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85 lines
2.4 KiB
85 lines
2.4 KiB
/*
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* Copyright (C) 2015-2022 Département de l'Instruction Publique (DIP-SEM)
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*
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* Copyright (C) 2013 Open Education Foundation
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*
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* Copyright (C) 2010-2013 Groupement d'Intérêt Public pour
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* l'Education Numérique en Afrique (GIP ENA)
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*
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* This file is part of OpenBoard.
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*
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* OpenBoard is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, version 3 of the License,
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* with a specific linking exception for the OpenSSL project's
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* "OpenSSL" library (or with modified versions of it that use the
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* same license as the "OpenSSL" library).
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*
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* OpenBoard 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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*
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* You should have received a copy of the GNU General Public License
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* along with OpenBoard. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "RunLengthDecode.h"
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#include <QtGlobal>
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#include "core/memcheck.h"
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using namespace merge_lib;
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bool RunLengthDecode::encode(std::string & decoded)
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{
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Q_UNUSED(decoded);
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return false;
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}
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/* The encoded data is a sequence of
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runs, where each run consists of a length byte followed by 1 to 128 bytes of data. If
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the length byte is in the range 0 to 127, the following length + 1 (1 to 128) bytes
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are copied literally during decompression. If length is in the range 129 to 255, the
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following single byte is to be copied 257 - length (2 to 128) times during decom-
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pression. A length value of 128 denotes EOD. */
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// Function performs RunLength Decoder for PDF, very simple
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bool RunLengthDecode::decode(std::string & encoded)
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{
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std::string decoded;
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for(unsigned enci = 0;enci < encoded.size();)
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{
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unsigned char c = encoded[enci++];
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if( c == 128 )
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{
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break; //EOD
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}
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else if( c < 128 )
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{
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for(int j = 0; j < (c+1);j++)
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{
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decoded.append(1,encoded[enci]);
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}
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enci++;
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}
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else
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{
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for(int j = 0; j < (257 - c);j++)
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{
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decoded.append(1,encoded[enci]);
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}
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enci++;
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}
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}
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return true;
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}
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void RunLengthDecode::initialize(Object * objectWithStream)
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{
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Q_UNUSED(objectWithStream);
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};
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