jsonpath.h

#ifndef jjp_jsonpath_h
#define jjp_jsonpath_h

#include <jsmn.h>




#define JJP_DEFAULT_ALLOCATED_RESULT_TOKENS 16
#define JJP_MAX_JSONPATH_LENGTH 10000

#ifndef JJP_NO_MALLOC
/**
 * jsmn-jsonpath result type.
 */
typedef struct {
	unsigned int count; /**< The count of found elements in the json that match the jsonpath. */
	unsigned int * tokens; /**< A pointer to an int[] with count elements or NULL if count == 0. */
} jjp_result_t;

/**
 * \Returns a pointer to a jjp_result_t that was allocated on the stack using malloc or NULL on error.
 * You must free the memory used by the returned object after using it, by calling jjp_result_destroy().
 */
jjp_result_t * jjp_jsonpath(
		const char * json, /**< The js parameter from jsmn_parse() */
		jsmntok_t * tokens, /**< The tokens parameter from jsmn_parse() */
		unsigned int tokens_count, /**< The return value from jsmn_parse() */
		const char * jsonpath, /**< The JSONPath you want to find matches for */
		unsigned int current_object /**< The index of the current element inside the tokens array */
		);

/**
 * Frees the memory used by result
 */
void jjp_result_destroy( jjp_result_t * result );
#endif

/**
 * \Returns the index of the first token that matches the jsonpath or -1 if no matches were found or -2 on error.
 */
int jjp_jsonpath_first(
		const char * json, /**< see jjp_jsonpath() */
		jsmntok_t * tokens, /**< see jjp_jsonpath() */
		unsigned int tokens_count, /**< see jjp_jsonpath() */
		const char * jsonpath, /**< see jjp_jsonpath() */
		unsigned int current_object /**< see jjp_jsonpath() */
		);

/**
 * An alternative to jjp_jsonpath() ( same functionality ) that doesn't perform memory allocations.
 * That means that you have to provide the array where the results get stored.
 */
void jjp_jsonpath_save(
		const char * json, /**< see jjp_jsonpath() */
		jsmntok_t * tokens, /**< see jjp_jsonpath() */
		unsigned int tokens_count, /**< see jjp_jsonpath() */
		const char * jsonpath, /**< see jjp_jsonpath() */
		unsigned int current_object, /**< see jjp_jsonpath() */
		int * results, /**< A pointer to an int[] that is at least num_results big */
		unsigned int num_results, /**< The max returned results */
		int * results_count /**< A pointer to an int where the count of found matches will be saved
				      or -2 on error ( wrong json, wrong jsonpath, ... )
				      or -3 if the results array was to small for all the results
				      ( the results still get saved and you can loop trough them
				      using num_results instead of results_count ) */
		);




/**
 * error handling, logging and debugging utilities not useful for the end developer
 */

#ifndef check
#ifdef JJP_LOG

#include <stdio.h>
#include <errno.h>
#include <string.h>

#define clean_errno() (errno==0 ? "None" : strerror(errno))

#define log_err_empty() fprintf(stderr, "[ERROR] (%s:%d: errno: %s)\n", __FILE__, __LINE__, clean_errno())

#define check(A, B) if(!(A)) { log_err_empty(); errno=0; goto B; }

#else

#define check(A, B) if(!(A)) { goto B; }

#endif
#endif




#endif