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00001 /* 00002 * vim:ts=4:sw=4:expandtab 00003 * 00004 * i3 - an improved dynamic tiling window manager 00005 * © 2009-2011 Michael Stapelberg and contributors (see also: LICENSE) 00006 * 00007 * regex.c: Interface to libPCRE (perl compatible regular expressions). 00008 * 00009 */ 00010 #include "all.h" 00011 00012 /* 00013 * Creates a new 'regex' struct containing the given pattern and a PCRE 00014 * compiled regular expression. Also, calls pcre_study because this regex will 00015 * most likely be used often (like for every new window and on every relevant 00016 * property change of existing windows). 00017 * 00018 * Returns NULL if the pattern could not be compiled into a regular expression 00019 * (and ELOGs an appropriate error message). 00020 * 00021 */ 00022 struct regex *regex_new(const char *pattern) { 00023 const char *error; 00024 int errorcode, offset; 00025 00026 struct regex *re = scalloc(sizeof(struct regex)); 00027 re->pattern = sstrdup(pattern); 00028 int options = PCRE_UTF8; 00029 #ifdef PCRE_HAS_UCP 00030 /* We use PCRE_UCP so that \B, \b, \D, \d, \S, \s, \W, \w and some POSIX 00031 * character classes play nicely with Unicode */ 00032 options |= PCRE_UCP; 00033 #endif 00034 while (!(re->regex = pcre_compile2(pattern, options, &errorcode, &error, &offset, NULL))) { 00035 /* If the error is that PCRE was not compiled with UTF-8 support we 00036 * disable it and try again */ 00037 if (errorcode == 32) { 00038 options &= ~PCRE_UTF8; 00039 continue; 00040 } 00041 ELOG("PCRE regular expression compilation failed at %d: %s\n", 00042 offset, error); 00043 return NULL; 00044 } 00045 re->extra = pcre_study(re->regex, 0, &error); 00046 /* If an error happened, we print the error message, but continue. 00047 * Studying the regular expression leads to faster matching, but it’s not 00048 * absolutely necessary. */ 00049 if (error) { 00050 ELOG("PCRE regular expression studying failed: %s\n", error); 00051 } 00052 return re; 00053 } 00054 00055 /* 00056 * Frees the given regular expression. It must not be used afterwards! 00057 * 00058 */ 00059 void regex_free(struct regex *regex) { 00060 if (!regex) 00061 return; 00062 FREE(regex->pattern); 00063 FREE(regex->regex); 00064 FREE(regex->extra); 00065 } 00066 00067 /* 00068 * Checks if the given regular expression matches the given input and returns 00069 * true if it does. In either case, it logs the outcome using LOG(), so it will 00070 * be visible without any debug loglevel. 00071 * 00072 */ 00073 bool regex_matches(struct regex *regex, const char *input) { 00074 int rc; 00075 00076 /* We use strlen() because pcre_exec() expects the length of the input 00077 * string in bytes */ 00078 if ((rc = pcre_exec(regex->regex, regex->extra, input, strlen(input), 0, 0, NULL, 0)) == 0) { 00079 LOG("Regular expression \"%s\" matches \"%s\"\n", 00080 regex->pattern, input); 00081 return true; 00082 } 00083 00084 if (rc == PCRE_ERROR_NOMATCH) { 00085 LOG("Regular expression \"%s\" does not match \"%s\"\n", 00086 regex->pattern, input); 00087 return false; 00088 } 00089 00090 ELOG("PCRE error %d while trying to use regular expression \"%s\" on input \"%s\", see pcreapi(3)\n", 00091 rc, regex->pattern, input); 00092 return false; 00093 }