1/**************************************************************************** 2** libebml : parse EBML files, see http://embl.sourceforge.net/ 3** 4** <file/class description> 5** 6** Copyright (C) 2002-2004 Steve Lhomme. All rights reserved. 7** 8** This file is part of libebml. 9** 10** This library is free software; you can redistribute it and/or 11** modify it under the terms of the GNU Lesser General Public 12** License as published by the Free Software Foundation; either 13** version 2.1 of the License, or (at your option) any later version. 14** 15** This library is distributed in the hope that it will be useful, 16** but WITHOUT ANY WARRANTY; without even the implied warranty of 17** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 18** Lesser General Public License for more details. 19** 20** You should have received a copy of the GNU Lesser General Public 21** License along with this library; if not, write to the Free Software 22** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 23** 24** See http://www.matroska.org/license/lgpl/ for LGPL licensing information. 25** 26** Contact license@matroska.org if any conditions of this licensing are 27** not clear to you. 28** 29**********************************************************************/ 30 31/*! 32 \file 33 \version \$Id: EbmlEndian.h 1298 2008-02-21 22:14:18Z mosu $ 34 \author Ingo Ralf Blum <ingoralfblum @ users.sf.net> 35 \author Lasse K�rkk�inen <tronic @ users.sf.net> 36 \author Steve Lhomme <robux4 @ users.sf.net> 37*/ 38#ifndef LIBEBML_ENDIAN_H 39#define LIBEBML_ENDIAN_H 40 41#include <algorithm> 42#include <cstring> 43 44#include "EbmlConfig.h" // contains _ENDIANESS_ 45 46START_LIBEBML_NAMESPACE 47 48enum endianess { 49 big_endian, ///< PowerPC, Alpha, 68000 50 little_endian ///< Intel x86 platforms 51}; 52 53/*! 54 \class Endian 55 \brief general class to handle endian-specific buffers 56 \note don't forget to define/undefine _ENDIANESS_ to BIG_ENDIAN depending on your machine 57*/ 58template<class TYPE, endianess ENDIAN> class Endian 59{ 60 public: 61 Endian() {} 62 63 Endian(const TYPE value) 64 { 65 memcpy(&platform_value, &value, sizeof(TYPE)); 66 process_endian(); 67 } 68 69 inline Endian & Eval(const binary *endian_buffer) 70 { 71 //endian_value = *(TYPE *)(endian_buffer); 72 memcpy(&endian_value, endian_buffer, sizeof(TYPE)); // Some (all?) RISC processors do not allow reading objects bigger than 1 byte from non-aligned addresses, and endian_buffer may point to a non-aligned address. 73 process_platform(); 74 return *this; 75 } 76 77 inline void Fill(binary *endian_buffer) const 78 { 79 //*(TYPE*)endian_buffer = endian_value; 80 memcpy(endian_buffer, &endian_value, sizeof(TYPE)); // See above. 81 } 82 83 inline operator const TYPE&() const { return platform_value; } 84// inline TYPE endian() const { return endian_value; } 85 inline const TYPE &endian() const { return endian_value; } 86 inline size_t size() const { return sizeof(TYPE); } 87 inline bool operator!=(const binary *buffer) const {return *((TYPE*)buffer) == platform_value;} 88 89 protected: 90 TYPE platform_value; 91 TYPE endian_value; 92 93 inline void process_endian() 94 { 95 endian_value = platform_value; 96#ifdef WORDS_BIGENDIAN 97 if (ENDIAN == little_endian) 98 std::reverse(reinterpret_cast<uint8*>(&endian_value),reinterpret_cast<uint8*>(&endian_value+1)); 99#else // _ENDIANESS_ 100 if (ENDIAN == big_endian) 101 std::reverse(reinterpret_cast<uint8*>(&endian_value),reinterpret_cast<uint8*>(&endian_value+1)); 102#endif // _ENDIANESS_ 103 } 104 105 inline void process_platform() 106 { 107 platform_value = endian_value; 108#ifdef WORDS_BIGENDIAN 109 if (ENDIAN == little_endian) 110 std::reverse(reinterpret_cast<uint8*>(&platform_value),reinterpret_cast<uint8*>(&platform_value+1)); 111#else // _ENDIANESS_ 112 if (ENDIAN == big_endian) 113 std::reverse(reinterpret_cast<uint8*>(&platform_value),reinterpret_cast<uint8*>(&platform_value+1)); 114#endif // _ENDIANESS_ 115 } 116}; 117 118END_LIBEBML_NAMESPACE 119 120#endif // LIBEBML_ENDIAN_H 121