text-regex.c

   1 #include <stdlib.h>
   2 #include <string.h>
   3 #include <regex.h>
   4
   5 #include "text-regex.h"
   6
   7 struct Regex {
   8         regex_t regex;
   9 };
  10
  11 Regex *text_regex_new(void) {
  12         Regex *r = calloc(1, sizeof(Regex));
  13         if (!r)
  14                 return NULL;
  15         regcomp(&r->regex, "\0\0", 0); /* this should not match anything */
  16         return r;
  17 }
  18
  19 int text_regex_compile(Regex *regex, const char *string, int cflags) {
  20         int r = regcomp(&regex->regex, string, cflags);
  21         if (r)
  22                 regcomp(&regex->regex, "\0\0", 0);
  23         return r;
  24 }
  25
  26 void text_regex_free(Regex *r) {
  27         if (!r)
  28                 return;
  29         regfree(&r->regex);
  30         free(r);
  31 }
  32
  33 int text_search_range_forward(Text *txt, size_t pos, size_t len, Regex *r, size_t nmatch, RegexMatch pmatch[], int eflags) {
  34         char *buf = text_bytes_alloc0(txt, pos, len);
  35         if (!buf)
  36                 return REG_NOMATCH;
  37         regmatch_t match[nmatch];
  38         int ret = regexec(&r->regex, buf, nmatch, match, eflags);
  39         if (!ret) {
  40                 for (size_t i = 0; i < nmatch; i++) {
  41                         pmatch[i].start = match[i].rm_so == -1 ? EPOS : pos + match[i].rm_so;
  42                         pmatch[i].end = match[i].rm_eo == -1 ? EPOS : pos + match[i].rm_eo;
  43                 }
  44         }
  45         free(buf);
  46         return ret;
  47 }
  48
  49 int text_search_range_backward(Text *txt, size_t pos, size_t len, Regex *r, size_t nmatch, RegexMatch pmatch[], int eflags) {
  50         char *buf = text_bytes_alloc0(txt, pos, len);
  51         if (!buf)
  52                 return REG_NOMATCH;
  53         regmatch_t match[nmatch];
  54         char *cur = buf;
  55         int ret = REG_NOMATCH;
  56         while (!regexec(&r->regex, cur, nmatch, match, eflags)) {
  57                 ret = 0;
  58                 for (size_t i = 0; i < nmatch; i++) {
  59                         pmatch[i].start = match[i].rm_so == -1 ? EPOS : pos + (size_t)(cur - buf) + match[i].rm_so;
  60                         pmatch[i].end = match[i].rm_eo == -1 ? EPOS : pos + (size_t)(cur - buf) + match[i].rm_eo;
  61                 }
  62                 if (match[0].rm_so == 0 && match[0].rm_eo == 0) {
  63                         /* empty match at the beginning of cur, advance to next line */
  64                         if ((cur = strchr(cur, '\n')))
  65                                 cur++;
  66                         else
  67                                 break;
  68
  69                 } else {
  70                         cur += match[0].rm_eo;
  71                 }
  72         }
  73         free(buf);
  74         return ret;
  75 }