| |
| /* |
| * @(#)LESwaps.h 1.3 00/03/15 |
| * |
| * (C) Copyright IBM Corp. 1998, 1999, 2000, 2001, 2002 - All Rights Reserved |
| * |
| */ |
| |
| #ifndef __LESWAPS_H |
| #define __LESWAPS_H |
| |
| #include "LETypes.h" |
| |
| U_NAMESPACE_BEGIN |
| |
| /** |
| * These are convenience macros which invoke the swap functions |
| * from a concise call. |
| * |
| * @draft ICU 2.2 |
| */ |
| #define SWAPW(value) (LESwaps::isBigEndian() ? (value) : LESwaps::swapWord(value)) |
| #define SWAPL(value) (LESwaps::isBigEndian() ? (value) : LESwaps::swapLong(value)) |
| |
| /** |
| * 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. |
| * |
| * @draft ICU 2.2 |
| */ |
| class LESwaps /* not : public UObject because all methods are static */ { |
| public: |
| |
| /** |
| * 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 |
| * |
| * @draft ICU 2.2 |
| */ |
| static le_bool isBigEndian() |
| { |
| static const le_uint16 word = 0xFF00; |
| |
| return *((le_uint8 *) &word); |
| }; |
| |
| /** |
| * 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 |
| * |
| * @draft ICU 2.2 |
| */ |
| 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 |
| * |
| * @draft ICU 2.2 |
| */ |
| 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 |