示例#1
0
        public string DecodeBlock(BitArray bits, int indexStart, int indexStop)
        {
            string textBlock = "";
            //string decoded = "";
            NodeHT current = this.Root;

            for (int i = indexStart; i < indexStop; i++)
            {
                if (bits[i])
                {
                    if (current.Right != null)
                    {
                        current = current.Right;
                    }
                }
                else
                {
                    if (current.Left != null)
                    {
                        current = current.Left;
                    }
                }

                if (IsLeaf(current))
                {
                    textBlock += current.Word;
                    current    = this.Root;
                }
            }

            return(textBlock);
        }
示例#2
0
        public void Decode(BitArray bits, int indexStart, string fileName)
        {
            StreamWriter fileWrite = new StreamWriter(@fileName);
            //string text = "";
            NodeHT current = this.Root;
            string decoded = "";

            int endBitArr = bits.Count - 1;

            while (bits[endBitArr] != true)
            {
                endBitArr--;
            }

            for (int i = indexStart; i < endBitArr; i++)
            {
                if (bits[i])
                {
                    if (current.Right != null)
                    {
                        current = current.Right;
                    }
                }
                else
                {
                    if (current.Left != null)
                    {
                        current = current.Left;
                    }
                }

                if (IsLeaf(current))
                {
                    decoded = current.Word;
                    fileWrite.Write(decoded);
                    //text += decoded;
                    current = this.Root;
                }
            }
            fileWrite.Close();
            //File.WriteAllText(fileName, text);
        }
示例#3
0
        public void BuildTree(FrequencyDictionary frequencyDictionary)
        {
            foreach (KeyValuePair <string, int> word in frequencyDictionary.Dictionary)
            {
                nodes.Add(new NodeHT()
                {
                    Word = word.Key, Frequency = word.Value
                });
                nodesDictionary.Add(word.Key, nodes.Last());
            }

            while (nodes.Count > 1)
            {
                List <NodeHT> orderedNodes = nodes.OrderBy(node => node.Frequency).ToList <NodeHT>();

                if (orderedNodes.Count >= 2)
                {
                    // Take first two items
                    List <NodeHT> taken = orderedNodes.Take(2).ToList();

                    // Create a parent node by combining the frequencies
                    NodeHT parent = new NodeHT()
                    {
                        Word      = "",
                        Frequency = taken[0].Frequency + taken[1].Frequency,
                        Left      = taken[0],
                        Right     = taken[1]
                    };
                    taken[0].Parent = parent;
                    taken[1].Parent = parent;

                    nodes.Remove(taken[0]);
                    nodes.Remove(taken[1]);
                    nodes.Add(parent);
                }

                Root        = nodes.FirstOrDefault();
                Root.Parent = null;
            }
        }
示例#4
0
        public List <bool> GetCode(NodeHT nodeLeaf)
        {
            List <bool> code     = new List <bool>();
            NodeHT      node     = nodeLeaf;
            NodeHT      nodePrev = node;

            while (node != Root)
            {
                node = node.Parent;
                if (node?.Right == nodePrev)
                {
                    code.Add(true);
                }
                if (node?.Left == nodePrev)
                {
                    code.Add(false);
                }
                nodePrev = node;
            }
            code?.Reverse();
            return(code);
        }
示例#5
0
 public bool IsLeaf(NodeHT node)
 {
     return(node.Left == null && node.Right == null);
 }
示例#6
0
 public HuffmanTree()
 {
     nodes       = new List <NodeHT>();
     Root        = null;
     Frequencies = new FrequencyDictionary();
 }