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// Copyright 2017 The CRC32C Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef CRC32C_CRC32C_READ_LE_H_
#define CRC32C_CRC32C_READ_LE_H_
#include <cstdint>
#include <cstring>
#include "crc32c/crc32c_config.h"
namespace crc32c {
// Reads a little-endian 32-bit integer from a 32-bit-aligned buffer.
inline uint32_t ReadUint32LE(const uint8_t* buffer) {
#if BYTE_ORDER_BIG_ENDIAN
return ((static_cast<uint32_t>(static_cast<uint8_t>(buffer[0]))) |
(static_cast<uint32_t>(static_cast<uint8_t>(buffer[1])) << 8) |
(static_cast<uint32_t>(static_cast<uint8_t>(buffer[2])) << 16) |
(static_cast<uint32_t>(static_cast<uint8_t>(buffer[3])) << 24));
#else // !BYTE_ORDER_BIG_ENDIAN
uint32_t result;
// This should be optimized to a single instruction.
std::memcpy(&result, buffer, sizeof(result));
return result;
#endif // BYTE_ORDER_BIG_ENDIAN
}
// Reads a little-endian 64-bit integer from a 64-bit-aligned buffer.
inline uint64_t ReadUint64LE(const uint8_t* buffer) {
#if BYTE_ORDER_BIG_ENDIAN
return ((static_cast<uint32_t>(static_cast<uint8_t>(buffer[0]))) |
(static_cast<uint32_t>(static_cast<uint8_t>(buffer[1])) << 8) |
(static_cast<uint32_t>(static_cast<uint8_t>(buffer[2])) << 16) |
(static_cast<uint32_t>(static_cast<uint8_t>(buffer[3])) << 24) |
(static_cast<uint32_t>(static_cast<uint8_t>(buffer[4])) << 32) |
(static_cast<uint32_t>(static_cast<uint8_t>(buffer[5])) << 40) |
(static_cast<uint32_t>(static_cast<uint8_t>(buffer[6])) << 48) |
(static_cast<uint32_t>(static_cast<uint8_t>(buffer[7])) << 56));
#else // !BYTE_ORDER_BIG_ENDIAN
uint64_t result;
// This should be optimized to a single instruction.
std::memcpy(&result, buffer, sizeof(result));
return result;
#endif // BYTE_ORDER_BIG_ENDIAN
}
} // namespace crc32c
#endif // CRC32C_CRC32C_READ_LE_H_
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