InfBlocks.cs

// 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 ComponentAce.Compression.Libs.zlib
{
	
	sealed class InfBlocks
	{
		private const int MANY = 1440;
		
		// And'ing with mask[n] masks the lower n bits		
		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};
		
		// Table for deflate from PKZIP's appnote.txt.		
		internal static readonly int[] border = new int[]{16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
		
		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;
		
		private const int TYPE = 0; // get type bits (3, including end bit)
		private const int LENS = 1; // get lengths for stored
		private const int STORED = 2; // processing stored block
		private const int TABLE = 3; // get table lengths
		private const int BTREE = 4; // get bit lengths tree for a dynamic block
		private const int DTREE = 5; // get length, distance trees for a dynamic block
		private const int CODES = 6; // processing fixed or dynamic block
		private const int DRY = 7; // output remaining window bytes
		private const int DONE = 8; // finished last block, done
		private const int BAD = 9; // ot a data error--stuck here
		
		internal int mode; // current inflate_block mode 
		
		internal int left; // if STORED, bytes left to copy 
		
		internal int table; // table lengths (14 bits) 
		internal int index; // index into blens (or border) 
		internal int[] blens; // bit lengths of codes 
		internal int[] bb = new int[1]; // bit length tree depth 
		internal int[] tb = new int[1]; // bit length decoding tree 
		
		internal InfCodes codes; // if CODES, current state 
		
		internal int last; // true if this block is the last block 
		
		// mode independent information 
		internal int bitk; // bits in bit buffer 
		internal int bitb; // bit buffer 
		internal int[] hufts; // single malloc for tree space 
		internal byte[] window; // sliding window 
		internal int end; // one byte after sliding window 
		internal int read; // window read pointer 
		internal int write; // window write pointer 
		internal System.Object checkfn; // check function 
		internal long check; // check on output 
		
		internal InfBlocks(ZStream z, System.Object checkfn, int w)
		{
			hufts = new int[MANY * 3];
			window = new byte[w];
			end = w;
			this.checkfn = checkfn;
			mode = TYPE;
			reset(z, null);
		}
		
		internal void  reset(ZStream z, long[] c)
		{
			if (c != null)
				c[0] = check;
			if (mode == BTREE || mode == DTREE)
			{
				blens = null;
			}
			if (mode == CODES)
			{
				codes.free(z);
			}
			mode = TYPE;
			bitk = 0;
			bitb = 0;
			read = write = 0;
			
			if (checkfn != null)
				z.adler = check = z._adler.adler32(0L, null, 0, 0);
		}
		
		internal int proc(ZStream z, int r)
		{
			int t; // temporary storage
			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
			
			// copy input/output information to locals (UPDATE macro restores)
			{
				p = z.next_in_index; n = z.avail_in; b = bitb; k = bitk;
			}
			{
				q = write; m = (int) (q < read?read - q - 1:end - q);
			}
			
			// process input based on current state
			while (true)
			{
				switch (mode)
				{
					
					case TYPE: 
						
						while (k < (3))
						{
							if (n != 0)
							{
								r = Z_OK;
							}
							else
							{
								bitb = b; bitk = k;
								z.avail_in = n;
								z.total_in += p - z.next_in_index; z.next_in_index = p;
								write = q;
								return inflate_flush(z, r);
							}
							;
							n--;
							b |= (z.next_in[p++] & 0xff) << k;
							k += 8;
						}
						t = (int) (b & 7);
						last = t & 1;
						
						switch (SupportClass.URShift(t, 1))
						{
							
							case 0:  // stored 
								{
									b = SupportClass.URShift(b, (3)); k -= (3);
								}
								t = k & 7; // go to byte boundary
								
								{
									b = SupportClass.URShift(b, (t)); k -= (t);
								}
								mode = LENS; // get length of stored block
								break;
							
							case 1:  // fixed
								{
									int[] bl = new int[1];
									int[] bd = new int[1];
									int[][] tl = new int[1][];
									int[][] td = new int[1][];
									
