fourcc as uint32_t

gistfile1.c

#include <stdint.h>
#include <endian.h>

#define _MAGIC_FROM_CHARS(C1,C2,C3,C4) (uint32_t)(((C1) << 24) | ((C2) << 16) | ((C3) << 8) | (C4))

#if __BYTE_ORDER == __LITTLE_ENDIAN

#  define MAGIC_FROM_CHARS(C1,C2,C3,C4) _MAGIC_FROM_CHARS(C4,C3,C2,C1)

#elif __BYTE_ORDER == __BIG_ENDIAN

#	define MAGIC_FROM_CHARS(C1,C2,C3,C4) _MAGIC_FROM_CHARS(C1,C2,C3,C4)

#elif __BYTE_ORDER == __PDP_ENDIAN

#	define MAGIC_FROM_CHARS(C1,C2,C3,C4) _MAGIC_FROM_CHARS(C3,C4,C1,C2)

#else

#	error unsupported byte order

#endif

#define MAGIC(S) MAGIC_FROM_CHARS((S)[0], (S)[1], (S)[2], (S)[3])