/*
 * endianness.h
 *
 * Copyright (C) 2012 Eric Biggers
 *
 * wimlib - Library for working with WIM files 
 *
 * This library is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation; either version 2.1 of the License, or (at your option) any
 * later version.
 *
 * This library 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. See the GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along
 * with this library; if not, write to the Free Software Foundation, Inc., 59
 * Temple Place, Suite 330, Boston, MA 02111-1307 USA 
 */

#ifndef _WIMLIB_ENDIANNESS_H
#define _WIMLIB_ENDIANNESS_H


#include "config.h"
#include <inttypes.h>

/* Changes the endianness of a 32-bit value. */
static inline uint32_t bswap32(uint32_t n)
{
#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)
	return __builtin_bswap32(n);
#else
	return (n << 24) | ((n & 0xff00) << 8) | ((n & 0xff0000) >> 8) | 
							(n >> 24);
#endif
}

#ifdef WORDS_BIGENDIAN

/* Big endian. */

/* Changes the endianness of a 16-bit value. */
static inline uint16_t bswap16(uint16_t n)
{
	return (n << 8) | (n >> 8);
}


/* Changes the endianness of a 64-bit value. */
static inline uint64_t bswap64(uint64_t n)
{
#ifdef __GNUC__
	return __builtin_bswap64(n);
#else
	return (n << 56) | ((n & 0xff00) << 40) | ((n & 0xff0000) << 24) | 
			((n & 0xff000000) << 8) | ((n & 0xff00000000) >> 8) | 
			((n & 0xff0000000000) >> 24) | 
			((n & 0xff000000000000) >> 40) | (n >> 56);
#endif
}

/* Not in place */
#define to_le16(n) bswap16(n)
#define to_le32(n) bswap32(n)
#define to_le64(n) bswap64(n)
#define to_be16(n) (n)
#define to_be32(n) (n)
#define to_be64(n) (n)

/* In place */
#define TO_LE16(n) (n = to_le16(n))
#define TO_LE32(n) (n = to_le32(n))
#define TO_LE64(n) (n = to_le64(n))

static inline void array_to_le16(uint16_t *p, uint64_t n)
{
	while (n--)
		*p++ = to_le16(*p);
}
static inline void array_to_le32(uint32_t *p, uint64_t n)
{
	while (n--)
		*p++ = to_le32(*p);
}
static inline void array_to_le64(uint64_t *p, uint64_t n)
{
	while (n--)
		*p++ = to_le64(*p);
}

#else

/* Little endian. */

/* Not in place */
#define to_le16(n) (n)
#define to_le32(n) (n)
#define to_le64(n) (n)

#define to_be16(n) (bswap16(n))
#define to_be32(n) (bswap32(n))
#define to_be64(n) (bswap64(n))

/* In place */
#define TO_LE16(n)
#define TO_LE32(n)
#define TO_LE64(n)

#define array_to_le16(p, n)
#define array_to_le32(p, n)
#define array_to_le64(p, n)

#endif


#endif /* _WIMLIB_ENDIANNESS_H */