94 lines
2.9 KiB
C
94 lines
2.9 KiB
C
/*
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* vim:ts=4:sw=4:expandtab
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*
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* i3 - an improved dynamic tiling window manager
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* © 2009 Michael Stapelberg and contributors (see also: LICENSE)
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*
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* regex.c: Interface to libPCRE (perl compatible regular expressions).
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*
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*/
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#include "all.h"
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/*
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* Creates a new 'regex' struct containing the given pattern and a PCRE
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* compiled regular expression. Also, calls pcre_study because this regex will
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* most likely be used often (like for every new window and on every relevant
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* property change of existing windows).
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*
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* Returns NULL if the pattern could not be compiled into a regular expression
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* (and ELOGs an appropriate error message).
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*
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*/
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struct regex *regex_new(const char *pattern) {
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const char *error;
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int errorcode, offset;
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struct regex *re = scalloc(1, sizeof(struct regex));
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re->pattern = sstrdup(pattern);
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int options = PCRE_UTF8;
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/* We use PCRE_UCP so that \B, \b, \D, \d, \S, \s, \W, \w and some POSIX
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* character classes play nicely with Unicode */
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options |= PCRE_UCP;
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while (!(re->regex = pcre_compile2(pattern, options, &errorcode, &error, &offset, NULL))) {
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/* If the error is that PCRE was not compiled with UTF-8 support we
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* disable it and try again */
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if (errorcode == 32) {
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options &= ~PCRE_UTF8;
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continue;
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}
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ELOG("PCRE regular expression compilation failed at %d: %s\n",
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offset, error);
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regex_free(re);
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return NULL;
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}
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re->extra = pcre_study(re->regex, 0, &error);
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/* If an error happened, we print the error message, but continue.
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* Studying the regular expression leads to faster matching, but it’s not
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* absolutely necessary. */
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if (error) {
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ELOG("PCRE regular expression studying failed: %s\n", error);
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}
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return re;
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}
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/*
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* Frees the given regular expression. It must not be used afterwards!
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*
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*/
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void regex_free(struct regex *regex) {
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if (!regex)
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return;
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FREE(regex->pattern);
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FREE(regex->regex);
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FREE(regex->extra);
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FREE(regex);
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}
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/*
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* Checks if the given regular expression matches the given input and returns
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* true if it does. In either case, it logs the outcome using LOG(), so it will
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* be visible without debug logging.
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*
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*/
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bool regex_matches(struct regex *regex, const char *input) {
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int rc;
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/* We use strlen() because pcre_exec() expects the length of the input
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* string in bytes */
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if ((rc = pcre_exec(regex->regex, regex->extra, input, strlen(input), 0, 0, NULL, 0)) == 0) {
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LOG("Regular expression \"%s\" matches \"%s\"\n",
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regex->pattern, input);
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return true;
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}
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if (rc == PCRE_ERROR_NOMATCH) {
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LOG("Regular expression \"%s\" does not match \"%s\"\n",
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regex->pattern, input);
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return false;
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}
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ELOG("PCRE error %d while trying to use regular expression \"%s\" on input \"%s\", see pcreapi(3)\n",
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rc, regex->pattern, input);
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return false;
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}
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