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

   1 /****************************************************************************
   2 ** libebml : parse EBML files, see http://embl.sourceforge.net/
   3 **
   4 ** <file/class description>
   5 **
   6 ** Copyright (C) 2003 Jory Stone.  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: MemIOCallback.cpp 693 2004-07-31 08:56:28Z robux4 $
  32         \author Jory Stone <jcsston @ toughguy.net>
  33 */
  34
  35 #include "ebml/MemIOCallback.h"
  36 #include "ebml/Debug.h"
  37 #include "ebml/EbmlConfig.h"
  38
  39 START_LIBEBML_NAMESPACE
  40
  41 MemIOCallback::MemIOCallback(uint64 DefaultSize)
  42 {
  43         //The default size of the buffer is 128 bytes
  44         dataBuffer = (binary *)malloc(DefaultSize);
  45         if (dataBuffer == NULL) {
  46                 mOk = false;
  47                 std::stringstream Msg;
  48                 Msg << "Failed to alloc memory block of size ";
  49 // not working with VC6         Msg << DefaultSize;
  50                 mLastErrorStr = Msg.str();
  51                 return;
  52         }
  53
  54         dataBufferMemorySize = DefaultSize;
  55         dataBufferPos = 0;
  56         dataBufferTotalSize = 0;
  57         mOk = true;
  58 }
  59
  60 MemIOCallback::~MemIOCallback()
  61 {
  62         if (dataBuffer != NULL)
  63                 free(dataBuffer);
  64 }
  65
  66 uint32 MemIOCallback::read(void *Buffer, size_t Size)
  67 {
  68         if (Buffer == NULL || Size < 1)
  69                 return 0;
  70         //If the size is larger than than the amount left in the buffer
  71         if (Size + dataBufferPos > dataBufferTotalSize)
  72         {
  73                 //We will only return the remaining data
  74                 memcpy(Buffer, dataBuffer + dataBufferPos, dataBufferTotalSize - dataBufferPos);
  75                 dataBufferPos = dataBufferTotalSize;
  76                 return dataBufferTotalSize - dataBufferPos;
  77         }
  78
  79         //Well... We made it here, so do a quick and simple copy
  80         memcpy(Buffer, dataBuffer+dataBufferPos, Size);
  81         dataBufferPos += Size;
  82
  83         return Size;
  84 }
  85
  86 void MemIOCallback::setFilePointer(int64 Offset, seek_mode Mode)
  87 {
  88         if (Mode == seek_beginning)
  89                 dataBufferPos = Offset;
  90         else if (Mode == seek_current)
  91                 dataBufferPos = dataBufferPos + Offset;
  92         else if (Mode == seek_end)
  93                 dataBufferPos = dataBufferTotalSize + Offset;
  94 }
  95
  96 size_t MemIOCallback::write(const void *Buffer, size_t Size)
  97 {
  98         if (dataBufferMemorySize < dataBufferPos + Size)
  99         {
 100                 //We need more memory!
 101                 dataBuffer = (binary *)realloc((void *)dataBuffer, dataBufferPos + Size);
 102         }
 103         memcpy(dataBuffer+dataBufferPos, Buffer, Size);
 104         dataBufferPos += Size;
 105         if (dataBufferPos > dataBufferTotalSize)
 106                 dataBufferTotalSize = dataBufferPos;
 107
 108         return Size;
 109 }
 110
 111 uint32 MemIOCallback::write(IOCallback & IOToRead, size_t Size)
 112 {
 113         if (dataBufferMemorySize < dataBufferPos + Size)
 114         {
 115                 //We need more memory!
 116                 dataBuffer = (binary *)realloc((void *)dataBuffer, dataBufferPos + Size);
 117         }
 118         IOToRead.readFully(&dataBuffer[dataBufferPos], Size);
 119         dataBufferTotalSize = Size;
 120         return Size;
 121 }
 122
 123 END_LIBEBML_NAMESPACE