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Huffman base2/3

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This commit is contained in:
Ahmed Zamil
2023-03-27 15:12:40 +03:00
parent 60738d01b4
commit 9a74a01bdf
8 changed files with 268 additions and 96 deletions
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190
Esiur.Analysis/Coding/Huffman.cs
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@@ -10,9 +10,11 @@ using System.Xml.Linq;
namespace Esiur.Analysis.Coding
{
public class Huffman : ICodec
public class Huffman<T> : IStreamCodec<T> where T : System.Enum
{
public CodeSet<T> CodeSet { get; } = new CodeSet<T>();
public class Node<TKey, TValue, TFrequency>
{
public TKey Key { get; set; } // decision maker (bit)
@@ -103,20 +105,16 @@ namespace Esiur.Analysis.Coding
}
}
public class HuffmanTable
{
public Dictionary<byte, BitArray> ForwardMap { get; set; } = new Dictionary<byte, BitArray>();
public Dictionary<BitArray, byte> BackwardMap { get; set; } = new Dictionary<BitArray, byte>();
}
public Tree<bool, byte, int> DecisionTree { get; set; }
public Huffman(byte[] source, uint offset, uint length)
public Tree<T, CodeWord<T>, int> DecisionTree { get; set; }
public Huffman(CodeWord<T>[] source, uint offset, uint length)
{
//var freq = new int[byte.MaxValue + 1];
var freq = new Dictionary<byte, int>();
var freq = new Dictionary<CodeWord<T>, int>();
// var root = new Branch<bool, KeyValuePair<byte, int>>();
@@ -128,29 +126,37 @@ namespace Esiur.Analysis.Coding
else
freq.Add(source[i], 1);
var nodes = freq.OrderBy(x => x.Value).Select(x => new Node<bool, byte, int>()
{ Frequency = x.Value, Key = false, Value = x.Key }).ToList();
var nodes = freq.OrderBy(x => x.Value).Select(x => new Node<T, CodeWord<T>, int>()
{ Frequency = x.Value, Key = default(T), Value = x.Key }).ToList();
//var leafs = nodes.ToList();
while (nodes.Count() > 1)
{
var decision = nodes.Take(2).ToList();
var decision = nodes.Take(CodeSet.ElementsCount).ToList();
decision[1].Key = true;
//decision[1].Key = true;
var branch = new Node<bool, byte, int>
var branch = new Node<T, CodeWord<T>, int>
{
Branches = new Dictionary<bool, Node<bool, byte, int>>()
{
[decision[0].Key] = decision[0],
[decision[1].Key] = decision[1]
},
Key = false,
Branches = new Dictionary<T, Node<T, CodeWord<T>, int>>(),
//{
// [decision[0].Key] = decision[0],
// [decision[1].Key] = decision[1]
//},
Key = CodeSet.Elements.First(),
Frequency = decision[0].Frequency + decision[1].Frequency
};
// assign values
for (var i = 0; i < decision.Count; i++)
{
branch.Branches.Add(CodeSet.Elements[i], decision[i]);
decision[i].Key = CodeSet.Elements[i];
}
decision[0].Parent = branch;
decision[1].Parent = branch;
@@ -159,76 +165,104 @@ namespace Esiur.Analysis.Coding
// create tree
DecisionTree = new Tree<bool, byte, int>(nodes[0]);
DecisionTree = new Tree<T, CodeWord<T>, int>(nodes[0]);
Console.WriteLine();
}
public byte[] Encode(byte[] source, uint offset, uint length)
public T[] Encode(CodeWord<T>[] source, uint offset, uint length)
{
var rt = new List<T>();
var end = offset + length;
var seq = new List<bool>();
for (var i = offset; i < end; i++)
for(var i = offset; i < end; i++)
{
seq.AddRange(DecisionTree.Leafs[source[i]].Sequence);
}
var str = (String.Join("", seq.Select(x => x ? "1" : "0")));
// convert sequence to bytes
//var bits = new BitArray(seq.ToArray());
var rt = new byte[(seq.Count - 1) / 8 + 1];
var dst = 0;
for (var i = 0; i < rt.Length; i++)
{
for (var j = 7; j >= 0; j--)
{
if (dst >= seq.Count)
break;
if (seq[dst++])
rt[i] |= (byte)(0x1 << j);
}
}
// bits.CopyTo(rt, 0);
return rt;
}
public byte[] Decode(byte[] source, uint offset, uint length)
{
var rt = new List<byte>();
var bits = new bool[length * 8];
var end = offset + length;
var dst = 0;
for (var i = offset; i < end; i++)
{
for (var j = 7; j >= 0; j--)
{
bits[dst++] = ((source[i] >> j) & 0x1) > 0 ? true : false;
}
}
uint b = 0;
while (b < bits.Length)
{
var (len, value) = DecisionTree.Decide(bits, b);
rt.Add(value);
b += len;
rt.AddRange(DecisionTree.Leafs[source[i]].Sequence);
}
return rt.ToArray();
}
public CodeWord<T>[] Decode(T[] source, uint offset, uint length)
{
var rt = new List<CodeWord<T>>();
uint processed = 0;
while (processed < length)
{
var (len, value) = DecisionTree.Decide(source, offset);
rt.Add(value);
processed += len;
offset += len;
}
return rt.ToArray();
}
//public byte[] Encode(byte[] source, uint offset, uint length)
//{
// var end = offset + length;
// var seq = new List<T>();
// for (var i = offset; i < end; i++)
// {
// seq.AddRange(DecisionTree.Leafs[source[i]].Sequence);
// }
// //var str = (String.Join("", seq.Select(x => x ? "1" : "0")));
// // convert sequence to bytes
// var rt = new byte[(seq.Count - 1) / 8 + 1];
// var dst = 0;
// for (var i = 0; i < rt.Length; i++)
// {
// for (var j = 7; j >= 0; j--)
// {
// if (dst >= seq.Count)
// break;
// if (seq[dst++])
// rt[i] |= (byte)(0x1 << j);
// }
// }
// // bits.CopyTo(rt, 0);
// return rt;
//}
//public T[] Decode(T[] source, uint offset, uint length)
//{
// var rt = new List<byte>();
// var bits = new bool[length * 8];
// var end = offset + length;
// var dst = 0;
// for (var i = offset; i < end; i++)
// {
// for (var j = 7; j >= 0; j--)
// {
// bits[dst++] = ((source[i] >> j) & 0x1) > 0 ? true : false;
// }
// }
// uint b = 0;
// while (b < bits.Length)
// {
// var (len, value) = DecisionTree.Decide(bits, b);
// rt.Add(value);
// b += len;
// }
// return rt.ToArray();
//}
}
}