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0ad/source/lib/byte_order.h
janwas 0bb0df5b2c # new year's cleanup (reduce dependencies, clean up headers)
- remove headers always included from PCH
- nommgr.h is only included ifdef REDEFINED_NEW (allows leaving out the
mmgr stuff)
- in lib/*.cpp, moved the corresponding include file to right behind the
PCH (catches headers that aren't compilable by themselves)
- byte_order no longer depends on SDL
- add debug_level (another means of filtering debug output; needed for
thesis)
- split posix stuff up into subdirs (lib/posix and sysdep/win/wposix).
makes including only some of the modules (e.g. sockets, time) much
easier.

This was SVN commit r4728.
2007-01-01 21:25:47 +00:00

111 lines
3.7 KiB
C

/**
* =========================================================================
* File : byte_order.h
* Project : 0 A.D.
* Description : byte order (endianness) support routines.
*
* @author Jan.Wassenberg@stud.uni-karlsruhe.de
* =========================================================================
*/
/*
* Copyright (c) 2003 Jan Wassenberg
*
* Redistribution and/or modification are also permitted under the
* terms of the GNU General Public License as published by the
* Free Software Foundation (version 2 or later, at your option).
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
*/
#ifndef INCLUDED_BYTE_ORDER
#define INCLUDED_BYTE_ORDER
#include "config.h"
/**
* convert 4 characters to u32 (at compile time) for easy comparison.
* output is in native byte order; e.g. FOURCC_LE can be used instead.
**/
#define FOURCC(a,b,c,d) // real definition is below
#undef FOURCC
// implementation rationale:
// - can't pass code as string, and use s[0]..s[3], because
// VC6/7 don't realize the macro is constant
// (it should be usable as a switch{} expression)
// - the casts are ugly but necessary. u32 is required because u8 << 8 == 0;
// the additional u8 cast ensures each character is treated as unsigned
// (otherwise, they'd be promoted to signed int before the u32 cast,
// which would break things).
/// big-endian version of FOURCC
#define FOURCC_BE(a,b,c,d) ( ((u32)(u8)a) << 24 | ((u32)(u8)b) << 16 | \
((u32)(u8)c) << 8 | ((u32)(u8)d) << 0 )
/// little-endian version of FOURCC
#define FOURCC_LE(a,b,c,d) ( ((u32)(u8)a) << 0 | ((u32)(u8)b) << 8 | \
((u32)(u8)c) << 16 | ((u32)(u8)d) << 24 )
#if BYTE_ORDER == BIG_ENDIAN
# define FOURCC FOURCC_BE
#else
# define FOURCC FOURCC_LE
#endif
/// convert a little-endian number to/from native byte order.
extern u16 to_le16(u16 x);
extern u32 to_le32(u32 x); /// see to_le16
extern u64 to_le64(u64 x); /// see to_le16
/// convert a big-endian number to/from native byte order.
extern u16 to_be16(u16 x);
extern u32 to_be32(u32 x); /// see to_be16
extern u64 to_be64(u64 x); /// see to_be16
/// read a little-endian number from memory into native byte order.
extern u16 read_le16(const void* p);
extern u32 read_le32(const void* p); /// see read_le16
extern u64 read_le64(const void* p); /// see read_le16
/// read a big-endian number from memory into native byte order.
extern u16 read_be16(const void* p);
extern u32 read_be32(const void* p); /// see read_be16
extern u64 read_be64(const void* p); /// see read_be16
/// write a little-endian number to memory in native byte order.
extern void write_le16(void* p, u16 x);
extern void write_le32(void* p, u32 x); /// see write_le16
extern void write_le64(void* p, u64 x); /// see write_le16
/// write a big-endian number to memory in native byte order.
extern void write_be16(void* p, u16 x);
extern void write_be32(void* p, u32 x); /// see write_be16
extern void write_be64(void* p, u64 x); /// see write_be16
// Debug-mode ICC doesn't like the intrinsics, so only use them
// for MSVC and non-debug ICC.
#if MSC_VERSION && !( defined(__INTEL_COMPILER) && !defined(NDEBUG) )
extern unsigned short _byteswap_ushort(unsigned short);
extern unsigned long _byteswap_ulong(unsigned long);
extern unsigned __int64 _byteswap_uint64(unsigned __int64);
#pragma intrinsic(_byteswap_ushort)
#pragma intrinsic(_byteswap_ulong)
#pragma intrinsic(_byteswap_uint64)
# define swap16 _byteswap_ushort
# define swap32 _byteswap_ulong
# define swap64 _byteswap_uint64
#else
extern u16 swap16(const u16 x);
extern u32 swap32(const u32 x);
extern u64 swap64(const u64 x);
#endif // no swap intrinsics
#endif // #ifndef INCLUDED_BYTE_ORDER