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138 lines
4.5 KiB
C++
138 lines
4.5 KiB
C++
/*
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* (c) Copyright Ascensio System SIA 2010-2017
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*
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* This program is a free software product. You can redistribute it and/or
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* modify it under the terms of the GNU Affero General Public License (AGPL)
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* version 3 as published by the Free Software Foundation. In accordance with
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* Section 7(a) of the GNU AGPL its Section 15 shall be amended to the effect
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* that Ascensio System SIA expressly excludes the warranty of non-infringement
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* of any third-party rights.
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*
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* This program is distributed WITHOUT ANY WARRANTY; without even the implied
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* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. For
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* details, see the GNU AGPL at: http://www.gnu.org/licenses/agpl-3.0.html
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*
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* You can contact Ascensio System SIA at Lubanas st. 125a-25, Riga, Latvia,
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* EU, LV-1021.
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*
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* The interactive user interfaces in modified source and object code versions
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* of the Program must display Appropriate Legal Notices, as required under
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* Section 5 of the GNU AGPL version 3.
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*
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* Pursuant to Section 7(b) of the License you must retain the original Product
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* logo when distributing the program. Pursuant to Section 7(e) we decline to
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* grant you any rights under trademark law for use of our trademarks.
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*
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* All the Product's GUI elements, including illustrations and icon sets, as
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* well as technical writing content are licensed under the terms of the
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* Creative Commons Attribution-ShareAlike 4.0 International. See the License
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* terms at http://creativecommons.org/licenses/by-sa/4.0/legalcode
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*
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*/
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#ifndef _PDF_READER_JARITHMETICDECODER_H
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#define _PDF_READER_JARITHMETICDECODER_H
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namespace PdfReader
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{
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class Stream;
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//-------------------------------------------------------------------------------------------------------------------------------
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// JArithmeticDecoderStats
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//-------------------------------------------------------------------------------------------------------------------------------
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class JArithmeticDecoderStats
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{
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public:
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JArithmeticDecoderStats(int nContextSize);
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~JArithmeticDecoderStats();
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JArithmeticDecoderStats *Copy();
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void Reset();
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int GetContextSize()
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{
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return m_nContextSize;
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}
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void CopyFrom(JArithmeticDecoderStats *pStats);
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void SetEntry(unsigned int unCx, int nIndex, int nMPS);
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private:
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unsigned char *m_pContextTable; // cxTab[cx] = (i[cx] << 1) + mps[cx]
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int m_nContextSize;
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friend class JArithmeticDecoder;
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};
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//-------------------------------------------------------------------------------------------------------------------------------
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// JArithmeticDecoder
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//-------------------------------------------------------------------------------------------------------------------------------
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class JArithmeticDecoder
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{
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public:
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JArithmeticDecoder();
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~JArithmeticDecoder();
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void SetStream(Stream *pStream)
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{
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m_pStream = pStream;
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m_nDataSize = 0;
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m_bLimitStream = false;
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}
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void SetStream(Stream *pStream, int nDataSize)
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{
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m_pStream = pStream;
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m_nDataSize = nDataSize;
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m_bLimitStream = true;
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}
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// Начинаем декодировать новый поток. Заполняем буффер и запускаем INITDEC.
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void Start();
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// Заново декодируем прервынный поток. Заново заполняем буффер, но не запускаем INITDEC. (Используется в потоках JPEG 2000, где
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// данные могут быть разделены на блоки.)
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void Restart(int nDataSize);
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// Читаем оставшиеся данные в потоке.
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void Cleanup();
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// Декодируем один бит.
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int DecodeBit(unsigned int unContext, JArithmeticDecoderStats *pStats);
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// Декодируем один байт.
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int DecodeByte(unsigned int unContext, JArithmeticDecoderStats *pStats);
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bool DecodeInt(int *pnValue, JArithmeticDecoderStats *pStats);
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unsigned int DecodeIAID(unsigned int unCodeLen, JArithmeticDecoderStats *pStats);
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private:
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unsigned int ReadByte();
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int DecodeIntBit(JArithmeticDecoderStats *pStats);
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void ByteIn();
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private:
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static unsigned int arrunQeTable[47];
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static int arrnNMPSTable[47];
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static int arrnNLPSTable[47];
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static int arrnSwitchTable[47];
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unsigned int m_unBuffer0;
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unsigned int m_unBuffer1;
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unsigned int m_unC;
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unsigned int m_unA;
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int m_nCT;
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unsigned int m_unPrev;
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Stream *m_pStream;
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int m_nDataSize;
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bool m_bLimitStream;
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};
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}
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#endif // _PDF_READER_JARITHMETICDECODER_H
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