// Licensed to the Apache Software Foundation (ASF) under one // or more contributor license agreements. See the NOTICE file // distributed with this work for additional information // regarding copyright ownership. The ASF licenses this file // to you under the Apache License, Version 2.0 (the // "License"); you may not use this file except in compliance // with the License. You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, // software distributed under the License is distributed on an // "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY // KIND, either express or implied. See the License for the // specific language governing permissions and limitations // under the License. #pragma once #ifdef _WIN32 #define ARROW_LITTLE_ENDIAN 1 #else #if defined(__APPLE__) || defined(__FreeBSD__) #include // IWYU pragma: keep #elif defined(sun) || defined(__sun) #include // IWYU pragma: keep #else #include // IWYU pragma: keep #endif # #ifndef __BYTE_ORDER__ #error "__BYTE_ORDER__ not defined" #endif # #ifndef __ORDER_LITTLE_ENDIAN__ #error "__ORDER_LITTLE_ENDIAN__ not defined" #endif # #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ #define ARROW_LITTLE_ENDIAN 1 #else #define ARROW_LITTLE_ENDIAN 0 #endif #endif #if defined(_MSC_VER) #include // IWYU pragma: keep #define ARROW_BYTE_SWAP64 _byteswap_uint64 #define ARROW_BYTE_SWAP32 _byteswap_ulong #else #define ARROW_BYTE_SWAP64 __builtin_bswap64 #define ARROW_BYTE_SWAP32 __builtin_bswap32 #endif #include #include #include "arrow/util/type_traits.h" #include "arrow/util/ubsan.h" namespace arrow { namespace bit_util { // // Byte-swap 16-bit, 32-bit and 64-bit values // // Swap the byte order (i.e. endianness) static inline int64_t ByteSwap(int64_t value) { return ARROW_BYTE_SWAP64(value); } static inline uint64_t ByteSwap(uint64_t value) { return static_cast(ARROW_BYTE_SWAP64(value)); } static inline int32_t ByteSwap(int32_t value) { return ARROW_BYTE_SWAP32(value); } static inline uint32_t ByteSwap(uint32_t value) { return static_cast(ARROW_BYTE_SWAP32(value)); } static inline int16_t ByteSwap(int16_t value) { constexpr auto m = static_cast(0xff); return static_cast(((value >> 8) & m) | ((value & m) << 8)); } static inline uint16_t ByteSwap(uint16_t value) { return static_cast(ByteSwap(static_cast(value))); } static inline uint8_t ByteSwap(uint8_t value) { return value; } static inline int8_t ByteSwap(int8_t value) { return value; } static inline double ByteSwap(double value) { const uint64_t swapped = ARROW_BYTE_SWAP64(util::SafeCopy(value)); return util::SafeCopy(swapped); } static inline float ByteSwap(float value) { const uint32_t swapped = ARROW_BYTE_SWAP32(util::SafeCopy(value)); return util::SafeCopy(swapped); } // Write the swapped bytes into dst. Src and dst cannot overlap. static inline void ByteSwap(void* dst, const void* src, int len) { switch (len) { case 1: *reinterpret_cast(dst) = *reinterpret_cast(src); return; case 2: *reinterpret_cast(dst) = ByteSwap(*reinterpret_cast(src)); return; case 4: *reinterpret_cast(dst) = ByteSwap(*reinterpret_cast(src)); return; case 8: *reinterpret_cast(dst) = ByteSwap(*reinterpret_cast(src)); return; default: break; } auto d = reinterpret_cast(dst); auto s = reinterpret_cast(src); for (int i = 0; i < len; ++i) { d[i] = s[len - i - 1]; } } // Convert to little/big endian format from the machine's native endian format. #if ARROW_LITTLE_ENDIAN template > static inline T ToBigEndian(T value) { return ByteSwap(value); } template > static inline T ToLittleEndian(T value) { return value; } #else template > static inline T ToBigEndian(T value) { return value; } template > static inline T ToLittleEndian(T value) { return ByteSwap(value); } #endif // Convert from big/little endian format to the machine's native endian format. #if ARROW_LITTLE_ENDIAN template > static inline T FromBigEndian(T value) { return ByteSwap(value); } template > static inline T FromLittleEndian(T value) { return value; } #else template > static inline T FromBigEndian(T value) { return value; } template > static inline T FromLittleEndian(T value) { return ByteSwap(value); } #endif // Handle endianness in *word* granuality (keep individual array element untouched) namespace little_endian { namespace detail { // Read a native endian array as little endian template struct Reader { const std::array& native_array; explicit Reader(const std::array& native_array) : native_array(native_array) {} const T& operator[](size_t i) const { return native_array[ARROW_LITTLE_ENDIAN ? i : N - 1 - i]; } }; // Read/write a native endian array as little endian template struct Writer { std::array* native_array; explicit Writer(std::array* native_array) : native_array(native_array) {} const T& operator[](size_t i) const { return (*native_array)[ARROW_LITTLE_ENDIAN ? i : N - 1 - i]; } T& operator[](size_t i) { return (*native_array)[ARROW_LITTLE_ENDIAN ? i : N - 1 - i]; } }; } // namespace detail // Construct array reader and try to deduce template augments template static inline detail::Reader Make(const std::array& native_array) { return detail::Reader(native_array); } // Construct array writer and try to deduce template augments template static inline detail::Writer Make(std::array* native_array) { return detail::Writer(native_array); } // Convert little endian array to native endian template static inline std::array ToNative(std::array array) { if (!ARROW_LITTLE_ENDIAN) { std::reverse(array.begin(), array.end()); } return array; } // Convert native endian array to little endian template static inline std::array FromNative(std::array array) { return ToNative(array); } } // namespace little_endian } // namespace bit_util } // namespace arrow