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/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code 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
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/
/*
*
* (C) Copyright IBM Corp. 1998-2010 - All Rights Reserved
*
*/
#ifndef __LESWAPS_H
#define __LESWAPS_H
#include "LETypes.h"
/**
* \file
* \brief C++ API: Endian independent access to data for LayoutEngine
*/
U_NAMESPACE_BEGIN
/**
* A convenience macro which invokes the swapWord member function
* from a concise call.
*
* @stable ICU 2.8
*/
#if defined(U_IS_BIG_ENDIAN)
#if U_IS_BIG_ENDIAN
#define SWAPW(value) (value)
#else
#define SWAPW(value) LESwaps::swapWord(value)
#endif
#else
#define SWAPW(value) (LESwaps::isBigEndian() ? (value) : LESwaps::swapWord(value))
#endif
/**
* A convenience macro which invokes the swapLong member function
* from a concise call.
*
* @stable ICU 2.8
*/
#if defined(U_IS_BIG_ENDIAN)
#if U_IS_BIG_ENDIAN
#define SWAPL(value) (value)
#else
#define SWAPL(value) LESwaps::swapLong(value)
#endif
#else
#define SWAPL(value) (LESwaps::isBigEndian() ? (value) : LESwaps::swapLong(value))
#endif
/**
* This class is used to access data which stored in big endian order
* regardless of the conventions of the platform. It has been designed
* to automatically detect the endian-ness of the platform, so that a
* compilation flag is not needed.
*
* All methods are static and inline in an attempt to induce the compiler
* to do most of the calculations at compile time.
*
* @stable ICU 2.8
*/
class U_LAYOUT_API LESwaps /* not : public UObject because all methods are static */ {
public:
#if !defined(U_IS_BIG_ENDIAN)
/**
* This method detects the endian-ness of the platform by
* casting a pointer to a word to a pointer to a byte. On
* big endian platforms the FF will be in the byte with the
* lowest address. On little endian platforms, the FF will
* be in the byte with the highest address.
*
* @return TRUE if the platform is big endian
*
* @stable ICU 2.8
*/
static le_uint8 isBigEndian()
{
const le_uint16 word = 0xFF00;
return *((le_uint8 *) &word);
};
#endif
/**
* This method does the byte swap required on little endian platforms
* to correctly access a (16-bit) word.
*
* @param value - the word to be byte swapped
*
* @return the byte swapped word
*
* @stable ICU 2.8
*/
static le_uint16 swapWord(le_uint16 value)
{
return (((le_uint8) (value >> 8)) | (value << 8));
};
/**
* This method does the byte swapping required on little endian platforms
* to correctly access a (32-bit) long.
*
* @param value - the long to be byte swapped
*
* @return the byte swapped long
*
* @stable ICU 2.8
*/
static le_uint32 swapLong(le_uint32 value)
{
return swapWord((le_uint16) (value >> 16)) | (swapWord((le_uint16) value) << 16);
};
private:
LESwaps() {} // private - forbid instantiation
};
U_NAMESPACE_END
#endif
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