/*
* vim:ts=4:sw=4:expandtab
*
* i3 - an improved dynamic tiling window manager
* © 2009 Michael Stapelberg and contributors (see also: LICENSE)
*
* regex.c: Interface to libPCRE (perl compatible regular expressions).
*
*/
#include "all.h"
/*
* Creates a new 'regex' struct containing the given pattern and a PCRE
* compiled regular expression. Also, calls pcre_study because this regex will
* most likely be used often (like for every new window and on every relevant
* property change of existing windows).
*
* Returns NULL if the pattern could not be compiled into a regular expression
* (and ELOGs an appropriate error message).
*
*/
struct regex *regex_new(const char *pattern) {
int errorcode;
PCRE2_SIZE offset;
struct regex *re = scalloc(1, sizeof(struct regex));
re->pattern = sstrdup(pattern);
uint32_t options = PCRE2_UTF;
/* We use PCRE_UCP so that \B, \b, \D, \d, \S, \s, \W, \w and some POSIX
* character classes play nicely with Unicode */
options |= PCRE2_UCP;
if (!(re->regex = pcre2_compile((PCRE2_SPTR)pattern, PCRE2_ZERO_TERMINATED, options, &errorcode, &offset, NULL))) {
PCRE2_UCHAR buffer[256];
pcre2_get_error_message(errorcode, buffer, sizeof(buffer));
ELOG("PCRE regular expression compilation failed at %lu: %s\n",
offset, buffer);
regex_free(re);
return NULL;
}
return re;
}
/*
* Frees the given regular expression. It must not be used afterwards!
*
*/
void regex_free(struct regex *regex) {
if (!regex)
return;
FREE(regex->pattern);
FREE(regex->regex);
FREE(regex);
}
/*
* Checks if the given regular expression matches the given input and returns
* true if it does. In either case, it logs the outcome using LOG(), so it will
* be visible without debug logging.
*
*/
bool regex_matches(struct regex *regex, const char *input) {
pcre2_match_data *match_data;
int rc;
match_data = pcre2_match_data_create_from_pattern(regex->regex, NULL);
/* We use strlen() because pcre_exec() expects the length of the input
* string in bytes */
rc = pcre2_match(regex->regex, (PCRE2_SPTR)input, strlen(input), 0, 0, match_data, NULL);
pcre2_match_data_free(match_data);
if (rc > 0) {
LOG("Regular expression \"%s\" matches \"%s\"\n",
regex->pattern, input);
return true;
}
if (rc == PCRE2_ERROR_NOMATCH) {
LOG("Regular expression \"%s\" does not match \"%s\"\n",
regex->pattern, input);
return false;
}
ELOG("PCRE error %d while trying to use regular expression \"%s\" on input \"%s\", see pcreapi(3)\n",
rc, regex->pattern, input);
return false;
}