// Deflate.cs
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// ------------------------------------------------------------------
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//
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// Copyright (c) 2009 Dino Chiesa and Microsoft Corporation.
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// All rights reserved.
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//
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// This code module is part of DotNetZip, a zipfile class library.
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//
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// ------------------------------------------------------------------
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//
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// This code is licensed under the Microsoft Public License.
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// See the file License.txt for the license details.
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// More info on: http://dotnetzip.codeplex.com
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//
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// ------------------------------------------------------------------
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//
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// last saved (in emacs):
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// Time-stamp: <2011-August-03 19:52:15>
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//
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// ------------------------------------------------------------------
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//
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// This module defines logic for handling the Deflate or compression.
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//
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// This code is based on multiple sources:
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// - the original zlib v1.2.3 source, which is Copyright (C) 1995-2005 Jean-loup Gailly.
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// - the original jzlib, which is Copyright (c) 2000-2003 ymnk, JCraft,Inc.
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//
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// However, this code is significantly different from both.
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// The object model is not the same, and many of the behaviors are different.
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//
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// In keeping with the license for these other works, the copyrights for
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// jzlib and zlib are here.
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//
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// -----------------------------------------------------------------------
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// Copyright (c) 2000,2001,2002,2003 ymnk, JCraft,Inc. All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are met:
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//
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// 1. Redistributions of source code must retain the above copyright notice,
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// this list of conditions and the following disclaimer.
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//
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// 2. Redistributions in binary form must reproduce the above copyright
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// notice, this list of conditions and the following disclaimer in
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// the documentation and/or other materials provided with the distribution.
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//
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// 3. The names of the authors may not be used to endorse or promote products
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// derived from this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
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// INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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// FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JCRAFT,
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// INC. OR ANY CONTRIBUTORS TO THIS SOFTWARE BE LIABLE FOR ANY DIRECT, INDIRECT,
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// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
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// OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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// EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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//
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// -----------------------------------------------------------------------
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//
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// This program is based on zlib-1.1.3; credit to authors
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// Jean-loup Gailly(jloup@gzip.org) and Mark Adler(madler@alumni.caltech.edu)
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// and contributors of zlib.
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//
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// -----------------------------------------------------------------------
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using System;
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namespace HH.WMS.Utils.Ionic.Zlib
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{
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internal enum BlockState
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{
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NeedMore = 0, // block not completed, need more input or more output
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BlockDone, // block flush performed
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FinishStarted, // finish started, need only more output at next deflate
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FinishDone // finish done, accept no more input or output
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}
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internal enum DeflateFlavor
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{
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Store,
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Fast,
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Slow
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}
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internal sealed class DeflateManager
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{
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private static readonly int MEM_LEVEL_MAX = 9;
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private static readonly int MEM_LEVEL_DEFAULT = 8;
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internal delegate BlockState CompressFunc(FlushType flush);
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internal class Config
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{
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// Use a faster search when the previous match is longer than this
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internal int GoodLength; // reduce lazy search above this match length
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// Attempt to find a better match only when the current match is
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// strictly smaller than this value. This mechanism is used only for
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// compression levels >= 4. For levels 1,2,3: MaxLazy is actually
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// MaxInsertLength. (See DeflateFast)
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internal int MaxLazy; // do not perform lazy search above this match length
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internal int NiceLength; // quit search above this match length
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// To speed up deflation, hash chains are never searched beyond this
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// length. A higher limit improves compression ratio but degrades the speed.
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internal int MaxChainLength;
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internal DeflateFlavor Flavor;
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private Config(int goodLength, int maxLazy, int niceLength, int maxChainLength, DeflateFlavor flavor)
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{
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this.GoodLength = goodLength;
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this.MaxLazy = maxLazy;
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this.NiceLength = niceLength;
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this.MaxChainLength = maxChainLength;
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this.Flavor = flavor;
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}
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public static Config Lookup(CompressionLevel level)
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{
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return Table[(int)level];
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}
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static Config()
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{
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Table = new Config[] {
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new Config(0, 0, 0, 0, DeflateFlavor.Store),
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new Config(4, 4, 8, 4, DeflateFlavor.Fast),
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new Config(4, 5, 16, 8, DeflateFlavor.Fast),
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new Config(4, 6, 32, 32, DeflateFlavor.Fast),
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new Config(4, 4, 16, 16, DeflateFlavor.Slow),
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new Config(8, 16, 32, 32, DeflateFlavor.Slow),
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new Config(8, 16, 128, 128, DeflateFlavor.Slow),
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new Config(8, 32, 128, 256, DeflateFlavor.Slow),
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new Config(32, 128, 258, 1024, DeflateFlavor.Slow),
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new Config(32, 258, 258, 4096, DeflateFlavor.Slow),
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};
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}
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private static readonly Config[] Table;
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}
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private CompressFunc DeflateFunction;
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private static readonly System.String[] _ErrorMessage = new System.String[]
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{
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"need dictionary",
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"stream end",
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"",
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"file error",
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"stream error",
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"data error",
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"insufficient memory",
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"buffer error",
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"incompatible version",
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""
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};
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// preset dictionary flag in zlib header
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private static readonly int PRESET_DICT = 0x20;
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private static readonly int INIT_STATE = 42;
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private static readonly int BUSY_STATE = 113;
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private static readonly int FINISH_STATE = 666;
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// The deflate compression method
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private static readonly int Z_DEFLATED = 8;
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private static readonly int STORED_BLOCK = 0;
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private static readonly int STATIC_TREES = 1;
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private static readonly int DYN_TREES = 2;
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// The three kinds of block type
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private static readonly int Z_BINARY = 0;
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private static readonly int Z_ASCII = 1;
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private static readonly int Z_UNKNOWN = 2;
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private static readonly int Buf_size = 8 * 2;
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private static readonly int MIN_MATCH = 3;
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private static readonly int MAX_MATCH = 258;
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private static readonly int MIN_LOOKAHEAD = (MAX_MATCH + MIN_MATCH + 1);
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private static readonly int HEAP_SIZE = (2 * InternalConstants.L_CODES + 1);
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private static readonly int END_BLOCK = 256;
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internal ZlibCodec _codec; // the zlib encoder/decoder
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internal int status; // as the name implies
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internal byte[] pending; // output still pending - waiting to be compressed
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internal int nextPending; // index of next pending byte to output to the stream
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internal int pendingCount; // number of bytes in the pending buffer
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internal sbyte data_type; // UNKNOWN, BINARY or ASCII
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internal int last_flush; // value of flush param for previous deflate call
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internal int w_size; // LZ77 window size (32K by default)
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internal int w_bits; // log2(w_size) (8..16)
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internal int w_mask; // w_size - 1
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//internal byte[] dictionary;
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internal byte[] window;
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// Sliding window. Input bytes are read into the second half of the window,
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// and move to the first half later to keep a dictionary of at least wSize
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// bytes. With this organization, matches are limited to a distance of
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// wSize-MAX_MATCH bytes, but this ensures that IO is always
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// performed with a length multiple of the block size.
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//
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// To do: use the user input buffer as sliding window.
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internal int window_size;
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// Actual size of window: 2*wSize, except when the user input buffer
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// is directly used as sliding window.
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internal short[] prev;
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// Link to older string with same hash index. To limit the size of this
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// array to 64K, this link is maintained only for the last 32K strings.
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// An index in this array is thus a window index modulo 32K.
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internal short[] head; // Heads of the hash chains or NIL.
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internal int ins_h; // hash index of string to be inserted
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internal int hash_size; // number of elements in hash table
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internal int hash_bits; // log2(hash_size)
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internal int hash_mask; // hash_size-1
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// Number of bits by which ins_h must be shifted at each input
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// step. It must be such that after MIN_MATCH steps, the oldest
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// byte no longer takes part in the hash key, that is:
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// hash_shift * MIN_MATCH >= hash_bits
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internal int hash_shift;
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// Window position at the beginning of the current output block. Gets
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// negative when the window is moved backwards.
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internal int block_start;
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Config config;
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internal int match_length; // length of best match
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internal int prev_match; // previous match
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internal int match_available; // set if previous match exists
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internal int strstart; // start of string to insert into.....????
