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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
// Based on eos' Huffman code
#ifndef COMMON_HUFFMAN_H
#define COMMON_HUFFMAN_H
#include "common/array.h"
#include "common/list.h"
#include "common/types.h"
namespace Common {
/**
* Huffman bitstream decoding
*
* Used in engines:
* - scumm
*/
class Huffman {
public:
/** Construct a Huffman decoder.
*
* @param maxLength Maximal code length. If 0, it's searched for.
* @param codeCount Number of codes.
* @param codes The actual codes.
* @param lengths Lengths of the individual codes.
* @param symbols The symbols. If 0, assume they are identical to the code indices.
*/
Huffman(uint8 maxLength, uint32 codeCount, const uint32 *codes, const uint8 *lengths, const uint32 *symbols = nullptr);
~Huffman();
/** Modify the codes' symbols. */
void setSymbols(const uint32 *symbols = nullptr);
/** Return the next symbol in the bitstream. */
template<class BITSTREAM>
uint32 getSymbol(BITSTREAM &bits) const {
uint32 code = 0;
for (uint32 i = 0; i < _codes.size(); i++) {
bits.addBit(code, i);
for (CodeList::const_iterator cCode = _codes[i].begin(); cCode != _codes[i].end(); ++cCode)
if (code == cCode->code)
return cCode->symbol;
}
error("Unknown Huffman code");
return 0;
}
private:
struct Symbol {
uint32 code;
uint32 symbol;
Symbol(uint32 c, uint32 s);
};
typedef List<Symbol> CodeList;
typedef Array<CodeList> CodeLists;
typedef Array<Symbol *> SymbolList;
/** Lists of codes and their symbols, sorted by code length. */
CodeLists _codes;
/** Sorted list of pointers to the symbols. */
SymbolList _symbols;
};
} // End of namespace Common
#endif // COMMON_HUFFMAN_H
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