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    1   /*
    2    * Copyright 2012 The Netty Project
    3    *
    4    * The Netty Project licenses this file to you under the Apache License,
    5    * version 2.0 (the "License"); you may not use this file except in compliance
    6    * with the License. You may obtain a copy of the License at:
    7    *
    8    *   http://www.apache.org/licenses/LICENSE-2.0
    9    *
    10   * Unless required by applicable law or agreed to in writing, software
    11   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
    12   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
    13   * License for the specific language governing permissions and limitations
    14   * under the License.
    15   */
    16  /*
    17  Copyright (c) 2000,2001,2002,2003 ymnk, JCraft,Inc. All rights reserved.
    18
    19  Redistribution and use in source and binary forms, with or without
    20  modification, are permitted provided that the following conditions are met:
    21
    22    1. Redistributions of source code must retain the above copyright notice,
    23       this list of conditions and the following disclaimer.
    24
    25    2. Redistributions in binary form must reproduce the above copyright
    26       notice, this list of conditions and the following disclaimer in
    27       the documentation and/or other materials provided with the distribution.
    28
    29    3. The names of the authors may not be used to endorse or promote products
    30       derived from this software without specific prior written permission.
    31
    32  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
    33  INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
    34  FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JCRAFT,
    35  INC. OR ANY CONTRIBUTORS TO THIS SOFTWARE BE LIABLE FOR ANY DIRECT, INDIRECT,
    36  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    37  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
    38  OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
    39  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
    40  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
    41  EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
    42   */
    43  /*
    44   * This program is based on zlib-1.1.3, so all credit should go authors
    45   * Jean-loup Gailly(jloup@gzip.org) and Mark Adler(madler@alumni.caltech.edu)
    46   * and contributors of zlib.
    47   */
    48  package org.jboss.netty.util.internal.jzlib;
    49
    50  public final class JZlib {
    51
    52      // wrapper types
    53      public static final Enum<?> W_NONE = WrapperType.NONE;
    54      public static final Enum<?> W_ZLIB = WrapperType.ZLIB;
    55      public static final Enum<?> W_GZIP = WrapperType.GZIP;
    56      public static final Enum<?> W_ZLIB_OR_NONE = WrapperType.ZLIB_OR_NONE;
    57
    58      // compression levels
    59      public static final int Z_NO_COMPRESSION = 0;
    60      public static final int Z_BEST_SPEED = 1;
    61      public static final int Z_BEST_COMPRESSION = 9;
    62      public static final int Z_DEFAULT_COMPRESSION = -1;
    63
    64      // compression strategy
    65      public static final int Z_FILTERED = 1;
    66      public static final int Z_HUFFMAN_ONLY = 2;
    67      public static final int Z_DEFAULT_STRATEGY = 0;
    68
    69      // flush method
    70      public static final int Z_NO_FLUSH = 0;
    71      public static final int Z_PARTIAL_FLUSH = 1;
    72      public static final int Z_SYNC_FLUSH = 2;
    73      public static final int Z_FULL_FLUSH = 3;
    74      public static final int Z_FINISH = 4;
    75
    76      // return codes
    77      public static final int Z_OK = 0;
    78      public static final int Z_STREAM_END = 1;
    79      public static final int Z_NEED_DICT = 2;
    80      public static final int Z_ERRNO = -1;
    81      public static final int Z_STREAM_ERROR = -2;
    82      public static final int Z_DATA_ERROR = -3;
    83      public static final int Z_MEM_ERROR = -4;
    84      public static final int Z_BUF_ERROR = -5;
    85      public static final int Z_VERSION_ERROR = -6;
    86
    87      // internal stuff
    88      static final int Z_DEFLATED = 8;
    89      static final int MAX_MEM_LEVEL = 9;
    90      static final int DEF_MEM_LEVEL = 8;
    91      static final int MAX_WBITS = 15; // 32K LZ77 window
    92      static final int DEF_WBITS = MAX_WBITS;
    93      static final int MAX_BITS = 15;
    94      static final int PRESET_DICT = 0x20; // preset dictionary flag in zlib header
    95      static final int MANY = 1440;
    96      static final int BL_CODES = 19;
    97      static final int D_CODES = 30;
    98      static final int LITERALS = 256;
    99      static final int LENGTH_CODES = 29;
    100     static final int L_CODES = LITERALS + 1 + LENGTH_CODES;
    101     static final int HEAP_SIZE = 2 * L_CODES + 1;
    102     // Bit length codes must not exceed MAX_BL_BITS bits
    103     static final int MAX_BL_BITS = 7;
    104
    105     static enum WrapperType {
    106         NONE, ZLIB, GZIP, ZLIB_OR_NONE;
    107     }
    108
    109     private JZlib() {
    110         // Utility class
    111     }
    112 }