header.h

FreeAMP(MP3播放)程序源代码-用来研究MP3解码

// -*- C++ -*-
// $Id: header.h,v 1.1 2001/01/12 00:41:08 robert Exp $

// id3lib: a C++ library for creating and manipulating id3v1/v2 tags
// Copyright 1999, 2000  Scott Thomas Haug

// This library is free software; you can redistribute it and/or modify it
// under the terms of the GNU Library General Public License as published by
// the Free Software Foundation; either version 2 of the License, or (at your
// option) any later version.
//
// 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 Library General Public
// License for more details.
//
// You should have received a copy of the GNU Library General Public License
// along with this library; if not, write to the Free Software Foundation,
// Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

// The id3lib authors encourage improvements and optimisations to be sent to
// the id3lib coordinator.  Please see the README file for details on where to
// send such submissions.  See the AUTHORS file for a list of people who have
// contributed to id3lib.  See the ChangeLog file for a list of changes to
// id3lib.  These files are distributed with id3lib at
// http://download.sourceforge.net/id3lib/

#ifndef _ID3LIB_HEADER_H_
#define _ID3LIB_HEADER_H_

#include "globals.h"
#include "flags.h"

class ID3_Reader;
class ID3_Writer;

class ID3_Header
{
public:
  struct Info
  {
    uchar      frame_bytes_id;
    uchar      frame_bytes_size;
    uchar      frame_bytes_flags;
    bool       is_extended;
    size_t     extended_bytes;
    bool       is_experimental;
  };

  ID3_Header() 
    : _spec (ID3V2_UNKNOWN),
      _data_size (0),
      _changed (false)
  { 
    this->Clear();
    _changed = false;
  }
  virtual ~ID3_Header() { ; }
  
  virtual bool       SetSpec(ID3_V2Spec);
  /*   */ ID3_V2Spec GetSpec() const { return _spec; }

  /*   */ bool       SetDataSize(size_t size)
  { 
    bool changed = size != _data_size; 
    _changed = _changed || changed;
    _data_size = size;
    return changed;
  }
  /*   */ size_t     GetDataSize() const { return _data_size; }
  
  virtual bool       Clear()
  {
    bool changed = this->SetDataSize(0);
    if (this->GetSpec() == ID3V2_UNKNOWN)
    {
      this->SetSpec(ID3V2_LATEST);
      changed = true;
    }
    changed = _flags.clear() || changed;
    _changed = changed || _changed;
    return changed;
  }
  virtual size_t     Size() const = 0;
  
  virtual void       Render(ID3_Writer&) const = 0;
  virtual bool       Parse(ID3_Reader&) = 0;

  ID3_Header &operator=( const ID3_Header &rhs)
  { 
    if (this != &rhs)
    { 
      this->SetSpec(rhs.GetSpec());
      this->SetDataSize(rhs.GetSpec());
      this->_flags = rhs._flags;
    }
    return *this;
  }

protected:
  ID3_V2Spec      _spec;             // which version of the spec 
  size_t          _data_size;        // how big is the data?
  ID3_Flags       _flags;            // header flags
  const Info*     _info;             // header info w.r.t. id3v2 spec
  bool            _changed;          // has the header changed since parsing
}
;

#endif /* _ID3LIB_HEADER_H */