context: // Copyright (c) 2006, ComponentAce
  // http://www.componentace.com
  // All rights reserved.
  
  // Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
  
  // Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 
  // Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 
  // Neither the name of ComponentAce nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. 
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  /*
  Copyright (c) 2000,2001,2002,2003 ymnk, JCraft,Inc. All rights reserved.
  
  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are met:
  
  1. Redistributions of source code must retain the above copyright notice,
  this list of conditions and the following disclaimer.
  
  2. Redistributions in binary form must reproduce the above copyright 
  notice, this list of conditions and the following disclaimer in 
  the documentation and/or other materials provided with the distribution.
  
  3. The names of the authors may not be used to endorse or promote products
  derived from this software without specific prior written permission.
  
  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
  INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
  FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JCRAFT,
  INC. OR ANY CONTRIBUTORS TO THIS SOFTWARE BE LIABLE FOR ANY DIRECT, INDIRECT,
  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
  OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
  EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
  /*
  * This program is based on zlib-1.1.3, so all credit should go authors
  * Jean-loup Gailly(jloup@gzip.org) and Mark Adler(madler@alumni.caltech.edu)
  * and contributors of zlib.
  */
  using System;
  namespace zlib
  {
  	
  	sealed class InfCodes
  	{
  				
  		private static readonly int[] inflate_mask = new int[]{0x00000000, 0x00000001, 0x00000003, 0x00000007, 0x0000000f, 0x0000001f, 0x0000003f, 0x0000007f, 0x000000ff, 0x000001ff, 0x000003ff, 0x000007ff, 0x00000fff, 0x00001fff, 0x00003fff, 0x00007fff, 0x0000ffff};
  		
  		private const int Z_OK = 0;
  		private const int Z_STREAM_END = 1;
  		private const int Z_NEED_DICT = 2;
  		private const int Z_ERRNO = - 1;
  		private const int Z_STREAM_ERROR = - 2;
  		private const int Z_DATA_ERROR = - 3;
  		private const int Z_MEM_ERROR = - 4;
  		private const int Z_BUF_ERROR = - 5;
  		private const int Z_VERSION_ERROR = - 6;
  		
  		// waiting for "i:"=input,
  		//             "o:"=output,
  		//             "x:"=nothing
  		private const int START = 0; // x: set up for LEN
  		private const int LEN = 1; // i: get length/literal/eob next
  		private const int LENEXT = 2; // i: getting length extra (have base)
  		private const int DIST = 3; // i: get distance next
  		private const int DISTEXT = 4; // i: getting distance extra
  		private const int COPY = 5; // o: copying bytes in window, waiting for space
  		private const int LIT = 6; // o: got literal, waiting for output space
  		private const int WASH = 7; // o: got eob, possibly still output waiting
  		private const int END = 8; // x: got eob and all data flushed
  		private const int BADCODE = 9; // x: got error
  		
  		internal int mode; // current inflate_codes mode
  		
  		// mode dependent information
  		internal int len;
  		
  		internal int[] tree; // pointer into tree
  		internal int tree_index = 0;
  		internal int need; // bits needed
  		
  		internal int lit;
  		
  		// if EXT or COPY, where and how much
  		internal int get_Renamed; // bits to get for extra
  		internal int dist; // distance back to copy from
  		
  		internal byte lbits; // ltree bits decoded per branch
  		internal byte dbits; // dtree bits decoder per branch
  		internal int[] ltree; // literal/length/eob tree
  		internal int ltree_index; // literal/length/eob tree
  		internal int[] dtree; // distance tree
  		internal int dtree_index; // distance tree
  		
  		internal InfCodes(int bl, int bd, int[] tl, int tl_index, int[] td, int td_index, ZStream z)
  		{
  			mode = START;
  			lbits = (byte) bl;
  			dbits = (byte) bd;
  			ltree = tl;
  			ltree_index = tl_index;
  			dtree = td;
  			dtree_index = td_index;
  		}
  		
  		internal InfCodes(int bl, int bd, int[] tl, int[] td, ZStream z)
  		{
  			mode = START;
  			lbits = (byte) bl;
  			dbits = (byte) bd;
  			ltree = tl;
  			ltree_index = 0;
  			dtree = td;
  			dtree_index = 0;
  		}
  		
  		internal int proc(InfBlocks s, ZStream z, int r)
  		{
  			int j; // temporary storage
  			 //int[] t; // temporary pointer
  			int tindex; // temporary pointer
  			int e; // extra bits or operation
  			var b = 0; // bit buffer
  			var k = 0; // bits in bit buffer
  			var p = 0; // input data pointer
  			int n; // bytes available there
  			int q; // output window write pointer
  			int m; // bytes to end of window or read pointer
  			int f; // pointer to copy strings from
  			
