/* ***** BEGIN LICENSE BLOCK *****
*
* $Id: dirac_byte_stream.cpp,v 1.2 2007/03/29 16:43:38 asuraparaju Exp $ $Name: Dirac_0_7_0 $
*
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License
* Version 1.1 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for
* the specific language governing rights and limitations under the License.
*
* The Original Code is BBC Research and Development code.
*
* The Initial Developer of the Original Code is the British Broadcasting
* Corporation.
* Portions created by the Initial Developer are Copyright (C) 2004.
* All Rights Reserved.
*
* Contributor(s): Andrew Kennedy
*
* Alternatively, the contents of this file may be used under the terms of
* the GNU General Public License Version 2 (the "GPL"), or the GNU Lesser
* Public License Version 2.1 (the "LGPL"), in which case the provisions of
* the GPL or the LGPL are applicable instead of those above. If you wish to
* allow use of your version of this file only under the terms of the either
* the GPL or LGPL and not to allow others to use your version of this file
* under the MPL, indicate your decision by deleting the provisions above
* and replace them with the notice and other provisions required by the GPL
* or LGPL. If you do not delete the provisions above, a recipient may use
* your version of this file under the terms of any one of the MPL, the GPL
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* ***** END LICENSE BLOCK ***** */

#include <libdirac_byteio/dirac_byte_stream.h>
#include <libdirac_byteio/endofsequence_byteio.h>
#include <libdirac_common/dirac_exception.h>

using namespace dirac;
using namespace std;

DiracByteStream::DiracByteStream():
ByteIO(),
mp_prev_parse_unit(NULL),
mp_next_parse_unit(NULL)
{

}

DiracByteStream::~DiracByteStream()
{
    delete mp_prev_parse_unit;
}

//---------------decoding----------------------------------------------------

void DiracByteStream::AddBytes(char* start, 
                               int count)
{
    // add to input stream
    string str(start, count);
    ByteIO::OutputBytes(str);
 
}

DiracByteStats DiracByteStream::GetLastUnitStats() 
{
    DiracByteStats dirac_byte_stats;
    
    if(m_parse_unit_list.empty())
        return dirac_byte_stats;

    ParseUnitByteIO* p_parse_unit = m_parse_unit_list.back().second;
    p_parse_unit->CollateByteStats(dirac_byte_stats);

    return dirac_byte_stats;
}

ParseUnitByteIO* DiracByteStream::GetNextParseUnit()
{
    if(GetSize()==0)
        return NULL;

    int pos=0;
    if(mp_prev_parse_unit)
    {
        // remove the unwanted bytes associated with the previous parse-unit
        RemoveRedundantBytes(mp_prev_parse_unit->GetNextParseOffset());
        delete mp_prev_parse_unit;
        mp_prev_parse_unit=NULL;
        if(!GetSize())
            return NULL;
    }

   bool unit_found=false;
   ParseUnitByteIO* p_curr_unit=NULL;
   try {

        while(!unit_found)
        {
            p_curr_unit=mp_next_parse_unit;
            pos  = GetReadBytePosition();

            if(!p_curr_unit)
            {
                p_curr_unit = new ParseUnitByteIO(*this);
                p_curr_unit->Input();
            }

            // skip past current unit
            if(!p_curr_unit->Skip())
            {
                // no unit specificed to skip to
                unit_found=true;
                mp_next_parse_unit=NULL;
                break;
            }

            // create and read next unit in the stream
            mp_next_parse_unit = new ParseUnitByteIO(*this);
            mp_next_parse_unit->Input();

            // look to see if next unit validates the current one
            if(!p_curr_unit->IsValid(*mp_next_parse_unit))
            {
                // delete the unit - it's invalid
                delete p_curr_unit;
                // remove unwanted portion of bytes
                RemoveRedundantBytes(pos);
                // look for next potential parse-unit
                continue;
            }

            unit_found=true;
        } // while
      
   }// try
   catch (DiracException& dirac_exception)
   {
        delete p_curr_unit;
        mp_next_parse_unit = NULL;
        SeekGet(pos, ios_base::beg);
        return NULL;
   }

