#pragma warning disable CA1822 // Mark members as static
public string Decompress(BitArray compressedTarget, HuffmanCodeNode huffmanEncodingTree)
#pragma warning restore CA1822 // Mark members as static
{
var currentBitPointer = 0;
var currentNode = huffmanEncodingTree;
var resultBuilder = new StringBuilder(compressedTarget?.Length ?? 0);
while (currentBitPointer <= compressedTarget?.Length)
{
if (currentNode?.Character.HasValue == true)
{
resultBuilder.Append(currentNode.Character.Value);
currentNode = huffmanEncodingTree;
}
if (currentBitPointer == compressedTarget.Length)
{
break;
}
var currentBit = compressedTarget[currentBitPointer];
currentBitPointer++;
currentNode = currentBit == false ? currentNode?.Left : currentNode?.Right;
}
return(resultBuilder.ToString());
}
private static HuffmanCodeNode CreateSubTree(int combinedFrequency, HuffmanCodeNode highestFrequency, HuffmanCodeNode secondHighestFrequency)
{
var combinedTreeHead =
new HuffmanCodeNode
{
Frequency = combinedFrequency,
Left = highestFrequency,
Right = secondHighestFrequency
};
return(combinedTreeHead);
}
private static void BuildEncodingMap(HuffmanCodeNode huffmanEncodingTree, IDictionary <char, List <bool> > huffmanEncodingMap, List <bool> encoding)
{
if (huffmanEncodingTree is null)
{
return;
}
if (huffmanEncodingTree.Character.HasValue)
{
huffmanEncodingMap[huffmanEncodingTree.Character.Value] = encoding;
return;
}
var leftEncoding = new List <bool>(encoding);
var rightEncoding = new List <bool>(encoding);
leftEncoding.Add(false);
rightEncoding.Add(true);
BuildEncodingMap(huffmanEncodingTree.Left, huffmanEncodingMap, leftEncoding);
BuildEncodingMap(huffmanEncodingTree.Right, huffmanEncodingMap, rightEncoding);
}
