llvm/BinaryFormat/MsgPack.h

0001 //===-- MsgPack.h - MessagePack Constants -----------------------*- C++ -*-===//
0002 //
0003 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0004 // See https://llvm.org/LICENSE.txt for license information.
0005 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0006 //
0007 //===----------------------------------------------------------------------===//
0008 ///
0009 /// \file
0010 /// This file contains constants used for implementing MessagePack support.
0011 ///
0012 //===----------------------------------------------------------------------===//
0013
0014 #ifndef LLVM_BINARYFORMAT_MSGPACK_H
0015 #define LLVM_BINARYFORMAT_MSGPACK_H
0016
0017 #include "llvm/Support/DataTypes.h"
0018 #include "llvm/Support/Endian.h"
0019
0020 namespace llvm {
0021 namespace msgpack {
0022
0023 /// The endianness of all multi-byte encoded values in MessagePack.
0024 constexpr llvm::endianness Endianness = llvm::endianness::big;
0025
0026 /// The first byte identifiers of MessagePack object formats.
0027 namespace FirstByte {
0028 #define HANDLE_MP_FIRST_BYTE(ID, NAME) constexpr uint8_t NAME = ID;
0029 #include "llvm/BinaryFormat/MsgPack.def"
0030 }
0031
0032 /// Most significant bits used to identify "Fix" variants in MessagePack.
0033 ///
0034 /// For example, FixStr objects encode their size in the five least significant
0035 /// bits of their first byte, which is identified by the bit pattern "101" in
0036 /// the three most significant bits. So FixBits::String contains 0b10100000.
0037 ///
0038 /// A corresponding mask of the bit pattern is found in \c FixBitsMask.
0039 namespace FixBits {
0040 #define HANDLE_MP_FIX_BITS(ID, NAME) constexpr uint8_t NAME = ID;
0041 #include "llvm/BinaryFormat/MsgPack.def"
0042 }
0043
0044 /// Mask of bits used to identify "Fix" variants in MessagePack.
0045 ///
0046 /// For example, FixStr objects encode their size in the five least significant
0047 /// bits of their first byte, which is identified by the bit pattern "101" in
0048 /// the three most significant bits. So FixBitsMask::String contains
0049 /// 0b11100000.
0050 ///
0051 /// The corresponding bit pattern to mask for is found in FixBits.
0052 namespace FixBitsMask {
0053 #define HANDLE_MP_FIX_BITS_MASK(ID, NAME) constexpr uint8_t NAME = ID;
0054 #include "llvm/BinaryFormat/MsgPack.def"
0055 }
0056
0057 /// The maximum value or size encodable in "Fix" variants of formats.
0058 ///
0059 /// For example, FixStr objects encode their size in the five least significant
0060 /// bits of their first byte, so the largest encodable size is 0b00011111.
0061 namespace FixMax {
0062 #define HANDLE_MP_FIX_MAX(ID, NAME) constexpr uint8_t NAME = ID;
0063 #include "llvm/BinaryFormat/MsgPack.def"
0064 }
0065
0066 /// The exact size encodable in "Fix" variants of formats.
0067 ///
0068 /// The only objects for which an exact size makes sense are of Extension type.
0069 ///
0070 /// For example, FixExt4 stores an extension type containing exactly four bytes.
0071 namespace FixLen {
0072 #define HANDLE_MP_FIX_LEN(ID, NAME) constexpr uint8_t NAME = ID;
0073 #include "llvm/BinaryFormat/MsgPack.def"
0074 }
0075
0076 /// The minimum value or size encodable in "Fix" variants of formats.
0077 ///
0078 /// The only object for which a minimum makes sense is a negative FixNum.
0079 ///
0080 /// Negative FixNum objects encode their signed integer value in one byte, but
0081 /// they must have the pattern "111" as their three most significant bits. This
0082 /// means all values are negative, and the smallest representable value is
0083 /// 0b11100000.
0084 namespace FixMin {
0085 #define HANDLE_MP_FIX_MIN(ID, NAME) constexpr int8_t NAME = ID;
0086 #include "llvm/BinaryFormat/MsgPack.def"
0087 }
0088
0089 } // end namespace msgpack
0090 } // end namespace llvm
0091
0092 #endif // LLVM_BINARYFORMAT_MSGPACK_H