Mercurial > minori
annotate include/core/endian.h @ 364:99c961c91809
core: refactor out byte stream into its own file
easy dubs
| author | Paper <paper@paper.us.eu.org> |
|---|---|
| date | Tue, 16 Jul 2024 21:15:59 -0400 |
| parents | 9aaf1e788896 |
| children |
| rev | line source |
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| 351 | 1 #ifndef MINORI_CORE_ENDIAN_H_ |
| 2 #define MINORI_CORE_ENDIAN_H_ | |
| 3 | |
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4 /* definition of endian-related stuff. primarily used for x11 |
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5 * binary structures */ |
| 351 | 6 |
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7 #include "core/bit_cast.h" |
| 351 | 8 #include <cstdint> |
| 9 #include <type_traits> | |
| 10 | |
| 11 class Endian { | |
| 12 private: | |
| 13 /* check for compiler builtins for byteswapping */ | |
| 14 #ifdef __has_builtin | |
| 15 # if __has_builtin(__builtin_bswap16) | |
| 16 # define COMPILER_BUILTIN_BSWAP16(x) __builtin_bswap16(x) | |
| 17 # endif | |
| 18 # if __has_builtin(__builtin_bswap32) | |
| 19 # define COMPILER_BUILTIN_BSWAP32(x) __builtin_bswap32(x) | |
| 20 # endif | |
| 21 # if __has_builtin(__builtin_bswap64) | |
| 22 # define COMPILER_BUILTIN_BSWAP64(x) __builtin_bswap64(x) | |
| 23 # endif | |
| 24 #endif | |
| 25 | |
| 26 static constexpr uint16_t byteswap_16(uint16_t x) { | |
| 27 #ifdef COMPILER_BUILTIN_BSWAP16 | |
| 28 return COMPILER_BUILTIN_BSWAP16(x); | |
| 29 #else | |
| 30 return ( | |
| 31 ((x & UINT16_C(0x00FF)) << 8) | |
| 32 | ((x & UINT16_C(0xFF00)) >> 8) | |
| 33 ); | |
| 34 #endif | |
| 35 } | |
| 36 | |
| 37 static constexpr uint32_t byteswap_32(uint32_t x) { | |
| 38 #ifdef COMPILER_BUILTIN_BSWAP32 | |
| 39 return COMPILER_BUILTIN_BSWAP32(x); | |
| 40 #else | |
| 41 return ( | |
| 42 ((x & UINT32_C(0x000000FF)) << 24) | |
| 43 | ((x & UINT32_C(0x0000FF00)) << 8) | |
| 44 | ((x & UINT32_C(0x00FF0000)) >> 8) | |
| 45 | ((x & UINT32_C(0xFF000000)) >> 24) | |
| 46 ); | |
| 47 #endif | |
| 48 } | |
| 49 | |
| 50 static constexpr uint64_t byteswap_64(uint64_t x) { | |
| 51 #ifdef COMPILER_BUILTIN_BSWAP64 | |
| 52 return COMPILER_BUILTIN_BSWAP64(x); | |
| 53 #else | |
| 54 return ( | |
| 55 ((x & UINT64_C(0x00000000000000FF)) << 56) | |
| 56 | ((x & UINT64_C(0x000000000000FF00)) << 40) | |
| 57 | ((x & UINT64_C(0x0000000000FF0000)) << 24) | |
| 58 | ((x & UINT64_C(0x00000000FF000000)) << 8) | |
| 59 | ((x & UINT64_C(0x000000FF00000000)) >> 8) | |
| 60 | ((x & UINT64_C(0x0000FF0000000000)) >> 24) | |
| 61 | ((x & UINT64_C(0x00FF000000000000)) >> 40) | |
| 62 | ((x & UINT64_C(0xFF00000000000000)) >> 56) | |
| 63 ); | |
| 64 #endif | |
| 65 } | |
| 66 | |
| 67 #ifdef COMPILER_BUILTIN_BSWAP16 | |
| 68 # undef COMPILER_BUILTIN_BSWAP16 | |
| 69 #endif | |
| 70 #ifdef COMPILER_BUILTIN_BSWAP32 | |
| 71 # undef COMPILER_BUILTIN_BSWAP32 | |
| 72 #endif | |
| 73 #ifdef COMPILER_BUILTIN_BSWAP64 | |
| 74 # undef COMPILER_BUILTIN_BSWAP64 | |
| 75 #endif | |
| 76 public: | |
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77 #if defined(BYTE_ORDER_BIG) |
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78 static constexpr bool big = true; |
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79 static constexpr bool little = false; |
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80 #elif defined(BYTE_ORDER_LITTLE) |
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81 static constexpr bool big = false; |
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82 static constexpr bool little = true; |
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83 #else |
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84 #error "unsupported endianness" |
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85 #endif |
| 351 | 86 |
| 87 template<typename T> | |
| 88 static constexpr T byteswap(T x) { | |
| 89 static_assert(std::is_integral<T>::value); | |
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90 static_assert(std::is_unsigned<T>::value, "use signed_byteswap"); |
| 351 | 91 |
| 92 if constexpr (std::is_same<T, uint8_t>::value) { | |
| 93 return x; | |
| 94 } else if constexpr (std::is_same<T, uint16_t>::value) { | |
| 95 return byteswap_16(x); | |
| 96 } else if constexpr (std::is_same<T, uint32_t>::value) { | |
| 97 return byteswap_32(x); | |
| 98 } else if constexpr (std::is_same<T, uint64_t>::value) { | |
| 99 return byteswap_64(x); | |
| 100 } else { | |
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101 static_assert(!sizeof(T), "invalid integer type given to byteswap"); |
| 351 | 102 } |
| 103 } | |
| 104 | |
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105 /* this can't be constexpr */ |
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106 template<typename T> |
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107 static T signed_byteswap(T x) { |
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108 static_assert(std::is_integral<T>::value); |
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109 static_assert(std::is_signed<T>::value, "use regular byteswap"); |
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110 |
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111 using uT = typename std::make_unsigned<T>::type; |
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112 return minori::BitCast<T, uT>(byteswap<uT>(minori::BitCast<uT, T>(x))); |
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113 } |
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114 |
| 351 | 115 template<typename T> |
| 116 static constexpr T byteswap_little_to_host(T x) { | |
| 117 if constexpr (little) { | |
| 118 return x; | |
| 119 } else if constexpr (big) { | |
| 120 return byteswap(x); | |
| 121 } | |
| 122 } | |
| 123 | |
| 124 template<typename T> | |
| 125 static constexpr T byteswap_big_to_host(T x) { | |
| 126 if constexpr (big) { | |
| 127 return x; | |
| 128 } else if constexpr (little) { | |
| 129 return byteswap(x); | |
| 130 } | |
| 131 } | |
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132 |
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133 template<typename T> |
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134 static T signed_byteswap_little_to_host(T x) { |
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135 if constexpr (little) { |
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136 return x; |
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137 } else if constexpr (big) { |
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138 return signed_byteswap(x); |
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139 } |
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140 } |
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141 |
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142 template<typename T> |
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143 static T signed_byteswap_big_to_host(T x) { |
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144 if constexpr (big) { |
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145 return x; |
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146 } else if constexpr (little) { |
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147 return signed_byteswap(x); |
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148 } |
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149 } |
| 351 | 150 private: |
| 151 Endian() = delete; | |
| 152 }; | |
| 153 | |
| 154 #endif /* MINORI_CORE_ENDIAN_H_ */ |