/* * $Id: json_object.h,v 1.12 2006/01/30 23:07:57 mclark Exp $ * * Copyright (c) 2004, 2005 Metaparadigm Pte. Ltd. * Michael Clark <michael@metaparadigm.com> * Copyright (c) 2009 Hewlett-Packard Development Company, L.P. * * This library is free software; you can redistribute it and/or modify * it under the terms of the MIT license. See COPYING for details. * */ #ifndef _json_object_h_ #define _json_object_h_ #ifdef __GNUC__ #define THIS_FUNCTION_IS_DEPRECATED(func) func __attribute__ ((deprecated)) #elif defined(_MSC_VER) #define THIS_FUNCTION_IS_DEPRECATED(func) __declspec(deprecated) func #else #define THIS_FUNCTION_IS_DEPRECATED(func) func #endif #include "json_inttypes.h" #ifdef __cplusplus extern "C" { #endif #define JSON_OBJECT_DEF_HASH_ENTRIES 16 /** * A flag for the json_object_to_json_string_ext() and * json_object_to_file_ext() functions which causes the output * to have no extra whitespace or formatting applied. */ #define JSON_C_TO_STRING_PLAIN 0 /** * A flag for the json_object_to_json_string_ext() and * json_object_to_file_ext() functions which causes the output to have * minimal whitespace inserted to make things slightly more readable. */ #define JSON_C_TO_STRING_SPACED (1<<0) /** * A flag for the json_object_to_json_string_ext() and * json_object_to_file_ext() functions which causes * the output to be formatted. * * See the "Two Space Tab" option at http://jsonformatter.curiousconcept.com/ * for an example of the format. */ #define JSON_C_TO_STRING_PRETTY (1<<1) /** * A flag to drop trailing zero for float values */ #define JSON_C_TO_STRING_NOZERO (1<<2) #undef FALSE #define FALSE ((json_bool)0) #undef TRUE #define TRUE ((json_bool)1) extern const char *json_number_chars; extern const char *json_hex_chars; /* CAW: added for ANSI C iteration correctness */ struct json_object_iter { char *key; struct json_object *val; struct lh_entry *entry; }; /* forward structure definitions */ typedef int json_bool; typedef struct printbuf printbuf; typedef struct lh_table lh_table; typedef struct array_list array_list; typedef struct json_object json_object; typedef struct json_object_iter json_object_iter; typedef struct json_tokener json_tokener; /** * Type of custom user delete functions. See json_object_set_serializer. */ typedef void (json_object_delete_fn)(struct json_object *jso, void *userdata); /** * Type of a custom serialization function. See json_object_set_serializer. */ typedef int (json_object_to_json_string_fn)(struct json_object *jso, struct printbuf *pb, int level, int flags); /* supported object types */ typedef enum json_type { /* If you change this, be sure to update json_type_to_name() too */ json_type_null, json_type_boolean, json_type_double, json_type_int, json_type_object, json_type_array, json_type_string } json_type; /* reference counting functions */ /** * Increment the reference count of json_object, thereby grabbing shared * ownership of obj. * * @param obj the json_object instance */ extern struct json_object* json_object_get(struct json_object *obj); /** * Decrement the reference count of json_object and free if it reaches zero. * You must have ownership of obj prior to doing this or you will cause an * imbalance in the reference count. * * @param obj the json_object instance * @returns 1 if the object was freed. */ int json_object_put(struct json_object *obj); /** * Check if the json_object is of a given type * @param obj the json_object instance * @param type one of: json_type_null (i.e. obj == NULL), json_type_boolean, json_type_double, json_type_int, json_type_object, json_type_array, json_type_string */ extern int json_object_is_type(struct json_object *obj, enum json_type type); /** * Get the type of the json_object. See also json_type_to_name() to turn this * into a string suitable, for instance, for logging. * * @param obj the json_object instance * @returns type being one of: json_type_null (i.e. obj == NULL), json_type_boolean, json_type_double, json_type_int, json_type_object, json_type_array, json_type_string */ extern enum json_type json_object_get_type(struct json_object *obj); /** Stringify object to json format. * Equivalent to json_object_to_json_string_ext(obj, JSON_C_TO_STRING_SPACED) * The pointer you get is an internal of your json object. You don't * have to free it, later use of json_object_put() should be sufficient. * If you can not ensure there's no concurrent access to *obj use * strdup(). * @param obj the json_object instance * @returns a string in JSON format */ extern const char* json_object_to_json_string(struct json_object *obj); /** Stringify object to json format * @see json_object_to_json_string() for details on how to free string. * @param obj the json_object instance * @param flags formatting options, see JSON_C_TO_STRING_PRETTY and other constants * @returns a string in JSON format */ extern const char* json_object_to_json_string_ext(struct json_object *obj, int flags); /** * Set a custom serialization function to be used when this particular object * is converted to a string by json_object_to_json_string. * * If a custom serializer is already set on this object, any existing * user_delete function is called before the new one is set. * * If to_string_func is NULL, the