mirror of
https://github.com/JakubMelka/PDF4QT.git
synced 2025-06-05 21:59:17 +02:00
440 lines
12 KiB
C++
440 lines
12 KiB
C++
// Copyright (C) 2022 Jakub Melka
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//
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// This file is part of PDF4QT.
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//
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// PDF4QT is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// with the written consent of the copyright owner, any later version.
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//
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// PDF4QT 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 Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with PDF4QT. If not, see <https://www.gnu.org/licenses/>.
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#include "pdf3d_u3d.h"
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#include <array>
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namespace pdf
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{
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namespace u3d
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{
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PDF3D_U3D_DataReader::PDF3D_U3D_DataReader(QByteArray data) :
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m_data(std::move(data)),
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m_high(0x0000FFFF),
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m_low(0),
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m_underflow(0),
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m_code(0)
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{
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}
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PDF3D_U3D_DataReader::~PDF3D_U3D_DataReader()
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{
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}
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uint8_t PDF3D_U3D_DataReader::readU8()
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{
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uint32_t value = readSymbol(PDF3D_U3D_Constants::S_CONTEXT_8);
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--value;
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return swapBits8(value);
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}
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uint16_t PDF3D_U3D_DataReader::readU16()
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{
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const uint16_t low = readU8();
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const uint16_t high = readU8();
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return low + (high << 8);
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}
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uint32_t PDF3D_U3D_DataReader::readU32()
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{
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const uint32_t low = readU16();
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const uint32_t high = readU16();
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return low + (high << 16);
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}
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uint64_t PDF3D_U3D_DataReader::readU64()
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{
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const uint64_t low = readU32();
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const uint64_t high = readU32();
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return low + (high << 32);
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}
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int32_t PDF3D_U3D_DataReader::readI32()
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{
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return static_cast<int32_t>(readU32());
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}
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float PDF3D_U3D_DataReader::readF32()
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{
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const uint32_t value = readU32();
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return static_cast<float>(value);
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}
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uint8_t PDF3D_U3D_DataReader::readCompressedU8(uint32_t context)
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{
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if (m_contextManager.isContextCompressed(context))
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{
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const uint32_t symbol = readSymbol(context);
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if (symbol != 0)
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{
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// Compressed symbol
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return symbol - 1;
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}
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else
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{
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// New symbol
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const uint32_t value = readU8();
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m_contextManager.addSymbol(context, value + 1);
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return value;
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}
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}
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return readU8();
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}
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uint16_t PDF3D_U3D_DataReader::readCompressedU16(uint32_t context)
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{
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if (m_contextManager.isContextCompressed(context))
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{
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const uint32_t symbol = readSymbol(context);
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if (symbol != 0)
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{
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// Compressed symbol
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return symbol - 1;
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}
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else
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{
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// New symbol
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const uint32_t value = readU16();
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m_contextManager.addSymbol(context, value + 1);
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return value;
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}
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}
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return readU16();
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}
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uint32_t PDF3D_U3D_DataReader::readCompressedU32(uint32_t context)
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{
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if (m_contextManager.isContextCompressed(context))
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{
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const uint32_t symbol = readSymbol(context);
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if (symbol != 0)
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{
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// Compressed symbol
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return symbol - 1;
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}
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else
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{
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// New symbol
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const uint32_t value = readU32();
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m_contextManager.addSymbol(context, value + 1);
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return value;
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}
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}
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return readU32();
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}
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uint32_t PDF3D_U3D_DataReader::readSymbol(uint32_t context)
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{
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uint32_t position = m_position;
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m_code = readBit();
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m_position += m_underflow;
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m_code = (m_code << 15) | read15Bits();
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m_position = position;
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const uint32_t totalCumFreq = m_contextManager.getTotalSymbolFrequency(context);
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const uint32_t range = (m_high + 1) - m_low;
