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/*
*
* (C) Copyright IBM Corp. 1998-2005 - 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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