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internal int match_start; // start of matching string
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internal int lookahead; // number of valid bytes ahead in window
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// Length of the best match at previous step. Matches not greater than this
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// are discarded. This is used in the lazy match evaluation.
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internal int prev_length;
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// Insert new strings in the hash table only if the match length is not
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// greater than this length. This saves time but degrades compression.
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// max_insert_length is used only for compression levels <= 3.
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internal CompressionLevel compressionLevel; // compression level (1..9)
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internal CompressionStrategy compressionStrategy; // favor or force Huffman coding
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internal short[] dyn_ltree; // literal and length tree
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internal short[] dyn_dtree; // distance tree
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internal short[] bl_tree; // Huffman tree for bit lengths
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internal Tree treeLiterals = new Tree(); // desc for literal tree
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internal Tree treeDistances = new Tree(); // desc for distance tree
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internal Tree treeBitLengths = new Tree(); // desc for bit length tree
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// number of codes at each bit length for an optimal tree
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internal short[] bl_count = new short[InternalConstants.MAX_BITS + 1];
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// heap used to build the Huffman trees
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internal int[] heap = new int[2 * InternalConstants.L_CODES + 1];
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internal int heap_len; // number of elements in the heap
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internal int heap_max; // element of largest frequency
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// The sons of heap[n] are heap[2*n] and heap[2*n+1]. heap[0] is not used.
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// The same heap array is used to build all trees.
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// Depth of each subtree used as tie breaker for trees of equal frequency
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internal sbyte[] depth = new sbyte[2 * InternalConstants.L_CODES + 1];
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internal int _lengthOffset; // index for literals or lengths
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// Size of match buffer for literals/lengths. There are 4 reasons for
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// limiting lit_bufsize to 64K:
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// - frequencies can be kept in 16 bit counters
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// - if compression is not successful for the first block, all input
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// data is still in the window so we can still emit a stored block even
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// when input comes from standard input. (This can also be done for
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// all blocks if lit_bufsize is not greater than 32K.)
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// - if compression is not successful for a file smaller than 64K, we can
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// even emit a stored file instead of a stored block (saving 5 bytes).
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// This is applicable only for zip (not gzip or zlib).
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// - creating new Huffman trees less frequently may not provide fast
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// adaptation to changes in the input data statistics. (Take for
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// example a binary file with poorly compressible code followed by
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// a highly compressible string table.) Smaller buffer sizes give
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// fast adaptation but have of course the overhead of transmitting
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// trees more frequently.
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internal int lit_bufsize;
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internal int last_lit; // running index in l_buf
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// Buffer for distances. To simplify the code, d_buf and l_buf have
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// the same number of elements. To use different lengths, an extra flag
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// array would be necessary.
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internal int _distanceOffset; // index into pending; points to distance data??
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internal int opt_len; // bit length of current block with optimal trees
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internal int static_len; // bit length of current block with static trees
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internal int matches; // number of string matches in current block
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internal int last_eob_len; // bit length of EOB code for last block
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// Output buffer. bits are inserted starting at the bottom (least
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// significant bits).
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internal short bi_buf;
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// Number of valid bits in bi_buf. All bits above the last valid bit
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// are always zero.
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internal int bi_valid;
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internal DeflateManager()
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{
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dyn_ltree = new short[HEAP_SIZE * 2];
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dyn_dtree = new short[(2 * InternalConstants.D_CODES + 1) * 2]; // distance tree
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bl_tree = new short[(2 * InternalConstants.BL_CODES + 1) * 2]; // Huffman tree for bit lengths
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}
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// lm_init
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private void _InitializeLazyMatch()
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{
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window_size = 2 * w_size;
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// clear the hash - workitem 9063
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Array.Clear(head, 0, hash_size);
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//for (int i = 0; i < hash_size; i++) head[i] = 0;
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config = Config.Lookup(compressionLevel);
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SetDeflater();
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strstart = 0;
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block_start = 0;
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lookahead = 0;
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match_length = prev_length = MIN_MATCH - 1;
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match_available = 0;
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ins_h = 0;
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}
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// Initialize the tree data structures for a new zlib stream.
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private void _InitializeTreeData()
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{
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treeLiterals.dyn_tree = dyn_ltree;
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treeLiterals.staticTree = StaticTree.Literals;
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treeDistances.dyn_tree = dyn_dtree;
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treeDistances.staticTree = StaticTree.Distances;
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treeBitLengths.dyn_tree = bl_tree;
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treeBitLengths.staticTree = StaticTree.BitLengths;
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bi_buf = 0;
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bi_valid = 0;
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last_eob_len = 8; // enough lookahead for inflate
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// Initialize the first block of the first file:
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_InitializeBlocks();
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}
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internal void _InitializeBlocks()
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{
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// Initialize the trees.
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for (int i = 0; i < InternalConstants.L_CODES; i++)
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dyn_ltree[i * 2] = 0;
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for (int i = 0; i < InternalConstants.D_CODES; i++)
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dyn_dtree[i * 2] = 0;
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for (int i = 0; i < InternalConstants.BL_CODES; i++)
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bl_tree[i * 2] = 0;
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dyn_ltree[END_BLOCK * 2] = 1;
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opt_len = static_len = 0;
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last_lit = matches = 0;
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}
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// Restore the heap property by moving down the tree starting at node k,
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// exchanging a node with the smallest of its two sons if necessary, stopping
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// when the heap property is re-established (each father smaller than its
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// two sons).
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internal void pqdownheap(short[] tree, int k)
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{
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int v = heap[k];
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int j = k << 1; // left son of k
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while (j <= heap_len)
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{
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// Set j to the smallest of the two sons:
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if (j < heap_len && _IsSmaller(tree, heap[j + 1], heap[j], depth))
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{
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j++;
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}
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// Exit if v is smaller than both sons
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if (_IsSmaller(tree, v, heap[j], depth))
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break;
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// Exchange v with the smallest son
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heap[k] = heap[j]; k = j;
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// And continue down the tree, setting j to the left son of k
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j <<= 1;
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}
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heap[k] = v;
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}
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internal static bool _IsSmaller(short[] tree, int n, int m, sbyte[] depth)
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{
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short tn2 = tree[n * 2];
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short tm2 = tree[m * 2];
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return (tn2 < tm2 || (tn2 == tm2 && depth[n] <= depth[m]));
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}
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// Scan a literal or distance tree to determine the frequencies of the codes
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// in the bit length tree.
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internal void scan_tree(short[] tree, int max_code)
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{
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int n; // iterates over all tree elements
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int prevlen = -1; // last emitted length
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int curlen; // length of current code
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int nextlen = (int)tree[0 * 2 + 1]; // length of next code
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int count = 0; // repeat count of the current code
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int max_count = 7; // max repeat count
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int min_count = 4; // min repeat count
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if (nextlen == 0)
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{
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max_count = 138; min_count = 3;
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}
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tree[(max_code + 1) * 2 + 1] = (short)0x7fff; // guard //??
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for (n = 0; n <= max_code; n++)
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{
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curlen = nextlen; nextlen = (int)tree[(n + 1) * 2 + 1];
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if (++count < max_count && curlen == nextlen)
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{
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continue;
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}
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else if (count < min_count)
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{
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bl_tree[curlen * 2] = (short)(bl_tree[curlen * 2] + count);
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}
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else if (curlen != 0)
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{
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if (curlen != prevlen)
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bl_tree[curlen * 2]++;
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bl_tree[InternalConstants.REP_3_6 * 2]++;
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}
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else if (count <= 10)
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{
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bl_tree[InternalConstants.REPZ_3_10 * 2]++;
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}
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else
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{
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bl_tree[InternalConstants.REPZ_11_138 * 2]++;
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}
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count = 0; prevlen = curlen;
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if (nextlen == 0)
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{
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max_count = 138; min_count = 3;
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}
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else if (curlen == nextlen)
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{
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max_count = 6; min_count = 3;
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}
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else
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{
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max_count = 7; min_count = 4;
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}
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}
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}
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// Construct the Huffman tree for the bit lengths and return the index in
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// bl_order of the last bit length code to send.
