src/add-ons/media/plugins/matroska/libebml/ebml/EbmlEndian.h

   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 Kärkkäinen <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
  46 START_LIBEBML_NAMESPACE
  47
  48 enum 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 */
  58 template<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
 118 END_LIBEBML_NAMESPACE
 119
 120 #endif // LIBEBML_ENDIAN_H