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construct/include/ircd/cbor/cbor.h

96 lines
3.2 KiB
C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2019 Jason Volk <jason@zemos.net>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice is present in all copies. The
// full license for this software is available in the LICENSE file.
#pragma once
#define HAVE_IRCD_CBOR_H
/// Concise Binary Object Representation (RFC7049)
///
namespace ircd::cbor
{
IRCD_EXCEPTION(ircd::error, error);
IRCD_EXCEPTION(error, type_error);
IRCD_EXCEPTION(error, parse_error);
IRCD_EXCEPTION(parse_error, buffer_underrun);
enum major :uint8_t;
enum minor :uint8_t;
struct head;
string_view reflect(const enum major &);
enum major major(const const_buffer &);
}
/// Item head.
///
/// This object represents the head byte and any following-integer bytes under
/// its const_buffer. If the major type has a payload, it starts immediately
/// following the end of this object's buffer. The first byte of this object's
/// buffer is the leading head byte. This object's buffer will never be empty()
/// unless it's default-initialized (i.e not pointing at anything).
///
/// This is used to query information about the item from the head data.
///
struct ircd::cbor::head
:const_buffer
{
static uint8_t major(const uint8_t &); // Major type
static uint8_t minor(const uint8_t &); // Minor type
static size_t length(const uint8_t &); // (1 + size(following()))
// Member ops when buffer has >= 1 byte
const uint8_t &leading() const; // Reference the leading byte
enum major major() const; // major(leading())
enum minor minor() const; // minor(leading())
size_t length() const; // length(leading())
// Get bytes following leading byte based on major/minor
const_buffer following() const;
template<class T> const T &following() const;
// Construct from at least first byte of item or more
head(const const_buffer &);
head() = default;
head(head &&) = default;
head(const head &) = default;
};
/// RFC7049 Major type codes
enum ircd::cbor::major
:uint8_t
{
POSITIVE = 0, ///< Z*
NEGATIVE = 1, ///< Z-
BINARY = 2, ///< Raw byte sequence
STRING = 3, ///< UTF-8 character sequence
ARRAY = 4, ///< Array of items
OBJECT = 5, ///< Dictionary of items
TAG = 6, ///< CBOR extensions (IANA registered)
PRIMITIVE = 7, ///< Literals / floats
};
/// RFC7049 Minor type codes
enum ircd::cbor::minor
:uint8_t
{
FALSE = 20, ///< False
TRUE = 21, ///< True
NUL = 22, ///< Null
UD = 23, ///< Undefined value
U8 = 24, ///< 8 bits follow
U16 = 25, ///< 16 bits follow
F16 = 25, ///< IEEE754 half-precision (16 bits follow)
U32 = 26, ///< 32 bits follow
F32 = 26, ///< IEEE754 single-precision (32 bits follow)
U64 = 27, ///< 64 bits follow
F64 = 27, ///< IEEE754 double-precision (64 bits follow)
STREAM = 31, ///< Variable length (terminated by BREAK)
BREAK = 31, ///< Terminator code
};