/*

  *

  * (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