95 lines
3.3 KiB
C#
95 lines
3.3 KiB
C#
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// LzwConstants.cs
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//
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// Copyright (C) 2009 Gabriel Burca
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//
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// This program is free software; you can redistribute it and/or
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// modify it under the terms of the GNU General Public License
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// as published by the Free Software Foundation; either version 2
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// of the License, or (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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//
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// Linking this library statically or dynamically with other modules is
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// making a combined work based on this library. Thus, the terms and
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// conditions of the GNU General Public License cover the whole
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// combination.
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//
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// As a special exception, the copyright holders of this library give you
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// permission to link this library with independent modules to produce an
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// executable, regardless of the license terms of these independent
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// modules, and to copy and distribute the resulting executable under
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// terms of your choice, provided that you also meet, for each linked
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// independent module, the terms and conditions of the license of that
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// module. An independent module is a module which is not derived from
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// or based on this library. If you modify this library, you may extend
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// this exception to your version of the library, but you are not
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// obligated to do so. If you do not wish to do so, delete this
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// exception statement from your version.
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namespace ICSharpCode.SharpZipLib.LZW {
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/// <summary>
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/// This class contains constants used for LZW
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/// </summary>
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sealed public class LzwConstants {
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/// <summary>
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/// Magic number found at start of LZW header: 0x1f 0x9d
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/// </summary>
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public const int MAGIC = 0x1f9d;
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/// <summary>
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/// Maximum number of bits per code
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/// </summary>
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public const int MAX_BITS = 16;
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/* 3rd header byte:
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* bit 0..4 Number of compression bits
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* bit 5 Extended header
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* bit 6 Free
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* bit 7 Block mode
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*/
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/// <summary>
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/// Mask for 'number of compression bits'
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/// </summary>
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public const int BIT_MASK = 0x1f;
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/// <summary>
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/// Indicates the presence of a fourth header byte
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/// </summary>
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public const int EXTENDED_MASK = 0x20;
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//public const int FREE_MASK = 0x40;
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/// <summary>
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/// Reserved bits
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/// </summary>
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public const int RESERVED_MASK = 0x60;
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/// <summary>
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/// Block compression: if table is full and compression rate is dropping,
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/// clear the dictionary.
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/// </summary>
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public const int BLOCK_MODE_MASK = 0x80;
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/// <summary>
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/// LZW file header size (in bytes)
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/// </summary>
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public const int HDR_SIZE = 3;
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/// <summary>
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/// Initial number of bits per code
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/// </summary>
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public const int INIT_BITS = 9;
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LzwConstants() {
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}
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}
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}
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