public PeekBits ( int bitCount ) : int | ||
bitCount | int | The number of bits to peek. |
return | int |
public int GetSymbol(StreamManipulator input) { int lookahead, symbol; if ((lookahead = input.PeekBits(9)) >= 0) { if ((symbol = tree[lookahead]) >= 0) { input.DropBits(symbol & 15); return symbol >> 4; } int subtree = -(symbol >> 4); int bitlen = symbol & 15; if ((lookahead = input.PeekBits(bitlen)) >= 0) { symbol = tree[subtree | (lookahead >> 9)]; input.DropBits(symbol & 15); return symbol >> 4; } else { int bits = input.AvailableBits; lookahead = input.PeekBits(bits); symbol = tree[subtree | (lookahead >> 9)]; if ((symbol & 15) <= bits) { input.DropBits(symbol & 15); return symbol >> 4; } else { return -1; } } } else { int bits = input.AvailableBits; lookahead = input.PeekBits(bits); symbol = tree[lookahead]; if (symbol >= 0 && (symbol & 15) <= bits) { input.DropBits(symbol & 15); return symbol >> 4; } else { return -1; } } }
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; } } }
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); mode = DNUM; goto case DNUM; case DNUM: dnum = input.PeekBits(5); if (dnum < 0) { return false; } dnum++; input.DropBits(5); num = lnum+dnum; litdistLens = new byte[num]; mode = BLNUM; goto case BLNUM; case BLNUM: blnum = input.PeekBits(4); if (blnum < 0) { return false; } blnum += 4; input.DropBits(4); blLens = new byte[19]; ptr = 0; mode = BLLENS; goto case BLLENS; case BLLENS: while (ptr < blnum) { int len = input.PeekBits(3); if (len < 0) { return false; } input.DropBits(3); blLens[BL_ORDER[ptr]] = (byte) len; ptr++; } blTree = new InflaterHuffmanTree(blLens); blLens = null; ptr = 0; mode = LENS; goto case LENS; case LENS: { int symbol; while (((symbol = blTree.GetSymbol(input)) & ~15) == 0) { litdistLens[ptr++] = lastLen = (byte)symbol; if (ptr == num) { return true; } } if (symbol < 0) { return false; } if (symbol >= 17) { lastLen = 0; } else { if (ptr == 0) { throw new SharpZipBaseException(); } } repSymbol = symbol-16; } mode = REPS; goto case REPS; case REPS: { int bits = repBits[repSymbol]; int count = input.PeekBits(bits); if (count < 0) { return false; } input.DropBits(bits); count += repMin[repSymbol]; if (ptr + count > num) { throw new SharpZipBaseException(); } while (count-- > 0) { litdistLens[ptr++] = lastLen; } if (ptr == num) { return true; } } mode = LENS; goto decode_loop; } } }
public bool Decode(StreamManipulator input) { int num2; int num3; Label_0000: switch (this.mode) { case 0: this.lnum = input.PeekBits(5); if (this.lnum >= 0) { this.lnum += 0x101; input.DropBits(5); this.mode = 1; break; } return false; case 1: break; case 2: goto Label_00B9; case 3: goto Label_013B; case 4: goto Label_01A8; case 5: goto Label_01EE; default: goto Label_0000; } this.dnum = input.PeekBits(5); if (this.dnum < 0) { return false; } this.dnum++; input.DropBits(5); this.num = this.lnum + this.dnum; this.litdistLens = new byte[this.num]; this.mode = 2; Label_00B9: this.blnum = input.PeekBits(4); if (this.blnum < 0) { return false; } this.blnum += 4; input.DropBits(4); this.blLens = new byte[0x13]; this.ptr = 0; this.mode = 3; Label_013B: while (this.ptr < this.blnum) { int num = input.PeekBits(3); if (num < 0) { return false; } input.DropBits(3); this.blLens[BL_ORDER[this.ptr]] = (byte) num; this.ptr++; } this.blTree = new InflaterHuffmanTree(this.blLens); this.blLens = null; this.ptr = 0; this.mode = 4; Label_01A8: while (((num2 = this.blTree.GetSymbol(input)) & -16) == 0) { this.litdistLens[this.ptr++] = this.lastLen = (byte) num2; if (this.ptr == this.num) { return true; } } if (num2 < 0) { return false; } if (num2 >= 0x11) { this.lastLen = 0; } else if (this.ptr == 0) { throw new SharpZipBaseException(); } this.repSymbol = num2 - 0x10; this.mode = 5; Label_01EE: num3 = repBits[this.repSymbol]; int num4 = input.PeekBits(num3); if (num4 < 0) { return false; } input.DropBits(num3); num4 += repMin[this.repSymbol]; if ((this.ptr + num4) > this.num) { throw new SharpZipBaseException(); } while (num4-- > 0) { this.litdistLens[this.ptr++] = this.lastLen; } if (this.ptr == this.num) { return true; } this.mode = 4; goto Label_0000; }
public int GetSymbol(StreamManipulator input) { int num2; int index = input.PeekBits(9); if (index >= 0) { num2 = this.tree[index]; if (num2 >= 0) { input.DropBits(num2 & 15); return (num2 >> 4); } int num3 = -(num2 >> 4); int bitCount = num2 & 15; index = input.PeekBits(bitCount); if (index >= 0) { num2 = this.tree[num3 | (index >> 9)]; input.DropBits(num2 & 15); return (num2 >> 4); } int num5 = input.AvailableBits; index = input.PeekBits(num5); num2 = this.tree[num3 | (index >> 9)]; if ((num2 & 15) <= num5) { input.DropBits(num2 & 15); return (num2 >> 4); } return -1; } int availableBits = input.AvailableBits; index = input.PeekBits(availableBits); num2 = this.tree[index]; if ((num2 >= 0) && ((num2 & 15) <= availableBits)) { input.DropBits(num2 & 15); return (num2 >> 4); } return -1; }