other parameters are ignored * and the default behaviour is reset. * * The userdata parameter is optional and may be passed as NULL. If provided, * it is passed to to_string_func as-is. This parameter may be NULL even * if user_delete is non-NULL. * * The user_delete parameter is optional and may be passed as NULL, even if * the userdata parameter is non-NULL. It will be called just before the * json_object is deleted, after it's reference count goes to zero * (see json_object_put()). * If this is not provided, it is up to the caller to free the userdata at * an appropriate time. (i.e. after the json_object is deleted) * * @param jso the object to customize * @param to_string_func the custom serialization function * @param userdata an optional opaque cookie * @param user_delete an optional function from freeing userdata */ extern void json_object_set_serializer(json_object *jso, json_object_to_json_string_fn to_string_func, void *userdata, json_object_delete_fn *user_delete); /** * Simply call free on the userdata pointer. * Can be used with json_object_set_serializer(). * * @param jso unused * @param userdata the pointer that is passed to free(). */ json_object_delete_fn json_object_free_userdata; /** * Copy the jso->_userdata string over to pb as-is. * Can be used with json_object_set_serializer(). * * @param jso The object whose _userdata is used. * @param pb The destination buffer. * @param level Ignored. * @param flags Ignored. */ json_object_to_json_string_fn json_object_userdata_to_json_string; /* object type methods */ /** Create a new empty object with a reference count of 1. The caller of * this object initially has sole ownership. Remember, when using * json_object_object_add or json_object_array_put_idx, ownership will * transfer to the object/array. Call json_object_get if you want to maintain * shared ownership or also add this object as a child of multiple objects or * arrays. Any ownerships you acquired but did not transfer must be released * through json_object_put. * * @returns a json_object of type json_type_object */ extern struct json_object* json_object_new_object(void); /** Get the hashtable of a json_object of type json_type_object * @param obj the json_object instance * @returns a linkhash */ extern struct lh_table* json_object_get_object(struct json_object *obj); /** Get the size of an object in terms of the number of fields it has. * @param obj the json_object whose length to return */ extern int json_object_object_length(struct json_object* obj); /** Add an object field to a json_object of type json_type_object * * The reference count will *not* be incremented. This is to make adding * fields to objects in code more compact. If you want to retain a reference * to an added object, independent of the lifetime of obj, you must wrap the * passed object with json_object_get. * * Upon calling this, the ownership of val transfers to obj. Thus you must * make sure that you do in fact have ownership over this object. For instance, * json_object_new_object will give you ownership until you transfer it, * whereas json_object_object_get does not. * * @param obj the json_object instance * @param key the object field name (a private copy will be duplicated) * @param val a json_object or NULL member to associate with the given field */ extern void json_object_object_add(struct json_object* obj, const char *key, struct json_object *val); /** Get the json_object associate with a given object field * * *No* reference counts will be changed. There is no need to manually adjust * reference counts through the json_object_put/json_object_get methods unless * you need to have the child (value) reference maintain a different lifetime * than the owning parent (obj). Ownership of the returned value is retained * by obj (do not do json_object_put unless you have done a json_object_get). * If you delete the value from obj (json_object_object_del) and wish to access * the returned reference afterwards, make sure you have first gotten shared * ownership through json_object_get (& don't forget to do a json_object_put * or transfer ownership to prevent a memory leak). * * @param obj the json_object instance * @param key the object field name * @returns the json_object associated with the given field name * @deprecated Please use json_object_object_get_ex */ THIS_FUNCTION_IS_DEPRECATED(extern struct json_object* json_object_object_get(struct json_object* obj, const char *key)); /** Get the json_object associated with a given object field. * * This returns true if the key is found, false in all other cases (including * if obj isn't a json_type_object). * * *No* reference counts will be changed. There is no need to manually adjust * reference counts through the json_object_put/json_object_get methods unless * you need to have the child (value) reference maintain a different lifetime * than the owning parent (obj). Ownership of value is retained by obj. * * @param obj the json_object instance * @param key the object field name * @param value a pointer where to store a reference to the json_object * associated with the given field name. * * It is safe to pass a NULL value. * @returns whether or not the key exists */ extern json_bool