src/regex_parser.c

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. 
 * Copyright 2018 Mike Becker. All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 * 1. Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * 
 * 2. Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "regex_parser.h"

regex_parser_t* new_regex_parser_t() {
  regex_parser_t* ret = malloc(sizeof(regex_parser_t));
  if (ret != NULL) {
    ret->pattern_list = new_string_list_t();
    ret->matched_lines = 0;
    ret->pattern_match = 0;
    ret->compiled_patterns = NULL;
    ret->compiled_pattern_count = 0;
  }
  return ret;
}

void regex_parser_reset(regex_parser_t* parser) {
  parser->pattern_match = parser->matched_lines = 0;
}

void regex_destcomppats(regex_parser_t* parser) {
  if (parser->compiled_patterns != NULL) {
    for (int i = 0 ; i < parser->compiled_pattern_count ; i++) {
      if (parser->compiled_patterns[i] != NULL) {
        free(parser->compiled_patterns[i]);
      }
    }
    free(parser->compiled_patterns);
    parser->compiled_patterns = NULL;
    parser->compiled_pattern_count = 0;
  }
}

void destroy_regex_parser_t(regex_parser_t* parser) {
  regex_destcomppats(parser);
  destroy_string_list_t(parser->pattern_list);
  free(parser);
}

bool regex_parser_matching(regex_parser_t* parser) {
  return parser->pattern_match > 0;
}

int regex_parser_do(regex_parser_t* parser, char* input) {
  int err = REG_NOMATCH;
  if (parser->compiled_pattern_count > 0) {
    regmatch_t match;

    if (regex_parser_matching(parser)) {
      parser->matched_lines++;

      err = regexec(parser->compiled_patterns[parser->pattern_match],
          input, 1, &match, 0);
      if (err > 0 && err != REG_NOMATCH) {
        fprintf(stderr, "Regex-Error: 0x%08x", err);
      }
      if (err == 0) {
        parser->pattern_match = 0;
        /* do not match line, if it does not end with the pattern */
        if (match.rm_eo < strlen(input)) {
          parser->matched_lines--;
        }
      }
    } else {
      for (int i = 0 ; i < parser->compiled_pattern_count - 1 ; i += 2) {
        err = regexec(parser->compiled_patterns[i], input, 1, &match, 0);
        if (err > 0 && err != REG_NOMATCH) {
          fprintf(stderr, "Regex-Error: 0x%08x", err);
        }
        if (err == 0) {
          parser->pattern_match = i+1;
          parser->matched_lines = 0;
          /* Check, if end pattern is also in this line */
          regex_parser_do(parser, input);
          /* do not match line, if it does not start with the pattern */
          if (match.rm_so > 0 && parser->matched_lines > 0) {
            parser->matched_lines--;
          }
          break;
        }
      }
    }
  }
  return err;
}

bool regex_compile_all(regex_parser_t* parser) {
  bool success = true;
  size_t pcount = parser->pattern_list->count;
  if (pcount > 0) {
    regex_destcomppats(parser);
    parser->compiled_patterns = calloc(pcount, sizeof(regex_t));
    parser->compiled_pattern_count = pcount;

    regex_t* re;
    for (int i = 0 ; i < pcount ; i++) {
      re = malloc(sizeof(regex_t));
      if (regcomp(re, parser->pattern_list->items[i], REG_EXTENDED) == 0) {
        parser->compiled_patterns[i] = re;
      } else {
        fprintf(stderr, "Cannot compile pattern: %s\n",
            (parser->pattern_list->items[i]));
        parser->compiled_patterns[i] = NULL;
        success = false;
      }
    }
  }
  return success;
}