manage the reference, i.e. increase and decrease the reference count
as needed. However, some functions **steal** the reference, i.e. they
have the same result as if the user called :cfunc:`json_decref()` on
-the argument right after calling the function. These are usually
-convenience functions for adding new references to containers and not
-to worry about the reference count.
+the argument right after calling the function. These functions are
+suffixed with ``_new`` or have ``_new_`` somewhere in their name.
+
+For example, the following code creates a new JSON array and appends
+an integer to it::
+
+ json_t *array, *integer;
+
+ array = json_array();
+ integer = json_integer(42);
+
+ json_array_append(array, integer);
+ json_decref(integer);
+
+Note how the caller has to release the reference to the integer value
+by calling :cfunc:`json_decref()`. By using a reference stealing
+function :cfunc:`json_array_append_new()` instead of
+:cfunc:`json_array_append()`, the code becomes much simpler::
+
+ json_t *array = json_array();
+ json_array_append_new(array, json_integer(42));
+
+In this case, the user doesn't have to explicitly release the
+reference to the integer value, as :cfunc:`json_array_append_new()`
+steals the reference when appending the value to the array.
In the following sections it is clearly documented whether a function
will return a new or borrowed reference or steal a reference to its
Returns a new JSON string, or *NULL* on error. *value* must be a
valid UTF-8 encoded Unicode string.
+.. cfunction:: json_t *json_string_nocheck(const char *value)
+
+ .. refcounting:: new
+
+ Like :cfunc:`json_string`, but doesn't check that *value* is valid
+ UTF-8. Use this function only if you are certain that this really
+ is the case (e.g. you have already checked it by other means).
+
+ .. versionadded:: 1.2
+
.. cfunction:: const char *json_string_value(const json_t *string)
Returns the associated value of *string* as a null terminated UTF-8
.. versionadded:: 1.1
+.. cfunction:: int json_string_set_nocheck(const json_t *string, const char *value)
+
+ Like :cfunc:`json_string_set`, but doesn't check that *value* is
+ valid UTF-8. Use this function only if you are certain that this
+ really is the case (e.g. you have already checked it by other
+ means).
+
+ .. versionadded:: 1.2
+
Number
======
Returns a new JSON array, or *NULL* on error. Initially, the array
is empty.
-.. cfunction:: unsigned int json_array_size(const json_t *array)
+.. cfunction:: size_t json_array_size(const json_t *array)
Returns the number of elements in *array*, or 0 if *array* is NULL
or not a JSON array.
-.. cfunction:: json_t *json_array_get(const json_t *array, unsigned int index)
+.. cfunction:: json_t *json_array_get(const json_t *array, size_t index)
.. refcounting:: borrow
if *array* is *NULL*, or if *index* is out of range, *NULL* is
returned.
-.. cfunction:: int json_array_set(json_t *array, unsigned int index, json_t *value)
+.. cfunction:: int json_array_set(json_t *array, size_t index, json_t *value)
Replaces the element in *array* at position *index* with *value*.
The valid range for *index* is from 0 to the return value of
:cfunc:`json_array_size()` minus 1. Returns 0 on success and -1 on
error.
-.. cfunction:: int json_array_set_new(json_t *array, unsigned int index, json_t *value)
+.. cfunction:: int json_array_set_new(json_t *array, size_t index, json_t *value)
Like :cfunc:`json_array_set()` but steals the reference to *value*.
This is useful when *value* is newly created and not used after
.. versionadded:: 1.1
-.. cfunction:: int json_array_insert(json_t *array, unsigned int index, json_t *value)
+.. cfunction:: int json_array_insert(json_t *array, size_t index, json_t *value)
Inserts *value* to *array* at position *index*, shifting the
elements at *index* and after it one position towards the end of
.. versionadded:: 1.1
-.. cfunction:: int json_array_insert_new(json_t *array, unsigned int index, json_t *value)
+.. cfunction:: int json_array_insert_new(json_t *array, size_t index, json_t *value)
Like :cfunc:`json_array_insert()` but steals the reference to
*value*. This is useful when *value* is newly created and not used
.. versionadded:: 1.1
-.. cfunction:: int json_array_remove(json_t *array, unsigned int index)
+.. cfunction:: int json_array_remove(json_t *array, size_t index)
Removes the element in *array* at position *index*, shifting the
elements after *index* one position towards the start of the array.
Returns a new JSON object, or *NULL* on error. Initially, the
object is empty.
-.. cfunction:: unsigned int json_object_size(const json_t *object)
+.. cfunction:: size_t json_object_size(const json_t *object)
Returns the number of elements in *object*, or 0 if *object* is not
a JSON object.
already is a value for *key*, it is replaced by the new value.
Returns 0 on success and -1 on error.
+.. cfunction:: int json_object_set_nocheck(json_t *object, const char *key, json_t *value)
+
+ Like :cfunc:`json_object_set`, but doesn't check that *key* is
+ valid UTF-8. Use this function only if you are certain that this
+ really is the case (e.g. you have already checked it by other
+ means).
+
+ .. versionadded:: 1.2
+
.. cfunction:: int json_object_set_new(json_t *object, const char *key, json_t *value)
Like :cfunc:`json_object_set()` but steals the reference to
.. versionadded:: 1.1
+.. cfunction:: int json_object_set_new_nocheck(json_t *object, const char *key, json_t *value)
+
+ Like :cfunc:`json_object_set_new`, but doesn't check that *key* is
+ valid UTF-8. Use this function only if you are certain that this
+ really is the case (e.g. you have already checked it by other
+ means).
