869 | tags[*next_tags++] = pos;
|
---|
870 | }
|
---|
871 | else
|
---|
872 | {
|
---|
873 | backtrack:
|
---|
874 | /* A matching transition was not found. Try to backtrack. */
|
---|
875 | if (stack->prev)
|
---|
876 | {
|
---|
877 | if (stack->item.state->assertions & ASSERT_BACKREF)
|
---|
878 | {
|
---|
879 | states_seen[stack->item.state_id] = 0;
|
---|
880 | }
|
---|
881 |
|
---|
882 | BT_STACK_POP();
|
---|
883 | }
|
---|
884 | else if (match_eo < 0)
|
---|
885 | {
|
---|
886 | /* Try starting from a later position in the input string. */
|
---|
887 | /* Check for end of string. */
|
---|
888 | if (next_c == L'\0')
|
---|
889 | {
|
---|
890 | break;
|
---|
891 | }
|
---|
892 | next_c = next_c_start;
|
---|
893 | #ifdef TRE_MBSTATE
|
---|
894 | mbstate = mbstate_start;
|
---|
895 | #endif /* TRE_MBSTATE */
|
---|
896 | str_byte = str_byte_start;
|
---|
897 | goto retry;
|
---|
898 | }
|
---|
899 | else
|
---|
900 | {
|
---|
901 | break;
|
---|
902 | }
|
---|
903 | }
|
---|
904 | }
|
---|
905 |
|
---|
906 | ret = match_eo >= 0 ? REG_OK : REG_NOMATCH;
|
---|
907 | *match_end_ofs = match_eo;
|
---|
908 |
|
---|
909 | error_exit:
|
---|
910 | tre_bt_mem_destroy(mem);
|
---|
911 | #ifndef TRE_USE_ALLOCA
|
---|
912 | if (tags)
|
---|
913 | xfree(tags);
|
---|
914 | if (pmatch)
|
---|
915 | xfree(pmatch);
|
---|
916 | if (states_seen)
|
---|
917 | xfree(states_seen);
|
---|
918 | #endif /* !TRE_USE_ALLOCA */
|
---|
919 |
|
---|
920 | return ret;
|
---|
921 | }
|
---|
922 |
|
---|
923 | /***********************************************************************
|
---|
924 | from regexec.c
|
---|
925 | ***********************************************************************/
|
---|
926 |
|
---|
927 | /* Fills the POSIX.2 regmatch_t array according to the TNFA tag and match
|
---|
928 | endpoint values. */
|
---|
929 | static void
|
---|
930 | tre_fill_pmatch(size_t nmatch, regmatch_t pmatch[], int cflags,
|
---|
931 | const tre_tnfa_t *tnfa, regoff_t *tags, regoff_t match_eo)
|
---|
932 | {
|
---|
933 | tre_submatch_data_t *submatch_data;
|
---|
934 | unsigned int i, j;
|
---|
935 | int *parents;
|
---|
936 |
|
---|
937 | i = 0;
|
---|
938 | if (match_eo >= 0 && !(cflags & REG_NOSUB))
|
---|
939 | {
|
---|
940 | /* Construct submatch offsets from the tags. */
|
---|
941 | submatch_data = tnfa->submatch_data;
|
---|
942 | while (i < tnfa->num_submatches && i < nmatch)
|
---|
943 | {
|
---|
944 | if (submatch_data[i].so_tag == tnfa->end_tag)
|
---|
945 | pmatch[i].rm_so = match_eo;
|
---|
946 | else
|
---|
947 | pmatch[i].rm_so = tags[submatch_data[i].so_tag];
|
---|
948 |
|
---|
949 | if (submatch_data[i].eo_tag == tnfa->end_tag)
|
---|
950 | pmatch[i].rm_eo = match_eo;
|
---|
951 | else
|
---|
952 | pmatch[i].rm_eo = tags[submatch_data[i].eo_tag];
