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Edit File: json_object.h

/* * $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. * */ /** * @file * @brief Core json-c API. Start here, or with json_tokener.h */ #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 #elif defined(__clang__) #define THIS_FUNCTION_IS_DEPRECATED(func) func __deprecated #else #define THIS_FUNCTION_IS_DEPRECATED(func) func #endif #ifdef __GNUC__ #define JSON_C_CONST_FUNCTION(func) func __attribute__((const)) #else #define JSON_C_CONST_FUNCTION(func) func #endif #include "json_inttypes.h" #include "json_types.h" #include "printbuf.h" #include <stddef.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 for the json_object_to_json_string_ext() and * json_object_to_file_ext() functions which causes * the output to be formatted. * * Instead of a "Two Space Tab" this gives a single tab character. */ #define JSON_C_TO_STRING_PRETTY_TAB (1 << 3) /** * A flag to drop trailing zero for float values */ #define JSON_C_TO_STRING_NOZERO (1 << 2) /** * Don't escape forward slashes. */ #define JSON_C_TO_STRING_NOSLASHESCAPE (1 << 4) /** * A flag for the json_object_object_add_ex function which * causes the value to be added without a check if it already exists. * Note: it is the responsibility of the caller to ensure that no * key is added multiple times. If this is done, results are * unpredictable. While this option is somewhat dangerous, it * permits potentially large performance savings in code that * knows for sure the key values are unique (e.g. because the * code adds a well-known set of constant key values). */ #define JSON_C_OBJECT_ADD_KEY_IS_NEW (1 << 1) /** * A flag for the json_object_object_add_ex function which * flags the key as being constant memory. This means that * the key will NOT be copied via strdup(), resulting in a * potentially huge performance win (malloc, strdup and * free are usually performance hogs). It is acceptable to * use this flag for keys in non-constant memory blocks if * the caller ensure that the memory holding the key lives * longer than the corresponding json object. However, this * is somewhat dangerous and should only be done if really * justified. * The general use-case for this flag is cases where the * key is given as a real constant value in the function * call, e.g. as in * json_object_object_add_ex(obj, "ip", json, * JSON_C_OBJECT_KEY_IS_CONSTANT); */ #define JSON_C_OBJECT_KEY_IS_CONSTANT (1 << 2) /** * Set the global value of an option, which will apply to all * current and future threads that have not set a thread-local value. * * @see json_c_set_serialization_double_format */ #define JSON_C_OPTION_GLOBAL (0) /** * Set a thread-local value of an option, overriding the global value. * This will fail if json-c is not compiled with threading enabled, and * with the __thread specifier (or equivalent) available. * * @see json_c_set_serialization_double_format */ #define JSON_C_OPTION_THREAD (1) /* reference counting functions */ /** * Increment the reference count of json_object, thereby grabbing shared * ownership of obj. * * @param obj the json_object instance */ JSON_EXPORT 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. * An obj of NULL may be passed; in that case this call is a no-op. * * @param obj the json_object instance * @returns 1 if the object was freed. */ JSON_EXPORT 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 */ JSON_EXPORT int json_object_is_type(const 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 */ JSON_EXPORT enum json_type json_object_get_type(const 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 */ JSON_EXPORT 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 */ JSON_EXPORT const char *json_object_to_json_string_ext(struct json_object *obj, int flags); /** 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 * @param length a pointer where, if not NULL, the length (without null) is stored * @returns a string in JSON format and the length if not NULL */ JSON_EXPORT const char *json_object_to_json_string_length(struct json_object *obj, int flags, size_t *length); /** * Returns the userdata set by json_object_set_userdata() or * json_object_set_serializer() * * @param jso the object to return the userdata for */ JSON_EXPORT void *json_object_get_userdata(json_object *jso); /** * Set an opaque userdata value for an object * * The userdata can be retrieved using json_object_get_userdata(). * * If custom userdata is already set on this object, any existing user_delete * function is called before the new one is set. * * 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) * * Note: Objects created by parsing strings may have custom serializers set * which expect the userdata to contain specific data (due