include/ntfs/endians.h

/*
 * endians.h - Definitions related to handling of byte ordering. Part of the
 *	       Linux-NTFS project.
 *
 * Copyright (c) 2000-2005 Anton Altaparmakov
 * Copyright (c)      2007 Yura Pakhuchiy
 *
 * This program/include file is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as published
 * by the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program/include file 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program (in the main directory of the Linux-NTFS
 * distribution in the file COPYING); if not, write to the Free Software
 * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#ifndef _NTFS_ENDIANS_H
#define _NTFS_ENDIANS_H

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

/*
 * Notes:
 *	We define the conversion functions including typecasts since the
 * defaults don't necessarily perform appropriate typecasts.
 *	Also, using our own functions means that we can change them if it
 * turns out that we do need to use the unaligned access macros on
 * architectures requiring aligned memory accesses...
 */

#ifdef HAVE_ENDIAN_H
#include <endian.h>
#endif
#ifdef HAVE_SYS_ENDIAN_H
#include <sys/endian.h>
#endif
#ifdef HAVE_MACHINE_ENDIAN_H
#include <machine/endian.h>
#endif
#ifdef HAVE_SYS_BYTEORDER_H
#include <sys/byteorder.h>
#endif
#ifdef HAVE_SYS_PARAM_H
#include <sys/param.h>
#endif

#ifndef __BYTE_ORDER
#	if defined(_BYTE_ORDER)
#		define __BYTE_ORDER _BYTE_ORDER
#		define __LITTLE_ENDIAN _LITTLE_ENDIAN
#		define __BIG_ENDIAN _BIG_ENDIAN
#	elif defined(BYTE_ORDER)
#		define __BYTE_ORDER BYTE_ORDER
#		define __LITTLE_ENDIAN LITTLE_ENDIAN
#		define __BIG_ENDIAN BIG_ENDIAN
#	elif defined(__BYTE_ORDER__)
#		define __BYTE_ORDER __BYTE_ORDER__
#		define __LITTLE_ENDIAN __LITTLE_ENDIAN__
#		define __BIG_ENDIAN __BIG_ENDIAN__
#	elif (defined(_LITTLE_ENDIAN) && !defined(_BIG_ENDIAN)) || \
			defined(WORDS_LITTLEENDIAN)
#		define __BYTE_ORDER 1
#		define __LITTLE_ENDIAN 1
#		define __BIG_ENDIAN 0
#	elif (!defined(_LITTLE_ENDIAN) && defined(_BIG_ENDIAN)) || \
			defined(WORDS_BIGENDIAN)
#		define __BYTE_ORDER 0
#		define __LITTLE_ENDIAN 1
#		define __BIG_ENDIAN 0
#	else
#		error "__BYTE_ORDER is not defined."
#	endif
#endif

#define __ntfs_bswap_constant_16(x)		\
	  (u16)((((u16)(x) & 0xff00) >> 8) |	\
		(((u16)(x) & 0x00ff) << 8))

#define __ntfs_bswap_constant_32(x)			\
	  (u32)((((u32)(x) & 0xff000000u) >> 24) |	\
		(((u32)(x) & 0x00ff0000u) >>  8) |	\
		(((u32)(x) & 0x0000ff00u) <<  8) |	\
		(((u32)(x) & 0x000000ffu) << 24))

#define __ntfs_bswap_constant_64(x)				\
	  (u64)((((u64)(x) & 0xff00000000000000ull) >> 56) |	\
		(((u64)(x) & 0x00ff000000000000ull) >> 40) |	\
		(((u64)(x) & 0x0000ff0000000000ull) >> 24) |	\
		(((u64)(x) & 0x000000ff00000000ull) >>  8) |	\
		(((u64)(x) & 0x00000000ff000000ull) <<  8) |	\
		(((u64)(x) & 0x0000000000ff0000ull) << 24) |	\
		(((u64)(x) & 0x000000000000ff00ull) << 40) |	\
		(((u64)(x) & 0x00000000000000ffull) << 56))

