frame_impl.cpp

FreeAMP(MP3播放)程序源代码-用来研究MP3解码

// $Id: frame_impl.cpp,v 1.3 2001/01/17 19:14:17 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/

#include "id3config.h"
#include <string.h>
#include "tag.h"
#include "frame_impl.h"
#include "field_impl.h"
#include "frame_def.h"
#include "field_def.h"

ID3_FrameImpl::ID3_FrameImpl(ID3_FrameID id)
  : _changed(false),
    _field_bitset(NULL),
    _fields(),
    _encryption_id('\0'),
    _grouping_id('\0')
{
  this->_InitFieldBits();
  this->_InitFields();
  this->SetSpec(ID3V2_LATEST);
  this->SetID(id);
}

ID3_FrameImpl::ID3_FrameImpl(const ID3_FrameHeader &hdr)
  : _changed(false),
    _field_bitset(NULL),
    _fields(),
    _hdr(hdr),
    _encryption_id('\0'),
    _grouping_id('\0')
{
  this->_InitFieldBits();
  this->_InitFields();
}

ID3_FrameImpl::ID3_FrameImpl(const ID3_Frame& frame)
  : _changed(false),
    _field_bitset(NULL),
    _fields(),
    _encryption_id('\0'),
    _grouping_id('\0')
{
  *this = frame;
  if(_field_bitset == NULL)
  {
 this->_InitFieldBits();
    this->_InitFields();
  }
}

ID3_FrameImpl::~ID3_FrameImpl()
{
  Clear();

  if (_field_bitset != NULL)
  {
    delete [] _field_bitset;
  }
}

bool ID3_FrameImpl::_ClearFields()
{
  for (iterator fi = _fields.begin(); fi != _fields.end(); ++fi)
  {
    delete (ID3_FieldImpl*) *fi;
  }

  _fields.clear();

  size_t lWordsForFields =
    (((uint32) ID3FN_LASTFIELDID) - 1) / (sizeof(uint32) * 8);

  if ((((uint32) ID3FN_LASTFIELDID) - 1) % (sizeof(uint32) * 8) != 0)
  {
    lWordsForFields++;
  }

  for (index_t i = 0; i < lWordsForFields; i++)
  {
    if(_field_bitset)
 {
      _field_bitset[i] = 0;
 }
  }

  _changed = true;
  return true;
}

void ID3_FrameImpl::_InitFieldBits()
{
  size_t lWordsForFields =
    (((uint32) ID3FN_LASTFIELDID) - 1) / (sizeof(uint32) * 8);

  if ((((uint32) ID3FN_LASTFIELDID) - 1) % (sizeof(uint32) * 8) != 0)
  {
    lWordsForFields++;
  }

  if (_field_bitset != NULL)
  {
    delete [] _field_bitset;
  }
  _field_bitset = new uint32[lWordsForFields];
  for (index_t i = 0; i < lWordsForFields; i++)
  {
    _field_bitset[i] = 0;
  }
}

void ID3_FrameImpl::Clear()
{
  this->_ClearFields();
  _hdr.Clear();
  _encryption_id   = '\0';
  _grouping_id     = '\0';
}

void ID3_FrameImpl::_InitFields()
{
  const ID3_FrameDef* info = _hdr.GetFrameDef();
  if (NULL == info)
  {
    // log this
    ID3_Field* fld = new ID3_FieldImpl(ID3_FieldDef::DEFAULT[0]);
    _fields.push_back(fld);
    BS_SET(_field_bitset, fld->GetID());
  }
  else
  {
    
    for (size_t i = 0; info->aeFieldDefs[i]._id != ID3FN_NOFIELD; ++i)
    {
      ID3_Field* fld = new ID3_FieldImpl(info->aeFieldDefs[i]);
      _fields.push_back(fld);
      BS_SET(_field_bitset, fld->GetID());
    }
    
    _changed = true;
  }
}

bool ID3_FrameImpl::SetID(ID3_FrameID id)
{
  bool changed = (this->GetID() != id);
  if (changed)
  {
    this->_SetID(id);
    _changed = true;
  }
  return changed;
}

bool ID3_FrameImpl::_SetID(ID3_FrameID id)
{
  bool changed = this->_ClearFields();
  changed = _hdr.SetFrameID(id) || changed;
  this->_InitFields();
  return changed;
}

bool ID3_FrameImpl::SetSpec(ID3_V2Spec spec)
{
  return _hdr.SetSpec(spec);
}

ID3_V2Spec ID3_FrameImpl::GetSpec() const
{
  return _hdr.GetSpec();
}

ID3_Field* ID3_FrameImpl::GetField(ID3_FieldID fieldName) const
{
  ID3_Field* field = NULL;
  if (this->Contains(fieldName))
  {
    for (const_iterator fi = _fields.begin(); fi != _fields.end(); ++fi)
    {
      if ((*fi)->GetID() == fieldName)
      {
        field = *fi;
        break;
      }
    }
  }
  return field;
}

size_t ID3_FrameImpl::NumFields() const
{
  return _fields.size();
}

size_t ID3_FrameImpl::Size()
{
  size_t bytesUsed = _hdr.Size();
  
  if (this->GetEncryptionID())
  {
    bytesUsed++;
  }
    
  if (this->GetGroupingID())
  {
    bytesUsed++;
  }
    
  ID3_TextEnc enc = ID3TE_ASCII;
  for (iterator fi = _fields.begin(); fi != _fields.end(); ++fi)
  {
    if (*fi && (*fi)->InScope(this->GetSpec()))
    {
      if ((*fi)->GetID() == ID3FN_TEXTENC)
      {
        enc = (ID3_TextEnc) (*fi)->Get();
      }
      else
      {
        (*fi)->SetEncoding(enc);
      }
      bytesUsed += (*fi)->BinSize();
    }
  }
  
  return bytesUsed;
}


bool ID3_FrameImpl::HasChanged() const
{
  bool changed = _changed;
  
  for (const_iterator fi = _fields.begin(); fi != _fields.end(); ++fi)
  {
    if (*fi && (*fi)->InScope(this->GetSpec()))
    {
      changed = (*fi)->HasChanged();
    }
  }
  
  return changed;
}

ID3_FrameImpl &
ID3_FrameImpl::operator=( const ID3_Frame &rFrame )
{
  ID3_FrameID eID = rFrame.GetID();
  this->SetID(eID);
  ID3_Frame::ConstIterator* ri = rFrame.CreateIterator();
  iterator li = this->begin();
  while (li != this->end())
  {
    ID3_Field* thisFld = *li++;
    const ID3_Field* thatFld = ri->GetNext();
    if (thisFld != NULL && thatFld != NULL)
    {
      *thisFld = *thatFld;
    }
  }
  delete ri;
  this->SetEncryptionID(rFrame.GetEncryptionID());
  this->SetGroupingID(rFrame.GetGroupingID());
  this->SetCompression(rFrame.GetCompression());
  this->SetSpec(rFrame.GetSpec());
  _changed = false;
  
  return *this;
}

const char* ID3_FrameImpl::GetDescription(ID3_FrameID id)
{
  ID3_FrameDef* myFrameDef = ID3_FindFrameDef(id);
  if (myFrameDef != NULL)
  {
    return myFrameDef->sDescription;
  }
  return NULL;
}

const char* ID3_FrameImpl::GetDescription() const
{
  const ID3_FrameDef* def = _hdr.GetFrameDef();
  if (def)
  {
    return def->sDescription;
  }
  return NULL;
}