to use of * json_object_new_double_s()). In this case, json_object_set_serialiser() with * NULL as to_string_func should be used instead to set the userdata and reset * the serializer to its default value. * * @param jso the object to set the userdata for * @param userdata an optional opaque cookie * @param user_delete an optional function from freeing userdata */ JSON_EXPORT void json_object_set_userdata(json_object *jso, void *userdata, json_object_delete_fn *user_delete); /** * Set a custom serialization function to be used when this particular object * is converted to a string by json_object_to_json_string. * * If custom userdata 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 default behaviour is reset (but the userdata * and user_delete fields are still set). * * The userdata parameter is optional and may be passed as NULL. It can be used * to provide additional data for to_string_func to use. 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) * * Note that the userdata is the same as set by json_object_set_userdata(), so * care must be taken not to overwrite the value when both a custom serializer * and json_object_set_userdata() are used. * * @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 */ JSON_EXPORT 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); #ifdef __clang__ /* * Clang doesn't pay attention to the parameters defined in the * function typedefs used here, so turn off spurious doc warnings. * { */ #pragma clang diagnostic push #pragma clang diagnostic ignored "-Wdocumentation" #endif /** * 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_EXPORT 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_EXPORT json_object_to_json_string_fn json_object_userdata_to_json_string; #ifdef __clang__ /* } */ #pragma clang diagnostic pop #endif /* 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 */ JSON_EXPORT 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 */ JSON_EXPORT struct lh_table *json_object_get_object(const 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 */ JSON_EXPORT int json_object_object_length(const struct json_object *obj); /** Get the sizeof (struct json_object). * @returns a size_t with the sizeof (struct json_object) */ JSON_C_CONST_FUNCTION(JSON_EXPORT size_t json_c_object_sizeof(void)); /** 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 * * @return On success, <code>0</code> is returned. * On error, a negative value is returned. */ JSON_EXPORT int json_object_object_add(struct json_object *obj, const char *key, struct json_object *val); /** Add an object field to a json_object of type json_type_object * * The semantics are identical to json_object_object_add, except that an * additional flag fields gives you more control over some detail aspects * of processing. See the description of JSON_C_OBJECT_ADD_* flags for more * details. * * @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 * @param opts process-modifying options. To specify multiple options, use * arithmetic or (OPT1|OPT2) */ JSON_EXPORT int json_object_object_add_ex(struct json_object *obj, const char *const key, struct json_object *const val, const unsigned opts); /** Get the json_object associate with a given object field. * Deprecated/discouraged: used json_object_object_get_ex instead. * * This returns NULL if the field is found but its value is null, or if * the field is not found, or if obj is not a json_type_object. If you * need to distinguish between these cases, use json_object_object_get_ex(). * * *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 */ JSON_EXPORT struct json_object *json_object_object_get(const 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 */ JSON_EXPORT json_bool json_object_object_get_ex(const 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 */ JSON_EXPORT 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 = NULL; \ struct json_object *val __attribute__((__unused__)) = NULL; \ for (struct lh_entry *entry##key = json_object_get_object(obj)->head, \ *entry_next##key = NULL; \ ({ \ if (entry##key) \ { \ key = (char *)lh_entry_k(entry##key); \ val = (struct json_object *)lh_entry_v(entry##key); \ 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 = NULL; \ struct json_object *val = NULL; \ 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 *)lh_entry_k(entry##key), \ val = (struct json_object *)lh_entry_v(entry##key), \ 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, use type json_object_iter */ #define json_object_object_foreachC(obj, iter) \ for (iter.entry = json_object_get_object(obj)->head; \ (iter.entry ? (iter.key = (char *)lh_entry_k(iter.entry), \ iter.val = (struct json_object *)lh_entry_v(iter.entry), 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 */ JSON_EXPORT 