Line data    Source code

       1             : // Copyright (c) 2014-2019 The Bitcoin Core developers
       2             : // Distributed under the MIT software license, see the accompanying
       3             : // file COPYING or http://www.opensource.org/licenses/mit-license.php.
       4             : 
       5             : #ifndef BITCOIN_COMPAT_BYTESWAP_H
       6             : #define BITCOIN_COMPAT_BYTESWAP_H
       7             : 
       8             : #include <cstdint>
       9             : #ifdef _MSC_VER
      10             : #include <cstdlib>
      11             : #endif
      12             : 
      13             : 
      14             : // All internal_bswap_* functions can be replaced with std::byteswap once we
      15             : // require c++23. Both libstdc++ and libc++ implement std::byteswap via these
      16             : // builtins.
      17             : 
      18             : #ifndef DISABLE_BUILTIN_BSWAPS
      19             : #  if defined __has_builtin
      20             : #    if __has_builtin(__builtin_bswap16)
      21             : #      define bitcoin_builtin_bswap16(x) __builtin_bswap16(x)
      22             : #    endif
      23             : #    if __has_builtin(__builtin_bswap32)
      24             : #      define bitcoin_builtin_bswap32(x) __builtin_bswap32(x)
      25             : #    endif
      26             : #    if __has_builtin(__builtin_bswap64)
      27             : #      define bitcoin_builtin_bswap64(x) __builtin_bswap64(x)
      28             : #    endif
      29             : #  elif defined(_MSC_VER)
      30             : #      define bitcoin_builtin_bswap16(x) _byteswap_ushort(x)
      31             : #      define bitcoin_builtin_bswap32(x) _byteswap_ulong(x)
      32             : #      define bitcoin_builtin_bswap64(x) _byteswap_uint64(x)
      33             : #  endif
      34             : #endif
      35             : 
      36             : // MSVC's _byteswap_* functions are not constexpr
      37             : 
      38             : #ifndef _MSC_VER
      39             : #define BSWAP_CONSTEXPR constexpr
      40             : #else
      41             : #define BSWAP_CONSTEXPR
      42             : #endif
      43             : 
      44        1376 : inline BSWAP_CONSTEXPR uint16_t internal_bswap_16(uint16_t x)
      45             : {
      46             : #ifdef bitcoin_builtin_bswap16
      47        1376 :     return bitcoin_builtin_bswap16(x);
      48             : #else
      49             :     return (x >> 8) | (x << 8);
      50             : #endif
      51             : }
      52             : 
      53   217598700 : inline BSWAP_CONSTEXPR uint32_t internal_bswap_32(uint32_t x)
      54             : {
      55             : #ifdef bitcoin_builtin_bswap32
      56   217598700 :     return bitcoin_builtin_bswap32(x);
      57             : #else
      58             :     return (((x & 0xff000000U) >> 24) | ((x & 0x00ff0000U) >>  8) |
      59             :             ((x & 0x0000ff00U) <<  8) | ((x & 0x000000ffU) << 24));
      60             : #endif
      61             : }
      62             : 
      63   356240234 : inline BSWAP_CONSTEXPR uint64_t internal_bswap_64(uint64_t x)
      64             : {
      65             : #ifdef bitcoin_builtin_bswap64
      66   356240234 :     return bitcoin_builtin_bswap64(x);
      67             : #else
      68             :      return (((x & 0xff00000000000000ull) >> 56)
      69             :           | ((x & 0x00ff000000000000ull) >> 40)
      70             :           | ((x & 0x0000ff0000000000ull) >> 24)
      71             :           | ((x & 0x000000ff00000000ull) >> 8)
      72             :           | ((x & 0x00000000ff000000ull) << 8)
      73             :           | ((x & 0x0000000000ff0000ull) << 24)
      74             :           | ((x & 0x000000000000ff00ull) << 40)
      75             :           | ((x & 0x00000000000000ffull) << 56));
      76             : #endif
      77             : }
      78             : 
      79             : #endif // BITCOIN_COMPAT_BYTESWAP_H