/*********************************************************************************
* *
* Function: regexp_sub *
* *
* Purpose: Test if a string matches the specified regular expression. If yes *
* then create a return value by substituting '\<n>' sequences in *
* output template with the captured groups. *
* *
* Parameters: string - [IN] the string to parse *
* pattern - [IN] the regular expression *
* output_template - [IN] the output string template. The output *
* string is constructed from template by *
* replacing \<n> sequences with the captured *
* regexp group. *
* If output template is NULL or contains *
* empty string then the whole input string *
* is used as output value. *
* flags - [IN] the regcomp() function flags. *
* See regcomp() manual. *
* *
* Return value: Allocated string containing output value if the input *
* string matches the specified regular expression or NULL *
* otherwise. *
* *
*********************************************************************************/
static char *regexp_sub(const char *string, const char *pattern, const char *output_template, int flags)
{
ZBX_THREAD_LOCAL static char *old_pattern = NULL;
ZBX_THREAD_LOCAL static int old_flags;
ZBX_THREAD_LOCAL static regex_t re;
regmatch_t match[10]; /* up to 10 capture groups in regexp */
char *ptr = NULL;
if (NULL == string)
return NULL;
if (NULL == output_template || '\0' == *output_template)
flags |= REG_NOSUB;
/* performance optimization: if possible then reuse the last compiled regexp */
if (NULL == old_pattern)
goto compile;
if (0 != strcmp(old_pattern, pattern) || old_flags != flags)
regfree(&re);
else
goto execute;
compile:
if (0 == regcomp(&re, pattern, flags))
{
old_pattern = zbx_strdup(old_pattern, pattern);
old_flags = flags;
}
else
{
#ifdef _WINDOWS
/* the Windows gnuregex implementation does not correctly clean up */
/* allocated memory after regcomp() failure */
regfree(&re);
#endif
zbx_free(old_pattern);
return NULL;
}
execute:
if (0 == regexec(&re, string, ARRSIZE(match), match, 0))
ptr = regexp_sub_replace(string, output_template, match, ARRSIZE(match));
return ptr;
}
/*********************************************************************************
* *
* Function: regexp_sub *
* *
* Purpose: Test if a string matches the specified regular expression. If yes *
* then create a return value by substituting '\<n>' sequences in *
* output template with the captured groups. *
* *
* Parameters: string - [IN] the string to parse *
* pattern - [IN] the regular expression *
* output_template - [IN] the output string template. The output *
* string is constructed from template by *
* replacing \<n> sequences with the captured *
* regexp group. *
* If output template is NULL or contains *
* empty string then the whole input string *
* is used as output value. *
* flags - [IN] the regcomp() function flags. *
* See regcomp() manual. *
* *
* Return value: Allocated string containing output value if the input *
* string matches the specified regular expression or NULL *
* otherwise. *
* *
*********************************************************************************/
static char *regexp_sub(const char *string, const char *pattern, const char *output_template, int flags)
{
regex_t re;
regmatch_t match[10];
char *ptr = NULL;
if (NULL == string)
return NULL;
if (NULL == output_template || '\0' == *output_template)
flags |= REG_NOSUB;
if (0 != regcomp(&re, pattern, flags))
return NULL;
if (0 == regexec(&re, string, ARRSIZE(match), match, 0))
ptr = regexp_sub_replace(string, output_template, match, ARRSIZE(match));
regfree(&re);
return ptr;
}
