/*
*
* (C) Copyright IBM Corp. 1998-2011 - 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
*/
#define SWAPW(value) LESwaps::swapWord((le_uint16)(value))
/**
* A convenience macro which invokes the swapLong member function
* from a concise call.
*
* @stable ICU 2.8
*/
#define SWAPL(value) LESwaps::swapLong((le_uint32)(value))
/**
* This class is used to access data which stored in big endian order
* regardless of the conventions of the platform.
*
* 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:
/**
* Reads a big-endian 16-bit word and returns a native-endian value.
* No-op on a big-endian platform, byte-swaps on a little-endian platform.
*
* @param value - the word to be byte swapped
*
* @return the byte swapped word
*
* @stable ICU 2.8
*/
static le_uint16 swapWord(le_uint16 value)
{
#if (defined(U_IS_BIG_ENDIAN) && U_IS_BIG_ENDIAN) || \
(defined(BYTE_ORDER) && defined(BIG_ENDIAN) && (BYTE_ORDER == BIG_ENDIAN)) || \
defined(__BIG_ENDIAN__)
// Fastpath when we know that the platform is big-endian.
return value;
#else
// Reads a big-endian value on any platform.
const le_uint8 *p = reinterpret_cast<const le_uint8 *>(&value);
return (le_uint16)((p[0] << 8) | p[1]);
#endif
};
/**
* Reads a big-endian 32-bit word and returns a native-endian value.
* No-op on a big-endian platform, byte-swaps on a little-endian platform.
*
* @param value - the long to be byte swapped
*
* @return the byte swapped long
*
* @stable ICU 2.8
*/
static le_uint32 swapLong(le_uint32 value)
{
#if (defined(U_IS_BIG_ENDIAN) && U_IS_BIG_ENDIAN) || \
(defined(BYTE_ORDER) && defined(BIG_ENDIAN) && (BYTE_ORDER == BIG_ENDIAN)) || \
defined(__BIG_ENDIAN__)
// Fastpath when we know that the platform is big-endian.
return value;
#else
// Reads a big-endian value on any platform.
const le_uint8 *p = reinterpret_cast<const le_uint8 *>(&value);
return (le_uint32)((p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3]);
#endif
};
private:
LESwaps() {} // private - forbid instantiation
};
U_NAMESPACE_END
#endif