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#ifndef SRC_REGEX_H_
#define SRC_REGEX_H_
#include <stdio.h>
#ifdef USE_PCRE2
#include <pcre2.h>
#else
#include <pcre.h>
#endif
enum {
REGEX_MATCH,
REGEX_MATCH_PARTIAL,
REGEX_NO_MATCH,
REGEX_ERROR = -1,
};
#ifdef USE_PCRE2
struct regex_data {
pcre2_code * regex; /* compiled regular expression */
pcre2_match_data * match_data; /* match data block required for the compiled
pattern in regex2 */
};
struct regex_error_data {
int error_code;
PCRE2_SIZE error_offset;
};
/* ^^^^^^ USE_PCRE2 ^^^^^^ */
#else
/* vvvvvv USE_PCRE vvvvvv */
/* Prior to version 8.20, libpcre did not have pcre_free_study() */
#if (PCRE_MAJOR < 8 || (PCRE_MAJOR == 8 && PCRE_MINOR < 20))
#define pcre_free_study pcre_free
#endif
struct regex_data {
pcre *regex; /* compiled regular expression */
int extra_owned;
union {
pcre_extra *sd; /* pointer to extra compiled stuff */
pcre_extra lsd; /* used to hold the mmap'd version */
};
};
struct regex_error_data {
char const * error_buffer;
int error_offset;
};
#endif /* USE_PCRE2 */
struct mmap_area;
/**
* regex_verison returns the version string of the underlying regular
* regular expressions library. In the case of PCRE it just returns the
* result of pcre_version(). In the case of PCRE2, the very first time this
* function is called it allocates a buffer large enough to hold the version
* string and reads the PCRE2_CONFIG_VERSION option to fill the buffer.
* The allocated buffer will linger in memory until the calling process is being
* reaped.
*
* It may return NULL on error.
*/
char const * regex_version();
/**
* This constructor function allocates a buffer for a regex_data structure.
* The buffer is being initialized with zeroes.
*/
struct regex_data * regex_data_create();
/**
* This complementary destructor function frees the a given regex_data buffer.
* It also frees any non NULL member pointers with the appropriate pcreX_X_free
* function. For PCRE this function respects the extra_owned field and frees
* the pcre_extra data conditionally. Calling this function on a NULL pointer is
* save.
*/
void regex_data_free(struct regex_data * regex);
/**
* This function compiles the regular expression. Additionally, it prepares
* data structures required by the different underlying engines. For PCRE
* it calls pcre_study to generate optional data required for optimized
* execution of the compiled pattern. In the case of PCRE2, it allocates
* a pcre2_match_data structure of appropriate size to hold all possible
* matches created by the pattern.
*
* @arg regex If successful, the structure returned through *regex was allocated
* with regex_data_create and must be freed with regex_data_free.
* @arg pattern_string The pattern string that is to be compiled.
* @arg errordata A pointer to a regex_error_data structure must be passed
* to this function. This structure depends on the underlying
* implementation. It can be passed to regex_format_error
* to generate a human readable error message.
* @retval 0 on success
* @retval -1 on error
*/
int regex_prepare_data(struct regex_data ** regex, char const * pattern_string,
struct regex_error_data * errordata);
/**
* This function loads a serialized precompiled pattern from a contiguous
* data region given by map_area.
*
* @arg map_area Description of the memory region holding a serialized
* representation of the precompiled pattern.
* @arg regex If successful, the structure returned through *regex was allocated
* with regex_data_create and must be freed with regex_data_free.
*
* @retval 0 on success
* @retval -1 on error
*/
int regex_load_mmap(struct mmap_area * map_area, struct regex_data ** regex);
/**
* This function stores a precompiled regular expression to a file.
* In the case of PCRE, it just dumps the binary representation of the
* precomplied pattern into a file. In the case of PCRE2, it uses the
* serialization function provided by the library.
*
* @arg regex The precomplied regular expression data.
* @arg fp A file stream specifying the output file.
*/
int regex_writef(struct regex_data * regex, FILE * fp);
/**
* This function applies a precompiled pattern to a subject string and
* returns whether or not a match was found.
*
* @arg regex The precompiled pattern.
* @arg subject The subject string.
* @arg partial Boolean indicating if partial matches are wanted. A nonzero
* value is equivalent to specifying PCRE[2]_PARTIAL_SOFT as
* option to pcre_exec of pcre2_match.
* @retval REGEX_MATCH if a match was found
* @retval REGEX_MATCH_PARTIAL if a partial match was found
* @retval REGEX_NO_MATCH if no match was found
* @retval REGEX_ERROR if an error was encountered during the execution of the
* regular expression
*/
int regex_match(struct regex_data * regex, char const * subject, int partial);
/**
* This function compares two compiled regular expressions (regex1 and regex2).
* It compares the binary representations of the compiled patterns. It is a very
* crude approximation because the binary representation holds data like
* reference counters, that has nothing to do with the actual state machine.
*
* @retval SELABEL_EQUAL if the pattern's binary representations are exactly
* the same
* @retval SELABEL_INCOMPARABLE otherwise
*/
int regex_cmp(struct regex_data * regex1, struct regex_data * regex2);
/**
* This function takes the error data returned by regex_prepare_data and turns
* it in to a human readable error message.
* If the buffer given to hold the error message is to small it truncates the
* message and indicates the truncation with an ellipsis ("...") at the end of
* the buffer.
*
* @arg error_data Error data as returned by regex_prepare_data.
* @arg buffer String buffer to hold the formated error string.
* @arg buf_size Total size of the given bufer in bytes.
*/
void regex_format_error(struct regex_error_data const * error_data,
char * buffer, size_t buf_size);
#endif /* SRC_REGEX_H_ */
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