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/**
 * (c) 2002-2021 JADAPTIVE Limited. All Rights Reserved.
 *
 * This file is part of the Maverick Synergy Java SSH API.
 *
 * Maverick Synergy is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Maverick Synergy 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with Maverick Synergy.  If not, see .
 */
/* HEADER */
package com.sshtools.common.ssh.compression;

import java.io.IOException;

import com.sshtools.common.ssh.components.SshComponent;

/**
 *
 * Compression interface which can be implemented to provide the SSH
 * Transport Protocol with compression.
 * @author Lee David Painter
 */
public interface SshCompression extends SshComponent {

  /**
   * Inflation mode
   */
  static public final int INFLATER = 0;

  /**
   * Deflation mode
   */
  static public final int DEFLATER = 1;

  /**
   * Initialize the compression.
   * @param type  the mode of the compression, should be either INFLATER or DEFLATER
   * @param level the level of compression
   */
  public void init(int type, int level);

  /**
   * Compress a block of data.
   * @param data  the data to compress
   * @param start the offset of the data to compress
   * @param len   the length of the data
   * @return the compressed data with any uncompressed data at the start
   *         remaining intact.
   * @throws IOException
   */
  public byte[] compress(byte[] data, int start, int len) throws IOException;

  /**
   * Uncompress a block of data.
   * @param data   the data to uncompress
   * @param start  the offset of the data to uncompress
   * @param len    the length of the data
   * @return the uncompressed data with any data not compressed at the start
   *         remaining intact.
   * @throws IOException
   */
  public byte[] uncompress(byte[] data, int start, int len) throws IOException;

  /**
   * Get the algorithm name for this compression implementation.
   * @return the algorithm name.
   */
  public String getAlgorithm();
  
}