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13728
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1 /* Construct a regular expression from a literal string. |
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2 Copyright (C) 1995, 2010 Free Software Foundation, Inc. |
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3 Written by Bruno Haible <haible@clisp.cons.org>, 2010. |
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4 |
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5 This program is free software: you can redistribute it and/or modify |
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6 it under the terms of the GNU General Public License as published by |
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7 the Free Software Foundation; either version 3 of the License, or |
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8 (at your option) any later version. |
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9 |
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10 This program is distributed in the hope that it will be useful, |
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11 but WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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13 GNU General Public License for more details. |
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14 |
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15 You should have received a copy of the GNU General Public License |
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16 along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
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17 |
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18 #include <config.h> |
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19 |
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20 /* Specification. */ |
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21 #include "regex-quote.h" |
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22 |
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23 #include <string.h> |
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24 |
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25 #include "mbuiter.h" |
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26 #include "xalloc.h" |
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27 |
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28 /* Characters that are special in a BRE. */ |
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29 static const char bre_special[] = "$^.*[]\\"; |
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30 |
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31 /* Characters that are special in an ERE. */ |
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32 static const char ere_special[] = "$^.*[]\\+?()"; |
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33 |
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34 size_t |
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35 regex_quote_length (const char *string, int cflags) |
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36 { |
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37 const char *special = (cflags != 0 ? ere_special : bre_special); |
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38 size_t length; |
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39 mbui_iterator_t iter; |
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40 |
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41 length = 0; |
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42 for (mbui_init (iter, string); mbui_avail (iter); mbui_advance (iter)) |
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43 { |
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44 /* We know that special contains only ASCII characters. */ |
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45 if (mb_len (mbui_cur (iter)) == 1 |
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46 && strchr (special, * mbui_cur_ptr (iter))) |
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47 length += 1; |
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48 length += mb_len (mbui_cur (iter)); |
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49 } |
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50 return length; |
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51 } |
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52 |
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53 /* Copies the quoted string to p and returns the incremented p. |
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54 There must be room for regex_quote_length (string, cflags) + 1 bytes at p. |
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55 */ |
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56 char * |
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57 regex_quote_copy (char *p, const char *string, int cflags) |
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58 { |
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59 const char *special = (cflags != 0 ? ere_special : bre_special); |
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60 mbui_iterator_t iter; |
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61 |
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62 for (mbui_init (iter, string); mbui_avail (iter); mbui_advance (iter)) |
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63 { |
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64 /* We know that special contains only ASCII characters. */ |
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65 if (mb_len (mbui_cur (iter)) == 1 |
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66 && strchr (special, * mbui_cur_ptr (iter))) |
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67 *p++ = '\\'; |
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68 memcpy (p, mbui_cur_ptr (iter), mb_len (mbui_cur (iter))); |
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69 p += mb_len (mbui_cur (iter)); |
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70 } |
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71 return p; |
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72 } |
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73 |
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74 /* Returns the freshly allocated quoted string. */ |
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75 char * |
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76 regex_quote (const char *string, int cflags) |
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77 { |
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78 size_t length = regex_quote_length (string, cflags); |
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79 char *result = XNMALLOC (length + 1, char); |
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80 char *p; |
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81 |
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82 p = result; |
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83 p = regex_quote_copy (p, string, cflags); |
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84 *p = '\0'; |
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85 return result; |
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86 } |