  			// copy input/output information to locals (UPDATE macro restores)
  			p = z.next_in_index; n = z.avail_in; b = s.bitb; k = s.bitk;
  			q = s.write; m = q < s.read?s.read - q - 1:s.end - q;
  			
  			// process input and output based on current state
  			while (true)
  			{
  				switch (mode)
  				{
  					
  					// waiting for "i:"=input, "o:"=output, "x:"=nothing
  					case START:  // x: set up for LEN
  						if (m >= 258 && n >= 10)
  						{
  							
  							s.bitb = b; s.bitk = k;
  							z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
  							s.write = q;
  							r = inflate_fast(lbits, dbits, ltree, ltree_index, dtree, dtree_index, s, z);
  							
  							p = z.next_in_index; n = z.avail_in; b = s.bitb; k = s.bitk;
  							q = s.write; m = q < s.read?s.read - q - 1:s.end - q;
  							
  							if (r != Z_OK)
  							{
  								mode = r == Z_STREAM_END?WASH:BADCODE;
  								break;
  							}
  						}
  						need = lbits;
  						tree = ltree;
  						tree_index = ltree_index;
  						
  						mode = LEN;
  						goto case LEN;
  					
  					case LEN:  // i: get length/literal/eob next
  						j = need;
  						
  						while (k < (j))
  						{
  							if (n != 0)
  								r = Z_OK;
  							else
  							{
  								
  								s.bitb = b; s.bitk = k;
  								z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
  								s.write = q;
  								return s.inflate_flush(z, r);
  							}
  							n--;
  							b |= (z.next_in[p++] & 0xff) << k;
  							k += 8;
  						}
  						
  						tindex = (tree_index + (b & inflate_mask[j])) * 3;
  						
  						b = SupportClass.URShift(b, (tree[tindex + 1]));
  						k -= (tree[tindex + 1]);
  						
  						e = tree[tindex];
  						
  						if (e == 0)
  						{
  							// literal
  							lit = tree[tindex + 2];
  							mode = LIT;
  							break;
  						}
  						if ((e & 16) != 0)
  						{
  							// length
  							get_Renamed = e & 15;
  							len = tree[tindex + 2];
  							mode = LENEXT;
  							break;
  						}
  						if ((e & 64) == 0)
  						{
  							// next table
  							need = e;
  							tree_index = tindex / 3 + tree[tindex + 2];
  							break;
  						}
  						if ((e & 32) != 0)
  						{
  							// end of block
  							mode = WASH;
  							break;
  						}
  						mode = BADCODE; // invalid code
  						z.msg = "invalid literal/length code";
  						r = Z_DATA_ERROR;
  						
  						s.bitb = b; s.bitk = k;
  						z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
  						s.write = q;
  						return s.inflate_flush(z, r);
  					
  					
  					case LENEXT:  // i: getting length extra (have base)
  						j = get_Renamed;
  						
  						while (k < (j))
  						{
  							if (n != 0)
  								r = Z_OK;
  							else
  							{
  								
  								s.bitb = b; s.bitk = k;
  								z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
  								s.write = q;
  								return s.inflate_flush(z, r);
  							}
  							n--; b |= (z.next_in[p++] & 0xff) << k;
  							k += 8;
  						}
  						
  						len += (b & inflate_mask[j]);
  						
  						b >>= j;
  						k -= j;
  						
  						need = dbits;
  						tree = dtree;
  						tree_index = dtree_index;
  						mode = DIST;
  						goto case DIST;
  					
  					case DIST:  // i: get distance next
  						j = need;
  						
  						while (k < (j))
  						{
  							if (n != 0)
  								r = Z_OK;
  							else
  							{
  								
  								s.bitb = b; s.bitk = k;
  								z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
  								s.write = q;
  								return s.inflate_flush(z, r);
  							}
  							n--; b |= (z.next_in[p++] & 0xff) << k;
  							k += 8;
  						}
  						
  						tindex = (tree_index + (b & inflate_mask[j])) * 3;
  						
  						b >>= tree[tindex + 1];
  						k -= tree[tindex + 1];
  						
  						e = (tree[tindex]);
  						if ((e & 16) != 0)
  						{
  							// distance
  							get_Renamed = e & 15;
  							dist = tree[tindex + 2];
  							mode = DISTEXT;
  							break;
  						}
  						if ((e & 64) == 0)
  						{
  							// next table
  							need = e;
  							tree_index = tindex / 3 + tree[tindex + 2];
  							break;
  						}
  						mode = BADCODE; // invalid code
  						z.msg = "invalid distance code";
  						r = Z_DATA_ERROR;
  						
  						s.bitb = b; s.bitk = k;
  						z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
  						s.write = q;
  						return s.inflate_flush(z, r);
  					
  					
  					case DISTEXT:  // i: getting distance extra
  						j = get_Renamed;
  						
  						while (k < (j))
  						{
  							if (n != 0)
  								r = Z_OK;
  							else
  							{
  								
