| /* |
| * |
| * (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) && (BYTE_ORDER == 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) && (BYTE_ORDER == 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 |