      // Remove all redundant bytes that are not part of a parse unit
      int remove_size = std::max (0, GetReadBytePosition()-p_curr_unit->GetSize());
      if (remove_size)
      {
            //std::cerr << "Size="<<GetSize() << " Un-useful bytes=" << remove_size << std::endl;
            RemoveRedundantBytes(remove_size);
      }

    mp_prev_parse_unit=p_curr_unit;
    return p_curr_unit;
}

DiracByteStats DiracByteStream::GetSequenceStats() const
{
    return m_sequence_stats;
}

//---------------encoding-----------------------------------------------------

void DiracByteStream::AddAccessUnit(AccessUnitByteIO *p_accessunit_byteio)
{
    // set previous parse-unit details
    ParseUnitByteIO *mp_previous_parse_unit=mp_prev_parse_unit;

    if(!m_parse_unit_list.empty())
        mp_previous_parse_unit = m_parse_unit_list.back().second;

    // set adjacent parse-unit
    p_accessunit_byteio->SetAdjacentParseUnits(mp_previous_parse_unit);
    
    // push onto to pending list
    m_parse_unit_list.push(std::make_pair (PU_ACCESS_UNIT, p_accessunit_byteio) );

    // set previous parse-unit
    mp_previous_parse_unit = p_accessunit_byteio;

    // save stats
    p_accessunit_byteio->CollateByteStats(m_sequence_stats);
}

void DiracByteStream::AddFrame(FrameByteIO *p_frame_byteio)
{
    // set previous parse-unit details
    ParseUnitByteIO *mp_previous_parse_unit=mp_prev_parse_unit;

    if(!m_parse_unit_list.empty())
        mp_previous_parse_unit = m_parse_unit_list.back().second;

    // set adjacent parse-unit
    p_frame_byteio->SetAdjacentParseUnits(mp_previous_parse_unit);

     // push onto to pending list
    m_parse_unit_list.push(std::make_pair(PU_FRAME, p_frame_byteio ) );

   // set previous parse-unit
    mp_previous_parse_unit = p_frame_byteio;

     // save stats
    p_frame_byteio->CollateByteStats(m_sequence_stats);
}

void DiracByteStream::Clear()
{
       while(!m_parse_unit_list.empty())
    {
        ParseUnitByteIO* p_parse_unit=m_parse_unit_list.front().second;
        m_parse_unit_list.pop();
        if(m_parse_unit_list.empty())
        {
            delete mp_prev_parse_unit;
            mp_prev_parse_unit=p_parse_unit;
        }
        else
            delete p_parse_unit;
    }
}

DiracByteStats DiracByteStream::EndSequence()
{
    // create
    EndOfSequenceByteIO *p_endofsequence_byteio = new EndOfSequenceByteIO(*this);

     // set previous parse-unit details
    ParseUnitByteIO *mp_previous_parse_unit=mp_prev_parse_unit;

    if(!m_parse_unit_list.empty())
        mp_previous_parse_unit = m_parse_unit_list.back().second;

    // set adjacent parse-unit
    p_endofsequence_byteio->SetAdjacentParseUnits(mp_previous_parse_unit);

     // push onto to pending list
    m_parse_unit_list.push(std::make_pair(PU_END_OF_SEQUENCE, p_endofsequence_byteio) );
    
    p_endofsequence_byteio->CollateByteStats(m_sequence_stats);

    // clear stats
    DiracByteStats seq_stats(m_sequence_stats);
    m_sequence_stats.Clear();

    // return seq stats
    return seq_stats;
}

const string DiracByteStream::GetBytes() 
{
    // take copy
    ParseUnitList parse_list = m_parse_unit_list;
    mp_stream->str("");

    while(!parse_list.empty())
    {
        *mp_stream << parse_list.front().second->GetBytes();
        parse_list.pop();
    }

    return mp_stream->str();
}

bool DiracByteStream::IsUnitAvailable() const
{
    return !m_parse_unit_list.empty();
}