#ifdef HAVE_BYTESWAP_H
#	include <byteswap.h>
#else
#	define bswap_16(x) __ntfs_bswap_constant_16(x)
#	define bswap_32(x) __ntfs_bswap_constant_32(x)
#	define bswap_64(x) __ntfs_bswap_constant_64(x)
#endif

#if defined(__LITTLE_ENDIAN) && (__BYTE_ORDER == __LITTLE_ENDIAN)

#define __le16_to_cpu(x) ((__force u16)(x))
#define __le32_to_cpu(x) ((__force u32)(x))
#define __le64_to_cpu(x) ((__force u64)(x))

#define __cpu_to_le16(x) ((__force le16)(x))
#define __cpu_to_le32(x) ((__force le32)(x))
#define __cpu_to_le64(x) ((__force le64)(x))

#define __constant_le16_to_cpu(x) ((__force u16)(x))
#define __constant_le32_to_cpu(x) ((__force u32)(x))
#define __constant_le64_to_cpu(x) ((__force u64)(x))

#define __constant_cpu_to_le16(x) ((__force le16)(x))
#define __constant_cpu_to_le32(x) ((__force le32)(x))
#define __constant_cpu_to_le64(x) ((__force le64)(x))

#elif defined(__BIG_ENDIAN) && (__BYTE_ORDER == __BIG_ENDIAN)

#define __le16_to_cpu(x) bswap_16((__force u16)(x))
#define __le32_to_cpu(x) bswap_32((__force u16)(x))
#define __le64_to_cpu(x) bswap_64((__force u16)(x))

#define __cpu_to_le16(x) (__force le16)bswap_16((__force u16)(x))
#define __cpu_to_le32(x) (__force le32)bswap_32((__force u32)(x))
#define __cpu_to_le64(x) (__force le64)bswap_64((__force u64)(x))

#define __constant_le16_to_cpu(x) __ntfs_bswap_constant_16((__force u16)(x))
#define __constant_le32_to_cpu(x) __ntfs_bswap_constant_32((__force u32)(x))
#define __constant_le64_to_cpu(x) __ntfs_bswap_constant_64((__force u64)(x))

#define __constant_cpu_to_le16(x) \
	(__force le16)__ntfs_bswap_constant_16((__force u16)(x))
#define __constant_cpu_to_le32(x) \
	(__force le32)__ntfs_bswap_constant_32((__force u32)(x))
#define __constant_cpu_to_le64(x) \
	(__force le64)__ntfs_bswap_constant_64((__force u64)(x))

#else

#error "You must define __BYTE_ORDER to be __LITTLE_ENDIAN or __BIG_ENDIAN."

#endif

/* Unsigned from LE to CPU conversion. */

#define le16_to_cpu(x)		(u16)__le16_to_cpu((le16)(x))
#define le32_to_cpu(x)		(u32)__le32_to_cpu((le32)(x))
#define le64_to_cpu(x)		(u64)__le64_to_cpu((le64)(x))

#define le16_to_cpup(x)		(u16)__le16_to_cpu(*(const le16*)(x))
#define le32_to_cpup(x)		(u32)__le32_to_cpu(*(const le32*)(x))
#define le64_to_cpup(x)		(u64)__le64_to_cpu(*(const le64*)(x))

/* Signed from LE to CPU conversion. */

#define sle16_to_cpu(x)		(s16)__le16_to_cpu((sle16)(x))
#define sle32_to_cpu(x)		(s32)__le32_to_cpu((sle32)(x))
#define sle64_to_cpu(x)		(s64)__le64_to_cpu((sle64)(x))

#define sle16_to_cpup(x)	(s16)__le16_to_cpu(*(const sle16*)(x))
#define sle32_to_cpup(x)	(s32)__le32_to_cpu(*(const sle32*)(x))
#define sle64_to_cpup(x)	(s64)__le64_to_cpu(*(const sle64*)(x))

