/// <summary>Построение дерева Хаффмана из таблицы частот.</summary>
internal HuffmanTree(FrequencyTable frequencyTable)
{
ushort Length = (ushort)frequencyTable.FoundBytes.Length;
this.frequencyTable = frequencyTable;
Leafs = new TreeNode[Length];
if (Length > 1) // один корень
{
for (ushort i = 0; i < Length; ++i)
{
Leafs[i] = new TreeNode
{
ByteValue = frequencyTable.FoundBytes[i],
Value = frequencyTable.Frequency[i]
};
}
OrphanNodes.AddRange(Leafs);
RootNode = BuildTree();
}
else
{
var TempNode = new TreeNode();
TempNode.ByteValue = frequencyTable.FoundBytes[0];
TempNode.Value = frequencyTable.Frequency[0];
RootNode = new TreeNode();
RootNode.Left = RootNode.Right = TempNode;
}
OrphanNodes.Clear();
OrphanNodes = null;
}
/// <summary> записать шапук </summary>
private void WriteHeader(Stream St, FrequencyTable frequencyTable, long OriginalSize,
Byte version, Byte ComplementsBits)
{
FileHeader Header = new FileHeader(version, frequencyTable, ref OriginalSize,
ComplementsBits);
BinFormat.Serialize(St, Header);
}
/// <summary> Сканирование на наличие повторяющихся байтов и в соответствии с ними построение таблицы частот. </summary>
/// <param name="DataSource">Поток бит.</param>
private FrequencyTable BuildFrequencyTable(Stream DataSource)
{
long OriginalPosition = DataSource.Position;
FrequencyTable frequencyTable = new FrequencyTable();
IsByteExist = new bool[256];
Byte bTemp;
// Подсчет байтов и сохранение их
for (long i = 0; i < DataSource.Length; ++i)
{
bTemp = (Byte)DataSource.ReadByte();
if (IsByteExist[bTemp]) //Если байт был найден, иначе новый
{
AmountList[ByteLocation[bTemp]] = (uint)AmountList[ByteLocation[bTemp]] + 1;
}
else
{
IsByteExist[bTemp] = true; //найден
ByteLocation[bTemp] = (Byte)BytesList.Count;
AmountList.Add(1u);
BytesList.Add(bTemp);
}
}
int ArraySize = BytesList.Count;
frequencyTable.FoundBytes = new byte[ArraySize];
frequencyTable.Frequency = new uint[ArraySize];
short ArraysSize = (short)ArraySize;
for (short i = 0; i < ArraysSize; ++i)
{
frequencyTable.FoundBytes[i] = (Byte)BytesList[i];
frequencyTable.Frequency[i] = (uint)AmountList[i];
}
SortArrays(frequencyTable.Frequency, frequencyTable.FoundBytes, ArraysSize);
//очистка ресурсов
IsByteExist = null;
BytesList.Clear();
AmountList.Clear();
DataSource.Seek(OriginalPosition, SeekOrigin.Begin);
return(frequencyTable);
}
/// <summary>конструктор </summary>
public FileHeader(Byte ver, FrequencyTable T, ref long OrgSize,
byte BitsToFill)
{
version = ver; frequencyTable = T; OriginalSize = OrgSize; ComplementsBits = BitsToFill;
}