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forked from 0ad/0ad
0ad/source/lib/byte_order.h
janwas a3967624af add 64-bit endian-safe read; also bit_mask
work continues on DDS decode. endian-safe; supports dxt1a; now fairly
efficient and cleaned up.

This was SVN commit r2751.
2005-09-18 18:10:23 +00:00

27 lines
1002 B
C

#include "config.h"
// converts 4 character string to u32 for easy comparison
// 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 useable as a switch{} expression)
//
// these 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).
#if BYTE_ORDER == BIG_ENDIAN
#define FOURCC(a,b,c,d) ( ((u32)(u8)a) << 24 | ((u32)(u8)b) << 16 | \
((u32)(u8)c) << 8 | ((u32)(u8)d) << 0 )
#else
#define FOURCC(a,b,c,d) ( ((u32)(u8)a) << 0 | ((u32)(u8)b) << 8 | \
((u32)(u8)c) << 16 | ((u32)(u8)d) << 24 )
#endif
extern u16 read_le16(const void* p);
extern u32 read_le32(const void* p);
extern u64 read_le64(const void* p);
extern u16 read_be16(const void* p);
extern u32 read_be32(const void* p);
extern u64 read_be64(const void* p);