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internal int build_bl_tree()
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{
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int max_blindex; // index of last bit length code of non zero freq
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// Determine the bit length frequencies for literal and distance trees
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scan_tree(dyn_ltree, treeLiterals.max_code);
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scan_tree(dyn_dtree, treeDistances.max_code);
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// Build the bit length tree:
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treeBitLengths.build_tree(this);
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// opt_len now includes the length of the tree representations, except
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// the lengths of the bit lengths codes and the 5+5+4 bits for the counts.
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// Determine the number of bit length codes to send. The pkzip format
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// requires that at least 4 bit length codes be sent. (appnote.txt says
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// 3 but the actual value used is 4.)
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for (max_blindex = InternalConstants.BL_CODES - 1; max_blindex >= 3; max_blindex--)
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{
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if (bl_tree[Tree.bl_order[max_blindex] * 2 + 1] != 0)
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break;
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}
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// Update opt_len to include the bit length tree and counts
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opt_len += 3 * (max_blindex + 1) + 5 + 5 + 4;
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return max_blindex;
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}
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// Send the header for a block using dynamic Huffman trees: the counts, the
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// lengths of the bit length codes, the literal tree and the distance tree.
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// IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.
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internal void send_all_trees(int lcodes, int dcodes, int blcodes)
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{
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int rank; // index in bl_order
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send_bits(lcodes - 257, 5); // not +255 as stated in appnote.txt
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send_bits(dcodes - 1, 5);
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send_bits(blcodes - 4, 4); // not -3 as stated in appnote.txt
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for (rank = 0; rank < blcodes; rank++)
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{
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send_bits(bl_tree[Tree.bl_order[rank] * 2 + 1], 3);
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}
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send_tree(dyn_ltree, lcodes - 1); // literal tree
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send_tree(dyn_dtree, dcodes - 1); // distance tree
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}
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// Send a literal or distance tree in compressed form, using the codes in
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// bl_tree.
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internal void send_tree(short[] tree, int max_code)
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{
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int n; // iterates over all tree elements
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int prevlen = -1; // last emitted length
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int curlen; // length of current code
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int nextlen = tree[0 * 2 + 1]; // length of next code
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int count = 0; // repeat count of the current code
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int max_count = 7; // max repeat count
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int min_count = 4; // min repeat count
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if (nextlen == 0)
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{
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max_count = 138; min_count = 3;
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}
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for (n = 0; n <= max_code; n++)
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{
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curlen = nextlen; nextlen = tree[(n + 1) * 2 + 1];
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if (++count < max_count && curlen == nextlen)
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{
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continue;
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}
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else if (count < min_count)
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{
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do
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{
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send_code(curlen, bl_tree);
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}
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while (--count != 0);
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}
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else if (curlen != 0)
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{
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if (curlen != prevlen)
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{
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send_code(curlen, bl_tree); count--;
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}
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send_code(InternalConstants.REP_3_6, bl_tree);
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send_bits(count - 3, 2);
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}
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else if (count <= 10)
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{
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send_code(InternalConstants.REPZ_3_10, bl_tree);
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send_bits(count - 3, 3);
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}
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else
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{
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send_code(InternalConstants.REPZ_11_138, bl_tree);
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send_bits(count - 11, 7);
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}
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count = 0; prevlen = curlen;
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if (nextlen == 0)
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{
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max_count = 138; min_count = 3;
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}
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else if (curlen == nextlen)
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{
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max_count = 6; min_count = 3;
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}
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else
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{
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max_count = 7; min_count = 4;
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}
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}
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}
|
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// Output a block of bytes on the stream.
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// IN assertion: there is enough room in pending_buf.
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private void put_bytes(byte[] p, int start, int len)
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{
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Array.Copy(p, start, pending, pendingCount, len);
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pendingCount += len;
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}
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|
#if NOTNEEDED
|
private void put_byte(byte c)
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{
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pending[pendingCount++] = c;
|
}
|
internal void put_short(int b)
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{
|
unchecked
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{
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pending[pendingCount++] = (byte)b;
|
pending[pendingCount++] = (byte)(b >> 8);
|
}
|
}
|
internal void putShortMSB(int b)
|
{
|
unchecked
|
{
|
pending[pendingCount++] = (byte)(b >> 8);
|
pending[pendingCount++] = (byte)b;
|
}
|
}
|
#endif
|
|
internal void send_code(int c, short[] tree)
|
{
|
int c2 = c * 2;
|
send_bits((tree[c2] & 0xffff), (tree[c2 + 1] & 0xffff));
|
}
|
|
internal void send_bits(int value, int length)
|
{
|
int len = length;
|
unchecked
|
{
|
if (bi_valid > (int)Buf_size - len)
|
{
|
//int val = value;
|
// bi_buf |= (val << bi_valid);
|
|
bi_buf |= (short)((value << bi_valid) & 0xffff);
|
//put_short(bi_buf);
|
pending[pendingCount++] = (byte)bi_buf;
|
pending[pendingCount++] = (byte)(bi_buf >> 8);
|
|
|
bi_buf = (short)((uint)value >> (Buf_size - bi_valid));
|
bi_valid += len - Buf_size;
|
}
|
else
|
{
|
// bi_buf |= (value) << bi_valid;
|
bi_buf |= (short)((value << bi_valid) & 0xffff);
|
bi_valid += len;
|
}
|
}
|
}
|
|
// Send one empty static block to give enough lookahead for inflate.
|
// This takes 10 bits, of which 7 may remain in the bit buffer.
|
// The current inflate code requires 9 bits of lookahead. If the
|
// last two codes for the previous block (real code plus EOB) were coded
|
// on 5 bits or less, inflate may have only 5+3 bits of lookahead to decode
|
// the last real code. In this case we send two empty static blocks instead
|
// of one. (There are no problems if the previous block is stored or fixed.)
|
// To simplify the code, we assume the worst case of last real code encoded
|
// on one bit only.
|
internal void _tr_align()
|
{
|
send_bits(STATIC_TREES << 1, 3);
|
send_code(END_BLOCK, StaticTree.lengthAndLiteralsTreeCodes);
|
|
bi_flush();
|
|
// Of the 10 bits for the empty block, we have already sent
|
// (10 - bi_valid) bits. The lookahead for the last real code (before
|
// the EOB of the previous block) was thus at least one plus the length
|
// of the EOB plus what we have just sent of the empty static block.
|
if (1 + last_eob_len + 10 - bi_valid < 9)
|
{
|
send_bits(STATIC_TREES << 1, 3);
|
send_code(END_BLOCK, StaticTree.lengthAndLiteralsTreeCodes);
|
bi_flush();
|
}
|
last_eob_len = 7;
|
}
|
|
|
// Save the match info and tally the frequency counts. Return true if
|
// the current block must be flushed.
|
internal bool _tr_tally(int dist, int lc)
|
{
|
pending[_distanceOffset + last_lit * 2] = unchecked((byte) ( (uint)dist >> 8 ) );
|
pending[_distanceOffset + last_lit * 2 + 1] = unchecked((byte)dist);
|
pending[_lengthOffset + last_lit] = unchecked((byte)lc);
|
last_lit++;
|
|
if (dist == 0)
|
{
|
// lc is the unmatched char
|
dyn_ltree[lc * 2]++;
|
}
|
else
|
{
|
matches++;
|
// Here, lc is the match length - MIN_MATCH
|
dist--; // dist = match distance - 1
|
dyn_ltree[(Tree.LengthCode[lc] + InternalConstants.LITERALS + 1) * 2]++;
|
dyn_dtree[Tree.DistanceCode(dist) * 2]++;
|
}
|
|
if ((last_lit & 0x1fff) == 0 && (int)compressionLevel > 2)
|
{
|
// Compute an upper bound for the compressed length
|
int out_length = last_lit << 3;
|
int in_length = strstart - block_start;
|
int dcode;
|
for (dcode = 0; dcode < InternalConstants.D_CODES; dcode++)
|
{
|
out_length = (int)(out_length + (int)dyn_dtree[dcode * 2] * (5L + Tree.ExtraDistanceBits[dcode]));
|
}
|
out_length >>= 3;
|
if ((matches < (last_lit / 2)) && out_length < in_length / 2)
|
return true;
|
}
|
|
return (last_lit == lit_bufsize - 1) || (last_lit == lit_bufsize);
|
// dinoch - wraparound?
