SA-MP/raknet/DS_HuffmanEncodingTree.h

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/// \file
/// \brief \b [Internal] Generates a huffman encoding tree, used for string and global compression.
///
/// This file is part of RakNet Copyright 2003 Kevin Jenkins.
///
/// Usage of RakNet is subject to the appropriate license agreement.
/// Creative Commons Licensees are subject to the
/// license found at
/// http://creativecommons.org/licenses/by-nc/2.5/
/// Single application licensees are subject to the license found at
/// http://www.rakkarsoft.com/SingleApplicationLicense.html
/// Custom license users are subject to the terms therein.
/// GPL license users are subject to the GNU General Public
/// License as published by the Free
/// Software Foundation; either version 2 of the License, or (at your
/// option) any later version.
#ifndef __HUFFMAN_ENCODING_TREE
#define __HUFFMAN_ENCODING_TREE
#include "DS_HuffmanEncodingTreeNode.h"
#include "BitStream.h"
#include "Export.h"
#include "DS_LinkedList.h"
/// This generates special cases of the huffman encoding tree using 8 bit keys with the additional condition that unused combinations of 8 bits are treated as a frequency of 1
class RAK_DLL_EXPORT HuffmanEncodingTree
{
public:
HuffmanEncodingTree();
~HuffmanEncodingTree();
/// Pass an array of bytes to array and a preallocated BitStream to receive the output
/// \param [in] input Array of bytes to encode
/// \param [in] sizeInBytes size of \a input
/// \param [out] output The bitstream to write to
void EncodeArray( unsigned char *input, unsigned sizeInBytes, RakNet::BitStream * output );
// Decodes an array encoded by EncodeArray()
unsigned DecodeArray( RakNet::BitStream * input, unsigned sizeInBits, unsigned maxCharsToWrite, unsigned char *output );
void DecodeArray( unsigned char *input, unsigned sizeInBits, RakNet::BitStream * output );
/// Given a frequency table of 256 elements, all with a frequency of 1 or more, generate the tree
void GenerateFromFrequencyTable( unsigned int frequencyTable[ 256 ] );
/// Free the memory used by the tree
void FreeMemory( void );
private:
/// The root node of the tree
HuffmanEncodingTreeNode *root;
/// Used to hold bit encoding for one character
struct CharacterEncoding
{
unsigned char* encoding;
unsigned short bitLength;
};
CharacterEncoding encodingTable[ 256 ];
void InsertNodeIntoSortedList( HuffmanEncodingTreeNode * node, DataStructures::LinkedList<HuffmanEncodingTreeNode *> *huffmanEncodingTreeNodeList ) const;
};
#endif