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const uint32_t codeCumFreq = ((totalCumFreq) * (1 + m_code - m_low) - 1) / range;
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const uint32_t value = m_contextManager.getSymbolFromFrequency(context, codeCumFreq);
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const uint32_t valueCumFreq = m_contextManager.getCumulativeSymbolFrequency(context, value);
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const uint32_t valueFreq = m_contextManager.getSymbolFrequency(context, value);
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uint32_t low = m_low;
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uint32_t high = m_high;
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high = low - 1 + range * (valueCumFreq + valueFreq) / totalCumFreq;
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low = low + range * valueCumFreq / totalCumFreq;
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m_contextManager.addSymbol(context, value);
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constexpr std::array S_BIT_COUNTS = { 4, 3, 2, 2, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0 };
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uint32_t bitCount = S_BIT_COUNTS[((low >> 12) ^ (high >> 12)) & 0x0000000F];
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constexpr std::array S_FAST_NOT_MASK = { 0x0000FFFF, 0x00007FFF, 0x00003FFF, 0x00001FFF, 0x00000FFF };
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low = low & S_FAST_NOT_MASK[bitCount];
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high = high & S_FAST_NOT_MASK[bitCount];
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if (bitCount > 0)
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{
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high <<= bitCount;
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low <<= bitCount;
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high = high | ((1 << bitCount) - 1);
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}
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uint32_t maskedLow = low & PDF3D_U3D_Constants::S_HALF_MASK;
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uint32_t maskedHigh = high & PDF3D_U3D_Constants::S_HALF_MASK;
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while (((maskedLow | maskedHigh) == 0) || ((maskedLow == PDF3D_U3D_Constants::S_HALF_MASK) && maskedHigh == PDF3D_U3D_Constants::S_HALF_MASK))
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{
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low = (low & PDF3D_U3D_Constants::S_NOT_HALF_MASK) << 1;
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high = ((high & PDF3D_U3D_Constants::S_NOT_HALF_MASK) << 1) | 1;
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maskedLow = low & PDF3D_U3D_Constants::S_HALF_MASK;
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maskedHigh = high & PDF3D_U3D_Constants::S_HALF_MASK;
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++bitCount;
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}
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const uint32_t savedBitsLow = maskedLow;
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const uint32_t savedBitsHigh = maskedHigh;
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if (bitCount > 0)
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{
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bitCount += m_underflow;
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m_underflow = 0;
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}
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maskedLow = low & PDF3D_U3D_Constants::S_QUARTER_MASK;
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maskedHigh = high & PDF3D_U3D_Constants::S_QUARTER_MASK;
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uint32_t underflow = 0;
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while ((maskedLow == 0x4000) && (maskedHigh == 0))
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{
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low = low & PDF3D_U3D_Constants::S_NOT_THREE_QUARTER_MASK;
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high = high & PDF3D_U3D_Constants::S_NOT_THREE_QUARTER_MASK;
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low += low;
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high += high;
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high = high | 1;
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maskedLow = low & PDF3D_U3D_Constants::S_QUARTER_MASK;
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maskedHigh = high & PDF3D_U3D_Constants::S_QUARTER_MASK;
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++underflow;
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}
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m_underflow += underflow;
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low = low | savedBitsLow;
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high = high | savedBitsHigh;
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m_low = low;
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m_high = high;
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m_position += bitCount;
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return value;
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}
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uint8_t PDF3D_U3D_DataReader::swapBits8(uint8_t source)
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{
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// Jakub Melka: Code is public domain from here:http:
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// graphics.stanford.edu/~seander/bithacks.html#ReverseByteWith32Bits
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return ((source * 0x80200802ULL) & 0x0884422110ULL) * 0x0101010101ULL >> 32;
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}
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uint32_t PDF3D_U3D_DataReader::readBit()
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{
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uint32_t bytePosition = m_position / 8;
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if (bytePosition < uint32_t(m_data.size()))
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{
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uint32_t data = m_data[bytePosition];
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uint32_t bitPosition = m_position % 8;
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return (data >> bitPosition) & 1;
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}
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return 0;
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}
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uint32_t PDF3D_U3D_DataReader::read15Bits()
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{
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std::array<uint32_t, 15> data;
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for (uint32_t& value : data)
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{
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value = readBit();
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}
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std::reverse(data.begin(), data.end());
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uint32_t result = 0;
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for (uint32_t value : data)
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{
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result = (result << 1) | value;
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}
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return result;
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}
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bool PDF3D_U3D_ContextManager::isContextCompressed(uint32_t context) const
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{
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return (context != PDF3D_U3D_Constants::S_CONTEXT_8) && context < PDF3D_U3D_Constants::S_MAX_RANGE;
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}
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bool PDF3D_U3D_ContextManager::isContextStaticAndCompressed(uint32_t context) const
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{
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return (context != PDF3D_U3D_Constants::S_CONTEXT_8) && context < PDF3D_U3D_Constants::S_STATIC_FULL;
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}
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uint32_t PDF3D_U3D_ContextManager::getTotalSymbolFrequency(uint32_t context) const
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{
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if (isContextStaticAndCompressed(context))
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{
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if (const ContextData* contextData = getContextData(context))
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{
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return contextData->symbols.at(0).cumulativeSymbolCount;
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}
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return 1;
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}
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else if (context == PDF3D_U3D_Constants::S_CONTEXT_8)