|
// We avoid equality with lit_bufsize because of wraparound at 64K
|
// on 16 bit machines and because stored blocks are restricted to
|
// 64K-1 bytes.
|
}
|
|
|
|
// Send the block data compressed using the given Huffman trees
|
internal void send_compressed_block(short[] ltree, short[] dtree)
|
{
|
int distance; // distance of matched string
|
int lc; // match length or unmatched char (if dist == 0)
|
int lx = 0; // running index in l_buf
|
int code; // the code to send
|
int extra; // number of extra bits to send
|
|
if (last_lit != 0)
|
{
|
do
|
{
|
int ix = _distanceOffset + lx * 2;
|
distance = ((pending[ix] << 8) & 0xff00) |
|
(pending[ix + 1] & 0xff);
|
lc = (pending[_lengthOffset + lx]) & 0xff;
|
lx++;
|
|
if (distance == 0)
|
{
|
send_code(lc, ltree); // send a literal byte
|
}
|
else
|
{
|
// literal or match pair
|
// Here, lc is the match length - MIN_MATCH
|
code = Tree.LengthCode[lc];
|
|
// send the length code
|
send_code(code + InternalConstants.LITERALS + 1, ltree);
|
extra = Tree.ExtraLengthBits[code];
|
if (extra != 0)
|
{
|
// send the extra length bits
|
lc -= Tree.LengthBase[code];
|
send_bits(lc, extra);
|
}
|
distance--; // dist is now the match distance - 1
|
code = Tree.DistanceCode(distance);
|
|
// send the distance code
|
send_code(code, dtree);
|
|
extra = Tree.ExtraDistanceBits[code];
|
if (extra != 0)
|
{
|
// send the extra distance bits
|
distance -= Tree.DistanceBase[code];
|
send_bits(distance, extra);
|
}
|
}
|
|
// Check that the overlay between pending and d_buf+l_buf is ok:
|
}
|
while (lx < last_lit);
|
}
|
|
send_code(END_BLOCK, ltree);
|
last_eob_len = ltree[END_BLOCK * 2 + 1];
|
}
|
|
|
|
// Set the data type to ASCII or BINARY, using a crude approximation:
|
// binary if more than 20% of the bytes are <= 6 or >= 128, ascii otherwise.
|
// IN assertion: the fields freq of dyn_ltree are set and the total of all
|
// frequencies does not exceed 64K (to fit in an int on 16 bit machines).
|
internal void set_data_type()
|
{
|
int n = 0;
|
int ascii_freq = 0;
|
int bin_freq = 0;
|
while (n < 7)
|
{
|
bin_freq += dyn_ltree[n * 2]; n++;
|
}
|
while (n < 128)
|
{
|
ascii_freq += dyn_ltree[n * 2]; n++;
|
}
|
while (n < InternalConstants.LITERALS)
|
{
|
bin_freq += dyn_ltree[n * 2]; n++;
|
}
|
data_type = (sbyte)(bin_freq > (ascii_freq >> 2) ? Z_BINARY : Z_ASCII);
|
}
|
|
|
|
// Flush the bit buffer, keeping at most 7 bits in it.
|
internal void bi_flush()
|
{
|
if (bi_valid == 16)
|
{
|
pending[pendingCount++] = (byte)bi_buf;
|
pending[pendingCount++] = (byte)(bi_buf >> 8);
|
bi_buf = 0;
|
bi_valid = 0;
|
}
|
else if (bi_valid >= 8)
|
{
|
//put_byte((byte)bi_buf);
|
pending[pendingCount++] = (byte)bi_buf;
|
bi_buf >>= 8;
|
bi_valid -= 8;
|
}
|
}
|
|
// Flush the bit buffer and align the output on a byte boundary
|
internal void bi_windup()
|
{
|
if (bi_valid > 8)
|
{
|
pending[pendingCount++] = (byte)bi_buf;
|
pending[pendingCount++] = (byte)(bi_buf >> 8);
|
}
|
else if (bi_valid > 0)
|
{
|
//put_byte((byte)bi_buf);
|
pending[pendingCount++] = (byte)bi_buf;
|
}
|
bi_buf = 0;
|
bi_valid = 0;
|
}
|
|
// Copy a stored block, storing first the length and its
|
// one's complement if requested.
|
internal void copy_block(int buf, int len, bool header)
|
{
|
bi_windup(); // align on byte boundary
|
last_eob_len = 8; // enough lookahead for inflate
|
|
if (header)
|
unchecked
|
{
|
//put_short((short)len);
|
pending[pendingCount++] = (byte)len;
|
pending[pendingCount++] = (byte)(len >> 8);
|
//put_short((short)~len);
|
pending[pendingCount++] = (byte)~len;
|
pending[pendingCount++] = (byte)(~len >> 8);
|
}
|
|
put_bytes(window, buf, len);
|
}
|
|
internal void flush_block_only(bool eof)
|
{
|
_tr_flush_block(block_start >= 0 ? block_start : -1, strstart - block_start, eof);
|
block_start = strstart;
|
_codec.flush_pending();
|
}
|
|
// Copy without compression as much as possible from the input stream, return
|
// the current block state.
|
// This function does not insert new strings in the dictionary since
|
// uncompressible data is probably not useful. This function is used
|
// only for the level=0 compression option.
|
// NOTE: this function should be optimized to avoid extra copying from
|
// window to pending_buf.
|
internal BlockState DeflateNone(FlushType flush)
|
{
|
// Stored blocks are limited to 0xffff bytes, pending is limited
|
// to pending_buf_size, and each stored block has a 5 byte header:
|
|
int max_block_size = 0xffff;
|
int max_start;
|
|
if (max_block_size > pending.Length - 5)
|
{
|
max_block_size = pending.Length - 5;
|
}
|
|
// Copy as much as possible from input to output:
|
while (true)
|
{
|
// Fill the window as much as possible:
|
if (lookahead <= 1)
|
{
|
_fillWindow();
|
if (lookahead == 0 && flush == FlushType.None)
|
return BlockState.NeedMore;
|
if (lookahead == 0)
|
break; // flush the current block
|
}
|
|
strstart += lookahead;
|
lookahead = 0;
|
|
// Emit a stored block if pending will be full:
|
max_start = block_start + max_block_size;
|
if (strstart == 0 || strstart >= max_start)
|
{
|
// strstart == 0 is possible when wraparound on 16-bit machine
|
lookahead = (int)(strstart - max_start);
|
strstart = (int)max_start;
|
|
flush_block_only(false);
|
if (_codec.AvailableBytesOut == 0)
|
return BlockState.NeedMore;
|
}
|
|
// Flush if we may have to slide, otherwise block_start may become
|
// negative and the data will be gone:
|
if (strstart - block_start >= w_size - MIN_LOOKAHEAD)
|
{
|
flush_block_only(false);
|
if (_codec.AvailableBytesOut == 0)
|
return BlockState.NeedMore;
|
}
|
}
|
|
flush_block_only(flush == FlushType.Finish);
|
if (_codec.AvailableBytesOut == 0)
|
return (flush == FlushType.Finish) ? BlockState.FinishStarted : BlockState.NeedMore;
|
|
return flush == FlushType.Finish ? BlockState.FinishDone : BlockState.BlockDone;
|
}
|
|
|
// Send a stored block
|
internal void _tr_stored_block(int buf, int stored_len, bool eof)
|
{
|
send_bits((STORED_BLOCK << 1) + (eof ? 1 : 0), 3); // send block type
|
copy_block(buf, stored_len, true); // with header
|
}
|
|
// Determine the best encoding for the current block: dynamic trees, static
|
// trees or store, and output the encoded block to the zip file.
