// the private contructor for the class
// den private contructor for denne klasse
private JSONAbleHuffmanNode(HuffmanNode node)
{
// symbol is symbol, since a string is normal for json
// symbol er symbol, eftersom at en tekststreng er normalt for json
symbol = node.Symbol;
// code is a string instead of an bit array, this is more json friendly
// code bliver konvertede til en tekststren for at være json venlig
code = node.Code.Print();
// right and left tree, is converted recursively
// højere og venstre node er konverteret rekursivt
leftTree = Parse(node.LeftChildNode);
rightTree = Parse(node.RightChildNode);
//leaf is just leaf
//et blad er et blad
isLeaf = node.IsLeaf;
}
// this is a recursive method to print the information, but not as a tree like the last one
public void PrintInformation(HuffmanNode node = null)
{
// if node is null use the root
if (node == null)
{
node = Root;
}
// print the symbol, code and frequency
Console.WriteLine("Symbol : " + node.Symbol + " - Code : " + node.Code.Print() + " - Frequency : " + node.Frequency);
// if it is not a leaf call the function recursivly for left and right
if (!node.IsLeaf)
{
PrintInformation(node.LeftChildNode);
PrintInformation(node.RightChildNode);
}
}
// this is a recursive method to print the information, but only the leafs
public void PrintfLeafAndCodes(HuffmanNode node = null)
{
// if node is null use the root
if (node == null)
{
node = Root;
}
// if there is no left and right node, print the symbol, code and frequency. Then return
if (node.LeftChildNode == null && node.RightChildNode == null)
{
Console.WriteLine("Symbol : " + node.Symbol + " - Code : " + node.Code.Print() + " - Frequency : " + node.Frequency);
return;
}
// recursivly call this method for the left and right node
PrintfLeafAndCodes(node.LeftChildNode);
PrintfLeafAndCodes(node.RightChildNode);
}
// this is a recursive method to print the information, but not as a tree like the last one
// Dette er en rekursiv funktion for at udskrive den information, men ikke som et træ ligesom før
public void PrintInformation(HuffmanNode node = null)
{
// if node is null use the root
// Hvis noden er null benyttes roden
if (node == null)
{
node = Root;
}
// print the symbol, code and frequency
// Udskriv symbolet, koden og frekvensen
Console.WriteLine("Symbol : " + node.Symbol + " - Code : " + node.Code.Print() + " - Frequency : " + node.Frequency);
// if it is not a leaf call the function recursivly for left and right
// Hvis det ikker er et blad kaldes den funktion rekursivt for venstre og højre side
if (!node.IsLeaf)
{
PrintInformation(node.LeftChildNode);
PrintInformation(node.RightChildNode);
}
}
// this is a recursive method to print the information, but only the leafs
// Dette er en rekursiv funktion for at udskrive den information, men kun de venstre blade
public void PrintfLeafAndCodes(HuffmanNode node = null)
{
// if node is null use the root
// Hvis noden er null benyttes roden
if (node == null)
{
node = Root;
}
// if there is no left and right node, print the symbol, code and frequency. Then return
// Hvis der ikke er nogen venstre node, udskriv symbolet, koden og frekvensen. Derefter returner
if (node.LeftChildNode == null && node.RightChildNode == null)
{
Console.WriteLine("Symbol : " + node.Symbol + " - Code : " + node.Code.Print() + " - Frequency : " + node.Frequency);
return;
}
// recursivly call this method for the left and right node
// Rekursivt kald denne funktion for den venstre og højre node
PrintfLeafAndCodes(node.LeftChildNode);
PrintfLeafAndCodes(node.RightChildNode);
}
/// <summary>
/// Traverse the tree while setting the Path values of each node
/// </summary>
/// <param name="root"></param>
/// <param name="recursionDepth"></param>
/// <param name="path"></param>
private void SetCodes(HuffmanNode root = null, int recursionDepth = 0, string path = "")
{
if (root == null)
{
if (recursionDepth == 0)
{
root = Root;
}
else
{
return;
}
}
root.Path = new BitArray(path
.Select(x => x == '1')
.ToArray());
SetCodes(root.Left, ++recursionDepth, path + "0");
SetCodes(root.Right, ++recursionDepth, path + "1");
}
/// <summary>
/// Recursively search a specific value in the tree
/// </summary>
/// <param name="value">The value to be searched for.</param>
/// <param name="root">The root <see cref="HuffmanNode"/> from where the search begins.</param>
/// <param name="recursionDepth">Specifies how deep we are in the call stack.
/// It lets us decide whether it has been called for the first time or are we
/// deeper in the call stack.
