コード例 #1
0
ファイル: Lz77Coder.cs プロジェクト: marianrabagel/CCSD
        public void Compress(string inputFile, string outputFile)
        {
            FileInfo file = new FileInfo(inputFile);

            buffer = new byte[file.Length];
            int index = 0;

            using (BitReader bitReader = new BitReader(inputFile))
                using (BitWriter bitWriter = new BitWriter(outputFile))
                {
                    FillBuffer(bitReader);

                    int character = buffer[index];
                    int position  = 0;
                    int length    = 0;

                    //first token
                    WriteToken(bitWriter, position, length, character);
                    _slidingWindow.Add(character);
                    index++;

                    character = buffer[index];
                    length    = 0;

                    while (index < buffer.Length)
                    {
                        int    i        = 0;
                        string prevChar = null;

                        while (i < _searchBufferMaxLength)
                        {
                            if (i < _slidingWindow.Count)
                            {
                                break;
                            }

                            int lookAheadIndex = index - i - 1;

                            if (buffer[lookAheadIndex] == character)
                            {
                                //vezi cat de lunga ii secventa de potrivire
                                prevChar = character.ToString();
                                int j = lookAheadIndex;

                                while (j < _lookAheadBufferMaxLength + i)
                                {
                                    if (j > buffer.Length)
                                    {
                                        break;
                                    }

                                    character = buffer[lookAheadIndex];
                                }
                            }
                            else
                            {
                                i++;
                            }
                        }
                    }

                    /*******************************************************************************/
                    //first token
                    WriteToken(bitWriter, position, length, character);
                    _slidingWindow.Add(character);

                    character = bitReader.readNBits(8);
                    position  = 0;

                    if (_slidingWindow[0] == character)
                    {
                        length = 1;
                        _slidingWindow.Add(character);
                        character = bitReader.readNBits(8);
                    }
                    else
                    {
                        length = 0;
                    }

                    //second token
                    WriteToken(bitWriter, position, length, character);
                    _slidingWindow.Add(character);

                    character = bitReader.readNBits(8);

                    if (_slidingWindow[1] == character)
                    {
                        position = 0;
                        _slidingWindow.Add(character);
                        character = bitReader.readNBits(8);

                        if (_slidingWindow[2] == character)
                        {
                        }
                        else
                        {
                        }
                    }
                    else
                    if (_slidingWindow[0] == character)
                    {
                        position = 1;
                        _slidingWindow.Add(character);
                        character = bitReader.readNBits(8);

                        if (_slidingWindow[1] == character)
                        {
                        }
                        else
                        {
                            length = 1;
                        }
                    }

                    //third token
                    WriteToken(bitWriter, position, length, character);
                }
        }