Telodendria/src/include/CanonicalJson.h

86 lines
3.2 KiB
C

/*
* Copyright (C) 2022 Jordan Bancino <@jordan:bancino.net>
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation files
* (the "Software"), to deal in the Software without restriction,
* including without limitation the rights to use, copy, modify, merge,
* publish, distribute, sublicense, and/or sell copies of the Software,
* and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
/*
* CanonicalJson.h: An expansion of the JSON encoding functionality
* that is specifically designed to produce the Matrix spec's
* "canonical" JSON.
*
* Canonical JSON is defined as JSON that:
*
* - Does not have any unecessary whitespace.
* - Has all object keys lexicographically sorted.
* - Does not contain any float values.
*
* The regular JSON encoder has no such rules, because normally they
* are not needed. However, Canonical JSON is needed to be able to
* sign JSON objects in a consistent way.
*/
#ifndef TELODENDRIA_CANONICALJSON_H
#define TELODENDRIA_CANONICALJSON_H
#include <stdio.h>
#include <HashMap.h>
/*
* Encode a JSON object following the rules of canonical JSON. See
* JsonEncode() for more details on how JSON encoding operates.
*
* This function exists as an alternative to JsonEncode(), but should
* not be preferred to JsonEncode() in normal circumstances. It is
* a lot more costly, as it must lexicographically sort all keys and
* strip out float values. If at all possible, use JsonEncode(),
* because it is much cheaper in terms of memory and CPU time.
*
* Params:
*
* (HashMap *) The JSON object to encode. Note that all values must
* be JsonValues.
* (FILE *) The output stream to write the JSON object to.
*
* Return: Whether or not the JSON encoding was successful. This
* function may fail if NULL was given for any parameter.
*/
extern int
CanonicalJsonEncode(HashMap *, FILE *);
/*
* Encode the JSON object to a string. The regular JSON encoding
* library doesn't have a way to send JSON to strings, because there's
* absolutely no reason to handle JSON strings. However, the sole
* reason canonical JSON exists is so that JSON objects can be signed.
* Thus, you need a string to pass to the signing function.
*
* Params:
*
* (HashMap *) The JSON object to encode. Note that all values must
* be JsonValues.
*
* Return: A string containing the canonical JSON representation of
* the given object, or NULL if the encoding failed.
*/
extern char *
CanonicalJsonEncodeToString(HashMap *);
#endif