Aegisub/aegisub/src/aegisub_endian.h
Amar Takhar 774fb0f674 Fix all the headers in *., this includes:
* Wrapping all headers that are in agi_pre.h with AGI_PRE.
  * Sorting alphabetically.
  * Same operation as r3515.

Note: This is broken when precompiled headers are not in use, I'll fix that after this commit so the two changes don't get jumbled up.

Originally committed to SVN as r3525.
2009-09-11 02:36:34 +00:00

463 lines
9.9 KiB
C++

// Copyright (c) 2008, Niels Martin Hansen
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
// * Neither the name of the Aegisub Group nor the names of its contributors
// may be used to endorse or promote products derived from this software
// without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//
// Aegisub Project http://www.aegisub.org/
//
// $Id$
/// @file aegisub_endian.h
/// @brief Convert numbers between various endianness
/// @ingroup utility
///
// Sanity check
#ifndef HAVE_LITTLE_ENDIAN
# ifndef HAVE_BIG_ENDIAN
// We neither have big nor little endian from configuration
# ifdef HAVE_UNIVERSAL_ENDIAN
// But this is an OS X system building a universal binary
// Apple's GCC defines _BIG_ENDIAN when building for PPC
# ifdef _BIG_ENDIAN
/// DOCME
# define HAVE_BIG_ENDIAN
# else
/// DOCME
# define HAVE_LITTLE_ENDIAN
# endif
/// DOCME
# undef HAVE_DYNAMIC_ENDIAN
# else // !HAVE_UNIVERSAL_ENDIAN
// We aren't building an OS X universal binary
// Use the dynamic endian code
# ifndef HAVE_DYNAMIC_ENDIAN
/// DOCME
# define HAVE_DYNAMIC_ENDIAN
# endif
# endif //HAVE_UNIVERSAL_ENDIAN
# endif // HAVE_BIG_ENDIAN
#endif // HAVE_LITTLE_ENDIAN
#ifdef HAVE_LITTLE_ENDIAN
# ifdef HAVE_BIG_ENDIAN
# error You cannot have both HAVE_LITTLE_ENDIAN and HAVE_BIG_ENDIAN defined at the same time
# endif
#endif
#ifndef AGI_PRE
#include <stdint.h>
#endif
/// DOCME
namespace Endian {
// Unconditionally reverse endianness
// These are only defined for unsigned ints,
// Use reinterpret_cast on the values if you need signed values.
/// @brief DOCME
/// @param val
/// @return
///
inline uint16_t Reverse(uint16_t val)
{
return
((val & 0x00FF) << 8) |
((val & 0xFF00) >> 8);
}
/// @brief DOCME
/// @param val
/// @return
///
inline uint32_t Reverse(uint32_t val)
{
return
((val & 0x000000FF) << 24) |
((val & 0x0000FF00) << 8) |
((val & 0x00FF0000) >> 8) |
((val & 0xFF000000) >> 24);
}
/// @brief DOCME
/// @param val
/// @return
///
inline uint64_t Reverse(uint64_t val)
{
return
((val & 0x00000000000000FFULL) << 56) |
((val & 0x000000000000FF00ULL) << 40) |
((val & 0x0000000000FF0000ULL) << 24) |
((val & 0x00000000FF000000ULL) << 8) |
((val & 0x000000FF00000000ULL) >> 8) |
((val & 0x0000FF0000000000ULL) >> 24) |
((val & 0x00FF000000000000ULL) >> 40) |
((val & 0xFF00000000000000ULL) >> 56);
}
#ifndef HAVE_DYNAMIC_ENDIAN
// Regular, fast, templatized conditional reversing
template <class T>
/// @brief DOCME
/// @param val
/// @return
///
inline T LittleToMachine(T val)
{
#ifdef HAVE_BIG_ENDIAN
// We're on big endian, reverse little to big
return Reverse(val);
#else
// We're on little endian and input is little
return val;
#endif
}
template <class T>
/// @brief DOCME
/// @param val
/// @return
///
inline T BigToMachine(T val)
{
#ifdef HAVE_LITTLE_ENDIAN
// We're on little endian, reverse big to little
return Reverse(val);
#else
// We're on big endian and input is big
return val;
#endif
}
template <class T>
/// @brief DOCME
/// @param val
/// @return
///
inline T MachineToLittle(T val)
{
#ifdef HAVE_BIG_ENDIAN
// We're on big endian, reverse to little
return Reverse(val);
#else
// Already on little, nothing to be done
return val;
#endif
}
template <class T>
/// @brief DOCME
/// @param val
/// @return
///
inline T MachineToBig(T val)
{
#ifdef HAVE_LITTLE_ENDIAN
// We're on little endian, reverse to big
return Reverse(val);
#else
// Already on big, nothing to be done
return val;
#endif
}
#else // HAVE_DYNAMIC_ENDIAN
// Dynamic endianness handling
// Exploit that bit-shifting operations always can put bytes into
// machine word order, while unions can be used to access bytes
// only from an explicitly given byte order.
// This is probably slower than when we explicitly know
// the endianness of the machine we are on, but it's the same
// code for any platform!
// Unions to pack together ints and get their physical bytes
/// DOCME
union bytes16 {
