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forked from 0ad/0ad
0ad/source/lib/byte_order.h
janwas ee4c7965dd # merge all local changes; moving over to new SVN server
* app_hooks: add display_error; can be used by atlas to override our
dialog box
* lots of small fixes (mostly pertaining to headers)
* debug: clean up display_error, protect from reentrancy, fix a few edge
cases (e.g. error message from dtor -> exit pressed -> suppress all
subsequent errors)
* delay_load: add warning: NLSO ctors are unreliable since we're
compiling into static lib

This was SVN commit r4009.
2006-06-22 18:26:08 +00:00

86 lines
3.0 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.
*/
#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