static InflaterHuffmanTree() { try { byte[] codeLengths = new byte[288]; int i = 0; while (i < 144) { codeLengths[i++] = 8; } while (i < 256) { codeLengths[i++] = 9; } while (i < 280) { codeLengths[i++] = 7; } while (i < 288) { codeLengths[i++] = 8; } defLitLenTree = new InflaterHuffmanTree(codeLengths); codeLengths = new byte[32]; i = 0; while (i < 32) { codeLengths[i++] = 5; } defDistTree = new InflaterHuffmanTree(codeLengths); } catch (Exception) { throw new SharpZipBaseException("InflaterHuffmanTree: static tree length illegal"); } }
public bool Decode(StreamManipulator input) { decode_loop: for (; ; ) { switch (mode) { case LNUM: lnum = input.PeekBits(5); if (lnum < 0) { return false; } lnum += 257; input.DropBits(5); // System.err.println("LNUM: "+lnum); mode = DNUM; goto case DNUM; // fall through case DNUM: dnum = input.PeekBits(5); if (dnum < 0) { return false; } dnum++; input.DropBits(5); // System.err.println("DNUM: "+dnum); num = lnum + dnum; litdistLens = new byte[num]; mode = BLNUM; goto case BLNUM; // fall through case BLNUM: blnum = input.PeekBits(4); if (blnum < 0) { return false; } blnum += 4; input.DropBits(4); blLens = new byte[19]; ptr = 0; // System.err.println("BLNUM: "+blnum); mode = BLLENS; goto case BLLENS; // fall through case BLLENS: while (ptr < blnum) { int len = input.PeekBits(3); if (len < 0) { return false; } input.DropBits(3); // System.err.println("blLens["+BL_ORDER[ptr]+"]: "+len); blLens[BL_ORDER[ptr]] = (byte)len; ptr++; } blTree = new InflaterHuffmanTree(blLens); blLens = null; ptr = 0; mode = LENS; goto case LENS; // fall through case LENS: { int symbol; while (((symbol = blTree.GetSymbol(input)) & ~15) == 0) { /* Normal case: symbol in [0..15] */ // System.err.println("litdistLens["+ptr+"]: "+symbol); litdistLens[ptr++] = lastLen = (byte)symbol; if (ptr == num) { /* Finished */ return true; } } /* need more input ? */ if (symbol < 0) { return false; } /* otherwise repeat code */ if (symbol >= 17) { /* repeat zero */ // System.err.println("repeating zero"); lastLen = 0; } else { if (ptr == 0) { throw new SharpZipBaseException(); } } repSymbol = symbol - 16; } mode = REPS; goto case REPS; // fall through case REPS: { int bits = repBits[repSymbol]; int count = input.PeekBits(bits); if (count < 0) { return false; } input.DropBits(bits); count += repMin[repSymbol]; // System.err.println("litdistLens repeated: "+count); if (ptr + count > num) { throw new SharpZipBaseException(); } while (count-- > 0) { litdistLens[ptr++] = lastLen; } if (ptr == num) { /* Finished */ return true; } } mode = LENS; goto decode_loop; } } }