mirror of
https://github.com/libretro/scummvm.git
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87 lines
2.5 KiB
C++
87 lines
2.5 KiB
C++
/* ScummVM - Graphic Adventure Engine
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*
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* ScummVM is the legal property of its developers, whose names
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* are too numerous to list here. Please refer to the COPYRIGHT
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* file distributed with this source distribution.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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*/
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// Based on eos' Huffman code
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#include "common/huffman.h"
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#include "common/util.h"
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#include "common/textconsole.h"
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#include "common/bitstream.h"
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namespace Common {
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Huffman::Symbol::Symbol(uint32 c, uint32 s) : code(c), symbol(s) {
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}
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Huffman::Huffman(uint8 maxLength, uint32 codeCount, const uint32 *codes, const uint8 *lengths, const uint32 *symbols) {
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assert(codeCount > 0);
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assert(codes);
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assert(lengths);
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if (maxLength == 0)
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for (uint32 i = 0; i < codeCount; i++)
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maxLength = MAX(maxLength, lengths[i]);
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assert(maxLength <= 32);
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_codes.resize(maxLength);
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_symbols.resize(codeCount);
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for (uint32 i = 0; i < codeCount; i++) {
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// The symbol. If none were specified, just assume it's identical to the code index
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uint32 symbol = symbols ? symbols[i] : i;
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// Put the code and symbol into the correct list
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_codes[lengths[i] - 1].push_back(Symbol(codes[i], symbol));
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// And put the pointer to the symbol/code struct into the symbol list.
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_symbols[i] = &_codes[lengths[i] - 1].back();
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}
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}
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Huffman::~Huffman() {
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}
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void Huffman::setSymbols(const uint32 *symbols) {
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for (uint32 i = 0; i < _symbols.size(); i++)
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_symbols[i]->symbol = symbols ? *symbols++ : i;
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}
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uint32 Huffman::getSymbol(BitStream &bits) const {
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uint32 code = 0;
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for (uint32 i = 0; i < _codes.size(); i++) {
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bits.addBit(code, i);
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for (CodeList::const_iterator cCode = _codes[i].begin(); cCode != _codes[i].end(); ++cCode)
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if (code == cCode->code)
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return cCode->symbol;
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}
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error("Unknown Huffman code");
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return 0;
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}
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} // End of namespace Common
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