									InfTree.inflate_trees_fixed(bl, bd, tl, td, z);
									codes = new InfCodes(bl[0], bd[0], tl[0], td[0], z);
								}
								
								{
									b = SupportClass.URShift(b, (3)); k -= (3);
								}
								
								mode = CODES;
								break;
							
							case 2:  // dynamic
								
								{
									b = SupportClass.URShift(b, (3)); k -= (3);
								}
								
								mode = TABLE;
								break;
							
							case 3:  // illegal
								
								{
									b = SupportClass.URShift(b, (3)); k -= (3);
								}
								mode = BAD;
								z.msg = "invalid block type";
								r = Z_DATA_ERROR;
								
								bitb = b; bitk = k;
								z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
								write = q;
								return inflate_flush(z, r);
							}
						break;
					
					case LENS: 
						
						while (k < (32))
						{
							if (n != 0)
							{
								r = Z_OK;
							}
							else
							{
								bitb = b; bitk = k;
								z.avail_in = n;
								z.total_in += p - z.next_in_index; z.next_in_index = p;
								write = q;
								return inflate_flush(z, r);
							}
							;
							n--;
							b |= (z.next_in[p++] & 0xff) << k;
							k += 8;
						}
						
						if (((SupportClass.URShift((~ b), 16)) & 0xffff) != (b & 0xffff))
						{
							mode = BAD;
							z.msg = "invalid stored block lengths";
							r = Z_DATA_ERROR;
							
							bitb = b; bitk = k;
							z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
							write = q;
							return inflate_flush(z, r);
						}
						left = (b & 0xffff);
						b = k = 0; // dump bits
						mode = left != 0?STORED:(last != 0?DRY:TYPE);
						break;
					
					case STORED: 
						if (n == 0)
						{
							bitb = b; bitk = k;
							z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
							write = q;
							return inflate_flush(z, r);
						}
						
						if (m == 0)
						{
							if (q == end && read != 0)
							{
								q = 0; m = (int) (q < read?read - q - 1:end - q);
							}
							if (m == 0)
							{
								write = q;
								r = inflate_flush(z, r);
								q = write; m = (int) (q < read?read - q - 1:end - q);
								if (q == end && read != 0)
								{
									q = 0; m = (int) (q < read?read - q - 1:end - q);
								}
								if (m == 0)
								{
									bitb = b; bitk = k;
									z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
									write = q;
									return inflate_flush(z, r);
								}
							}
						}
						r = Z_OK;
						
						t = left;
						if (t > n)
							t = n;
						if (t > m)
							t = m;
						Array.Copy(z.next_in, p, window, q, t);
						p += t; n -= t;
						q += t; m -= t;
						if ((left -= t) != 0)
							break;
						mode = last != 0?DRY:TYPE;
						break;
					
					case TABLE: 
						
						while (k < (14))
						{
							if (n != 0)
							{
								r = Z_OK;
							}
							else
							{
								bitb = b; bitk = k;
								z.avail_in = n;
								z.total_in += p - z.next_in_index; z.next_in_index = p;
								write = q;
								return inflate_flush(z, r);
							}
							;
							n--;
							b |= (z.next_in[p++] & 0xff) << k;
							k += 8;
						}
						
						table = t = (b & 0x3fff);
						if ((t & 0x1f) > 29 || ((t >> 5) & 0x1f) > 29)
						{
							mode = BAD;
							z.msg = "too many length or distance symbols";
							r = Z_DATA_ERROR;
							
							bitb = b; bitk = k;
							z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
							write = q;
							return inflate_flush(z, r);
						}
						t = 258 + (t & 0x1f) + ((t >> 5) & 0x1f);
						blens = new int[t];
						
