net.jpountz.lz4.LZ4Constants Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of lz4-java Show documentation

Java ports and bindings of the LZ4 compression algorithm and the xxHash hashing algorithm

There is a newer version: 1.8.0

package net.jpountz.lz4;

/*
 * 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.
 */


enum LZ4Constants {
  ;

  static final int DEFAULT_COMPRESSION_LEVEL = 8+1;
  static final int MAX_COMPRESSION_LEVEL = 16+1;

  static final int MEMORY_USAGE = 14;
  static final int NOT_COMPRESSIBLE_DETECTION_LEVEL = 6;

  static final int MIN_MATCH = 4;

  static final int HASH_LOG = MEMORY_USAGE - 2;
  static final int HASH_TABLE_SIZE = 1 << HASH_LOG;

  static final int SKIP_STRENGTH = Math.max(NOT_COMPRESSIBLE_DETECTION_LEVEL, 2);
  static final int COPY_LENGTH = 8;
  static final int LAST_LITERALS = 5;
  static final int MF_LIMIT = COPY_LENGTH + MIN_MATCH;
  static final int MIN_LENGTH = MF_LIMIT + 1;

  static final int MAX_DISTANCE = 1 << 16;

  static final int ML_BITS = 4;
  static final int ML_MASK = (1 << ML_BITS) - 1;
  static final int RUN_BITS = 8 - ML_BITS;
  static final int RUN_MASK = (1 << RUN_BITS) - 1;

  static final int LZ4_64K_LIMIT = (1 << 16) + (MF_LIMIT - 1);
  static final int HASH_LOG_64K = HASH_LOG + 1;
  static final int HASH_TABLE_SIZE_64K = 1 << HASH_LOG_64K;

  static final int HASH_LOG_HC = 15;
  static final int HASH_TABLE_SIZE_HC = 1 << HASH_LOG_HC;
  static final int OPTIMAL_ML = ML_MASK - 1 + MIN_MATCH;

}