/// </param>
/// <returns>The corresponding node with the value or null if there isn't such node.</returns>
public HuffmanNode Search(int value, HuffmanNode root = null, int recursionDepth = 0)
{
if (root == null)
{
if (recursionDepth == 0)
{
root = Root;
}
else
{
return(null);
}
}
if (root.Value == value)
{
return(root);
}
recursionDepth++;
return(Search(value, root.Left) ?? Search(value, root.Right, recursionDepth));
}
// this is a recursive method to print the tree
public void PrintTree(int level, HuffmanNode node = null)
{
// if node is null use the root
if (node == null)
{
node = Root;
}
// print a tab for every level
for (int i = 0; i < level; i++)
{
Console.Write("\t");
}
// print the symbol
Console.Write("[" + node.Symbol + "]");
// set color
SetColor();
// print the code
Console.WriteLine("(" + node.Code.Print() + ")");
// set the color back to default
SetColorDefault();
// call this method recursivly with the right and left node, and on more level
PrintTree(level + 1, node.RightChildNode);
PrintTree(level + 1, node.LeftChildNode);
}
// The constructor sets the Root property, based on its argument
public HuffmanTree(HuffmanNode node)
{
Root = node;
}
// this method creates a tree based on text
public static HuffmanTree CreateFromText(string text)
{
// the list that we wanna fill up with nodes
List <HuffmanNode> nodeList = new List <HuffmanNode>();
// all the characters from the text
char[] characters = text.ToCharArray();
// loop thought the characters
for (int i = 0; i < characters.Length; i++)
{
// the character as a string
string read = characters[i].ToString();
// has the node already been created?
if (nodeList.Exists(x => x.Symbol == read))
{
// If is yes, find the index of the Node and increase the frequency of the Node.
nodeList[nodeList.FindIndex(y => y.Symbol == read)].Frequency++;
}
else
{
// If is no, create a new node and add to the List of Nodes
nodeList.Add(new HuffmanNode(read));
}
}
// sort them, this is done based on frequency because of IComparable<HuffmanNode>.CompareTo
nodeList.Sort();
// loop thought them, until only one is left
while (nodeList.Count > 1)
{
// Get the node of the first index of List, this is the one with the lowest frequency
HuffmanNode node1 = nodeList[0];
// and delete it.
nodeList.RemoveAt(0);
// do the same thing again
HuffmanNode node2 = nodeList[0];
nodeList.RemoveAt(0);
// make a parant node with node1 and node2 and the left and right child nodes
nodeList.Add(new HuffmanNode(node1, node2));
// and sort it again according to frequency.
nodeList.Sort();
}
// create a tree based on the remaining root node
HuffmanTree tree = new HuffmanTree(nodeList[0]);
// this is a recursive function to set the binary code of every leaf node
void setCodeToTheTree(HuffmanNode Nodes, BitArray code = null)
{
// if the current code is not set, set it to an empty BitArray
if (code == null)
{
code = new BitArray(new bool[] { });
}
// if the code is empty do nothing
if (Nodes == null)
{
return;
}
// if there is no left node and right node, then set the code based on the current code
if (Nodes.LeftChildNode == null && Nodes.RightChildNode == null)
{
Nodes.Code = code;
return;
}
// create a bitlist for the left node
BitList left = BitList.Parse(code);
// add false for the left side
left.Add(false);
// call this function recursively, with the left bitlist and the left side node
setCodeToTheTree(Nodes.LeftChildNode, left.ToBitArray());
// create a bitlist for the right node
BitList right = BitList.Parse(code);
// add true for the right side
right.Add(true);
// call the function recursively, with the right bitlist and the right side node
setCodeToTheTree(Nodes.RightChildNode, right.ToBitArray());
}
// call the recursive function
setCodeToTheTree(tree.Root);
// the tree
return(tree);
}
// this method creates a tree based on text
// Denne funktion laver et træ baseret på tekst
public static HuffmanTree CreateFromText(string text)
{
// the list that we wanna fill up with nodes
// Listen der skal fyldes med noder
List <HuffmanNode> nodeList = new List <HuffmanNode>();
// all the characters from the text
// Alle symbolerne fra teksten
char[] characters = text.ToCharArray();
// loop thought the characters
// Gentag igennem symbolerne
for (int i = 0; i < characters.Length; i++)
{
// the character as a string
// Symbolerne som strenge
string read = characters[i].ToString();
// has the node already been created?
// Er noden allerede blevet skabt?
if (nodeList.Exists(x => x.Symbol == read))
{
// If is yes, find the index of the Node and increase the frequency of the Node.
// Hvis ja, find indekset for noden og øg frekvensen for node
nodeList[nodeList.FindIndex(y => y.Symbol == read)].Frequency++;
}
else
{
// If is no, create a new node and add to the List of Nodes
// Hvis nej, skab en ny node og tilføj den til listen over node
nodeList.Add(new HuffmanNode(read));
}
}
// sort them, this is done based on frequency because of IComparable<HuffmanNode>.CompareTo
// Sorter dem, dette gøres baseret på frekvens fordi at IComparable<HuffmanNode>.CompareTo
nodeList.Sort();
// loop thought them, until only one is left
// Kør igennem dem alle sammen indtil der kun er en tilbage
while (nodeList.Count > 1)
{
// Get the node of the first index of List, this is the one with the lowest frequency
// Få noden for det første indeks af Listen, dette er den med den laveste frekvens
HuffmanNode node1 = nodeList[0];
// and delete it.
