uclibc-ng/utils/bswap.h

/*
 * Lame bswap replacements as we can't assume the host is sane and provides
 * working versions of these.
 */

#ifndef _BSWAP_H
#define	_BSWAP_H 1

#if !defined(__BYTE_ORDER) && defined(BYTE_ORDER)
# define __BYTE_ORDER BYTE_ORDER
# if !defined(__BIG_ENDIAN) && defined(BIG_ENDIAN)
#  define __BIG_ENDIAN BIG_ENDIAN
# endif
# if !defined(__LITTLE_ENDIAN) && defined(LITTLE_ENDIAN)
#  define __LITTLE_ENDIAN LITTLE_ENDIAN
# endif
#endif

#ifndef __BYTE_ORDER
# ifdef __linux__
#  include <endian.h>
# else
#  define __LITTLE_ENDIAN 1234	/* least-significant byte first (vax, pc) */
#  define __BIG_ENDIAN    4321	/* most-significant byte first (IBM, net) */
#  define __PDP_ENDIAN    3412	/* LSB first in word, MSW first in long (pdp) */

#  if defined(sun386) || defined(i386) || defined(__LITTLE_ENDIAN__)
#   define __BYTE_ORDER __LITTLE_ENDIAN
#  endif

#  if defined(sparc) || defined(__BIG_ENDIAN__)
#   define __BYTE_ORDER __BIG_ENDIAN
#  endif

# endif /* __linux__ */
#endif /* __BYTE_ORDER */


#ifndef __BYTE_ORDER
# error "Undefined __BYTE_ORDER"
#endif

#ifdef __linux__
# include <byteswap.h>
#else

static inline uint16_t bswap_16(uint16_t x)
{
	return ((((x) & 0xff00) >> 8) | \
	        (((x) & 0x00ff) << 8));
}
static inline uint32_t bswap_32(uint32_t x)
{
	return ((((x) & 0xff000000) >> 24) | \
	        (((x) & 0x00ff0000) >>  8) | \
	        (((x) & 0x0000ff00) <<  8) | \
	        (((x) & 0x000000ff) << 24));
}
#endif

#endif