hash_chunk.h

一个BT下载库. 支持DHT. 采用底层的网络通讯提速.

// libTorrent - BitTorrent library
// Copyright (C) 2005-2006, Jari Sundell
//
// 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  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
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// Contact:  Jari Sundell <[e-mail]>
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#ifndef LIBTORRENT_HASH_CHUNK_H
#define LIBTORRENT_HASH_CHUNK_H

#include "utils/sha1.h"

#include "chunk.h"
#include "chunk_handle.h"

namespace torrent {

// This class interface assumes we're always going to check the whole
// chunk. All we need is control of the (non-)blocking nature, and other
// stuff related to performance and responsiveness.

class ChunkListNode;

class HashChunk {
public:
  HashChunk()         {}
  HashChunk(ChunkHandle h)  { set_chunk(h); }
  
  void                set_chunk(ChunkHandle h)                { m_position = 0; m_chunk = h; m_hash.init(); }

  ChunkHandle*        chunk()                                 { return &m_chunk; }
  void                hash_c(char* buffer)                    { m_hash.final_c(buffer); }

  // If force is true, then the return value is always true.
  bool                perform(uint32_t length, bool force = true);

  void                advise_willneed(uint32_t length);

  uint32_t            remaining();

private:
  inline uint32_t     remaining_part(Chunk::iterator itr, uint32_t pos);
  uint32_t            perform_part(Chunk::iterator itr, uint32_t length);

  uint32_t            m_position;

  ChunkHandle         m_chunk;
  Sha1                m_hash;
};

inline uint32_t
HashChunk::remaining_part(Chunk::iterator itr, uint32_t pos) {
  return itr->size() - (pos - itr->position());
}

}

#endif