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 */ JSON_EXPORT struct array_list *json_object_get_array(const 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 */ JSON_EXPORT size_t json_object_array_length(const 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 jso the json_object instance * @param sort_fn a sorting function */ JSON_EXPORT void json_object_array_sort(struct json_object *jso, int (*sort_fn)(const void *, const void *)); /** Binary search a sorted array for a specified key object. * * It depends on your compare function what's sufficient as a key. * Usually you create some dummy object with the parameter compared in * it, to identify the right item you're actually looking for. * * @see json_object_array_sort() for hints on the compare function. * * @param key a dummy json_object with the right key * @param jso the array object we're searching * @param sort_fn the sort/compare function * * @return the wanted json_object instance */ JSON_EXPORT struct json_object * json_object_array_bsearch(const struct json_object *key, const 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 */ JSON_EXPORT 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 */ JSON_EXPORT int json_object_array_put_idx(struct json_object *obj, size_t idx, struct json_object *val); /** Get the element at specified 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) */ JSON_EXPORT struct json_object *json_object_array_get_idx(const struct json_object *obj, size_t idx); /** Delete an elements from a specified index in an array (a json_object of type json_type_array) * * The reference count will be decremented for each of the deleted objects. If there * are no more owners of an element that is being deleted, then the value is * freed. Otherwise, the reference to the value will remain in memory. * * @param obj the json_object instance * @param idx the index to start deleting elements at * @param count the number of elements to delete * @returns 0 if the elements were successfully deleted */ JSON_EXPORT int json_object_array_del_idx(struct json_object *obj, size_t idx, size_t count); /* json_bool type methods */ /** Create a new empty json_object of type json_type_boolean * @param b a json_bool 1 or 0 * @returns a json_object of type json_type_boolean */ JSON_EXPORT 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 0 if there value is zero * or 1 otherwise. If the passed object is a string it will return * 1 if it has a non zero length. If any other object type is passed * 1 will be returned if the object is not NULL. * * @param obj the json_object instance * @returns a json_bool */ JSON_EXPORT json_bool json_object_get_boolean(const struct json_object *obj); /** Set the json_bool value of a json_object * * The type of obj is checked to be a json_type_boolean and 0 is returned * if it is not without any further actions. If type of obj is json_type_boolean * the object value is changed to new_value * * @param obj the json_object instance * @param new_value the value to be set * @returns 1 if value is set correctly, 0 otherwise */ JSON_EXPORT int json_object_set_boolean(struct json_object *obj, json_bool new_value); /* 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 */ JSON_EXPORT 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 */ JSON_EXPORT struct json_object *json_object_new_int64(int64_t i); /** Create a new empty json_object of type json_type_uint * @param i the integer * @returns a json_object of type json_type_uint */ JSON_EXPORT struct json_object *json_object_new_uint64(uint64_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 */ JSON_EXPORT int32_t json_object_get_int(const struct json_object *obj); /** Set the int value of a json_object * * The type of obj is checked to be a json_type_int and 0 is returned * if it is not without any further actions. If type of obj is json_type_int * the object value is changed to new_value * * @param obj the json_object instance * @param new_value the value to be set * @returns 1 if value is set correctly, 0 otherwise */ JSON_EXPORT int json_object_set_int(struct json_object *obj, int new_value); /** Increment a json_type_int object by the given amount, which may be negative. * * If the type of obj is not json_type_int then 0 is returned with no further * action taken. * If the addition would result in a overflow, the object value * is set to INT64_MAX. * If the addition would result in a underflow, the object value * is set to INT64_MIN. * Neither overflow nor underflow affect the return value. * * @param obj the json_object instance * @param val the value to add * @returns 1 if the increment succeded, 0 otherwise */ JSON_EXPORT int json_object_int_inc(struct json_object *obj, int64_t val); /** 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 */ JSON_EXPORT int64_t json_object_get_int64(const struct json_object *obj); /** Get the uint value of a json_object * * The type is coerced to a uint64 if the passed object is not a uint64. * double objects will return their uint64 conversion. Strings will be * parsed as an uint64. 