2 * vim:ts=4:sw=4:expandtab
4 * i3 - an improved dynamic tiling window manager
5 * © 2009 Michael Stapelberg and contributors (see also: LICENSE)
7 * regex.c: Interface to libPCRE (perl compatible regular expressions).
13 * Creates a new 'regex' struct containing the given pattern and a PCRE
14 * compiled regular expression. Also, calls pcre_study because this regex will
15 * most likely be used often (like for every new window and on every relevant
16 * property change of existing windows).
18 * Returns NULL if the pattern could not be compiled into a regular expression
19 * (and ELOGs an appropriate error message).
22 struct regex *regex_new(const char *pattern) {
24 int errorcode, offset;
26 struct regex *re = scalloc(1, sizeof(struct regex));
27 re->pattern = sstrdup(pattern);
28 int options = PCRE_UTF8;
29 /* We use PCRE_UCP so that \B, \b, \D, \d, \S, \s, \W, \w and some POSIX
30 * character classes play nicely with Unicode */
32 while (!(re->regex = pcre_compile2(pattern, options, &errorcode, &error, &offset, NULL))) {
33 /* If the error is that PCRE was not compiled with UTF-8 support we
34 * disable it and try again */
35 if (errorcode == 32) {
36 options &= ~PCRE_UTF8;
39 ELOG("PCRE regular expression compilation failed at %d: %s\n",
44 re->extra = pcre_study(re->regex, 0, &error);
45 /* If an error happened, we print the error message, but continue.
46 * Studying the regular expression leads to faster matching, but it’s not
47 * absolutely necessary. */
49 ELOG("PCRE regular expression studying failed: %s\n", error);
55 * Frees the given regular expression. It must not be used afterwards!
58 void regex_free(struct regex *regex) {
68 * Checks if the given regular expression matches the given input and returns
69 * true if it does. In either case, it logs the outcome using LOG(), so it will
70 * be visible without debug logging.
73 bool regex_matches(struct regex *regex, const char *input) {
76 /* We use strlen() because pcre_exec() expects the length of the input
78 if ((rc = pcre_exec(regex->regex, regex->extra, input, strlen(input), 0, 0, NULL, 0)) == 0) {
79 LOG("Regular expression \"%s\" matches \"%s\"\n",
80 regex->pattern, input);
84 if (rc == PCRE_ERROR_NOMATCH) {
85 LOG("Regular expression \"%s\" does not match \"%s\"\n",
86 regex->pattern, input);
90 ELOG("PCRE error %d while trying to use regular expression \"%s\" on input \"%s\", see pcreapi(3)\n",
91 rc, regex->pattern, input);