/* Unsigned from CPU to LE conversion. */

#define cpu_to_le16(x)		(le16)__cpu_to_le16((u16)(x))
#define cpu_to_le32(x)		(le32)__cpu_to_le32((u32)(x))
#define cpu_to_le64(x)		(le64)__cpu_to_le64((u64)(x))

#define cpu_to_le16p(x)		(le16)__cpu_to_le16(*(const u16*)(x))
#define cpu_to_le32p(x)		(le32)__cpu_to_le32(*(const u32*)(x))
#define cpu_to_le64p(x)		(le64)__cpu_to_le64(*(const u64*)(x))

/* Signed from CPU to LE conversion. */

#define cpu_to_sle16(x)		(__force sle16)__cpu_to_le16((s16)(x))
#define cpu_to_sle32(x)		(__force sle32)__cpu_to_le32((s32)(x))
#define cpu_to_sle64(x)		(__force sle64)__cpu_to_le64((s64)(x))

#define cpu_to_sle16p(x)	(__force sle16)__cpu_to_le16(*(const s16*)(x))
#define cpu_to_sle32p(x)	(__force sle32)__cpu_to_le32(*(const s32*)(x))
#define cpu_to_sle64p(x)	(__force sle64)__cpu_to_le64(*(const s64*)(x))

/* Constant endianness conversion defines. */

#define const_le16_to_cpu(x)	(u16)__constant_le16_to_cpu((le16)(x))
#define const_le32_to_cpu(x)	(u32)__constant_le32_to_cpu((le32)(x))
#define const_le64_to_cpu(x)	(u64)__constant_le64_to_cpu((le64)(x))

#define const_cpu_to_le16(x)	(le16)__constant_cpu_to_le16((u16)(x))
#define const_cpu_to_le32(x)	(le32)__constant_cpu_to_le32((u32)(x))
#define const_cpu_to_le64(x)	(le64)__constant_cpu_to_le64((u64)(x))

#ifdef __CHECKER__
static void ntfs_endian_self_test(void)
{
	/* Should not generate warnings. */
	(le16)cpu_to_le16((u16)1);
	(le32)cpu_to_le32((u32)1);
	(le64)cpu_to_le64((u64)1);
	(sle16)cpu_to_sle16((s16)1);
	(sle32)cpu_to_sle32((s32)1);
	(sle64)cpu_to_sle64((s64)1);
	(u16)le16_to_cpu((__force le16)1);
	(u32)le32_to_cpu((__force le32)1);
	(u64)le64_to_cpu((__force le64)1);
	(s16)sle16_to_cpu((__force sle16)1);
	(s32)sle32_to_cpu((__force sle32)1);
	(s64)sle64_to_cpu((__force sle64)1);
	(le16)const_cpu_to_le16((u16)1);
	(le32)const_cpu_to_le32((u32)1);
	(le64)const_cpu_to_le64((u64)1);
	(u16)const_le16_to_cpu((__force le16)1);
	(u32)const_le32_to_cpu((__force le32)1);
	(u64)const_le64_to_cpu((__force le64)1);

	/*
	 * TODO: Need some how to test that warnings are actually generated,
	 * but without flooding output with them and vice-versa print warning
	 * in case if some one warning is not triggered, but should.  (Yura)
	 *
	 * I think it can only be done in  a ./configure like script / shell
	 * script that will compile known good  and known bad code and pipe the
	 * output from sparse to a file, then  grep the file for the wanted
	 * warnings/lack thereof and then it would  say "Tests: PASS " or
	 * "Tests: FAILED" or whatever.  And you can then  hook that into a
	 * "make test" make target or similar so it is only  done when one
	 * wants to do it...  (Anton)
	 *
	 * Also we can look on sparse self test script.  (Yura)
	 */
}
#endif

#endif /* defined _NTFS_ENDIANS_H */