|
---|
953 |
|
---|
954 | /* If either of the endpoints were not used, this submatch
|
---|
955 | was not part of the match. */
|
---|
956 | if (pmatch[i].rm_so == -1 || pmatch[i].rm_eo == -1)
|
---|
957 | pmatch[i].rm_so = pmatch[i].rm_eo = -1;
|
---|
958 |
|
---|
959 | i++;
|
---|
960 | }
|
---|
961 | /* Reset all submatches that are not within all of their parent
|
---|
962 | submatches. */
|
---|
963 | i = 0;
|
---|
964 | while (i < tnfa->num_submatches && i < nmatch)
|
---|
965 | {
|
---|
966 | if (pmatch[i].rm_eo == -1)
|
---|
967 | assert(pmatch[i].rm_so == -1);
|
---|
968 | assert(pmatch[i].rm_so <= pmatch[i].rm_eo);
|
---|
969 |
|
---|
970 | parents = submatch_data[i].parents;
|
---|
971 | if (parents != NULL)
|
---|
972 | for (j = 0; parents[j] >= 0; j++)
|
---|
973 | {
|
---|
974 | if (pmatch[i].rm_so < pmatch[parents[j]].rm_so
|
---|
975 | || pmatch[i].rm_eo > pmatch[parents[j]].rm_eo)
|
---|
976 | pmatch[i].rm_so = pmatch[i].rm_eo = -1;
|
---|
977 | }
|
---|
978 | i++;
|
---|
979 | }
|
---|
980 | }
|
---|
981 |
|
---|
982 | while (i < nmatch)
|
---|
983 | {
|
---|
984 | pmatch[i].rm_so = -1;
|
---|
985 | pmatch[i].rm_eo = -1;
|
---|
986 | i++;
|
---|
987 | }
|
---|
988 | }
|
---|
989 |
|
---|
990 |
|
---|
991 | /*
|
---|
992 | Wrapper functions for POSIX compatible regexp matching.
|
---|
993 | */
|
---|
994 |
|
---|
995 | int
|
---|
996 | regexec(const regex_t *restrict preg, const char *restrict string,
|
---|
997 | size_t nmatch, regmatch_t pmatch[restrict], int eflags)
|
---|
998 | {
|
---|
999 | tre_tnfa_t *tnfa = (void *)preg->TRE_REGEX_T_FIELD;
|
---|
1000 | reg_errcode_t status;
|
---|
1001 | regoff_t *tags = NULL, eo;
|
---|
1002 | if (tnfa->cflags & REG_NOSUB) nmatch = 0;
|
---|
1003 | if (tnfa->num_tags > 0 && nmatch > 0)
|
---|
1004 | {
|
---|
1005 | tags = xmalloc(sizeof(*tags) * tnfa->num_tags);
|
---|
1006 | if (tags == NULL)
|
---|
1007 | return REG_ESPACE;
|
---|
1008 | }
|
---|
1009 |
|
---|
1010 | /* Dispatch to the appropriate matcher. */
|
---|
1011 | if (tnfa->have_backrefs)
|
---|
1012 | {
|
---|
1013 | /* The regex has back references, use the backtracking matcher. */
|
---|
1014 | status = tre_tnfa_run_backtrack(tnfa, string, tags, eflags, &eo);
|
---|
1015 | }
|
---|
1016 | else
|
---|
1017 | {
|
---|
1018 | /* Exact matching, no back references, use the parallel matcher. */
|
---|
1019 | status = tre_tnfa_run_parallel(tnfa, string, tags, eflags, &eo);
|
---|
1020 | }
|
---|
1021 |
|
---|
1022 | if (status == REG_OK)
|
---|
1023 | /* A match was found, so fill the submatch registers. */
|
---|
1024 | tre_fill_pmatch(nmatch, pmatch, tnfa->cflags, tnfa, tags, eo);
|
---|
1025 | if (tags)
|
---|
1026 | xfree(tags);
|
---|
1027 | return status;
|
---|
1028 | }
|
---|