/// DOCME
uint8_t byte[2];
/// DOCME
uint16_t word;
};
/// DOCME
union bytes32 {
/// DOCME
uint8_t byte[4];
/// DOCME
uint32_t word;
};
/// DOCME
union bytes64 {
/// DOCME
uint8_t byte[8];
/// DOCME
uint64_t word;
};
// 16 bit words
/// @brief DOCME
/// @param val
/// @return
///
inline uint16_t MachineToBig(uint16_t val)
{
bytes16 pack;
// Store the bytes into the correct positions in the word
pack.byte[0] = (val & 0xFF00) >> 8;
pack.byte[1] = val & 0x00FF;
// And return a value now encoded as big endian
return pack.word;
}
/// @brief DOCME
/// @param val
/// @return
///
inline uint16_t MachineToLittle(uint16_t val)
{
bytes16 pack;
// Store the bytes into the correct positions in the word
pack.byte[0] = val & 0x00FF;
pack.byte[1] = (val & 0xFF00) >> 8;
// And return a value now encoded as little endian
return pack.word;
}
/// @brief DOCME
/// @param val
/// @return
///
inline uint16_t BigToMachine(uint16_t val)
{
bytes16 pack;
// Put our word into the pack
pack.word = val;
// And produce a machine endian value of it
return uint16_t(pack.byte[1]) | (uint16_t(pack.byte[0]) << 8);
}
/// @brief DOCME
/// @param val
/// @return
///
inline uint16_t LittleToMachine(uint16_t val)
{
bytes16 pack;
// Put our word into the pack
pack.word = val;
// And produce a machine endian value of it
return uint16_t(pack.byte[0]) | (uint16_t(pack.byte[1]) << 8);
}
// 32 bit words
/// @brief DOCME
/// @param val
/// @return
///
inline uint32_t MachineToBig(uint32_t val)
{
bytes32 pack;
pack.byte[0] = (val & 0xFF000000) >> 24;
pack.byte[1] = (val & 0x00FF0000) >> 16;
pack.byte[2] = (val & 0x0000FF00) >> 8;
pack.byte[3] = val & 0x000000FF ;
return pack.word;
}
/// @brief DOCME
/// @param val
/// @return
///
inline uint32_t MachineToLittle(uint32_t val)
{
bytes32 pack;
pack.byte[0] = val & 0x000000FF ;
pack.byte[1] = (val & 0x0000FF00) >> 8;
pack.byte[2] = (val & 0x00FF0000) >> 16;
pack.byte[3] = (val & 0xFF000000) >> 24;
return pack.word;
}
/// @brief DOCME
/// @param val
/// @return
///
inline uint32_t BigToMachine(uint32_t val)
{
bytes32 pack;
pack.word = val;
return
(uint32_t(pack.byte[0]) << 24) |
(uint32_t(pack.byte[1]) << 16) |
(uint32_t(pack.byte[2]) << 8) |
uint32_t(pack.byte[3]);
}
/// @brief DOCME
/// @param val
/// @return
///
inline uint32_t LittleToMachine(uint32_t val)
{
bytes32 pack;
pack.word = val;
return
(uint32_t(pack.byte[3]) << 24) |
(uint32_t(pack.byte[2]) << 16) |
(uint32_t(pack.byte[1]) << 8) |
uint32_t(pack.byte[0]);
}
// 64 bit words
/// @brief DOCME
/// @param val
/// @return
///
inline uint64_t MachineToBig(uint64_t val)
{
bytes64 pack;
pack.byte[0] = (val & 0xFF00000000000000ULL) >> 56;
pack.byte[1] = (val & 0x00FF000000000000ULL) >> 48;
pack.byte[2] = (val & 0x0000FF0000000000ULL) >> 40;
pack.byte[3] = (val & 0x000000FF00000000ULL) >> 32;
pack.byte[4] = (val & 0x00000000FF000000ULL) >> 24;
pack.byte[5] = (val & 0x0000000000FF0000ULL) >> 16;
pack.byte[6] = (val & 0x000000000000FF00ULL) >> 8;
pack.byte[7] = val & 0x00000000000000FFULL ;
return pack.word;
}
/// @brief DOCME
/// @param val
/// @return
///
inline uint64_t MachineToLittle(uint64_t val)
{
bytes64 pack;
pack.byte[0] = val & 0x00000000000000FFULL ;
pack.byte[1] = (val & 0x000000000000FF00ULL) >> 8;
pack.byte[2] = (val & 0x0000000000FF0000ULL) >> 16;
pack.byte[3] = (val & 0x00000000FF000000ULL) >> 24;
pack.byte[4] = (val & 0x000000FF00000000ULL) >> 32;
pack.byte[5] = (val & 0x0000FF0000000000ULL) >> 40;
pack.byte[6] = (val & 0x00FF000000000000ULL) >> 48;
pack.byte[7] = (val & 0xFF00000000000000ULL) >> 56;
return pack.word;
}
/// @brief DOCME
/// @param val
/// @return
///
inline uint64_t BigToMachine(uint64_t val)
{
bytes64 pack;
pack.word = val;
return
(uint64_t(pack.byte[0]) << 56) |
(uint64_t(pack.byte[1]) << 48) |
(uint64_t(pack.byte[2]) << 40) |
(uint64_t(pack.byte[3]) << 32) |
(uint64_t(pack.byte[4]) << 24) |
(uint64_t(pack.byte[5]) << 16) |
(uint64_t(pack.byte[6]) << 8) |
uint64_t(pack.byte[7]);
}
/// @brief DOCME
/// @param val
///
inline uint64_t LittleToMachine(uint64_t val)
{
bytes64 pack;
pack.word = val;
return
(uint64_t(pack.byte[7]) << 56) |
(uint64_t(pack.byte[6]) << 48) |
(uint64_t(pack.byte[5]) << 40) |
(uint64_t(pack.byte[4]) << 32) |
(uint64_t(pack.byte[3]) << 24) |
(uint64_t(pack.byte[2]) << 16) |
(uint64_t(pack.byte[1]) << 8) |
uint64_t(pack.byte[0]);
}
#endif
};