97 lines
2.6 KiB
C++
97 lines
2.6 KiB
C++
/*
|
|
*
|
|
* (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)) || 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)) || 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
|