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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
#include "common/huffman.h"
#include "common/util.h"
#include "common/textconsole.h"
#include "common/bitstream.h"
namespace Common {
Huffman::Symbol::Symbol(uint32 c, uint32 s) : code(c), symbol(s) {
}
Huffman::Huffman(uint8 maxLength, uint32 codeCount, const uint32 *codes, const uint8 *lengths, const uint32 *symbols) {
assert(codeCount > 0);
assert(codes);
assert(lengths);
if (maxLength == 0)
for (uint32 i = 0; i < codeCount; i++)
maxLength = MAX(maxLength, lengths[i]);
assert(maxLength <= 32);
_codes.resize(maxLength);
_symbols.resize(codeCount);
for (uint32 i = 0; i < codeCount; i++) {
// The symbol. If none were specified, just assume it's identical to the code index
uint32 symbol = symbols ? symbols[i] : i;
// Put the code and symbol into the correct list
_codes[lengths[i] - 1].push_back(Symbol(codes[i], symbol));
// And put the pointer to the symbol/code struct into the symbol list.
_symbols[i] = &_codes[lengths[i] - 1].back();
}
}
Huffman::~Huffman() {
}
void Huffman::setSymbols(const uint32 *symbols) {
for (uint32 i = 0; i < _symbols.size(); i++)
_symbols[i]->symbol = symbols ? *symbols++ : i;
}
uint32 Huffman::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;
}
} // End of namespace Common
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