include/llvm/BinaryFormat/MsgPack.h

   1 //===-- MsgPack.h - MessagePack Constants -----------------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 ///
   9 /// \file
  10 /// This file contains constants used for implementing MessagePack support.
  11 ///
  12 //===----------------------------------------------------------------------===//
  13
  14 #ifndef LLVM_BINARYFORMAT_MSGPACK_H
  15 #define LLVM_BINARYFORMAT_MSGPACK_H
  16
  17 #include "llvm/Support/DataTypes.h"
  18 #include "llvm/Support/Endian.h"
  19
  20 namespace llvm {
  21 namespace msgpack {
  22
  23 /// The endianness of all multi-byte encoded values in MessagePack.
  24 constexpr support::endianness Endianness = support::big;
  25
  26 /// The first byte identifiers of MessagePack object formats.
  27 namespace FirstByte {
  28 #define HANDLE_MP_FIRST_BYTE(ID, NAME) constexpr uint8_t NAME = ID;
  29 #include "llvm/BinaryFormat/MsgPack.def"
  30 }
  31
  32 /// Most significant bits used to identify "Fix" variants in MessagePack.
  33 ///
  34 /// For example, FixStr objects encode their size in the five least significant
  35 /// bits of their first byte, which is identified by the bit pattern "101" in
  36 /// the three most significant bits. So FixBits::String contains 0b10100000.
  37 ///
  38 /// A corresponding mask of the bit pattern is found in \c FixBitsMask.
  39 namespace FixBits {
  40 #define HANDLE_MP_FIX_BITS(ID, NAME) constexpr uint8_t NAME = ID;
  41 #include "llvm/BinaryFormat/MsgPack.def"
  42 }
  43
  44 /// Mask of bits used to identify "Fix" variants in MessagePack.
  45 ///
  46 /// For example, FixStr objects encode their size in the five least significant
  47 /// bits of their first byte, which is identified by the bit pattern "101" in
  48 /// the three most significant bits. So FixBitsMask::String contains
  49 /// 0b11100000.
  50 ///
  51 /// The corresponding bit pattern to mask for is found in FixBits.
  52 namespace FixBitsMask {
  53 #define HANDLE_MP_FIX_BITS_MASK(ID, NAME) constexpr uint8_t NAME = ID;
  54 #include "llvm/BinaryFormat/MsgPack.def"
  55 }
  56
  57 /// The maximum value or size encodable in "Fix" variants of formats.
  58 ///
  59 /// For example, FixStr objects encode their size in the five least significant
  60 /// bits of their first byte, so the largest encodable size is 0b00011111.
  61 namespace FixMax {
  62 #define HANDLE_MP_FIX_MAX(ID, NAME) constexpr uint8_t NAME = ID;
  63 #include "llvm/BinaryFormat/MsgPack.def"
  64 }
  65
  66 /// The exact size encodable in "Fix" variants of formats.
  67 ///
  68 /// The only objects for which an exact size makes sense are of Extension type.
  69 ///
  70 /// For example, FixExt4 stores an extension type containing exactly four bytes.
  71 namespace FixLen {
  72 #define HANDLE_MP_FIX_LEN(ID, NAME) constexpr uint8_t NAME = ID;
  73 #include "llvm/BinaryFormat/MsgPack.def"
  74 }
  75
  76 /// The minimum value or size encodable in "Fix" variants of formats.
  77 ///
  78 /// The only object for which a minimum makes sense is a negative FixNum.
  79 ///
  80 /// Negative FixNum objects encode their signed integer value in one byte, but
  81 /// they must have the pattern "111" as their three most significant bits. This
  82 /// means all values are negative, and the smallest representable value is
  83 /// 0b11100000.
  84 namespace FixMin {
  85 #define HANDLE_MP_FIX_MIN(ID, NAME) constexpr int8_t NAME = ID;
  86 #include "llvm/BinaryFormat/MsgPack.def"
  87 }
  88
  89 } // end namespace msgpack
  90 } // end namespace llvm
  91
  92 #endif // LLVM_BINARYFORMAT_MSGPACK_H