|
internal void _tr_flush_block(int buf, int stored_len, bool eof)
|
{
|
int opt_lenb, static_lenb; // opt_len and static_len in bytes
|
int max_blindex = 0; // index of last bit length code of non zero freq
|
|
// Build the Huffman trees unless a stored block is forced
|
if (compressionLevel > 0)
|
{
|
// Check if the file is ascii or binary
|
if (data_type == Z_UNKNOWN)
|
set_data_type();
|
|
// Construct the literal and distance trees
|
treeLiterals.build_tree(this);
|
|
treeDistances.build_tree(this);
|
|
// At this point, opt_len and static_len are the total bit lengths of
|
// the compressed block data, excluding the tree representations.
|
|
// Build the bit length tree for the above two trees, and get the index
|
// in bl_order of the last bit length code to send.
|
max_blindex = build_bl_tree();
|
|
// Determine the best encoding. Compute first the block length in bytes
|
opt_lenb = (opt_len + 3 + 7) >> 3;
|
static_lenb = (static_len + 3 + 7) >> 3;
|
|
if (static_lenb <= opt_lenb)
|
opt_lenb = static_lenb;
|
}
|
else
|
{
|
opt_lenb = static_lenb = stored_len + 5; // force a stored block
|
}
|
|
if (stored_len + 4 <= opt_lenb && buf != -1)
|
{
|
// 4: two words for the lengths
|
// The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.
|
// Otherwise we can't have processed more than WSIZE input bytes since
|
// the last block flush, because compression would have been
|
// successful. If LIT_BUFSIZE <= WSIZE, it is never too late to
|
// transform a block into a stored block.
|
_tr_stored_block(buf, stored_len, eof);
|
}
|
else if (static_lenb == opt_lenb)
|
{
|
send_bits((STATIC_TREES << 1) + (eof ? 1 : 0), 3);
|
send_compressed_block(StaticTree.lengthAndLiteralsTreeCodes, StaticTree.distTreeCodes);
|
}
|
else
|
{
|
send_bits((DYN_TREES << 1) + (eof ? 1 : 0), 3);
|
send_all_trees(treeLiterals.max_code + 1, treeDistances.max_code + 1, max_blindex + 1);
|
send_compressed_block(dyn_ltree, dyn_dtree);
|
}
|
|
// The above check is made mod 2^32, for files larger than 512 MB
|
// and uLong implemented on 32 bits.
|
|
_InitializeBlocks();
|
|
if (eof)
|
{
|
bi_windup();
|
}
|
}
|
|
// Fill the window when the lookahead becomes insufficient.
|
// Updates strstart and lookahead.
|
//
|
// IN assertion: lookahead < MIN_LOOKAHEAD
|
// OUT assertions: strstart <= window_size-MIN_LOOKAHEAD
|
// At least one byte has been read, or avail_in == 0; reads are
|
// performed for at least two bytes (required for the zip translate_eol
|
// option -- not supported here).
|
private void _fillWindow()
|
{
|
int n, m;
|
int p;
|
int more; // Amount of free space at the end of the window.
|
|
do
|
{
|
more = (window_size - lookahead - strstart);
|
|
// Deal with !@#$% 64K limit:
|
if (more == 0 && strstart == 0 && lookahead == 0)
|
{
|
more = w_size;
|
}
|
else if (more == -1)
|
{
|
// Very unlikely, but possible on 16 bit machine if strstart == 0
|
// and lookahead == 1 (input done one byte at time)
|
more--;
|
|
// If the window is almost full and there is insufficient lookahead,
|
// move the upper half to the lower one to make room in the upper half.
|
}
|
else if (strstart >= w_size + w_size - MIN_LOOKAHEAD)
|
{
|
Array.Copy(window, w_size, window, 0, w_size);
|
match_start -= w_size;
|
strstart -= w_size; // we now have strstart >= MAX_DIST
|
block_start -= w_size;
|
|
// Slide the hash table (could be avoided with 32 bit values
|
// at the expense of memory usage). We slide even when level == 0
|
// to keep the hash table consistent if we switch back to level > 0
|
// later. (Using level 0 permanently is not an optimal usage of
|
// zlib, so we don't care about this pathological case.)
|
|
n = hash_size;
|
p = n;
|
do
|
{
|
m = (head[--p] & 0xffff);
|
head[p] = (short)((m >= w_size) ? (m - w_size) : 0);
|
}
|
while (--n != 0);
|
|
n = w_size;
|
p = n;
|
do
|
{
|
m = (prev[--p] & 0xffff);
|
prev[p] = (short)((m >= w_size) ? (m - w_size) : 0);
|
// If n is not on any hash chain, prev[n] is garbage but
|
// its value will never be used.
|
}
|
while (--n != 0);
|
more += w_size;
|
}
|
|
if (_codec.AvailableBytesIn == 0)
|
return;
|
|
// If there was no sliding:
|
// strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 &&
|
// more == window_size - lookahead - strstart
|
// => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1)
|
// => more >= window_size - 2*WSIZE + 2
|
// In the BIG_MEM or MMAP case (not yet supported),
|
// window_size == input_size + MIN_LOOKAHEAD &&
|
// strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD.
|
// Otherwise, window_size == 2*WSIZE so more >= 2.
|
// If there was sliding, more >= WSIZE. So in all cases, more >= 2.
|
|
n = _codec.read_buf(window, strstart + lookahead, more);
|
lookahead += n;
|
|
// Initialize the hash value now that we have some input:
|
if (lookahead >= MIN_MATCH)
|
{
|
ins_h = window[strstart] & 0xff;
|
ins_h = (((ins_h) << hash_shift) ^ (window[strstart + 1] & 0xff)) & hash_mask;
|
}
|
// If the whole input has less than MIN_MATCH bytes, ins_h is garbage,
|
// but this is not important since only literal bytes will be emitted.
|
}
|
while (lookahead < MIN_LOOKAHEAD && _codec.AvailableBytesIn != 0);
|
}
|
|
// Compress as much as possible from the input stream, return the current
|
// block state.
|
// This function does not perform lazy evaluation of matches and inserts
|
// new strings in the dictionary only for unmatched strings or for short
|
// matches. It is used only for the fast compression options.
|
internal BlockState DeflateFast(FlushType flush)
|
{
|
// short hash_head = 0; // head of the hash chain
|
int hash_head = 0; // head of the hash chain
|
bool bflush; // set if current block must be flushed
|
|
while (true)
|
{
|
// Make sure that we always have enough lookahead, except
|
// at the end of the input file. We need MAX_MATCH bytes
|
// for the next match, plus MIN_MATCH bytes to insert the
|
// string following the next match.
|
if (lookahead < MIN_LOOKAHEAD)
|
{
|
_fillWindow();
|
if (lookahead < MIN_LOOKAHEAD && flush == FlushType.None)
|
{
|
return BlockState.NeedMore;
|
}
|
if (lookahead == 0)
|
break; // flush the current block
|
}
|
|
// Insert the string window[strstart .. strstart+2] in the
|
// dictionary, and set hash_head to the head of the hash chain:
|
if (lookahead >= MIN_MATCH)
|
{
|
ins_h = (((ins_h) << hash_shift) ^ (window[(strstart) + (MIN_MATCH - 1)] & 0xff)) & hash_mask;
|
|
// prev[strstart&w_mask]=hash_head=head[ins_h];
|
hash_head = (head[ins_h] & 0xffff);
|
prev[strstart & w_mask] = head[ins_h];
|
head[ins_h] = unchecked((short)strstart);
|
}
|
|
// Find the longest match, discarding those <= prev_length.
|
// At this point we have always match_length < MIN_MATCH
|
|
if (hash_head != 0L && ((strstart - hash_head) & 0xffff) <= w_size - MIN_LOOKAHEAD)
|
{
|
// To simplify the code, we prevent matches with the string
|
// of window index 0 (in particular we have to avoid a match
|
// of the string with itself at the start of the input file).