						{
							b = SupportClass.URShift(b, (14)); k -= (14);
						}
						
						index = 0;
						mode = BTREE;
						goto case BTREE;
					
					case BTREE: 
						while (index < 4 + (SupportClass.URShift(table, 10)))
						{
							while (k < (3))
							{
								if (n != 0)
								{
									r = Z_OK;
								}
								else
								{
									bitb = b; bitk = k;
									z.avail_in = n;
									z.total_in += p - z.next_in_index; z.next_in_index = p;
									write = q;
									return inflate_flush(z, r);
								}
								;
								n--;
								b |= (z.next_in[p++] & 0xff) << k;
								k += 8;
							}
							
							blens[border[index++]] = b & 7;
							
							{
								b = SupportClass.URShift(b, (3)); k -= (3);
							}
						}
						
						while (index < 19)
						{
							blens[border[index++]] = 0;
						}
						
						bb[0] = 7;
						t = InfTree.inflate_trees_bits(blens, bb, tb, hufts, z);
						if (t != Z_OK)
						{
							r = t;
							if (r == Z_DATA_ERROR)
							{
								blens = null;
								mode = BAD;
							}
							
							bitb = b; bitk = k;
							z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
							write = q;
							return inflate_flush(z, r);
						}
						
						index = 0;
						mode = DTREE;
						goto case DTREE;
					
					case DTREE: 
						while (true)
						{
							t = table;
							if (!(index < 258 + (t & 0x1f) + ((t >> 5) & 0x1f)))
							{
								break;
							}
							
							
							int i, j, c;
							
							t = bb[0];
							
							while (k < (t))
							{
								if (n != 0)
								{
									r = Z_OK;
								}
								else
								{
									bitb = b; bitk = k;
									z.avail_in = n;
									z.total_in += p - z.next_in_index; z.next_in_index = p;
									write = q;
									return inflate_flush(z, r);
								}
								;
								n--;
								b |= (z.next_in[p++] & 0xff) << k;
								k += 8;
							}
							
							if (tb[0] == - 1)
							{
								//System.err.println("null...");
							}
							
							t = hufts[(tb[0] + (b & inflate_mask[t])) * 3 + 1];
							c = hufts[(tb[0] + (b & inflate_mask[t])) * 3 + 2];
							
							if (c < 16)
							{
								b = SupportClass.URShift(b, (t)); k -= (t);
								blens[index++] = c;
							}
							else
							{
								// c == 16..18
								i = c == 18?7:c - 14;
								j = c == 18?11:3;
								
								while (k < (t + i))
								{
									if (n != 0)
									{
										r = Z_OK;
									}
									else
									{
										bitb = b; bitk = k;
										z.avail_in = n;
										z.total_in += p - z.next_in_index; z.next_in_index = p;
										write = q;
										return inflate_flush(z, r);
									}
									;
									n--;
									b |= (z.next_in[p++] & 0xff) << k;
									k += 8;
								}
								
								b = SupportClass.URShift(b, (t)); k -= (t);
								
								j += (b & inflate_mask[i]);
								
								b = SupportClass.URShift(b, (i)); k -= (i);
								
								i = index;
								t = table;
								if (i + j > 258 + (t & 0x1f) + ((t >> 5) & 0x1f) || (c == 16 && i < 1))
								{
									blens = null;
									mode = BAD;
									z.msg = "invalid bit length repeat";
									r = Z_DATA_ERROR;
									
									bitb = b; bitk = k;
									z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
									write = q;
									return inflate_flush(z, r);
								}
								
								c = c == 16?blens[i - 1]:0;
								do 
								{
									blens[i++] = c;
								}
								while (--j != 0);
								index = i;
							}
						}
						
						tb[0] = - 1;
						{
							int[] bl = new int[1];
							int[] bd = new int[1];
							int[] tl = new int[1];
							int[] td = new int[1];
							
							
							bl[0] = 9; // must be <= 9 for lookahead assumptions
							bd[0] = 6; // must be <= 9 for lookahead assumptions
							t = table;
							t = InfTree.inflate_trees_dynamic(257 + (t & 0x1f), 1 + ((t >> 5) & 0x1f), blens, bl, bd, tl, td, hufts, z);
							if (t != Z_OK)
							{
								if (t == Z_DATA_ERROR)
								{
									blens = null;
									mode = BAD;
								}
								r = t;
								
