Linter Demo

Errors: 1

Warnings: 47

File: /home/fstrocco/Dart/dart/benchmark/bzip2/lib/src/decompressor.dart

part of bzip2; /* state codes */ const int _STATE_INIT = 0; const int _STATE_READ_SIGNATURES = 1; const int _STATE_READ_BLOCK = 2; const int _STATE_STREAM_END = 3; const int _STATE_ERROR = 4; class _Bzip2Decompressor implements _Bzip2Coder { /* decompressor state */ int _state = _STATE_INIT; bool _checkCrc; /* input state */ _BitBuffer _buffer = new _BitBuffer(_MAX_BYTES_REQUIRED); bool _noMoreData = false; _Bzip2CombinedCrc _fileCrc = new _Bzip2CombinedCrc(); /* output state */ int _outputIndex; List<int> _output = []; /* decompressed block state */ int _expectedBlockCrc; int _originPointer; List<int> _huffmanBlock; List<int> _symbols; _Bzip2Decompressor(this._checkCrc); void writeByte(int byte) { _buffer.writeByte(byte); } void setEndOfData() { _noMoreData = true; } List<int> readOutput() { List<int> result = _output; _output = []; return result; } bool canProcess() { bool result = false; switch (_state) { case _STATE_INIT: case _STATE_READ_SIGNATURES: case _STATE_READ_BLOCK: result = ((_noMoreData && !_buffer.isEmpty()) || _buffer.freeBitCount() < 8); break; default: result = false; } return result; } void process() { switch (_state) { case _STATE_INIT: _readHeaders(); break; case _STATE_READ_SIGNATURES: _readSignatures(); break; case _STATE_READ_BLOCK: _decompressBlock(); break; case _STATE_STREAM_END: break; } } void _readHeaders() { int signature = _buffer.readBits(24); if (signature != _BZIP_SIGNATURE) { throw new StateError("invalid file signature"); } int dicSize = (_buffer.readByte() - 0x30) * _BLOCK_SIZE_STEP; if (dicSize <= 0 || dicSize > _MAX_BLOCK_SIZE) { throw new StateError("invalid dic size"); } _state = _STATE_READ_SIGNATURES; } void _readSignatures() { int sigHigh = _buffer.readBits(24); int sigLow = _buffer.readBits(24); int crc = _buffer.readBits(32); /* new block ? */ if (sigHigh == _BLOCK_SIGNATURE_HIGH && sigLow == _BLOCK_SIGNATURE_LOW) { _expectedBlockCrc = crc; _state = _STATE_READ_BLOCK; } /* file ended ? */ else if(sigHigh == _FINISH_SIGNATURE_HIGH && sigLow == _FINISH_SIGNATURE_LOW) { if (_checkCrc && _fileCrc.getDigest() != crc) { throw new StateError("file crc failed"); } _state = _STATE_STREAM_END; } /* invalid signature ? */ else { throw new StateError("invalid block signature"); } } void _decompressBlock() { _readCompressedBlock(); _output = _decodeHuffmanBlock(_huffmanBlock, _symbols); if (_checkCrc) { int blockCrc = _calculateBlockCrc(_output); if (blockCrc != _expectedBlockCrc) { throw new StateError("block crc failed"); } _fileCrc.update(blockCrc); } _state = _STATE_READ_SIGNATURES; } void _readCompressedBlock() { bool randomized = (_buffer.readBit() == 1); if (randomized) { throw new StateError("randomized mode is deprecated"); } int originPointer = _buffer.readBits(_ORIGIN_BIT_COUNT); if (originPointer >= _MAX_BLOCK_SIZE) { throw new StateError("invalid origin pointer"); } List<bool> inUse16 = new List<bool>(16); for (int i = 0; i < 16; i++) { inUse16[i] = (_buffer.readBit() == 1); } List<bool> inUse = new List<bool>.filled(256, false); for (int i = 0; i < 256; i++) { if (inUse16[i >> 4]) { inUse[i] = (_buffer.readBit() == 1); } } int symbolCount = 0; List<int> symbols = new List<int>(256); for (int i = 0; i < 256; i++) { if (inUse[i]) { symbols[symbolCount++] = i; } } if (symbolCount == 0) { throw new StateError("symbols used cannot be zero"); } int tableCount = _buffer.readBits(_TABLE_COUNT_BITS); if (tableCount < _TABLE_COUNT_MIN || tableCount > _TABLE_COUNT_MAX) { throw new StateError("invalid table count"); } int selectorCount = _buffer.readBits(_SELECTOR_COUNT_BITS); if (selectorCount < 1 || selectorCount > _SELECTOR_COUNT_MAX) { throw new StateError("invalid selector count"); } List<int> selectors = _readSelectors(selectorCount, tableCount); List<_HuffmanDecoder> huffmanDecoders = _readHuffmanTables(tableCount, symbolCount); List<int> huffmanBlock = _readHuffmanBlock(selectors, huffmanDecoders, symbolCount); _originPointer = originPointer; _symbols = symbols; _huffmanBlock = huffmanBlock; } List<_HuffmanDecoder> _readHuffmanTables(int tableCount, int symbolCount) { List<_HuffmanDecoder> _huffmanDecoders = new List<_HuffmanDecoder>(tableCount); for(int table = 0; table < tableCount; table++) { List<int> lengthArray = new List<int>.filled(_MAX_ALPHA_SIZE, 0); int currentLevel = _buffer.readBits(_LEVEL_BITS); for (int symbol = 0; symbol < symbolCount + 2; symbol++) { while (_buffer.readBit() == 1) { currentLevel += 1 - (_buffer.readBit() * 2); } if (currentLevel < 1 || currentLevel > _MAX_HUFFMAN_LEN) { throw new StateError("invalid len"); } lengthArray[symbol] = currentLevel; } _huffmanDecoders[table] = new _HuffmanDecoder(_MAX_HUFFMAN_LEN, _MAX_ALPHA_SIZE); if (!