|
if (compressionStrategy != CompressionStrategy.HuffmanOnly)
|
{
|
match_length = longest_match(hash_head);
|
}
|
// longest_match() sets match_start
|
}
|
if (match_length >= MIN_MATCH)
|
{
|
// check_match(strstart, match_start, match_length);
|
|
bflush = _tr_tally(strstart - match_start, match_length - MIN_MATCH);
|
|
lookahead -= match_length;
|
|
// Insert new strings in the hash table only if the match length
|
// is not too large. This saves time but degrades compression.
|
if (match_length <= config.MaxLazy && lookahead >= MIN_MATCH)
|
{
|
match_length--; // string at strstart already in hash table
|
do
|
{
|
strstart++;
|
|
ins_h = ((ins_h << hash_shift) ^ (window[(strstart) + (MIN_MATCH - 1)] & 0xff)) & hash_mask;
|
// prev[strstart&w_mask]=hash_head=head[ins_h];
|
hash_head = (head[ins_h] & 0xffff);
|
prev[strstart & w_mask] = head[ins_h];
|
head[ins_h] = unchecked((short)strstart);
|
|
// strstart never exceeds WSIZE-MAX_MATCH, so there are
|
// always MIN_MATCH bytes ahead.
|
}
|
while (--match_length != 0);
|
strstart++;
|
}
|
else
|
{
|
strstart += match_length;
|
match_length = 0;
|
ins_h = window[strstart] & 0xff;
|
|
ins_h = (((ins_h) << hash_shift) ^ (window[strstart + 1] & 0xff)) & hash_mask;
|
// If lookahead < MIN_MATCH, ins_h is garbage, but it does not
|
// matter since it will be recomputed at next deflate call.
|
}
|
}
|
else
|
{
|
// No match, output a literal byte
|
|
bflush = _tr_tally(0, window[strstart] & 0xff);
|
lookahead--;
|
strstart++;
|
}
|
if (bflush)
|
{
|
flush_block_only(false);
|
if (_codec.AvailableBytesOut == 0)
|
return BlockState.NeedMore;
|
}
|
}
|
|
flush_block_only(flush == FlushType.Finish);
|
if (_codec.AvailableBytesOut == 0)
|
{
|
if (flush == FlushType.Finish)
|
return BlockState.FinishStarted;
|
else
|
return BlockState.NeedMore;
|
}
|
return flush == FlushType.Finish ? BlockState.FinishDone : BlockState.BlockDone;
|
}
|
|
// Same as above, but achieves better compression. We use a lazy
|
// evaluation for matches: a match is finally adopted only if there is
|
// no better match at the next window position.
|
internal BlockState DeflateSlow(FlushType flush)
|
{
|
// short hash_head = 0; // head of hash chain
|
int hash_head = 0; // head of hash chain
|
bool bflush; // set if current block must be flushed
|
|
// Process the input block.
|
while (true)
|
{
|
// Make sure that we always have enough lookahead, except
|
// at the end of the input file. We need MAX_MATCH bytes
|
// for the next match, plus MIN_MATCH bytes to insert the
|
// string following the next match.
|
|
if (lookahead < MIN_LOOKAHEAD)
|
{
|
_fillWindow();
|
if (lookahead < MIN_LOOKAHEAD && flush == FlushType.None)
|
return BlockState.NeedMore;
|
|
if (lookahead == 0)
|
break; // flush the current block
|
}
|
|
// Insert the string window[strstart .. strstart+2] in the
|
// dictionary, and set hash_head to the head of the hash chain:
|
|
if (lookahead >= MIN_MATCH)
|
{
|
ins_h = (((ins_h) << hash_shift) ^ (window[(strstart) + (MIN_MATCH - 1)] & 0xff)) & hash_mask;
|
// prev[strstart&w_mask]=hash_head=head[ins_h];
|
hash_head = (head[ins_h] & 0xffff);
|
prev[strstart & w_mask] = head[ins_h];
|
head[ins_h] = unchecked((short)strstart);
|
}
|
|
// Find the longest match, discarding those <= prev_length.
|
prev_length = match_length;
|
prev_match = match_start;
|
match_length = MIN_MATCH - 1;
|
|
if (hash_head != 0 && prev_length < config.MaxLazy &&
|
((strstart - hash_head) & 0xffff) <= w_size - MIN_LOOKAHEAD)
|
{
|
// To simplify the code, we prevent matches with the string
|
// of window index 0 (in particular we have to avoid a match
|
// of the string with itself at the start of the input file).
|
|
if (compressionStrategy != CompressionStrategy.HuffmanOnly)
|
{
|
match_length = longest_match(hash_head);
|
}
|
// longest_match() sets match_start
|
|
if (match_length <= 5 && (compressionStrategy == CompressionStrategy.Filtered ||
|
(match_length == MIN_MATCH && strstart - match_start > 4096)))
|
{
|
|
// If prev_match is also MIN_MATCH, match_start is garbage
|
// but we will ignore the current match anyway.
|
match_length = MIN_MATCH - 1;
|
}
|
}
|
|
// If there was a match at the previous step and the current
|
// match is not better, output the previous match:
|
if (prev_length >= MIN_MATCH && match_length <= prev_length)
|
{
|
int max_insert = strstart + lookahead - MIN_MATCH;
|
// Do not insert strings in hash table beyond this.
|
|
// check_match(strstart-1, prev_match, prev_length);
|
|
bflush = _tr_tally(strstart - 1 - prev_match, prev_length - MIN_MATCH);
|
|
// Insert in hash table all strings up to the end of the match.
|
// strstart-1 and strstart are already inserted. If there is not
|
// enough lookahead, the last two strings are not inserted in
|
// the hash table.
|
lookahead -= (prev_length - 1);
|
prev_length -= 2;
|
do
|
{
|
if (++strstart <= max_insert)
|
{
|
ins_h = (((ins_h) << hash_shift) ^ (window[(strstart) + (MIN_MATCH - 1)] & 0xff)) & hash_mask;
|
//prev[strstart&w_mask]=hash_head=head[ins_h];
|
hash_head = (head[ins_h] & 0xffff);
|
prev[strstart & w_mask] = head[ins_h];
|
head[ins_h] = unchecked((short)strstart);
|
}
|
}
|
while (--prev_length != 0);
|
match_available = 0;
|
match_length = MIN_MATCH - 1;
|
strstart++;
|
|
if (bflush)
|
{
|
flush_block_only(false);
|
if (_codec.AvailableBytesOut == 0)
|
return BlockState.NeedMore;
|
}
|
}
|
else if (match_available != 0)
|
{
|
|
// If there was no match at the previous position, output a
|
// single literal. If there was a match but the current match
|
// is longer, truncate the previous match to a single literal.
|
|
bflush = _tr_tally(0, window[strstart - 1] & 0xff);
|
|
if (bflush)
|
{
|
flush_block_only(false);
|
}
|
strstart++;
|
lookahead--;
|
if (_codec.AvailableBytesOut == 0)
|
return BlockState.NeedMore;
|
}
|
else
|
{
|
// There is no previous match to compare with, wait for
|
// the next step to decide.
|
|
match_available = 1;
|
strstart++;
|
lookahead--;
|
}
|
}
|
|
if (match_available != 0)
|
{
|
bflush = _tr_tally(0, window[strstart - 1] & 0xff);
|
match_available = 0;
|
}
|
flush_block_only(flush == FlushType.Finish);
|
|
if (_codec.AvailableBytesOut == 0)
|
{
|
if (flush == FlushType.Finish)
|
return BlockState.FinishStarted;
|
else
|
return BlockState.NeedMore;
|
}
|
|
return flush == FlushType.Finish ? BlockState.FinishDone : BlockState.BlockDone;
|
}
|
|
|
internal int longest_match(int cur_match)
|
{
|
int chain_length = config.MaxChainLength; // max hash chain length
|
int scan = strstart; // current string
|
int match; // matched string
|
int len; // length of current match
|
int best_len = prev_length; // best match length so far
|
int limit = strstart > (w_size - MIN_LOOKAHEAD) ? strstart - (w_size - MIN_LOOKAHEAD) : 0;
|
|
int niceLength = config.NiceLength;
|
|
// Stop when cur_match becomes <= limit. To simplify the code,
|
// we prevent matches with the string of window index 0.