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 uint64 */ JSON_EXPORT uint64_t json_object_get_uint64(const struct json_object *obj); /** Set the int64_t value of a json_object * * The type of obj is checked to be a json_type_int and 0 is returned * if it is not without any further actions. If type of obj is json_type_int * the object value is changed to new_value * * @param obj the json_object instance * @param new_value the value to be set * @returns 1 if value is set correctly, 0 otherwise */ JSON_EXPORT int json_object_set_int64(struct json_object *obj, int64_t new_value); /** Set the uint64_t value of a json_object * * The type of obj is checked to be a json_type_uint and 0 is returned * if it is not without any further actions. If type of obj is json_type_uint * the object value is changed to new_value * * @param obj the json_object instance * @param new_value the value to be set * @returns 1 if value is set correctly, 0 otherwise */ JSON_EXPORT int json_object_set_uint64(struct json_object *obj, uint64_t new_value); /* double type methods */ /** Create a new empty json_object of type json_type_double * * @see json_object_double_to_json_string() for how to set a custom format string. * * @param d the double * @returns a json_object of type json_type_double */ JSON_EXPORT 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. * * Notes: * * This is used by json_tokener_parse_ex() to allow for * an exact re-serialization of a parsed object. * * The userdata field is used to store the string representation, so it * can't be used for other data if this function is used. * * A roughly equivalent sequence of calls, with the difference being that * the serialization function won't be reset by json_object_set_double(), is: * @code * jso = json_object_new_double(d); * json_object_set_serializer(jso, 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. */ JSON_EXPORT struct json_object *json_object_new_double_s(double d, const char *ds); /** * Set a global or thread-local json-c option, depending on whether * JSON_C_OPTION_GLOBAL or JSON_C_OPTION_THREAD is passed. * Thread-local options default to undefined, and inherit from the global * value, even if the global value is changed after the thread is created. * Attempting to set thread-local options when threading is not compiled in * will result in an error. Be sure to check the return value. * * double_format is a "%g" printf format, such as "%.20g" * * @return -1 on errors, 0 on success. */ JSON_EXPORT int json_c_set_serialization_double_format(const char *double_format, int global_or_thread); /** Serialize a json_object of type json_type_double to a string. * * This function isn't meant to be called directly. Instead, you can set a * custom format string for the serialization of this double using the * following call (where "%.17g" actually is the default): * * @code * jso = json_object_new_double(d); * json_object_set_serializer(jso, json_object_double_to_json_string, * "%.17g", NULL); * @endcode * * @see printf(3) man page for format strings * * @param jso The json_type_double object that is serialized. * @param pb The destination buffer. * @param level Ignored. * @param flags Ignored. */ JSON_EXPORT int json_object_double_to_json_string(struct json_object *jso, struct printbuf *pb, int level, int flags); /** 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 */ JSON_EXPORT double json_object_get_double(const struct json_object *obj); /** Set the double value of a json_object * * The type of obj is checked to be a json_type_double and 0 is returned * if it is not without any further actions. If type of obj is json_type_double * the object value is changed to new_value * * If the object was created with json_object_new_double_s(), the serialization * function is reset to the default and the cached serialized value is cleared. * * @param obj the json_object instance * @param new_value the value to be set * @returns 1 if value is set correctly, 0 otherwise */ JSON_EXPORT int json_object_set_double(struct json_object *obj, double new_value); /* 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 * @see json_object_new_string_len() */ JSON_EXPORT struct json_object *json_object_new_string(const char *s); /** Create a new empty json_object of type json_type_string and allocate * len characters for the new string. * * A copy of the string is made and the memory is managed by the json_object * * @param