icuSources/layout/LESwaps.h

   1 /*
   2  *
   3  * (C) Copyright IBM Corp. 1998-2010 - All Rights Reserved
   4  *
   5  */
   6
   7 #ifndef __LESWAPS_H
   8 #define __LESWAPS_H
   9
  10 #include "LETypes.h"
  11
  12 /**
  13  * \file
  14  * \brief C++ API: Endian independent access to data for LayoutEngine
  15  */
  16
  17 U_NAMESPACE_BEGIN
  18
  19 /**
  20  * A convenience macro which invokes the swapWord member function
  21  * from a concise call.
  22  *
  23  * @stable ICU 2.8
  24  */
  25 #define SWAPW(value) LESwaps::swapWord((le_uint16)(value))
  26
  27 /**
  28  * A convenience macro which invokes the swapLong member function
  29  * from a concise call.
  30  *
  31  * @stable ICU 2.8
  32  */
  33 #define SWAPL(value) LESwaps::swapLong((le_uint32)(value))
  34
  35 /**
  36  * This class is used to access data which stored in big endian order
  37  * regardless of the conventions of the platform.
  38  *
  39  * All methods are static and inline in an attempt to induce the compiler
  40  * to do most of the calculations at compile time.
  41  *
  42  * @stable ICU 2.8
  43  */
  44 class U_LAYOUT_API LESwaps /* not : public UObject because all methods are static */ {
  45 public:
  46
  47     /**
  48      * This method does the byte swap required on little endian platforms
  49      * to correctly access a (16-bit) word.
  50      *
  51      * @param value - the word to be byte swapped
  52      *
  53      * @return the byte swapped word
  54      *
  55      * @stable ICU 2.8
  56      */
  57     static le_uint16 swapWord(le_uint16 value)
  58     {
  59         return (le_uint16)((value << 8) | (value >> 8));
  60     };
  61
  62     /**
  63      * This method does the byte swapping required on little endian platforms
  64      * to correctly access a (32-bit) long.
  65      *
  66      * @param value - the long to be byte swapped
  67      *
  68      * @return the byte swapped long
  69      *
  70      * @stable ICU 2.8
  71      */
  72     static le_uint32 swapLong(le_uint32 value)
  73     {
  74         return (le_uint32)(
  75             (value << 24) |
  76             ((value << 8) & 0xff0000) |
  77             ((value >> 8) & 0xff00) |
  78             (value >> 24));
  79     };
  80
  81 private:
  82     LESwaps() {} // private - forbid instantiation
  83 };
  84
  85 U_NAMESPACE_END
  86 #endif