mirror of
https://github.com/libretro/scummvm.git
synced 2024-12-12 12:09:15 +00:00
dde259f068
All users of BitStream were in fact using a specific, hardcoded variant, so we can hardcode that variant, removing the need for virtual calls, and enabling inlining.
95 lines
2.5 KiB
C++
95 lines
2.5 KiB
C++
/* 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 = 0);
|
|
~Huffman();
|
|
|
|
/** Modify the codes' symbols. */
|
|
void setSymbols(const uint32 *symbols = 0);
|
|
|
|
/** 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
|