+
+ .. versionadded:: 1.2
+
.. cfunction:: int json_object_del(json_t *object, const char *key)
Delete *key* from *object* if it exists. Returns 0 on success, or
Returns an opaque iterator which can be used to iterate over all
key-value pairs in *object*, or *NULL* if *object* is empty.
+.. cfunction:: void *json_object_iter_at(json_t *object, const char *key)
+
+ Like :cfunc:`json_object_iter()`, but returns an iterator to the
+ key-value pair in *object* whose key is equal to *key*, or NULL if
+ *key* is not found in *object*. Iterating forward to the end of
+ *object* only yields all key-value pairs of the object if *key*
+ happens to be the first key in the underlying hash table.
+
+ .. versionadded:: 1.3
+
.. cfunction:: void *json_object_iter_next(json_t *object, void *iter)
Returns an iterator pointing to the next key-value pair in *object*
Extract the associated value from *iter*.
+.. cfunction:: int json_object_iter_set(json_t *object, void *iter, json_t *value)
+
+ Set the value of the key-value pair in *object*, that is pointed to
+ by *iter*, to *value*.
+
+ .. versionadded:: 1.3
+
+.. cfunction:: int json_object_iter_set_new(json_t *object, void *iter, json_t *value)
+
+ Like :cfunc:`json_object_iter_set()`, but steals the reference to
+ *value*. This is useful when *value* is newly created and not used
+ after the call.
+
+ .. versionadded:: 1.3
+
The iteration protocol can be used for example as follows::
/* obj is a JSON object */
.. versionadded:: 1.2
+``JSON_ENSURE_ASCII``
+ If this flag is used, the output is guaranteed to consist only of
+ ASCII characters. This is achived by escaping all Unicode
+ characters outside the ASCII range.
+
+ .. versionadded:: 1.2
+
+``JSON_SORT_KEYS``
+ If this flag is used, all the objects in output are sorted by key.
+ This is useful e.g. if two JSON texts are diffed or visually
+ compared.
+
+ .. versionadded:: 1.2
+
+``JSON_PRESERVE_ORDER``
+ If this flag is used, object keys in the output are sorted into the
+ same order in which they were first inserted to the object. For
+ example, decoding a JSON text and then encoding with this flag
+ preserves the order of object keys.
+
+ .. versionadded:: 1.3
+
The following functions perform the actual JSON encoding. The result
is in UTF-8.
-.. cfunction:: char *json_dumps(const json_t *root, unsigned long flags)
+.. cfunction:: char *json_dumps(const json_t *root, size_t flags)
Returns the JSON representation of *root* as a string, or *NULL* on
error. *flags* is described above. The return value must be freed
by the caller using :cfunc:`free()`.
-.. cfunction:: int json_dumpf(const json_t *root, FILE *output, unsigned long flags)
+.. cfunction:: int json_dumpf(const json_t *root, FILE *output, size_t flags)
Write the JSON representation of *root* to the stream *output*.
*flags* is described above. Returns 0 on success and -1 on error.
*output*. In this case, the output is undefined and most likely not
valid JSON.
-.. cfunction:: int json_dump_file(const json_t *json, const char *path, unsigned long flags)
+.. cfunction:: int json_dump_file(const json_t *json, const char *path, size_t flags)
Write the JSON representation of *root* to the file *path*. If
*path* already exists, it is overwritten. *flags* is described
object it contains, or *NULL* on error, in which case *error* is
filled with information about the error. See above for discussion
on the *error* parameter.
+
+
+Equality
+========
+
+Testing for equality of two JSON values cannot, in general, be
+achieved using the ``==`` operator. Equality in the terms of the
+``==`` operator states that the two :ctype:`json_t` pointers point to
+exactly the same JSON value. However, two JSON values can be equal not
+only if they are exactly the same value, but also if they have equal
+"contents":
+
+* Two integer or real values are equal if their contained numeric
+ values are equal. An integer value is never equal to a real value,
+ though.
+
+* Two strings are equal if their contained UTF-8 strings are equal.
+
+* Two arrays are equal if they have the same number of elements and
+ each element in the first array is equal to the corresponding
+ element in the second array.
+
+* Two objects are equal if they have exactly the same keys and the
+ value for each key in the first object is equal to the value of the
+ corresponding key in the second object.
+
+* Two true, false or null values have no "contents", so they are equal
+ if their types are equal. (Because these values are singletons,
+ their equality can actually be tested with ``==``.)
+
+The following function can be used to test whether two JSON values are
+equal.
+
+.. cfunction:: int json_equal(json_t *value1, json_t *value2)
+
+ Returns 1 if *value1* and *value2* are equal, as defined above.
+ Returns 0 if they are inequal or one or both of the pointers are
+ *NULL*.
+
+ .. versionadded:: 1.2
+
+
+Copying
+=======
+
+Because of reference counting, passing JSON values around doesn't
+require copying them. But sometimes a fresh copy of a JSON value is
+needed. For example, if you need to modify an array, but still want to
+use the original afterwards, you should take a copy of it first.
+
+Jansson supports two kinds of copying: shallow and deep. There is a
+difference between these methods only for arrays and objects. Shallow
+copying only copies the first level value (array or object) and uses
+the same child values in the copied value. Deep copying makes a fresh
+copy of the child values, too. Moreover, all the child values are deep
+copied in a recursive fashion.
+
+.. cfunction:: json_t *json_copy(json_t *value)
+
+ .. refcounting:: new
+
+ Returns a shallow copy of *value*, or *NULL* on error.
+
+ .. versionadded:: 1.2
+
+.. cfunction:: json_t *json_deep_copy(json_t *value)
+
+ .. refcounting:: new
+
+ Returns a deep copy of *value*, or *NULL* on error.
+
+ .. versionadded:: 1.2
projects / jansson.git / blobdiff