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/*
* Copyright (C) 2004-2012 Geometer Plus <contact@geometerplus.com>
*
* 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.
*/
#include <algorithm>
#include "HuffmanDecoder.h"
HuffmanDecoder::HuffmanDecoder() : myMaxBitsNumber(0) {
}
void HuffmanDecoder::reset() {
CodeLengths.clear();
}
bool HuffmanDecoder::buildTable() {
myMaxBitsNumber = 0;
for (unsigned short symbol = 0; symbol < CodeLengths.size(); symbol++) {
myMaxBitsNumber = std::max(CodeLengths[symbol], myMaxBitsNumber);
}
if (myMaxBitsNumber > 16) {
return false;
}
unsigned int tableSize = 1 << myMaxBitsNumber;
mySymbols.clear();
mySymbols.reserve(tableSize);
for (unsigned char i = 1; i <= myMaxBitsNumber; ++i) {
for (unsigned short symbol = 0; symbol < CodeLengths.size(); symbol++) {
if (CodeLengths[symbol] == i) {
mySymbols.insert(mySymbols.end(), 1 << (myMaxBitsNumber - i), symbol);
if (mySymbols.size() > tableSize) {
return false;
}
}
}
}
if (mySymbols.size() < tableSize) {
mySymbols.insert(mySymbols.end(), tableSize - mySymbols.size(), 0);
}
return true;
}
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