Ejemplo n.º 1
0
        public string decode(BitArray bits)
        {
            Node   current = this.Root;
            string decoded = "";

            foreach (bool bit in bits)
            {
                if (bit)
                {
                    if (current.Right != null)
                    {
                        current = current.Right;
                    }
                }
                else
                {
                    if (current.Left != null)
                    {
                        current = current.Left;
                    }
                }

                if (IsLeaf(current))
                {
                    decoded += current.Symbol;
                    //save row into table
                    bool existed = false;
                    //check if current symbol exist in table
                    foreach (row reference in table)
                    {
                        if (Convert.ToString(current.Symbol) == reference.symbol)
                        {
                            existed = true;
                        }
                    }
                    if (!existed)
                    {
                        row row = new row();
                        row.symbol   += current.Symbol;
                        row.codeword  = "";
                        row.frequency = current.Frequency;
                        List <bool> codeword = this.Root.Traverse(current.Symbol, new List <bool>());
                        foreach (bool char_bit in codeword)
                        {
                            row.codeword += (char_bit ? 1 : 0) + "";
                        }
                        table.Add(row);
                    }
                    //reset current node
                    current = this.Root;
                }
            }

            return(decoded);
        }
Ejemplo n.º 2
0
 public void create_table()
 {
     foreach (KeyValuePair <char, int> pair in Frequencies)
     {
         row  row  = new row();
         Node node = this.Root;
         row.symbol   += pair.Key;
         row.frequency = pair.Value;
         List <bool> codeword = node.Traverse(pair.Key, new List <bool>());
         foreach (bool char_bit in codeword)
         {
             row.codeword += (char_bit ? 1 : 0) + "";
         }
         table.Add(row);
     }
 }
Ejemplo n.º 3
0
        public BitArray encode(string source)
        {
            List <bool> encodedSource = new List <bool>();

            for (int i = 0; i < source.Length; i++)
            {
                List <bool> codeword = this.Root.Traverse(source[i], new List <bool>());
                encodedSource.AddRange(codeword);
                bool   existed = false;
                string symbol  = "";
                symbol += source[i];
                // check if current symbol existed in the table
                foreach (row reference in table)
                {
                    if (symbol == reference.symbol)
                    {
                        existed = true;
                    }
                }
                //if current row doesn't exist in the table, add it
                if (!existed)
                {
                    row row = new row();
                    row.symbol = symbol;
                    Frequencies.TryGetValue(source[i], out row.frequency);
                    row.codeword = "";
                    foreach (bool char_bit in codeword)
                    {
                        row.codeword += (char_bit ? 1 : 0) + "";
                    }
                    table.Add(row);
                }
            }

            BitArray bits = new BitArray(encodedSource.ToArray());

            return(bits);
        }