								bitb = b; bitk = k;
								z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
								write = q;
								return inflate_flush(z, r);
							}
							
							codes = new InfCodes(bl[0], bd[0], hufts, tl[0], hufts, td[0], z);
						}
						blens = null;
						mode = CODES;
						goto case CODES;
					
					case CODES: 
						bitb = b; bitk = k;
						z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
						write = q;
						
						if ((r = codes.proc(this, z, r)) != Z_STREAM_END)
						{
							return inflate_flush(z, r);
						}
						r = Z_OK;
						codes.free(z);
						
						p = z.next_in_index; n = z.avail_in; b = bitb; k = bitk;
						q = write; m = (int) (q < read?read - q - 1:end - q);
						
						if (last == 0)
						{
							mode = TYPE;
							break;
						}
						mode = DRY;
						goto case DRY;
					
					case DRY: 
						write = q;
						r = inflate_flush(z, r);
						q = write; m = (int) (q < read?read - q - 1:end - q);
						if (read != write)
						{
							bitb = b; bitk = k;
							z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
							write = q;
							return inflate_flush(z, r);
						}
						mode = DONE;
						goto case DONE;
					
					case DONE: 
						r = Z_STREAM_END;
						
						bitb = b; bitk = k;
						z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
						write = q;
						return inflate_flush(z, r);
					
					case BAD: 
						r = Z_DATA_ERROR;
						
						bitb = b; bitk = k;
						z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
						write = q;
						return inflate_flush(z, r);
					
					
					default: 
						r = Z_STREAM_ERROR;
						
						bitb = b; bitk = k;
						z.avail_in = n; z.total_in += p - z.next_in_index; z.next_in_index = p;
						write = q;
						return inflate_flush(z, r);
					
				}
			}
		}
		
		internal void  free(ZStream z)
		{
			reset(z, null);
			window = null;
			hufts = null;
			//ZFREE(z, s);
		}
		
		internal void  set_dictionary(byte[] d, int start, int n)
		{
			Array.Copy(d, start, window, 0, n);
			read = write = n;
		}
		
		// Returns true if inflate is currently at the end of a block generated
		// by Z_SYNC_FLUSH or Z_FULL_FLUSH. 
		internal int sync_point()
		{
			return mode == LENS?1:0;
		}
		
		// copy as much as possible from the sliding window to the output area
		internal int inflate_flush(ZStream z, int r)
		{
			int n;
			int p;
			int q;
			
			// local copies of source and destination pointers
			p = z.next_out_index;
			q = read;
			
			// compute number of bytes to copy as far as end of window
			n = (int) ((q <= write?write:end) - q);
			if (n > z.avail_out)
				n = z.avail_out;
			if (n != 0 && r == Z_BUF_ERROR)
				r = Z_OK;
			
			// update counters
			z.avail_out -= n;
			z.total_out += n;
			
			// update check information
			if (checkfn != null)
				z.adler = check = z._adler.adler32(check, window, q, n);
			
			// copy as far as end of window
			Array.Copy(window, q, z.next_out, p, n);
			p += n;
			q += n;
			
			// see if more to copy at beginning of window
			if (q == end)
			{
				// wrap pointers
				q = 0;
				if (write == end)
					write = 0;
				
				// compute bytes to copy
				n = write - q;
				if (n > z.avail_out)
					n = z.avail_out;
				if (n != 0 && r == Z_BUF_ERROR)
					r = Z_OK;
				
				// update counters
				z.avail_out -= n;
				z.total_out += n;
				
				// update check information
				if (checkfn != null)
					z.adler = check = z._adler.adler32(check, window, q, n);
				
				// copy
				Array.Copy(window, q, z.next_out, p, n);
				p += n;
				q += n;
			}
			
			// update pointers
			z.next_out_index = p;
			read = q;
			
			// done
			return r;
		}
	}
}