mirror of https://github.com/JakubMelka/PDF4QT.git
136 lines
3.9 KiB
C++
136 lines
3.9 KiB
C++
// Copyright (C) 2019 Jakub Melka
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//
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// This file is part of PdfForQt.
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//
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// PdfForQt 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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// (at your option) any later version.
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//
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// PdfForQt 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 PDFForQt. If not, see <https://www.gnu.org/licenses/>.
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#ifndef PDFUTILS_H
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#define PDFUTILS_H
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#include "pdfglobal.h"
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#include <QByteArray>
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#include <QDataStream>
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#include <vector>
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namespace pdf
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{
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/// Class for easy storing of cached item. This class is not thread safe,
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/// and for this reason, access function are not constant (they can modify the
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/// object).
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template<typename T>
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class PDFCachedItem
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{
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public:
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explicit inline PDFCachedItem() :
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m_dirty(true),
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m_object()
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{
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}
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/// Returns the cached object. If object is dirty, then cached object is refreshed.
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/// \param holder Holder object, which owns the cached item
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/// \param function Refresh function
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template<typename H>
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inline const T& get(const H* holder, T(H::* function)(void) const)
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{
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if (m_dirty)
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{
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m_object = (holder->*function)();
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m_dirty = false;
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}
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return m_object;
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}
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/// Invalidates the cached item, so it must be refreshed from the cache next time,
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/// if it is accessed.
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inline void dirty()
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{
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m_dirty = true;
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m_object = T();
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}
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private:
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bool m_dirty;
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T m_object;
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};
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/// Bit-reader, which can read n-bit unsigned integers from the stream.
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/// Number of bits can be set in the constructor and is constant.
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class PDFBitReader
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{
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public:
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using Value = uint64_t;
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explicit PDFBitReader(QDataStream* stream, Value bitsPerComponent);
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/// Returns maximal value of n-bit unsigned integer.
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Value max() const { return m_maximalValue; }
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/// Reads single n-bit value from the stream. If stream hasn't enough data,
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/// then exception is thrown.
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Value read();
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/// Seeks the desired position in the data stream. If position can't be seeked,
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/// then exception is thrown.
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void seek(qint64 position);
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private:
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QDataStream* m_stream;
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const Value m_bitsPerComponent;
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const Value m_maximalValue;
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Value m_buffer;
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Value m_bitsInBuffer;
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};
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/// Performs linear mapping of value x in interval [x_min, x_max] to the interval [y_min, y_max].
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/// \param x Value to be linearly remapped from interval [x_min, x_max] to the interval [y_min, y_max].
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/// \param x_min Start of the input interval
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/// \param x_max End of the input interval
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/// \param y_min Start of the output interval
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/// \param y_max End of the output interval
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static inline constexpr PDFReal interpolate(PDFReal x, PDFReal x_min, PDFReal x_max, PDFReal y_min, PDFReal y_max)
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{
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return y_min + (x - x_min) * (y_max - y_min) / (x_max - x_min);
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}
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inline
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std::vector<uint8_t> convertByteArrayToVector(const QByteArray& data)
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{
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return std::vector<uint8_t>(reinterpret_cast<const uint8_t*>(data.constData()), reinterpret_cast<const uint8_t*>(data.constData()) + data.size());
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}
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inline
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const unsigned char* convertByteArrayToUcharPtr(const QByteArray& data)
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{
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return reinterpret_cast<const unsigned char*>(data.constData());
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}
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inline
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unsigned char* convertByteArrayToUcharPtr(QByteArray& data)
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{
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return reinterpret_cast<unsigned char*>(data.data());
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}
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} // namespace pdf
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#endif // PDFUTILS_H
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