// Fjern den
nodeList.RemoveAt(0);
// do the same thing again
// Gør det samme igen
HuffmanNode node2 = nodeList[0];
nodeList.RemoveAt(0);
// make a parant node with node1 and node2 and the left and right child nodes
// Lav en parent-node med node1 og node1 og de venstre og højre child-noder
nodeList.Add(new HuffmanNode(node1, node2));
// and sort it again according to frequency.
// Og sorter det igen efter frekvens
nodeList.Sort();
}
// create a tree based on the remaining root node
// Lav et træ baseret på den tilbageværende rod-node
HuffmanTree tree = new HuffmanTree(nodeList[0]);
// this is a recursive function to set the binary code of every leaf node
// Dette er en rekursiv funktion for at sætte den binære værdi for hvert blad
void setCodeToTheTree(HuffmanNode Nodes, BitArray code = null)
{
// if the current code is not set, set it to an empty BitArray
// Hvis den nuværende kode ikke er sat, sættes den til et tomt BitArray
if (code == null)
{
code = new BitArray(new bool[] { });
}
// if the code is empty do nothing
// Hvis koden er tom, gør intet
if (Nodes == null)
{
return;
}
// if there is no left node and right node, then set the code based on the current code
// Hvis der ikke er nogen venstre node, sæt koden baseret på den nuværende kode
if (Nodes.LeftChildNode == null && Nodes.RightChildNode == null)
{
Nodes.Code = code;
return;
}
// create a bitlist for the left node
// lav en bitliste for den venstre node
BitList left = BitList.Parse(code);
// add false for the left side
// tilføj false for den venstre side
left.Add(false);
// call this function recursively, with the left bitlist and the left side node
// Kald denne funktion rekursivt, med den venstre bitliste og den venstre node
setCodeToTheTree(Nodes.LeftChildNode, left.ToBitArray());
// create a bitlist for the right node
// Lav en bitliste for den højre node
BitList right = BitList.Parse(code);
// add true for the right side
// tilføj true for den højre side
right.Add(true);
// call the function recursively, with the right bitlist and the right side node
// Kald denne funktion rekursivt, med den højre bitliste og den højre node
setCodeToTheTree(Nodes.RightChildNode, right.ToBitArray());
}
// call the recursive function
// Kald den rekursive funktion
setCodeToTheTree(tree.Root);
// the tree
// Træet returneres
return(tree);
}
// This method decodes bytes into a string, based on the current huffman tree
// Essentially, the opposite of the one above
// Denne funktion afkoder bytes til en string, baseret på det nuværende Huffman-træ
// Stort set bare det foregående baglæns
public string Decode(byte[] encoded)
{
// Turn the bytes into bits, and make a list of them
// Bytes omdannes til bits, og der laves en liste af dem
BitList bits = BitList.Parse(new BitArray(encoded));
// a recursive function to remove the ending of the bits
// the ending is there, only to make sure that the length of the list is divisible by 8
// this function therefore removes 0 from the end, until it hits a 1, which is then removed, and the function stops
// En rekursiv funktion for at fjerne enderne på bits
// Enderne er der kun for at sikre at længden på listen kan divideres med 8
// Denne funktion fjerner derfor 0'er fra enden, indtil at den rammer et 1, hvilket derefter fjernes og funktionen stopper
void clean(BitList list)
{
//if it is a 1
// Hvis det er et 1
if (list[list.Count - 1])
{
// remove the 1
// Fjern 1
list.RemoveAt(list.Count - 1);
}
// if it is a 0
// Hvis det er et 0
else
{
// remove the 0
// Fjern 0
list.RemoveAt(list.Count - 1);
// repeat
// Gentag
clean(list);
}
}
// call the function just described
// Kald funktionen fra før
clean(bits);
// init the string that is going to hold the decoded string
// strengen der skal indehold den afkodede streng laves
string str = "";
// define a variable to hold the current node that we are on
// Der defineres en variabel til at holde det nuværende node der kigges på
HuffmanNode currentNode = Root;
// loop thought all the bits
// Kør igennem alle bits
for (int i = 0; i < bits.Count; i++)
{
// if it is a 1, take the right node
// Hvis det er et 1, tag højre node
if (bits[i])
{
currentNode = currentNode.RightChildNode;
}
// if it is a 0, take the left node
// Hvis det er et 0, tag venstre node
else
{
currentNode = currentNode.LeftChildNode;
}
// if the current node is a leaf
// Hvis den nuværende node er et blad
if (currentNode.IsLeaf)
{
// add the symbol to the str variable
// Tilføj symbolet til streng-variablen "str"
str += currentNode.Symbol;
// go back to the root of the tree
// Gå tilbage til træets rod
currentNode = Root;
}
}
;
// return the decoded symbols
// Returner de afkodede symboler
return(str);
}
