Telodendria/src/include/CanonicalJson.h

95 lines
3.4 KiB
C

/*
* Copyright (C) 2022-2023 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.
*/
#ifndef TELODENDRIA_CANONICALJSON_H
#define TELODENDRIA_CANONICALJSON_H
/***
* @Nm CanonicalJson
* @Nd An extension of the JSON API that produces the Matrix spec's canonical JSON.
* @Dd November 30 2022
* @Xr Json
*
* This API is an extension of
* .Xr json 3
* that is specifically designed to produce the Matrix specification's
* "canonical" JSON.
* .Pp
* Canonical JSON is defined as JSON that:
* .Bl -bullet -offset indent
* .It
* Does not have any unecessary whitespace.
* .It
* Has all object key lexicographically sorted.
* .It
* Does not contain any floating point numerical values.
* .El
* .Pp
* The regular JSON encoder has no such rules, because normally they
* are not needed. However, Canonical JSON is needed in some cases to
* consistently sign JSON objects.
*/
#include <stdio.h>
#include <HashMap.h>
#include <Stream.h>
/**
* Encode a JSON object following the rules of Canonical JSON. See the
* documentation for
* .Fn JsonEncode ,
* documented in
* .Xr Json 3
* for more details on how JSON encoding operates. This function exists
* as an alternative to
* .Fn JsonEncode ,
* but should not be preferred to it in most circumstances. It is a lot
* more costly, as it must lexicographically sort all keys and strip
* out float values. If at all possible, use
* .Fn JsonEncode ,
* because it is much cheaper both in terms of memory and CPU time.
* .Pp
* This function returns a boolean value indicating whether or not the
* operation was sucessful. This function will fail only if NULL was
* given for any parameter. Otherwise, if an invalid pointer is given,
* undefined behavior results.
*/
extern int CanonicalJsonEncode(HashMap *, Stream *);
/**
* This function encodes a JSON object to a string.
* .Xr Json 3
* doesn't have any way to send JSON to a string, because there's
* absolutely no reason to handle JSON strings in most cases. However,
* the sole reason Canonical JSON exists is so that JSON objects can
* be signed in a consisten way. Thus, it is likely you need a string
* to pass to the signing function.
* .Pp
* This function returns a C string containing the canonical JSON
* representation of the given object, or NULL if the encoding failed.
*/
extern char * CanonicalJsonEncodeToString(HashMap *);
#endif /* TELODENDRIA_CANONICALJSON_H */