  								s.bitb = b; s.bitk = k;
  								z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
  								s.write = q;
  								return s.inflate_flush(z, r);
  							}
  							n--; b |= (z.next_in[p++] & 0xff) << k;
  							k += 8;
  						}
  						
  						dist += (b & inflate_mask[j]);
  						
  						b >>= j;
  						k -= j;
  						
  						mode = COPY;
  						goto case COPY;
  					
  					case COPY:  // o: copying bytes in window, waiting for space
  						f = q - dist;
  						while (f < 0)
  						{
  							// modulo window size-"while" instead
  							f += s.end; // of "if" handles invalid distances
  						}
  						while (len != 0)
  						{
  							
  							if (m == 0)
  							{
  								if (q == s.end && s.read != 0)
  								{
  									q = 0; m = q < s.read?s.read - q - 1:s.end - q;
  								}
  								if (m == 0)
  								{
  									s.write = q; r = s.inflate_flush(z, r);
  									q = s.write; m = q < s.read?s.read - q - 1:s.end - q;
  									
  									if (q == s.end && s.read != 0)
  									{
  										q = 0; m = q < s.read?s.read - q - 1:s.end - q;
  									}
  									
  									if (m == 0)
  									{
  										s.bitb = b; s.bitk = k;
  										z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
  										s.write = q;
  										return s.inflate_flush(z, r);
  									}
  								}
  							}
  							
  							s.window[q++] = s.window[f++]; m--;
  							
  							if (f == s.end)
  								f = 0;
  							len--;
  						}
  						mode = START;
  						break;
  					
  					case LIT:  // o: got literal, waiting for output space
  						if (m == 0)
  						{
  							if (q == s.end && s.read != 0)
  							{
  								q = 0; m = q < s.read?s.read - q - 1:s.end - q;
  							}
  							if (m == 0)
  							{
  								s.write = q; r = s.inflate_flush(z, r);
  								q = s.write; m = q < s.read?s.read - q - 1:s.end - q;
  								
  								if (q == s.end && s.read != 0)
  								{
  									q = 0; m = q < s.read?s.read - q - 1:s.end - q;
  								}
  								if (m == 0)
  								{
  									s.bitb = b; s.bitk = k;
  									z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
  									s.write = q;
  									return s.inflate_flush(z, r);
  								}
  							}
  						}
  						r = Z_OK;
  						
  						s.window[q++] = (byte) lit; m--;
  						
  						mode = START;
  						break;
  					
  					case WASH:  // o: got eob, possibly more output
  						if (k > 7)
  						{
  							// return unused byte, if any
  							k -= 8;
  							n++;
  							p--; // can always return one
  						}
  						
  						s.write = q; r = s.inflate_flush(z, r);
  						q = s.write; m = q < s.read?s.read - q - 1:s.end - q;
  						
  						if (s.read != s.write)
  						{
  							s.bitb = b; s.bitk = k;
  							z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
  							s.write = q;
  							return s.inflate_flush(z, r);
  						}
  						mode = END;
  						goto case END;
  					
  					case END: 
  						r = Z_STREAM_END;
  						s.bitb = b; s.bitk = k;
  						z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
  						s.write = q;
  						return s.inflate_flush(z, r);
  					
  					
  					case BADCODE:  // x: got error
  						
  						r = Z_DATA_ERROR;
  						
  						s.bitb = b; s.bitk = k;
  						z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
  						s.write = q;
  						return s.inflate_flush(z, r);
  					
  					
  					default: 
  						r = Z_STREAM_ERROR;
  						
  						s.bitb = b; s.bitk = k;
  						z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
  						s.write = q;
  						return s.inflate_flush(z, r);
  					
  				}
  			}
  		}
  		
  		internal void  free(ZStream z)
  		{
  			//  ZFREE(z, c);
  		}
  		
  		// Called with number of bytes left to write in window at least 258
  		// (the maximum string length) and number of input bytes available
  		// at least ten.  The ten bytes are six bytes for the longest length/
  		// distance pair plus four bytes for overloading the bit buffer.
  		
  		internal int inflate_fast(int bl, int bd, int[] tl, int tl_index, int[] td, int td_index, InfBlocks s, ZStream z)
  		{
  			int t; // temporary pointer
  			int[] tp; // temporary pointer
  			int tp_index; // temporary pointer
  			int e; // extra bits or operation
  			int b; // bit buffer
  			int k; // bits in bit buffer
  			int p; // input data pointer
  			int n; // bytes available there
  			int q; // output window write pointer
  			int m; // bytes to end of window or read pointer
  			int ml; // mask for literal/length tree
  			int md; // mask for distance tree
  			int c; // bytes to copy
  			int d; // distance back to copy from
  			int r; // copy source pointer
  			
  			// load input, output, bit values
  
gt: 			p = z.next_in_index; n = z.avail_in; b = s.bitb; k = s.bitk;