bzip2inputstream.cs

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			for (int i = 0; i < BZip2Constants.MAX_CODE_LEN; i++) {
				baseArray[i] = 0;
			}
			
			for (int i = 0; i < alphaSize; i++) {
				++baseArray[length[i] + 1];
			}
			
			for (int i = 1; i < BZip2Constants.MAX_CODE_LEN; i++) {
				baseArray[i] += baseArray[i - 1];
			}
			
			for (int i = 0; i < BZip2Constants.MAX_CODE_LEN; i++) {
				limit[i] = 0;
			}
			
			int vec = 0;
			
			for (int i = minLen; i <= maxLen; i++) {
				vec += (baseArray[i + 1] - baseArray[i]);
				limit[i] = vec - 1;
				vec <<= 1;
			}
			
			for (int i = minLen + 1; i <= maxLen; i++) {
				baseArray[i] = ((limit[i - 1] + 1) << 1) - baseArray[i];
			}
		}
		
		void RecvDecodingTables() 
		{
			char[][] len = new char[BZip2Constants.N_GROUPS][];
			for (int i = 0; i < BZip2Constants.N_GROUPS; ++i) {
				len[i] = new char[BZip2Constants.MAX_ALPHA_SIZE];
			}
			
			bool[] inUse16 = new bool[16];
			
			/*--- Receive the mapping table ---*/
			for (int i = 0; i < 16; i++) {
				inUse16[i] = (BsR(1) == 1);
			} 
			
			for (int i = 0; i < 16; i++) {
				if (inUse16[i]) {
					for (int j = 0; j < 16; j++) {
						inUse[i * 16 + j] = (BsR(1) == 1);
					}
				} else {
					for (int j = 0; j < 16; j++) {
						inUse[i * 16 + j] = false;
					}
				}
			}
			
			MakeMaps();
			int alphaSize = nInUse + 2;
			
			/*--- Now the selectors ---*/
			int nGroups    = BsR(3);
			int nSelectors = BsR(15);
			
			for (int i = 0; i < nSelectors; i++) {
				int j = 0;
				while (BsR(1) == 1) {
					j++;
				}
				selectorMtf[i] = (byte)j;
			}
			
			/*--- Undo the MTF values for the selectors. ---*/
			byte[] pos = new byte[BZip2Constants.N_GROUPS];
			for (int v = 0; v < nGroups; v++) {
				pos[v] = (byte)v;
			}
			
			for (int i = 0; i < nSelectors; i++) {
				int  v   = selectorMtf[i];
				byte tmp = pos[v];
				while (v > 0) {
					pos[v] = pos[v - 1];
					v--;
				}
				pos[0]      = tmp;
				selector[i] = tmp;
			}
			
			/*--- Now the coding tables ---*/
			for (int t = 0; t < nGroups; t++) {
				int curr = BsR(5);
				for (int i = 0; i < alphaSize; i++) {
					while (BsR(1) == 1) {
						if (BsR(1) == 0) {
							curr++;
						} else {
							curr--;
						}
					}
					len[t][i] = (char)curr;
				}
			}
			
			/*--- Create the Huffman decoding tables ---*/
			for (int t = 0; t < nGroups; t++) {
				int minLen = 32;
				int maxLen = 0;
				for (int i = 0; i < alphaSize; i++) {
					maxLen = Math.Max(maxLen, len[t][i]);
					minLen = Math.Min(minLen, len[t][i]);
				}
				HbCreateDecodeTables(limit[t], baseArray[t], perm[t], len[t], minLen, maxLen, alphaSize);
				minLens[t] = minLen;
			}
		}
		
		void GetAndMoveToFrontDecode() 
		{
			byte[] yy = new byte[256];
			int nextSym;
			
			int limitLast = BZip2Constants.baseBlockSize * blockSize100k;
			origPtr = BsGetIntVS(24);
			
			RecvDecodingTables();
			int EOB = nInUse+1;
			int groupNo = -1;
			int groupPos = 0;
			