s the string * @param len max length of the new string * @returns a json_object of type json_type_string * @see json_object_new_string() */ JSON_EXPORT struct json_object *json_object_new_string_len(const char *s, const int len); /** Get the string value of a json_object * * If the passed object is of type json_type_null (i.e. obj == NULL), * NULL is returned. * * If the passed object of type json_type_string, the string contents * are returned. * * Otherwise 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 or NULL */ JSON_EXPORT 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 */ JSON_EXPORT int json_object_get_string_len(const struct json_object *obj); /** Set the string value of a json_object with zero terminated strings * equivalent to json_object_set_string_len (obj, new_value, strlen(new_value)) * @returns 1 if value is set correctly, 0 otherwise */ JSON_EXPORT int json_object_set_string(json_object *obj, const char *new_value); /** Set the string value of a json_object str * * The type of obj is checked to be a json_type_string and 0 is returned * if it is not without any further actions. If type of obj is json_type_string * the object value is changed to new_value * * @param obj the json_object instance * @param new_value the value to be set; Since string length is given in len this need not be zero terminated * @param len the length of new_value * @returns 1 if value is set correctly, 0 otherwise */ JSON_EXPORT int json_object_set_string_len(json_object *obj, const char *new_value, int len); /** This method exists only to provide a complementary function * along the lines of the other json_object_new_* functions. * It always returns NULL, and it is entirely acceptable to simply use NULL directly. */ JSON_EXPORT struct json_object *json_object_new_null(void); /** Check if two json_object's are equal * * If the passed objects are equal 1 will be returned. * Equality is defined as follows: * - json_objects of different types are never equal * - json_objects of the same primitive type are equal if the * c-representation of their value is equal * - json-arrays are considered equal if all values at the same * indices are equal (same order) * - Complex json_objects are considered equal if all * contained objects referenced by their key are equal, * regardless their order. * * @param obj1 the first json_object instance * @param obj2 the second json_object instance * @returns whether both objects are equal or not */ JSON_EXPORT int json_object_equal(struct json_object *obj1, struct json_object *obj2); /** * Perform a shallow copy of src into *dst as part of an overall json_object_deep_copy(). * * If src is part of a containing object or array, parent will be non-NULL, * and key or index will be provided. * When shallow_copy is called *dst will be NULL, and must be non-NULL when it returns. * src will never be NULL. * * If shallow_copy sets the serializer on an object, return 2 to indicate to * json_object_deep_copy that it should not attempt to use the standard userdata * copy function. * * @return On success 1 or 2, -1 on errors */ typedef int(json_c_shallow_copy_fn)(json_object *src, json_object *parent, const char *key, size_t index, json_object **dst); /** * The default shallow copy implementation for use with json_object_deep_copy(). * This simply calls the appropriate json_object_new_<type>() function and * copies over the serializer function (_to_json_string internal field of * the json_object structure) but not any _userdata or _user_delete values. * * If you're writing a custom shallow_copy function, perhaps because you're using * your own custom serializer, you can call this first to create the new object * before customizing it with json_object_set_serializer(). * * @return 1 on success, -1 on errors, but never 2. */ JSON_EXPORT json_c_shallow_copy_fn json_c_shallow_copy_default; /** * Copy the contents of the JSON object. * The destination object must be initialized to NULL, * to make sure this function won't overwrite an existing JSON object. * * This does roughly the same thing as * `json_tokener_parse(json_object_get_string(src))`. * * @param src source JSON object whose contents will be copied * @param dst pointer to the destination object where the contents of `src`; * make sure this pointer is initialized to NULL * @param shallow_copy an optional function to copy individual objects, needed * when custom serializers are in use. See also * json_object set_serializer. * * @returns 0 if the copy went well, -1 if an error occured during copy * or if the destination pointer is non-NULL */ JSON_EXPORT int json_object_deep_copy(struct json_object *src, struct json_object **dst, json_c_shallow_copy_fn *shallow_copy); #ifdef __cplusplus } #endif #endif