_huffmanDecoders[table].setCodeLengths(lengthArray)) { throw new StateError("invalid len array"); } } return _huffmanDecoders; } List<int> _readSelectors(int selectorCount, int tableCount) { List<int> mtfEncodedSelectorList = new List<int>(selectorCount); for (int i = 0; i < selectorCount; i++) { int mtfEncodedSelector = 0; while (_buffer.readBit() == 1) { mtfEncodedSelector++; } mtfEncodedSelectorList[i] = mtfEncodedSelector; } List<int> selectorsSymbols = new List<int>.generate(_TABLE_COUNT_MAX, (x)=>x); List<int> selectorList = _mtfDecode(mtfEncodedSelectorList, selectorsSymbols); for (int selector in selectorList) { if (selector >= tableCount) { throw new StateError("invalid selector"); } } return selectorList; } List<int> _readHuffmanBlock(List<int> _selectors, List<_HuffmanDecoder> _huffmanDecoders, int symbolCount) { List<int> result = new List<int>(_GROUP_SIZE * _selectors.length + 2); int resultSize = 0; for (int group = 0; group < _selectors.length; group++) { bool isLastGroup = (group + 1 == _selectors.length); int selector = _selectors[group]; _HuffmanDecoder huffmanDecoder = _huffmanDecoders[selector]; for (int i = 0; i < _GROUP_SIZE; i++) { int symbol = huffmanDecoder.decodeSymbol(_buffer); if (symbol <= symbolCount) { result[resultSize++] = symbol; } else if (symbol == symbolCount + 1 && isLastGroup) { break; } else { throw new StateError("invalid next symbol"); } } } result = result.sublist(0, resultSize); return result; } List<int> _decodeHuffmanBlock(List<int> huffmanBlock, List<int> symbols) { List<int> rle2DecodedBlock = _rleDecode2(huffmanBlock); List<int> mtfDecodedBlock = _mtfDecode(rle2DecodedBlock, symbols); _BWTDecoder bwtDecoder = new _BWTDecoder(); _BWTResult bwtEncodedData = new _BWTResult(mtfDecodedBlock, _originPointer); List<int> bwtDecodedBlock = bwtDecoder.decode(bwtEncodedData); List<int> rle1DecodedBlock = _rleDecode1(bwtDecodedBlock); return rle1DecodedBlock; } List<int> _mtfDecode(List<int> buffer, List<int> symbols) { List<int> result = new List<int>(buffer.length); List<int> mtf = new List<int>.from(symbols); for (int index = 0; index < buffer.length; index++) { int symbolIndex = buffer[index]; result[index] = mtf[symbolIndex]; for (int index = symbolIndex; index > 0; index--) { mtf[index] = mtf[index - 1]; } mtf[0] = result[index]; } return result; } List<int> _rleDecode2(List<int> block) { List<int> result = new List<int>(_MAX_BLOCK_SIZE); int resultSize = 0; int runPower = 0; int runLength = 0; for (int symbol in block) { if (symbol < 2) { runLength += (symbol + 1) << runPower; runPower++; } else { for (int i = 0; i < runLength; i++) { result[resultSize++] = 0; } result[resultSize++] = symbol - 1; runLength = 0; runPower = 0; } } for (int i = 0; i < runLength; i++) { result[resultSize++] = 0; } result = result.sublist(0, resultSize); return result; } List<int> _rleDecode1(List<int> block) { List<int> result = new List<int>(_MAX_BLOCK_SIZE); int resultSize = 0; int lastSymbol = 0; int repeatCount = 0; for (int symbol in block) { /* make sure we have enough room */ if (result.length < resultSize + 256) { List<int> newResult = new List<int>(result.length * 2); newResult.setRange(0, result.length, result); result = newResult; } /* rle sequence ? */ if (repeatCount == _RLE_MODE_REP_SIZE) { for (int i = 0; i < symbol; i++) { result[resultSize++] = lastSymbol; } repeatCount = 0; lastSymbol = -1; } /* symbol ? */ else { result[resultSize++] = symbol; repeatCount = (symbol == lastSymbol) ? repeatCount + 1 : 1; lastSymbol = symbol; } } result = result.sublist(0, resultSize); return result; } }