/* <!-- copyright */
/*
 * aria2 - The high speed download utility
 *
 * Copyright (C) 2006 Tatsuhiro Tsujikawa
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * In addition, as a special exception, the copyright holders give
 * permission to link the code of portions of this program with the
 * OpenSSL library under certain conditions as described in each
 * individual source file, and distribute linked combinations
 * including the two.
 * You must obey the GNU General Public License in all respects
 * for all of the code used other than OpenSSL.  If you modify
 * file(s) with this exception, you may extend this exception to your
 * version of the file(s), but you are not obligated to do so.  If you
 * do not wish to do so, delete this exception statement from your
 * version.  If you delete this exception statement from all source
 * files in the program, then also delete it here.
 */
/* copyright --> */
#include "MultiFileAllocationIterator.h"
#include "MultiDiskAdaptor.h"
#include "FileEntry.h"
#include "SingleFileAllocationIterator.h"

MultiFileAllocationIterator::MultiFileAllocationIterator(MultiDiskAdaptor* diskAdaptor):
  _diskAdaptor(diskAdaptor),
  _entries(makeDiskWriterEntries(diskAdaptor->diskWriterEntries,
				 diskAdaptor->getPieceLength())),
  _fileAllocationIterator(0),
  _offset(0)
{}

MultiFileAllocationIterator::~MultiFileAllocationIterator() {}

void MultiFileAllocationIterator::allocateChunk()
{
  while(_fileAllocationIterator.isNull() || _fileAllocationIterator->finished()) {
    if(_entries.empty()) {
      break;
    }
    DiskWriterEntryHandle entry = _entries.front();
    _entries.pop_front();
    FileEntryHandle fileEntry = entry->getFileEntry();
    if(entry->size() < fileEntry->getLength()) {
      entry->getDiskWriter()->enableDirectIO();
      _fileAllocationIterator =
	new SingleFileAllocationIterator(entry->getDiskWriter().get(),
					 entry->size(),
					 fileEntry->getLength());
      _fileAllocationIterator->init();
    }
  }
  if(finished()) {
    return;
  }
  _fileAllocationIterator->allocateChunk();
}

bool MultiFileAllocationIterator::finished()
{
  return _entries.empty() && (_fileAllocationIterator.isNull() || _fileAllocationIterator->finished());
}

int64_t MultiFileAllocationIterator::getCurrentLength()
{
  if(_fileAllocationIterator.isNull()) {
    return 0;
  } else {
    return _fileAllocationIterator->getCurrentLength();
  }
}

int64_t MultiFileAllocationIterator::getTotalLength()
{
  if(_fileAllocationIterator.isNull()) {
    return 0;
  } else {
    return _fileAllocationIterator->getTotalLength();
  }
}

const DiskWriterEntries& MultiFileAllocationIterator::getDiskWriterEntries() const
{
  return _entries;
}

DiskWriterEntries MultiFileAllocationIterator::makeDiskWriterEntries(const DiskWriterEntries& srcEntries, int32_t pieceLength) const
{
  if(pieceLength == 0) {
    DiskWriterEntries entries;
    for(DiskWriterEntries::const_iterator itr = srcEntries.begin(); itr != srcEntries.end(); ++itr) {
      if((*itr)->getFileEntry()->isRequested()) {
	entries.push_back(*itr);
      }
    }
    return entries;
  }
  DiskWriterEntries temp(srcEntries);
  temp.push_front(new DiskWriterEntry(new FileEntry()));
  DiskWriterEntries entries;
  DiskWriterEntries::const_iterator done = temp.begin();
  for(DiskWriterEntries::const_iterator itr = temp.begin()+1; itr != temp.end(); ++itr) {
    FileEntryHandle fileEntry = (*itr)->getFileEntry();
    if(!fileEntry->isRequested()) {
      continue;
    }
    int64_t pieceStartOffset = (fileEntry->getOffset()/pieceLength)*pieceLength;
    for(DiskWriterEntries::const_iterator i = itr-1; i != done; --i) {
      if(pieceStartOffset < (*i)->getFileEntry()->getOffset()+(*i)->getFileEntry()->getLength()) {
	entries.push_back(*i);
      } else {
	break;
      }
    }
    entries.push_back(*itr);
    done = itr;
  }
  return entries;
}