			/*--
			Setting up the unzftab entries here is not strictly
			necessary, but it does save having to do it later
			in a separate pass, and so saves a block's worth of
			cache misses.
			--*/
			for (int i = 0; i <= 255; i++) {
				unzftab[i] = 0;
			}
			
			for (int i = 0; i <= 255; i++) {
				yy[i] = (byte)i;
			}
			
			last = -1;
			
			if (groupPos == 0) {
				groupNo++;
				groupPos = BZip2Constants.G_SIZE;
			}
			
			groupPos--;
			int zt = selector[groupNo];
			int zn = minLens[zt];
			int zvec = BsR(zn);
			int zj;
			
			while (zvec > limit[zt][zn]) {
				if (zn > 20) { // the longest code
					throw new BZip2Exception("Bzip data error");  // -jr- 17-Dec-2003 from bzip 1.02 why 20???
				}
				zn++;
				while (bsLive < 1) {
					FillBuffer();
				}
				zj = (bsBuff >> (bsLive-1)) & 1;
				bsLive--;
				zvec = (zvec << 1) | zj;
			}
			if (zvec - baseArray[zt][zn] < 0 || zvec - baseArray[zt][zn] >= BZip2Constants.MAX_ALPHA_SIZE) {
				throw new BZip2Exception("Bzip data error");  // -jr- 17-Dec-2003 from bzip 1.02
			}
			nextSym = perm[zt][zvec - baseArray[zt][zn]];
			
			while (true) {
				if (nextSym == EOB) {
					break;
				}
				
				if (nextSym == BZip2Constants.RUNA || nextSym == BZip2Constants.RUNB) {
					int s = -1;
					int n = 1;
					do {
						if (nextSym == BZip2Constants.RUNA) {
							s += (0 + 1) * n;
						} else if (nextSym == BZip2Constants.RUNB) {
							s += (1 + 1) * n;
						}

						n <<= 1;
						
						if (groupPos == 0) {
							groupNo++;
							groupPos = BZip2Constants.G_SIZE;
						}
						
						groupPos--;
						
						zt = selector[groupNo];
						zn = minLens[zt];
						zvec = BsR(zn);
						
						while (zvec > limit[zt][zn]) {
							zn++;
							while (bsLive < 1) {
								FillBuffer();
							}
							zj = (bsBuff >> (bsLive - 1)) & 1;
							bsLive--;
							zvec = (zvec << 1) | zj;
						}
						nextSym = perm[zt][zvec - baseArray[zt][zn]];
					} while (nextSym == BZip2Constants.RUNA || nextSym == BZip2Constants.RUNB);
					
					s++;
					byte ch = seqToUnseq[yy[0]];
					unzftab[ch] += s;
					
					while (s > 0) {
						last++;
						ll8[last] = ch;
						s--;
					}
					
					if (last >= limitLast) {
						BlockOverrun();
					}
					continue;
				} else {
					last++;
					if (last >= limitLast) {
						BlockOverrun();
					}
					
					byte tmp = yy[nextSym - 1];
					unzftab[seqToUnseq[tmp]]++;
					ll8[last] = seqToUnseq[tmp];
					
					for (int j = nextSym-1; j > 0; --j) {
						yy[j] = yy[j - 1];
					}
					yy[0] = tmp;
					
					if (groupPos == 0) {
						groupNo++;
						groupPos = BZip2Constants.G_SIZE;
					}
					
					groupPos--;
					zt = selector[groupNo];
					zn = minLens[zt];
					zvec = BsR(zn);
					while (zvec > limit[zt][zn]) {
						zn++;
						while (bsLive < 1) {
							FillBuffer();
						}
						zj = (bsBuff >> (bsLive-1)) & 1;
						bsLive--;
						zvec = (zvec << 1) | zj;
					}
					nextSym = perm[zt][zvec - baseArray[zt][zn]];
					continue;
				}
			}
		}
		
		void SetupBlock() 
		{
			int[] cftab = new int[257];
			
			cftab[0] = 0;
			Array.Copy(unzftab, 0, cftab, 1, 256);
			
			for (int i = 1; i <= 256; i++) {
				cftab[i] += cftab[i - 1];
			}
			
			for (int i = 0; i <= last; i++) {
				byte ch = ll8[i];
				tt[cftab[ch]] = i;
				cftab[ch]++;
			}
			
			cftab = null;
			
			tPos = tt[origPtr];
			
			count = 0;
			i2    = 0;
			ch2   = 256;   /*-- not a char and not EOF --*/
			
			if (blockRandomised) {
				rNToGo = 0;
				rTPos = 0;
				SetupRandPartA();
			} else {
				SetupNoRandPartA();
			}
		}
		
