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/*
* Copyright (c) 2016—2021 Andrei Tomashpolskiy and individual contributors.
*
* Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package bt.data;
import bt.metainfo.Torrent;
/**
* Each torrent is split into chunks (also called "pieces").
*
* A chunk is a part of the torrent's collection of files,
* possibly overlapping several files (in case of multi-file torrents)
* or being just a part of a single-file torrent.
*
*
There is a SHA-1 checksum for each chunk in the torrent's metainfo file,
* so it's effectively an elementary unit of data in BitTorrent.
* All chunks in a given torrent have the same size
* (determined by {@link Torrent#getChunkSize()}),
* except for the last one, which can be smaller.
*
*
A typical chunk is usually too large to work with at I/O level.
* So, for the needs of network transfer and storage each chunk is additionally split into "blocks".
* Size of a block is quite an important parameter of torrent messaging,
* and it's usually client-specific (meaning that each client is free to choose the concrete value).
*
* @since 1.0
*/
public interface ChunkDescriptor extends BlockSet {
/**
* Expected hash of this chunk's contents as indicated in torrent file.
*
* @return Expected hash of this chunk's contents; used to verify integrity of chunk's data
*
* @since 1.2
*/
byte[] getChecksum();
/**
* Get chunk's data accessor.
*
* @return Chunk's data accessor
* @since 1.2
*/
DataRange getData();
}