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{
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return 256;
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}
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else
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{
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return context - PDF3D_U3D_Constants::S_STATIC_FULL;
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}
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}
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uint32_t PDF3D_U3D_ContextManager::getSymbolFrequency(uint32_t context, uint32_t symbol) const
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{
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if (isContextStaticAndCompressed(context))
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{
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if (const ContextData* contextData = getContextData(context))
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{
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auto it = contextData->symbols.find(symbol);
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if (it != contextData->symbols.cend())
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{
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return it->second.symbolCount;
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}
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}
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else if (symbol == 0)
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{
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return 1;
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}
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return 0;
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}
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return 1;
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}
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uint32_t PDF3D_U3D_ContextManager::getCumulativeSymbolFrequency(uint32_t context, uint32_t symbol) const
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{
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if (isContextStaticAndCompressed(context))
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{
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uint32_t value = 0;
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if (const ContextData* contextData = getContextData(context))
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{
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auto it = contextData->symbols.find(symbol);
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if (it != contextData->symbols.cend())
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{
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return contextData->symbols.at(0).cumulativeSymbolCount - it->second.cumulativeSymbolCount;
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}
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else
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{
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return contextData->symbols.at(0).cumulativeSymbolCount;
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}
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}
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return value;
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}
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return symbol - 1;
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}
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uint32_t PDF3D_U3D_ContextManager::getSymbolFromFrequency(uint32_t context, uint32_t symbolFrequency) const
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{
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if (isContextStaticAndCompressed(context))
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{
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if (m_contexts.count(context) &&
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symbolFrequency > 0 &&
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m_contexts.at(context).symbols.at(0).cumulativeSymbolCount >= symbolFrequency)
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{
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uint32_t value = 0;
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for (const auto& item : m_contexts.at(context).symbols)
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{
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if (getCumulativeSymbolFrequency(context, item.first) <= symbolFrequency)
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{
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value = item.first;
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}
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else
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{
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break;
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}
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}
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return value;
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}
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return 0;
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}
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return symbolFrequency + 1;
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}
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void PDF3D_U3D_ContextManager::addSymbol(uint32_t context, uint32_t symbol)
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{
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if (isContextStaticAndCompressed(context) && symbol < PDF3D_U3D_Constants::S_MAXIMUM_SYMBOL_IN_HISTOGRAM)
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{
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ContextData& contextData = m_contexts[context];
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if (contextData.symbols[0].cumulativeSymbolCount >= PDF3D_U3D_Constants::S_MAX_CUMULATIVE_SYMBOL_COUNT)
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{
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// Scale down
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uint32_t tempAccum = 0;
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for (auto it = contextData.symbols.rbegin(); it != contextData.symbols.rend(); ++it)
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{
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ContextData::Data& data = it->second;
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data.symbolCount >>= 1;
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tempAccum += data.symbolCount;
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data.cumulativeSymbolCount = tempAccum;
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}
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// Preserve initial count of 1
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ContextData::Data& initialData = contextData.symbols[0];
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++initialData.symbolCount;
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++initialData.cumulativeSymbolCount;
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}
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auto it = contextData.symbols.find(symbol);
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if (it == contextData.symbols.cend())
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{
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it = contextData.symbols.insert(std::make_pair(symbol, ContextData::Data())).first;
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if (it != contextData.symbols.cend())
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{
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it->second.cumulativeSymbolCount = std::next(it)->second.cumulativeSymbolCount;
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}
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}
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++it->second.symbolCount;
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++it->second.cumulativeSymbolCount;
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for(auto cit = contextData.symbols.begin(); cit != it; ++cit)
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{
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++cit->second.cumulativeSymbolCount;
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}
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}
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}
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const PDF3D_U3D_ContextManager::ContextData* PDF3D_U3D_ContextManager::getContextData(uint32_t context) const
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{
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auto it = m_contexts.find(context);
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if (it != m_contexts.cend())
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{
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return &it->second;
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}
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return nullptr;
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}
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} // namespace u3d
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} // namespace pdf
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