text: /***************************************************************************
      copyright            : (C) 2002 - 2008 by Scott Wheeler
      email                : wheeler@kde.org
   ***************************************************************************/
  
  /***************************************************************************
   *   This library is free software; you can redistribute it and/or modify  *
   *   it under the terms of the GNU Lesser General Public License version   *
   *   2.1 as published by the Free Software Foundation.                     *
   *                                                                         *
   *   This library is distributed in the hope that it will be useful, but   *
   *   WITHOUT ANY WARRANTY; without even the implied warranty of            *
   *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU     *
   *   Lesser General Public License for more details.                       *
   *                                                                         *
   *   You should have received a copy of the GNU Lesser General Public      *
   *   License along with this library; if not, write to the Free Software   *
   *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA         *
   *   02110-1301  USA                                                       *
   *                                                                         *
   *   Alternatively, this file is available under the Mozilla Public        *
   *   License Version 1.1.  You may obtain a copy of the License at         *
   *   http://www.mozilla.org/MPL/                                           *
   ***************************************************************************/
  
  #include <iostream>
  
  #include "id3v2synchdata.h"
  
  using namespace TagLib;
  using namespace ID3v2;
  
  TagLib::uint SynchData::toUInt(const ByteVector &data)
  {
    uint sum = 0;
    bool notSynchSafe = false;
    int last = data.size() > 4 ? 3 : data.size() - 1;
  
    for(int i = 0; i <= last; i++) {
      if(data[i] & 0x80) {
        notSynchSafe = true;
        break;
      }
  
      sum |= (data[i] & 0x7f) << ((last - i) * 7);
    }
  
    if(notSynchSafe) {
      // Invalid data; assume this was created by some buggy software that just
      // put normal integers here rather than syncsafe ones, and try it that
      // way.
      sum = (data.size() > 4) ? data.mid(0, 4).toUInt() : data.toUInt();
    }
  
    return sum;
  }
  
  ByteVector SynchData::fromUInt(uint value)
  {
    ByteVector v(4, 0);
  
    for(int i = 0; i < 4; i++)
      v[i] = uchar(value >> ((3 - i) * 7) & 0x7f);
  
    return v;
  }
  
  ByteVector SynchData::decode(const ByteVector &data)
  {
    ByteVector result = data;
  
    ByteVector pattern(2, char(0));
    pattern[0] = '\xFF';
    pattern[1] = '\x00';
  
    return result.replace(pattern, '\xFF');
  }
  