src/add-ons/media/plugins/matroska/libebml/EbmlSInteger.cpp

   1 /****************************************************************************
   2 ** libebml : parse EBML files, see http://embl.sourceforge.net/
   3 **
   4 ** <file/class description>
   5 **
   6 ** Copyright (C) 2002-2005 Steve Lhomme.  All rights reserved.
   7 **
   8 ** This library is free software; you can redistribute it and/or
   9 ** modify it under the terms of the GNU Lesser General Public
  10 ** License as published by the Free Software Foundation; either
  11 ** version 2.1 of the License, or (at your option) any later version.
  12 **
  13 ** This library is distributed in the hope that it will be useful,
  14 ** but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16 ** Lesser General Public License for more details.
  17 **
  18 ** You should have received a copy of the GNU Lesser General Public
  19 ** License along with this library; if not, write to the Free Software
  20 ** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21 **
  22 ** See http://www.matroska.org/license/lgpl/ for LGPL licensing information.
  23 **
  24 ** Contact license@matroska.org if any conditions of this licensing are
  25 ** not clear to you.
  26 **
  27 **********************************************************************/
  28
  29 /*!
  30         \file
  31         \version \$Id: EbmlSInteger.cpp 1079 2005-03-03 13:18:14Z robux4 $
  32         \author Steve Lhomme     <robux4 @ users.sf.net>
  33         \author Moritz Bunkus <moritz @ bunkus.org>
  34 */
  35 #include <cassert>
  36
  37 #include "ebml/EbmlSInteger.h"
  38
  39 START_LIBEBML_NAMESPACE
  40
  41 EbmlSInteger::EbmlSInteger()
  42  :EbmlElement(DEFAULT_INT_SIZE, false)
  43 {}
  44
  45 EbmlSInteger::EbmlSInteger(const int64 aDefaultValue)
  46  :EbmlElement(DEFAULT_INT_SIZE, true), Value(aDefaultValue)
  47 {
  48         DefaultIsSet = true;
  49 }
  50
  51 EbmlSInteger::EbmlSInteger(const EbmlSInteger & ElementToClone)
  52  :EbmlElement(ElementToClone)
  53  ,Value(ElementToClone.Value)
  54  ,DefaultValue(ElementToClone.DefaultValue)
  55 {
  56 }
  57
  58 /*!
  59         \todo handle exception on errors
  60 */
  61 uint32 EbmlSInteger::RenderData(IOCallback & output, bool bForceRender, bool bKeepIntact)
  62 {
  63         binary FinalData[8]; // we don't handle more than 64 bits integers
  64         unsigned int i;
  65
  66         if (SizeLength > 8)
  67                 return 0; // integer bigger coded on more than 64 bits are not supported
  68
  69         int64 TempValue = Value;
  70         for (i=0; i<Size;i++) {
  71                 FinalData[Size-i-1] = binary(TempValue & 0xFF);
  72                 TempValue >>= 8;
  73         }
  74
  75         output.writeFully(FinalData,Size);
  76
  77         return Size;
  78 }
  79
  80 uint64 EbmlSInteger::UpdateSize(bool bKeepIntact, bool bForceRender)
  81 {
  82         if (!bKeepIntact && IsDefaultValue())
  83                 return 0;
  84
  85         if (Value <= 0x7F && Value >= (-0x80)) {
  86                 Size = 1;
  87         } else if (Value <= 0x7FFF && Value >= (-0x8000)) {
  88                 Size = 2;
  89         } else if (Value <= 0x7FFFFF && Value >= (-0x800000)) {
  90                 Size = 3;
  91         } else if (Value <= 0x7FFFFFFF && Value >= (-0x80000000)) {
  92                 Size = 4;
  93         } else if (Value <= EBML_PRETTYLONGINT(0x7FFFFFFFFF) &&
  94                    Value >= EBML_PRETTYLONGINT(-0x8000000000)) {
  95                 Size = 5;
  96         } else if (Value <= EBML_PRETTYLONGINT(0x7FFFFFFFFFFF) &&
  97                    Value >= EBML_PRETTYLONGINT(-0x800000000000)) {
  98                 Size = 6;
  99         } else if (Value <= EBML_PRETTYLONGINT(0x7FFFFFFFFFFFFF) &&
 100                    Value >= EBML_PRETTYLONGINT(-0x80000000000000)) {
 101                 Size = 7;
 102         } else {
 103                 Size = 8;
 104         }
 105
 106         if (DefaultSize > Size) {
 107                 Size = DefaultSize;
 108         }
 109
 110         return Size;
 111 }
 112
 113 uint64 EbmlSInteger::ReadData(IOCallback & input, ScopeMode ReadFully)
 114 {
 115         if (ReadFully != SCOPE_NO_DATA)
 116         {
 117                 binary Buffer[8];
 118                 input.readFully(Buffer, Size);
 119
 120                 if (Buffer[0] & 0x80)
 121                         Value = -1; // this is a negative value
 122                 else
 123                         Value = 0; // this is a positive value
 124
 125                 for (unsigned int i=0; i<Size; i++)
 126                 {
 127                         Value <<= 8;
 128                         Value |= Buffer[i];
 129                 }
 130                 bValueIsSet = true;
 131         }
 132
 133         return Size;
 134 }
 135
 136 END_LIBEBML_NAMESPACE