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Member "tin-2.4.2/src/regex.c" (8 Dec 2017, 5485 Bytes) of package /linux/misc/tin-2.4.2.tar.xz:

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    1 /*
    2  *  Project   : tin - a Usenet reader
    3  *  Module    : regex.c
    4  *  Author    : Jason Faultless <jason@altarstone.com>
    5  *  Created   : 1997-02-21
    6  *  Updated   : 2017-02-17
    7  *  Notes     : Regular expression subroutines
    8  *  Credits   :
    9  *
   10  * Copyright (c) 1997-2018 Jason Faultless <jason@altarstone.com>
   11  * All rights reserved.
   12  *
   13  * Redistribution and use in source and binary forms, with or without
   14  * modification, are permitted provided that the following conditions
   15  * are met:
   16  * 1. Redistributions of source code must retain the above copyright
   17  *    notice, this list of conditions and the following disclaimer.
   18  * 2. Redistributions in binary form must reproduce the above copyright
   19  *    notice, this list of conditions and the following disclaimer in the
   20  *    documentation and/or other materials provided with the distribution.
   21  * 3. The name of the author may not be used to endorse or promote
   22  *    products derived from this software without specific prior written
   23  *    permission.
   24  *
   25  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
   26  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
   27  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
   29  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
   31  * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   32  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
   33  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
   34  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   35  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   36  */
   37 
   38 
   39 #ifndef TIN_H
   40 #   include "tin.h"
   41 #endif /* !TIN_H */
   42 #ifndef TCURSES_H
   43 #   include "tcurses.h"
   44 #endif /* !TCURSES_H */
   45 
   46 /*
   47  * See if pattern is matched in string. Return TRUE or FALSE
   48  * if icase=TRUE then ignore case in the compare
   49  * if a precompiled regex is provided it will be used instead of pattern
   50  *
   51  * If you use match_regex() with full regexes within a loop you should always
   52  * provide a precompiled error because if the compilation of the regex fails
   53  * an error message will be display on each execution of match_regex()
   54  */
   55 t_bool
   56 match_regex(
   57     const char *string,
   58     char *pattern,
   59     struct regex_cache *cache,
   60     t_bool icase)
   61 {
   62     int error;
   63     struct regex_cache tmp_cache = { NULL, NULL };
   64     struct regex_cache *ptr_cache;
   65 
   66     if (!tinrc.wildcard)    /* wildmat matching */
   67         return wildmat(string, pattern, icase);
   68 
   69     /* full regexes */
   70     if (cache != NULL && cache->re != NULL)
   71         ptr_cache = cache;  /* use the provided regex cache */
   72     else {
   73         /* compile the regex internally */
   74         if (!compile_regex(pattern, &tmp_cache, (icase ? PCRE_CASELESS : 0)))
   75             return FALSE;
   76         ptr_cache = &tmp_cache;
   77     }
   78 
   79     if ((error = pcre_exec(ptr_cache->re, ptr_cache->extra, string, strlen(string), 0, 0, NULL, 0)) >= 0) {
   80         if (ptr_cache == &tmp_cache) {
   81             FreeIfNeeded(tmp_cache.re);
   82             FreeIfNeeded(tmp_cache.extra);
   83         }
   84 
   85         return TRUE;
   86     }
   87 
   88 #if 0
   89     /*
   90      * match_regex() is mostly used within loops and we don't want to display
   91      * an error message on each call
   92      */
   93     if (error != PCRE_ERROR_NOMATCH)
   94         error_message(2, _(txt_pcre_error_num), error);
   95 #endif /* 0 */
   96 
   97     FreeIfNeeded(tmp_cache.re);
   98     FreeIfNeeded(tmp_cache.extra);
   99 
  100     return FALSE;
  101 }
  102 
  103 
  104 /*
  105  * Compile and optimise 'regex'. Return TRUE if all went well
  106  */
  107 t_bool
  108 compile_regex(
  109     const char *regex,
  110     struct regex_cache *cache,
  111     int options)
  112 {
  113     const char *regex_errmsg = NULL;
  114     int regex_errpos, my_options = options;
  115 
  116 #if defined(MULTIBYTE_ABLE) && !defined(NO_LOCALE) && (defined(PCRE_MAJOR) && PCRE_MAJOR >= 4)
  117     if (IS_LOCAL_CHARSET("UTF-8")) {
  118         int i;
  119 
  120         pcre_config(PCRE_CONFIG_UTF8, &i);
  121         if (i)
  122             my_options |= PCRE_UTF8;
  123     }
  124 #endif /* MULTIBYTE_ABLE && !NO_LOCALE && PCRE_MAJOR && PCRE_MAJOR >= 4 */
  125 
  126     if ((cache->re = pcre_compile(regex, my_options, &regex_errmsg, &regex_errpos, NULL)) == NULL)
  127         error_message(2, _(txt_pcre_error_at), regex_errmsg, regex_errpos, regex);
  128     else {
  129         cache->extra = pcre_study(cache->re, 0, &regex_errmsg);
  130         if (regex_errmsg != NULL) {
  131             /* we failed, clean up */
  132             FreeAndNull(cache->re);
  133             error_message(2, _(txt_pcre_error_text), regex_errmsg);
  134         } else
  135             return TRUE;
  136     }
  137     return FALSE;
  138 }
  139 
  140 
  141 /*
  142  * Highlight any string on 'row' that match 'regex'
  143  */
  144 void
  145 highlight_regexes(
  146     int row,
  147     struct regex_cache *regex,
  148     int color)
  149 {
  150     char *ptr;
  151     int offsets[6]; /* we are not interrested in any supatterns, so 6 is sufficient */
  152     int offsets_size = ARRAY_SIZE(offsets);
  153 #ifdef USE_CURSES
  154     char buf[LEN];
  155 #else
  156     char *buf;
  157 #endif /* USE_CURSES */
  158 
  159     /* Get contents of line from the screen */
  160 #ifdef USE_CURSES
  161     screen_contents(row, 0, buf);
  162 #else
  163     buf = screen[row].col;
  164 #endif /* USE_CURSES */
  165     ptr = buf;
  166 
  167     /* also check for 0 as offsets[] might be too small to hold all captured subpatterns */
  168     while (pcre_exec(regex->re, regex->extra, ptr, strlen(ptr), 0, 0, offsets, offsets_size) >= 0) {
  169         /* we have a match */
  170         if (color >= 0) /* color the matching text */
  171             word_highlight_string(row, (ptr - buf) + offsets[0], offsets[1] - offsets[0], color);
  172         else
  173             /* inverse the matching text */
  174             highlight_string(row, (ptr - buf) + offsets[0], offsets[1] - offsets[0]);
  175 
  176         if (!tinrc.word_h_display_marks) {
  177 #ifdef USE_CURSES
  178             screen_contents(row, 0, buf);
  179 #endif /* USE_CURSES */
  180             ptr += offsets[1] - 2;
  181         } else
  182             ptr += offsets[1];
  183     }
  184 }