|
|
int wmask = w_mask;
|
|
int strend = strstart + MAX_MATCH;
|
byte scan_end1 = window[scan + best_len - 1];
|
byte scan_end = window[scan + best_len];
|
|
// The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
|
// It is easy to get rid of this optimization if necessary.
|
|
// Do not waste too much time if we already have a good match:
|
if (prev_length >= config.GoodLength)
|
{
|
chain_length >>= 2;
|
}
|
|
// Do not look for matches beyond the end of the input. This is necessary
|
// to make deflate deterministic.
|
if (niceLength > lookahead)
|
niceLength = lookahead;
|
|
do
|
{
|
match = cur_match;
|
|
// Skip to next match if the match length cannot increase
|
// or if the match length is less than 2:
|
if (window[match + best_len] != scan_end ||
|
window[match + best_len - 1] != scan_end1 ||
|
window[match] != window[scan] ||
|
window[++match] != window[scan + 1])
|
continue;
|
|
// The check at best_len-1 can be removed because it will be made
|
// again later. (This heuristic is not always a win.)
|
// It is not necessary to compare scan[2] and match[2] since they
|
// are always equal when the other bytes match, given that
|
// the hash keys are equal and that HASH_BITS >= 8.
|
scan += 2; match++;
|
|
// We check for insufficient lookahead only every 8th comparison;
|
// the 256th check will be made at strstart+258.
|
do
|
{
|
}
|
while (window[++scan] == window[++match] &&
|
window[++scan] == window[++match] &&
|
window[++scan] == window[++match] &&
|
window[++scan] == window[++match] &&
|
window[++scan] == window[++match] &&
|
window[++scan] == window[++match] &&
|
window[++scan] == window[++match] &&
|
window[++scan] == window[++match] && scan < strend);
|
|
len = MAX_MATCH - (int)(strend - scan);
|
scan = strend - MAX_MATCH;
|
|
if (len > best_len)
|
{
|
match_start = cur_match;
|
best_len = len;
|
if (len >= niceLength)
|
break;
|
scan_end1 = window[scan + best_len - 1];
|
scan_end = window[scan + best_len];
|
}
|
}
|
while ((cur_match = (prev[cur_match & wmask] & 0xffff)) > limit && --chain_length != 0);
|
|
if (best_len <= lookahead)
|
return best_len;
|
return lookahead;
|
}
|
|
|
private bool Rfc1950BytesEmitted = false;
|
private bool _WantRfc1950HeaderBytes = true;
|
internal bool WantRfc1950HeaderBytes
|
{
|
get { return _WantRfc1950HeaderBytes; }
|
set { _WantRfc1950HeaderBytes = value; }
|
}
|
|
|
internal int Initialize(ZlibCodec codec, CompressionLevel level)
|
{
|
return Initialize(codec, level, ZlibConstants.WindowBitsMax);
|
}
|
|
internal int Initialize(ZlibCodec codec, CompressionLevel level, int bits)
|
{
|
return Initialize(codec, level, bits, MEM_LEVEL_DEFAULT, CompressionStrategy.Default);
|
}
|
|
internal int Initialize(ZlibCodec codec, CompressionLevel level, int bits, CompressionStrategy compressionStrategy)
|
{
|
return Initialize(codec, level, bits, MEM_LEVEL_DEFAULT, compressionStrategy);
|
}
|
|
internal int Initialize(ZlibCodec codec, CompressionLevel level, int windowBits, int memLevel, CompressionStrategy strategy)
|
{
|
_codec = codec;
|
_codec.Message = null;
|
|
// validation
|
if (windowBits < 9 || windowBits > 15)
|
throw new ZlibException("windowBits must be in the range 9..15.");
|
|
if (memLevel < 1 || memLevel > MEM_LEVEL_MAX)
|
throw new ZlibException(String.Format("memLevel must be in the range 1.. {0}", MEM_LEVEL_MAX));
|
|
_codec.dstate = this;
|
|
w_bits = windowBits;
|
w_size = 1 << w_bits;
|
w_mask = w_size - 1;
|
|
hash_bits = memLevel + 7;
|
hash_size = 1 << hash_bits;
|
hash_mask = hash_size - 1;
|
hash_shift = ((hash_bits + MIN_MATCH - 1) / MIN_MATCH);
|
|
window = new byte[w_size * 2];
|
prev = new short[w_size];
|
head = new short[hash_size];
|
|
// for memLevel==8, this will be 16384, 16k
|
lit_bufsize = 1 << (memLevel + 6);
|
|
// Use a single array as the buffer for data pending compression,
|
// the output distance codes, and the output length codes (aka tree).
|
// orig comment: This works just fine since the average
|
// output size for (length,distance) codes is <= 24 bits.
|
pending = new byte[lit_bufsize * 4];
|
_distanceOffset = lit_bufsize;
|
_lengthOffset = (1 + 2) * lit_bufsize;
|
|
// So, for memLevel 8, the length of the pending buffer is 65536. 64k.
|
// The first 16k are pending bytes.
|
// The middle slice, of 32k, is used for distance codes.
|
// The final 16k are length codes.
|
|
this.compressionLevel = level;
|
this.compressionStrategy = strategy;
|
|
Reset();
|
return ZlibConstants.Z_OK;
|
}
|
|
|
internal void Reset()
|
{
|
_codec.TotalBytesIn = _codec.TotalBytesOut = 0;
|
_codec.Message = null;
|
//strm.data_type = Z_UNKNOWN;
|
|
pendingCount = 0;
|
nextPending = 0;
|
|
Rfc1950BytesEmitted = false;
|
|
status = (WantRfc1950HeaderBytes) ? INIT_STATE : BUSY_STATE;
|
_codec._Adler32 = Adler.Adler32(0, null, 0, 0);
|
|
last_flush = (int)FlushType.None;
|
|
_InitializeTreeData();
|
_InitializeLazyMatch();
|
}
|
|
|
internal int End()
|
{
|
if (status != INIT_STATE && status != BUSY_STATE && status != FINISH_STATE)
|
{
|
return ZlibConstants.Z_STREAM_ERROR;
|
}
|
// Deallocate in reverse order of allocations:
|
pending = null;
|
head = null;
|
prev = null;
|
window = null;
|
// free
|
// dstate=null;
|
return status == BUSY_STATE ? ZlibConstants.Z_DATA_ERROR : ZlibConstants.Z_OK;
|
}
|
|
|
private void SetDeflater()
|
{
|
switch (config.Flavor)
|
{
|
case DeflateFlavor.Store:
|
DeflateFunction = DeflateNone;
|
break;
|
case DeflateFlavor.Fast:
|
DeflateFunction = DeflateFast;
|
break;
|
case DeflateFlavor.Slow:
|
DeflateFunction = DeflateSlow;
|
break;
|
}
|
}
|
|
|
internal int SetParams(CompressionLevel level, CompressionStrategy strategy)
|
{
|
int result = ZlibConstants.Z_OK;
|
|
if (compressionLevel != level)
|
{
|
Config newConfig = Config.Lookup(level);
|
|
// change in the deflate flavor (Fast vs slow vs none)?
|
if (newConfig.Flavor != config.Flavor && _codec.TotalBytesIn != 0)
|
{
|
// Flush the last buffer:
|
result = _codec.Deflate(FlushType.Partial);
|
}
|
|
compressionLevel = level;
|
config = newConfig;
|
SetDeflater();
|
}
|
|
// no need to flush with change in strategy? Really?
|
compressionStrategy = strategy;
|
|
return result;
|
}
|
|
|
internal int SetDictionary(byte[] dictionary)
|
{
|
int length = dictionary.Length;
|
int index = 0;
|
|
if (dictionary == null || status != INIT_STATE)
|
throw new ZlibException("Stream error.");
|
|
_codec._Adler32 = Adler.Adler32(_codec._Adler32, dictionary, 0, dictionary.Length);
|
|
if (length < MIN_MATCH)
|
return ZlibConstants.Z_OK;
|
if (length > w_size - MIN_LOOKAHEAD)
|
{
|
length = w_size - MIN_LOOKAHEAD;
|
index = dictionary.Length - length; // use the tail of the dictionary
|
}
|
Array.Copy(dictionary, index, window, 0, length);
|
strstart = length;
|
block_start = length;
|
|
// Insert all strings in the hash table (except for the last two bytes).
