/// Takes the compressed text and the existing Huffman Tree and
/// parses the text through the tree to decode the message back into
/// it's original format.
private void BtnDecompressClick(object sender, RoutedEventArgs e)
{
if (txtCompressed.Text.Count() == 0)
{
MessageBox.Show("Cannot decompress text that doesn't exist!"
+ "\nPlease compress text before decompressing");
}
else if (encodeDict.Count() == 0)
{
MessageBox.Show("No frequency table/Huffman tree provided\nPlease "
+ "generate one by compressing some text before"
+ " decompressing");
}
else
{
HuffmanDecoder hd = new HuffmanDecoder();
txtPlain.Text = hd.Decode(txtCompressed.Text.ToCharArray(),
huffmanTree);
FreqListGenerator flg = new FreqListGenerator();
txtFreqTbl.Text = flg.CreateFreqTable(txtPlain.Text.ToCharArray());
nodeList = flg.GetFreqList();
txtCompressed.Text = "";
}
}
/// Takes an input string and calculates the frequency of the
/// characters in the text. It generates a list of Nodes
/// for each unique character symbol. This is used in
/// compression and decompression, and the list is stored
/// for later.
private void BtnFreqClick(object sender, RoutedEventArgs e)
{
FreqListGenerator flg = new FreqListGenerator();
String freqTable = flg.CreateFreqTable(txtPlain.Text.ToCharArray());
nodeList = flg.GetFreqList();
if (freqTable.Count() == 0)
{
MessageBox.Show("Cannot calculate frequency of a message that"
+ " doesn't exist!\nPlease enter (1) or more "
+ "alphanumeric characters");
}
else if (!flg.CharIsValid(freqTable[0])) /// Invalid character
{
MessageBox.Show("One or more characters is invalid. Please"
+ " use characters 0-9,\na-z, A-Z, space and"
+ " new line. Invalid characters : "
+ freqTable);
}
else
{
txtFreqTbl.Text = freqTable;
}
}