		void SetupRandPartA() 
		{
			if (i2 <= last) {
				chPrev = ch2;
				ch2  = ll8[tPos];
				tPos = tt[tPos];
				if (rNToGo == 0) {
					rNToGo = BZip2Constants.rNums[rTPos];
					rTPos++;
					if (rTPos == 512) {
						rTPos = 0;
					}
				}
				rNToGo--;
				ch2 ^= (int)((rNToGo == 1) ? 1 : 0);
				i2++;
				
				currentChar  = ch2;
				currentState = RAND_PART_B_STATE;
				mCrc.Update(ch2);
			} else {
				EndBlock();
				InitBlock();
				SetupBlock();
			}
		}
		
		void SetupNoRandPartA() 
		{
			if (i2 <= last) {
				chPrev = ch2;
				ch2  = ll8[tPos];
				tPos = tt[tPos];
				i2++;
				
				currentChar = ch2;
				currentState = NO_RAND_PART_B_STATE;
				mCrc.Update(ch2);
			} else {
				EndBlock();
				InitBlock();
				SetupBlock();
			}
		}
		
		void SetupRandPartB() 
		{
			if (ch2 != chPrev) {
				currentState = RAND_PART_A_STATE;
				count = 1;
				SetupRandPartA();
			} else {
				count++;
				if (count >= 4) {
					z = ll8[tPos];
					tPos = tt[tPos];
					if (rNToGo == 0) {
						rNToGo = BZip2Constants.rNums[rTPos];
						rTPos++;
						if (rTPos == 512) {
							rTPos = 0;
						}
					}
					rNToGo--;
					z ^= (byte)((rNToGo == 1) ? 1 : 0);
					j2 = 0;
					currentState = RAND_PART_C_STATE;
					SetupRandPartC();
				} else {
					currentState = RAND_PART_A_STATE;
					SetupRandPartA();
				}
			}
		}
		
		void SetupRandPartC() 
		{
			if (j2 < (int)z) {
				currentChar = ch2;
				mCrc.Update(ch2);
				j2++;
			} else {
				currentState = RAND_PART_A_STATE;
				i2++;
				count = 0;
				SetupRandPartA();
			}
		}
		
		void SetupNoRandPartB() 
		{
			if (ch2 != chPrev) {
				currentState = NO_RAND_PART_A_STATE;
				count = 1;
				SetupNoRandPartA();
			} else {
				count++;
				if (count >= 4) {
					z = ll8[tPos];
					tPos = tt[tPos];
					currentState = NO_RAND_PART_C_STATE;
					j2 = 0;
					SetupNoRandPartC();
				} else {
					currentState = NO_RAND_PART_A_STATE;
					SetupNoRandPartA();
				}
			}
		}
		
		void SetupNoRandPartC() 
		{
			if (j2 < (int)z) {
				currentChar = ch2;
				mCrc.Update(ch2);
				j2++;
			} else {
				currentState = NO_RAND_PART_A_STATE;
				i2++;
				count = 0;
				SetupNoRandPartA();
			}
		}
		
		void SetDecompressStructureSizes(int newSize100k) 
		{
			if (!(0 <= newSize100k && newSize100k <= 9 && 0 <= blockSize100k && blockSize100k <= 9)) {
				throw new BZip2Exception("Invalid block size");
			}
			
			blockSize100k = newSize100k;
			
			if (newSize100k == 0) {
				return;
			}
			
			int n = BZip2Constants.baseBlockSize * newSize100k;
			ll8 = new byte[n];
			tt  = new int[n];
		}
	}
}
/* This file was derived from a file containing under this license:
 * 
 * This file is a part of bzip2 and/or libbzip2, a program and
 * library for lossless, block-sorting data compression.
 * 
 * Copyright (C) 1996-1998 Julian R Seward.  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. The origin of this software must not be misrepresented; you must 
 * not claim that you wrote the original software.  If you use this 
 * software in a product, an acknowledgment in the product 
 * documentation would be appreciated but is not required.
 * 
 * 3. Altered source versions must be plainly marked as such, and must
 * not be misrepresented as being the original software.
 * 
 * 4. The name of the author may not be used to endorse or promote 
 * products derived from this software without specific prior written 
 * permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 * 
 * Java version ported by Keiron Liddle, Aftex Software <[e-mail]> 1999-2001
 */