/// <summary>
/// Builds Tree.
/// </summary>
/// <param name="input">
/// input byte array to build tree.
/// </param>
/// <param name="treeNodes"></param>
/// <returns></returns>
public PrefixCodeNode PrefixCodeTreeRebuild(byte[] input, ref PrefixCodeNode[] treeNodes)
{
PrefixCodeNode root = new PrefixCodeNode();
PrefixCodeSymbol[] symbolInfo = new PrefixCodeSymbol[512];
UInt32 i;
UInt32 j;
UInt32 mask;
UInt32 bits;
for (i = 0; i < 1024; i++)
{
treeNodes[i].symbol = 0;
treeNodes[i].leaf = false;
treeNodes[i].Child[0] = null;
treeNodes[i].Child[1] = null;
}
for (i = 0; i < 256; i++)
{
symbolInfo[2 * i].symbol = (UInt16)(2 * i);
symbolInfo[2 * i].length = (UInt16)(input[i] & 15);
symbolInfo[2 * i + 1].symbol = (UInt16)(2 * i + 1);
symbolInfo[2 * i + 1].length = (UInt16)(input[i] >> 4);
}
SortSymbols(ref symbolInfo);
i = 0;
while ((i < 512) && (symbolInfo[i].length == 0))
{
i++;
}
mask = 0;
bits = 1;
root = treeNodes[0];
root.leaf = false;
j = 1;
for (; i < 512; i++)
{
treeNodes[j].symbol = symbolInfo[i].symbol;
treeNodes[j].leaf = true;
mask = mask << (int)(symbolInfo[i].length - bits);
bits = symbolInfo[i].length;
j = PrefixCodeTreeAddLeaf(ref treeNodes, j, mask, bits);
mask++;
}
return(root);
}
/// <summary>
/// Compares two symbols
/// </summary>
/// <param name="a">
/// First Symbol
/// </param>
/// <param name="b">
/// Second Symbol
/// </param>
/// <returns></returns>
public int CompareSymbols(PrefixCodeSymbol a, PrefixCodeSymbol b)
{
if (a.length < b.length)
{
return(-1);
}
else if (a.length > b.length)
{
return(1);
}
else if (a.symbol < b.symbol)
{
return(-1);
}
else if (a.symbol > b.symbol)
{
return(1);
}
else
{
return(0);
}
}