/// <summary>
/// Factory for building a HuffmanTree from a frequency list.
/// Also builds up a Dictionary of the nodes for encoding.
/// </summary>
/// <param name="freqlist">List of frequencies of characters.</param>
/// <param name="htDict">Empty dictionary to be filled.</param>
/// <returns>A Composite HuffmanTreeNode which is the root of the tree. Also passes a dictionary of the nodes by reference.</returns>
public static HuffmanTreeNodeComposite HuffmanTreeFactory(List <Frequency> freqlist, Dictionary <char, HuffmanTreeNodeLeaf> htDict)
{
foreach (Frequency element in freqlist)
{
HuffmanTreeNodeLeaf newLeaf = HuffmanTreeFactory(element.symbol, element.frequency);
htDict.Add(newLeaf.symbol, newLeaf);
}
HuffmanTreeNode[] nodeArray = htDict.Values.ToArray();
//swapped for more dynamic function which uses the array
/*Heap heap = new Heap();
* for (int ii = 0; ii < nodeArray.Length; ii++)
* {
* if (nodeArray[ii] != null)
* heap.insert(nodeArray[ii]);
* }*/
Heap heap = new Heap(nodeArray);
HuffmanTreeNodeComposite root = null;
HuffmanTreeNode left;
HuffmanTreeNode right;
while (heap.size > 1)
{
left = heap.extractMin();
right = heap.extractMin();
root = HuffmanTreeFactory(left, right);
if (heap.size > 0)
{
heap.insert(root);
}
}
root.parent = null;
return(root);
}
/// <summary>
/// Event handler for when the Decompress button is clicked.
/// Uses the frequency table to build a HuffmanTree then uses that tree to decode the data.
/// The frequency table must be the same as the one to encode it or bad things happen.
/// </summary>
/// <param name="sender">Event Stuff (Don't ask me, I didn't put it there?</param>
/// <param name="e">State information</param>
private void btnDecompress_Click(object sender, RoutedEventArgs e)
{
try
{
string[] freqStringList = txtFreqTbl.Text.Split('\n');
List <Frequency> frequencies = new List <Frequency>();
foreach (string s in freqStringList)
{
frequencies.Add(new Frequency(s));
}
HuffmanTreeNodeComposite root = HuffmanTreeNode.HuffmanTreeFactory(frequencies, new Dictionary <char, HuffmanTreeNodeLeaf>());
Dictionary <char, DAABitArray> dict = new Dictionary <char, DAABitArray>();
for (int ii = 0; ii < 64; ii++)
{
long x = (long)ii;
DAABitArray bits = new DAABitArray();
bits.Append(x, 6);
dict.Add(DAABitArray.encoding[ii], bits);
}
DAABitArray encodedBits = new DAABitArray();
foreach (char character in txtCompressed.Text)
{
encodedBits.Append(dict[character]);
}
string decoded = "";
while (encodedBits.NumBits > 0)
{
decoded = decoded + root.decode(encodedBits).ToString();
}
txtPlain.Text = decoded;
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
/// <summary>
/// Event handler for when the Compress button is clicked.
/// Uses the frequency table to build a HuffmanTree and a Dictionary of nodes
/// then converts the symbols to DAABitArrays using the Dictionary to find the node.
/// Also appends 0 bits to make the entire bit sequence divisable by 6.
/// The frequency table must be the same as the one to encode it or bad things happen.
/// </summary>
/// <param name="sender">Event Stuff (Don't ask me, I didn't put it there?</param>
/// <param name="e">State information</param>
private void btnCompress_Click(object sender, RoutedEventArgs e)
{
//try
{
string[] freqStringList = txtFreqTbl.Text.Split('\n');
List <Frequency> frequencies = new List <Frequency>();
foreach (string s in freqStringList)
{
frequencies.Add(new Frequency(s));
}
Dictionary <char, HuffmanTreeNodeLeaf> dict = new Dictionary <char, HuffmanTreeNodeLeaf>();
HuffmanTreeNodeComposite root = HuffmanTreeNode.HuffmanTreeFactory(frequencies, dict);
DAABitArray bits = new DAABitArray();
string converted = "";
foreach (char character in txtPlain.Text)
{
DAABitArray append = new DAABitArray();
bits.Append(dict[character].encode(append));
}
while (bits.NumBits % 6 != 0)
{
bits.Append(false);
}
int index = 0;
while (index <= bits.NumBits - 6)
{
converted = converted + bits.SixToChar(index);
index = index + 6;
}
txtCompressed.Text = converted;
}
//catch (Exception ex)
{
// MessageBox.Show(ex.Message);
}
}