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);
}
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);
}
}
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);
}
