public override bool Equals(object ob)
{
if (!(ob is HuffmanTableNode))
{
return(false);
}
HuffmanTableNode Node2 = ob as HuffmanTableNode;
if (m_len != Node2.m_len)
{
return(false);
}
bool result = true;
for (int i = 0; i < m_Size; i++)
{
if (m_Code[i] != Node2.m_Code[i])
{
result = false;
break;
}
}
return(result);
}
static void EncodeArray(ref byte[] pBufIn, out byte[] pBufOut)
{
int lenIn = pBufIn.Length;
int lenOut = 0;
if (lenIn <= 1024)
{
Store(ref pBufIn, lenIn, out pBufOut, out lenOut);
return;
}
HistogramNode[] pHN = null;
int lHOut;
int offset = 0;
int nHuffmanTableSize;
// 1 === create histogram ===
GetHistogram(ref pBufIn, lenIn, out pHN, out lHOut);
// ==========================
// 1.1 === there is only 1 (one) value ===
if (lHOut == 1)
{
lenOut = 0;
lenOut++; // compress or uncompress
lenOut += sizeof(int); // lenght of huffman table
lenOut += sizeof(int); // uncompressed size
lenOut++; // value
pBufOut = new byte[lenOut];
byte Value = pHN[0].Value;
nHuffmanTableSize = 1;
pBufOut[0] = 1; offset++;
byte[] ar1 = BitConverter.GetBytes(nHuffmanTableSize);
byte[] ar2 = BitConverter.GetBytes(lenIn);
ar1.CopyTo(pBufOut, offset); offset += sizeof(int);
ar2.CopyTo(pBufOut, offset); offset += sizeof(int);
pBufOut[offset] = Value;
return;
}
// ========================================
// 2 === create zero level of tree ===
List <CHNode> arCHZeroLevel = new List <CHNode>();
int i;
for (i = 0; i < lHOut; i++)
{
arCHZeroLevel.Add(new CHNode(pHN[i].Value, pHN[i].Frequency));
}
// ===================================
// 3 === create tree ===
List <CHNode> arCHTree = new List <CHNode>(arCHZeroLevel);
int lCur = lHOut;
int nTreeSize;
while (lCur > 1)
{
int index1 = 0;
int index2 = 0;
CHNode pHuffman;
int min = 0xFFFFFFF;
nTreeSize = arCHTree.Count;
for (i = 0; i < nTreeSize; i++)
{
pHuffman = arCHTree[i];
if (pHuffman.Mark)
{
continue;
}
if (pHuffman.Weight < min)
{
index1 = i;
min = pHuffman.Weight;
}
}
min = 0xFFFFFFF;
for (i = 0; i < nTreeSize; i++)
{
pHuffman = arCHTree[i];
if (pHuffman.Mark)
{
continue;
}
if (i == index1)
{
continue;
}
if (pHuffman.Weight < min)
{
index2 = i;
min = pHuffman.Weight;
}
}
CHNode p1 = arCHTree[index1];
CHNode p2 = arCHTree[index2];
CHNode pNewNode = new CHNode();
CHNode emptyNode = null;
pNewNode.Weight = p1.Weight + p2.Weight;
pNewNode.SetLeft(ref p1);
pNewNode.SetRight(ref p2);
pNewNode.SetRoot(ref emptyNode);
arCHTree.Add(pNewNode);
p1.SetRoot(ref pNewNode);
p1.SetLeftType();
p1.Mark = true;
p2.SetRoot(ref pNewNode);
p2.SetRightType();
p2.Mark = true;
lCur--;
}
// =====================================
// 4 === compute size for compressed data ===
int nCompressedDataSize = 0;
nHuffmanTableSize = 0;
HuffmanTableNode[] pHuffmanNode = new HuffmanTableNode[arCHZeroLevel.Count];
for (i = 0; i < arCHZeroLevel.Count; i++)
{
pHuffmanNode[i] = new HuffmanTableNode();
}
for (i = 0; i < arCHZeroLevel.Count; i++)
{
CHNode pNode = arCHZeroLevel[i];
while (pNode.GetRoot() != null)
{
if (pNode.IsRightType)
{
pHuffmanNode[i].AddBitOne(); // 1
}
else
{
pHuffmanNode[i].AddBitZero(); // 0
}
pNode = pNode.GetRoot();
}
pNode = arCHZeroLevel[i];
pHuffmanNode[i].Value = pNode.Value;
pHuffmanNode[i].Invert();
nCompressedDataSize += (pHuffmanNode[i].Len * pNode.Weight); // measured in bits
}
if (nCompressedDataSize % 8 == 0)
{
nCompressedDataSize /= 8; // measured in bytes
}
else
{
nCompressedDataSize = nCompressedDataSize / 8 + 1; // measured in bytes
}
// ==========================================
// 5 === compute total memory ===
lenOut = 0;
lenOut++; // compress or uncompress
lenOut += sizeof(int); // lenght of huffman table
lenOut += lHOut * HistogramNode.Size; // histogram size
lenOut += sizeof(int); // uncompressed size
lenOut += nCompressedDataSize;
// ==============================
// 6 === Check for total size ===
if (lenOut > lenIn)
{
Store(ref pBufIn, lenIn, out pBufOut, out lenOut);
return;
}
// ================================
// 7 === Encoding ===
pBufOut = new byte[lenOut];
byte[] p = pBufOut;
Array.Clear(p, 0, p.Length);
offset = 0;
int index, j;
int nBits = 8;
byte Code, CodeForWriting;
int CodeLen;
int nZeroLevel = arCHZeroLevel.Count;
byte[] arInt = null;
p[0] = 1; offset++;
arInt = BitConverter.GetBytes(nZeroLevel);
arInt.CopyTo(p, offset); offset += sizeof(int);
// === store histogram ===
for (i = 0; i < nZeroLevel; i++)
{
offset = pHN[i].ToArray(ref p, offset);
}
// ======================
arInt = BitConverter.GetBytes(lenIn);
arInt.CopyTo(p, offset);
offset += sizeof(int);
byte[] pIndex = new byte[256];
for (i = 0; i < 256; i++)
{
for (j = 0; j < nZeroLevel; j++)
{
if (i == pHuffmanNode[j].Value)
{
pIndex[i] = Convert.ToByte(j);
break;
}
}
}
for (i = 0; i < lenIn; i++)
{
index = pIndex[pBufIn[i]];
CodeLen = pHuffmanNode[index].Len;
for (j = 0; j < CodeLen; j++)
{
if (nBits == 0)
{
nBits = 8;
offset++;
}
Code = pHuffmanNode[index].GetBit(j);
CodeForWriting = Convert.ToByte(Code << (nBits - 1));
p[offset] |= CodeForWriting;
nBits--;
}
}
}