Mercurial > minori
annotate include/core/endian.h @ 373:fbc8c617de80
dep/animone: exception handling is the worst c++ anti-feature
| author | Paper <paper@tflc.us> |
|---|---|
| date | Fri, 25 Jul 2025 11:03:05 -0400 |
| parents | 47c9f8502269 |
| 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 | |
| 369 | 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 | |
| 351 | 24 #endif |
| 25 | |
| 369 | 26 static constexpr uint16_t byteswap_16(uint16_t x) |
| 27 { | |
| 351 | 28 #ifdef COMPILER_BUILTIN_BSWAP16 |
| 29 return COMPILER_BUILTIN_BSWAP16(x); | |
| 30 #else | |
| 369 | 31 return (((x & UINT16_C(0x00FF)) << 8) | ((x & UINT16_C(0xFF00)) >> 8)); |
| 351 | 32 #endif |
| 33 } | |
| 34 | |
| 369 | 35 static constexpr uint32_t byteswap_32(uint32_t x) |
| 36 { | |
| 351 | 37 #ifdef COMPILER_BUILTIN_BSWAP32 |
| 38 return COMPILER_BUILTIN_BSWAP32(x); | |
| 39 #else | |
| 369 | 40 return (((x & UINT32_C(0x000000FF)) << 24) | ((x & UINT32_C(0x0000FF00)) << 8) | |
| 41 ((x & UINT32_C(0x00FF0000)) >> 8) | ((x & UINT32_C(0xFF000000)) >> 24)); | |
| 351 | 42 #endif |
| 43 } | |
| 44 | |
| 369 | 45 static constexpr uint64_t byteswap_64(uint64_t x) |
| 46 { | |
| 351 | 47 #ifdef COMPILER_BUILTIN_BSWAP64 |
| 48 return COMPILER_BUILTIN_BSWAP64(x); | |
| 49 #else | |
| 369 | 50 return (((x & UINT64_C(0x00000000000000FF)) << 56) | ((x & UINT64_C(0x000000000000FF00)) << 40) | |
| 51 ((x & UINT64_C(0x0000000000FF0000)) << 24) | ((x & UINT64_C(0x00000000FF000000)) << 8) | | |
| 52 ((x & UINT64_C(0x000000FF00000000)) >> 8) | ((x & UINT64_C(0x0000FF0000000000)) >> 24) | | |
| 53 ((x & UINT64_C(0x00FF000000000000)) >> 40) | ((x & UINT64_C(0xFF00000000000000)) >> 56)); | |
| 351 | 54 #endif |
| 55 } | |
| 56 | |
| 57 #ifdef COMPILER_BUILTIN_BSWAP16 | |
| 369 | 58 # undef COMPILER_BUILTIN_BSWAP16 |
| 351 | 59 #endif |
| 60 #ifdef COMPILER_BUILTIN_BSWAP32 | |
| 369 | 61 # undef COMPILER_BUILTIN_BSWAP32 |
| 351 | 62 #endif |
| 63 #ifdef COMPILER_BUILTIN_BSWAP64 | |
| 369 | 64 # undef COMPILER_BUILTIN_BSWAP64 |
| 351 | 65 #endif |
| 66 public: | |
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67 #if defined(BYTE_ORDER_BIG) |
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68 static constexpr bool big = true; |
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69 static constexpr bool little = false; |
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70 #elif defined(BYTE_ORDER_LITTLE) |
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71 static constexpr bool big = false; |
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72 static constexpr bool little = true; |
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73 #else |
| 369 | 74 # error "unsupported endianness" |
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75 #endif |
| 351 | 76 |
| 77 template<typename T> | |
| 369 | 78 static constexpr T byteswap(T x) |
| 79 { | |
| 351 | 80 static_assert(std::is_integral<T>::value); |
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81 static_assert(std::is_unsigned<T>::value, "use signed_byteswap"); |
| 351 | 82 |
| 83 if constexpr (std::is_same<T, uint8_t>::value) { | |
| 84 return x; | |
| 85 } else if constexpr (std::is_same<T, uint16_t>::value) { | |
| 86 return byteswap_16(x); | |
| 87 } else if constexpr (std::is_same<T, uint32_t>::value) { | |
| 88 return byteswap_32(x); | |
| 89 } else if constexpr (std::is_same<T, uint64_t>::value) { | |
| 90 return byteswap_64(x); | |
| 91 } else { | |
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92 static_assert(!sizeof(T), "invalid integer type given to byteswap"); |
| 351 | 93 } |
| 94 } | |
| 95 | |
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96 /* this can't be constexpr */ |
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97 template<typename T> |
| 369 | 98 static T signed_byteswap(T x) |
| 99 { | |
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100 static_assert(std::is_integral<T>::value); |
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101 static_assert(std::is_signed<T>::value, "use regular byteswap"); |
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102 |
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103 using uT = typename std::make_unsigned<T>::type; |
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104 return minori::BitCast<T, uT>(byteswap<uT>(minori::BitCast<uT, T>(x))); |
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105 } |
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106 |
| 351 | 107 template<typename T> |
| 369 | 108 static constexpr T byteswap_little_to_host(T x) |
| 109 { | |
| 351 | 110 if constexpr (little) { |
| 111 return x; | |
| 112 } else if constexpr (big) { | |
| 113 return byteswap(x); | |
| 114 } | |
| 115 } | |
| 116 | |
| 117 template<typename T> | |
| 369 | 118 static constexpr T byteswap_big_to_host(T x) |
| 119 { | |
| 351 | 120 if constexpr (big) { |
| 121 return x; | |
| 122 } else if constexpr (little) { | |
| 123 return byteswap(x); | |
| 124 } | |
| 125 } | |
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126 |
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127 template<typename T> |
| 369 | 128 static T signed_byteswap_little_to_host(T x) |
| 129 { | |
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130 if constexpr (little) { |
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131 return x; |
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132 } else if constexpr (big) { |
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133 return signed_byteswap(x); |
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134 } |
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135 } |
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136 |
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137 template<typename T> |
| 369 | 138 static T signed_byteswap_big_to_host(T x) |
| 139 { | |
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140 if constexpr (big) { |
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141 return x; |
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142 } else if constexpr (little) { |
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143 return signed_byteswap(x); |
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144 } |
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145 } |
| 369 | 146 |
| 351 | 147 private: |
| 148 Endian() = delete; | |
| 149 }; | |
| 150 | |
| 151 #endif /* MINORI_CORE_ENDIAN_H_ */ |