|
// s->lookahead stays null, so s->ins_h will be recomputed at the next
|
// call of fill_window.
|
|
ins_h = window[0] & 0xff;
|
ins_h = (((ins_h) << hash_shift) ^ (window[1] & 0xff)) & hash_mask;
|
|
for (int n = 0; n <= length - MIN_MATCH; n++)
|
{
|
ins_h = (((ins_h) << hash_shift) ^ (window[(n) + (MIN_MATCH - 1)] & 0xff)) & hash_mask;
|
prev[n & w_mask] = head[ins_h];
|
head[ins_h] = (short)n;
|
}
|
return ZlibConstants.Z_OK;
|
}
|
|
|
|
internal int Deflate(FlushType flush)
|
{
|
int old_flush;
|
|
if (_codec.OutputBuffer == null ||
|
(_codec.InputBuffer == null && _codec.AvailableBytesIn != 0) ||
|
(status == FINISH_STATE && flush != FlushType.Finish))
|
{
|
_codec.Message = _ErrorMessage[ZlibConstants.Z_NEED_DICT - (ZlibConstants.Z_STREAM_ERROR)];
|
throw new ZlibException(String.Format("Something is fishy. [{0}]", _codec.Message));
|
}
|
if (_codec.AvailableBytesOut == 0)
|
{
|
_codec.Message = _ErrorMessage[ZlibConstants.Z_NEED_DICT - (ZlibConstants.Z_BUF_ERROR)];
|
throw new ZlibException("OutputBuffer is full (AvailableBytesOut == 0)");
|
}
|
|
old_flush = last_flush;
|
last_flush = (int)flush;
|
|
// Write the zlib (rfc1950) header bytes
|
if (status == INIT_STATE)
|
{
|
int header = (Z_DEFLATED + ((w_bits - 8) << 4)) << 8;
|
int level_flags = (((int)compressionLevel - 1) & 0xff) >> 1;
|
|
if (level_flags > 3)
|
level_flags = 3;
|
header |= (level_flags << 6);
|
if (strstart != 0)
|
header |= PRESET_DICT;
|
header += 31 - (header % 31);
|
|
status = BUSY_STATE;
|
//putShortMSB(header);
|
unchecked
|
{
|
pending[pendingCount++] = (byte)(header >> 8);
|
pending[pendingCount++] = (byte)header;
|
}
|
// Save the adler32 of the preset dictionary:
|
if (strstart != 0)
|
{
|
pending[pendingCount++] = (byte)((_codec._Adler32 & 0xFF000000) >> 24);
|
pending[pendingCount++] = (byte)((_codec._Adler32 & 0x00FF0000) >> 16);
|
pending[pendingCount++] = (byte)((_codec._Adler32 & 0x0000FF00) >> 8);
|
pending[pendingCount++] = (byte)(_codec._Adler32 & 0x000000FF);
|
}
|
_codec._Adler32 = Adler.Adler32(0, null, 0, 0);
|
}
|
|
// Flush as much pending output as possible
|
if (pendingCount != 0)
|
{
|
_codec.flush_pending();
|
if (_codec.AvailableBytesOut == 0)
|
{
|
//System.out.println(" avail_out==0");
|
// Since avail_out is 0, deflate will be called again with
|
// more output space, but possibly with both pending and
|
// avail_in equal to zero. There won't be anything to do,
|
// but this is not an error situation so make sure we
|
// return OK instead of BUF_ERROR at next call of deflate:
|
last_flush = -1;
|
return ZlibConstants.Z_OK;
|
}
|
|
// Make sure there is something to do and avoid duplicate consecutive
|
// flushes. For repeated and useless calls with Z_FINISH, we keep
|
// returning Z_STREAM_END instead of Z_BUFF_ERROR.
|
}
|
else if (_codec.AvailableBytesIn == 0 &&
|
(int)flush <= old_flush &&
|
flush != FlushType.Finish)
|
{
|
// workitem 8557
|
//
|
// Not sure why this needs to be an error. pendingCount == 0, which
|
// means there's nothing to deflate. And the caller has not asked
|
// for a FlushType.Finish, but... that seems very non-fatal. We
|
// can just say "OK" and do nothing.
|
|
// _codec.Message = z_errmsg[ZlibConstants.Z_NEED_DICT - (ZlibConstants.Z_BUF_ERROR)];
|
// throw new ZlibException("AvailableBytesIn == 0 && flush<=old_flush && flush != FlushType.Finish");
|
|
return ZlibConstants.Z_OK;
|
}
|
|
// User must not provide more input after the first FINISH:
|
if (status == FINISH_STATE && _codec.AvailableBytesIn != 0)
|
{
|
_codec.Message = _ErrorMessage[ZlibConstants.Z_NEED_DICT - (ZlibConstants.Z_BUF_ERROR)];
|
throw new ZlibException("status == FINISH_STATE && _codec.AvailableBytesIn != 0");
|
}
|
|
// Start a new block or continue the current one.
|
if (_codec.AvailableBytesIn != 0 || lookahead != 0 || (flush != FlushType.None && status != FINISH_STATE))
|
{
|
BlockState bstate = DeflateFunction(flush);
|
|
if (bstate == BlockState.FinishStarted || bstate == BlockState.FinishDone)
|
{
|
status = FINISH_STATE;
|
}
|
if (bstate == BlockState.NeedMore || bstate == BlockState.FinishStarted)
|
{
|
if (_codec.AvailableBytesOut == 0)
|
{
|
last_flush = -1; // avoid BUF_ERROR next call, see above
|
}
|
return ZlibConstants.Z_OK;
|
// If flush != Z_NO_FLUSH && avail_out == 0, the next call
|
// of deflate should use the same flush parameter to make sure
|
// that the flush is complete. So we don't have to output an
|
// empty block here, this will be done at next call. This also
|
// ensures that for a very small output buffer, we emit at most
|
// one empty block.
|
}
|
|
if (bstate == BlockState.BlockDone)
|
{
|
if (flush == FlushType.Partial)
|
{
|
_tr_align();
|
}
|
else
|
{
|
// FlushType.Full or FlushType.Sync
|
_tr_stored_block(0, 0, false);
|
// For a full flush, this empty block will be recognized
|
// as a special marker by inflate_sync().
|
if (flush == FlushType.Full)
|
{
|
// clear hash (forget the history)
|
for (int i = 0; i < hash_size; i++)
|
head[i] = 0;
|
}
|
}
|
_codec.flush_pending();
|
if (_codec.AvailableBytesOut == 0)
|
{
|
last_flush = -1; // avoid BUF_ERROR at next call, see above
|
return ZlibConstants.Z_OK;
|
}
|
}
|
}
|
|
if (flush != FlushType.Finish)
|
return ZlibConstants.Z_OK;
|
|
if (!WantRfc1950HeaderBytes || Rfc1950BytesEmitted)
|
return ZlibConstants.Z_STREAM_END;
|
|
// Write the zlib trailer (adler32)
|
pending[pendingCount++] = (byte)((_codec._Adler32 & 0xFF000000) >> 24);
|
pending[pendingCount++] = (byte)((_codec._Adler32 & 0x00FF0000) >> 16);
|
pending[pendingCount++] = (byte)((_codec._Adler32 & 0x0000FF00) >> 8);
|
pending[pendingCount++] = (byte)(_codec._Adler32 & 0x000000FF);
|
//putShortMSB((int)(SharedUtils.URShift(_codec._Adler32, 16)));
|
//putShortMSB((int)(_codec._Adler32 & 0xffff));
|
|
_codec.flush_pending();
|
|
// If avail_out is zero, the application will call deflate again
|
// to flush the rest.
|
|
Rfc1950BytesEmitted = true; // write the trailer only once!
|
|
return pendingCount != 0 ? ZlibConstants.Z_OK : ZlibConstants.Z_STREAM_END;
|
}
|
|
}
|
}
|
