icuSources/layout/LESwaps.h

   1
   2 /*
   3  *
   4  * (C) Copyright IBM Corp. 1998-2008 - All Rights Reserved
   5  *
   6  */
   7
   8 #ifndef __LESWAPS_H
   9 #define __LESWAPS_H
  10
  11 #include "LETypes.h"
  12
  13 /**
  14  * \file
  15  * \brief C++ API: Endian independent access to data for LayoutEngine
  16  */
  17
  18 U_NAMESPACE_BEGIN
  19
  20 /**
  21  * A convenience macro which invokes the swapWord member function
  22  * from a concise call.
  23  *
  24  * @stable ICU 2.8
  25  */
  26 #define SWAPW(value) LESwaps::swapWord((const le_uint16 &) (value))
  27
  28 /**
  29  * A convenience macro which invokes the swapLong member function
  30  * from a concise call.
  31  *
  32  * @stable ICU 2.8
  33  */
  34 #define SWAPL(value) LESwaps::swapLong((const le_uint32 &) (value))
  35
  36 /**
  37  * This class is used to access data which stored in big endian order
  38  * regardless of the conventions of the platform.
  39  *
  40  * All methods are static and inline in an attempt to induce the compiler
  41  * to do most of the calculations at compile time.
  42  *
  43  * @stable ICU 2.8
  44  */
  45 class U_LAYOUT_API LESwaps /* not : public UObject because all methods are static */ {
  46 public:
  47
  48     /**
  49      * This method does the byte swap required on little endian platforms
  50      * to correctly access a (16-bit) word.
  51      *
  52      * @param value - the word to be byte swapped
  53      *
  54      * @return the byte swapped word
  55      *
  56      * @stable ICU 2.8
  57      */
  58     static le_uint16 swapWord(const le_uint16 &value)
  59     {
  60         const le_uint8 *p = (const le_uint8 *) &value;
  61
  62         return ((p[0] << 8) + p[1]);
  63     };
  64
  65     /**
  66      * This method does the byte swapping required on little endian platforms
  67      * to correctly access a (32-bit) long.
  68      *
  69      * @param value - the long to be byte swapped
  70      *
  71      * @return the byte swapped long
  72      *
  73      * @stable ICU 2.8
  74      */
  75     static le_uint32 swapLong(const le_uint32 &value)
  76     {
  77         const le_uint8 *p = (const le_uint8 *) &value;
  78
  79         return ((p[0] << 24) + (p[1] << 16) + (p[2] << 8) + p[3]);
  80     };
  81
  82 private:
  83     LESwaps() {} // private - forbid instantiation
  84 };
  85
  86 U_NAMESPACE_END
  87 #endif