json_object_object_get_ex(struct json_object* obj, const char *key, struct json_object **value); /** Delete the given json_object field * * The reference count will be decremented for the deleted object. If there * are no more owners of the value represented by this key, then the value is * freed. Otherwise, the reference to the value will remain in memory. * * @param obj the json_object instance * @param key the object field name */ extern void json_object_object_del(struct json_object* obj, const char *key); /** * Iterate through all keys and values of an object. * * Adding keys to the object while iterating is NOT allowed. * * Deleting an existing key, or replacing an existing key with a * new value IS allowed. * * @param obj the json_object instance * @param key the local name for the char* key variable defined in the body * @param val the local name for the json_object* object variable defined in * the body */ #if defined(__GNUC__) && !defined(__STRICT_ANSI__) && __STDC_VERSION__ >= 199901L # define json_object_object_foreach(obj,key,val) \ char *key; \ struct json_object *val __attribute__((__unused__)); \ for(struct lh_entry *entry ## key = json_object_get_object(obj)->head, *entry_next ## key = NULL; \ ({ if(entry ## key) { \ key = (char*)entry ## key->k; \ val = (struct json_object*)entry ## key->v; \ entry_next ## key = entry ## key->next; \ } ; entry ## key; }); \ entry ## key = entry_next ## key ) #else /* ANSI C or MSC */ # define json_object_object_foreach(obj,key,val) \ char *key;\ struct json_object *val; \ struct lh_entry *entry ## key; \ struct lh_entry *entry_next ## key = NULL; \ for(entry ## key = json_object_get_object(obj)->head; \ (entry ## key ? ( \ key = (char*)entry ## key->k, \ val = (struct json_object*)entry ## key->v, \ entry_next ## key = entry ## key->next, \ entry ## key) : 0); \ entry ## key = entry_next ## key) #endif /* defined(__GNUC__) && !defined(__STRICT_ANSI__) && __STDC_VERSION__ >= 199901L */ /** Iterate through all keys and values of an object (ANSI C Safe) * @param obj the json_object instance * @param iter the object iterator */ #define json_object_object_foreachC(obj,iter) \ for(iter.entry = json_object_get_object(obj)->head; (iter.entry ? (iter.key = (char*)iter.entry->k, iter.val = (struct json_object*)iter.entry->v, iter.entry) : 0); iter.entry = iter.entry->next) /* Array type methods */ /** Create a new empty json_object of type json_type_array * @returns a json_object of type json_type_array */ extern struct json_object* json_object_new_array(void); /** Get the arraylist of a json_object of type json_type_array * @param obj the json_object instance * @returns an arraylist */ extern struct array_list* json_object_get_array(struct json_object *obj); /** Get the length of a json_object of type json_type_array * @param obj the json_object instance * @returns an int */ extern int json_object_array_length(struct json_object *obj); /** Sorts the elements of jso of type json_type_array * * Pointers to the json_object pointers will be passed as the two arguments * to @sort_fn * * @param obj the json_object instance * @param sort_fn a sorting function */ extern void json_object_array_sort(struct json_object *jso, int(*sort_fn)(const void *, const void *)); /** Add an element to the end of a json_object of type json_type_array * * The reference count will *not* be incremented. This is to make adding * fields to objects in code more compact. If you want to retain a reference * to an added object you must wrap the passed object with json_object_get * * @param obj the json_object instance * @param val the json_object to be added */ extern int json_object_array_add(struct json_object *obj, struct json_object *val); /** Insert or replace an element at a specified index in an array (a json_object of type json_type_array) * * The reference count will *not* be incremented. This is to make adding * fields to objects in code more compact. If you want to retain a reference * to an added object you must wrap the passed object with json_object_get * * The reference count of a replaced object will be decremented. * * The array size will be automatically be expanded to the size of the * index if the index is larger than the current size. * * @param obj the json_object instance * @param idx the index to insert the element at * @param val the json_object to be added */ extern int json_object_array_put_idx(struct json_object *obj, int idx, struct json_object *val); /** Get the element at specificed index of the array (a json_object of type json_type_array) * @param obj the json_object instance * @param idx the index to get the element at * @returns the json_object at the specified index (or NULL) */ extern struct json_object* json_object_array_get_idx(struct json_object *obj, int idx); /* json_bool type methods */ /** Create a new empty json_object of type json_type_boolean * @param b a json_bool TRUE or FALSE (0 or 1) * @returns a json_object of type json_type_boolean */ extern struct json_object* json_object_new_boolean(json_bool b); /** Get the json_bool value of a json_object * * The type is coerced to a json_bool if the passed object is not a json_bool. * integer and double objects will return FALSE if there value is zero * or TRUE otherwise. If the passed object is a string it will return * TRUE if it has a non zero length. If any other object type is passed * TRUE will be returned if the object is not NULL. * * @param obj the json_object instance * @returns a json_bool */ extern json_bool json_object_get_boolean(struct json_object *obj); /* int type methods */ /** Create a new empty json_object of type json_type_int * Note that values are stored as 64-bit values internally. * To ensure the full range is maintained, use json_object_new_int64 instead. * @param i the integer * @returns a json_object of type json_type_int */ extern struct json_object* json_object_new_int(int32_t i); /** Create a new empty json_object of type json_type_int * @param i the integer * @returns a json_object of type json_type_int */ extern struct json_object* json_object_new_int64(int64_t i); /** Get the int value of a json_object * * The type is coerced to a int if the passed object is not a int. * double objects will return their integer conversion. Strings will be * parsed as an integer. If no conversion exists then 0 is returned * and errno is set to EINVAL. null is equivalent to 0 (no error values set) * * Note that integers are stored internally as 64-bit values. * If the value of too big or too small to fit into 32-bit, INT32_MAX or * INT32_MIN are returned, respectively. * * @param obj the json_object instance * @returns an int */ extern int32_t json_object_get_int(struct json_object *obj); /** Get the int value of a json_object * * The type is coerced to a int64 if the passed object is not a int64. * double objects will return their int64 conversion. Strings will be * parsed as an int64. If no conversion exists then 0 is returned. * * NOTE: Set errno to 0 directly before a call to this function to determine * whether or not conversion was successful (it does not clear the value for * you). * * @param obj the json_object instance * @returns an int64 */ extern int64_t json_object_get_int64(struct json_object *obj); /* double type methods */ /** Create a new empty json_object of type json_type_double * @param d the double * @returns a json_object of type json_type_double */ extern struct json_object* json_object_new_double(double d); /** * Create a new json_object of type json_type_double, using * the exact serialized representation of the value. * * This allows for numbers that would otherwise get displayed * inefficiently (e.g. 12.3 => "12.300000000000001") to be * serialized with the more convenient form. * * Note: this is used by json_tokener_parse_ex() to allow for * an exact re-serialization of a parsed object. * * An equivalent sequence of calls is: * @code * jso = json_object_new_double(d); * json_object_set_serializer(d, json_object_userdata_to_json_string, * strdup(ds), json_object_free_userdata) * @endcode * * @param d the numeric value of the double. * @param ds the string representation of the double. This will be copied. */ extern struct json_object* json_object_new_double_s(double d, const char *ds); /** Get the double floating point value of a json_object * * The type is coerced to a double if the passed object is not a double. * integer objects will return their double conversion. Strings will be * parsed as a double. If no conversion exists then 0.0 is returned and * errno is set to EINVAL. null is equivalent to 0 (no error values set) * * If the value is too big to fit in a double, then the value is set to * the closest infinity with errno set to ERANGE. If strings cannot be * converted to their double value, then EINVAL is set & NaN is returned. * * Arrays of length 0 are interpreted as 0 (with no error flags set). * Arrays of length 1 are effectively cast to the equivalent object and * converted using the above rules. All other arrays set the error to * EINVAL & return NaN. * * NOTE: Set errno to 0 directly before a call to this function to * determine whether or not conversion was successful (it does not clear * the value for you). * * @param obj the json_object instance * @returns a double floating point number */ extern double json_object_get_double(struct json_object *obj); /* string type methods */ /** Create a new empty json_object of type json_type_string * * A copy of the string is made and the memory is managed by the json_object * * @param s the string * @returns a json_object of type json_type_string */ extern struct json_object* json_object_new_string(const char *s); extern struct json_object* json_object_new_string_len(const char *s, int len); /** Get the string value of a json_object * * If the passed object is not of type json_type_string then the JSON * representation of the object is returned. * * The returned string memory is managed by the json_object and will * be freed when the reference count of the json_object drops to zero. * * @param obj the json_object instance * @returns a string */ extern const char* json_object_get_string(struct json_object *obj); /** Get the string length of a json_object * * If the passed object is not of type json_type_string then zero * will be returned. * * @param obj the json_object instance * @returns int */ extern int json_object_get_string_len(struct json_object *obj); #ifdef __cplusplus } #endif #endif