mirror of https://github.com/JakubMelka/PDF4QT.git
116 lines
3.4 KiB
C++
116 lines
3.4 KiB
C++
// Copyright (C) 2019 Jakub Melka
|
|
//
|
|
// This file is part of PdfForQt.
|
|
//
|
|
// PdfForQt is free software: you can redistribute it and/or modify
|
|
// it under the terms of the GNU Lesser General Public License as published by
|
|
// the Free Software Foundation, either version 3 of the License, or
|
|
// (at your option) any later version.
|
|
//
|
|
// PdfForQt is distributed in the hope that it will be useful,
|
|
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
// GNU Lesser General Public License for more details.
|
|
//
|
|
// You should have received a copy of the GNU Lesser General Public License
|
|
// along with PDFForQt. If not, see <https://www.gnu.org/licenses/>.
|
|
|
|
|
|
#ifndef PDFUTILS_H
|
|
#define PDFUTILS_H
|
|
|
|
#include "pdfglobal.h"
|
|
|
|
#include <QByteArray>
|
|
#include <QDataStream>
|
|
|
|
namespace pdf
|
|
{
|
|
|
|
/// Class for easy storing of cached item. This class is not thread safe,
|
|
/// and for this reason, access function are not constant (they can modify the
|
|
/// object).
|
|
template<typename T>
|
|
class PDFCachedItem
|
|
{
|
|
public:
|
|
explicit inline PDFCachedItem() :
|
|
m_dirty(true),
|
|
m_object()
|
|
{
|
|
|
|
}
|
|
|
|
/// Returns the cached object. If object is dirty, then cached object is refreshed.
|
|
/// \param holder Holder object, which owns the cached item
|
|
/// \param function Refresh function
|
|
template<typename H>
|
|
inline const T& get(const H* holder, T(H::* function)(void) const)
|
|
{
|
|
if (m_dirty)
|
|
{
|
|
m_object = (holder->*function)();
|
|
m_dirty = false;
|
|
}
|
|
|
|
return m_object;
|
|
}
|
|
|
|
/// Invalidates the cached item, so it must be refreshed from the cache next time,
|
|
/// if it is accessed.
|
|
inline void dirty()
|
|
{
|
|
m_dirty = true;
|
|
m_object = T();
|
|
}
|
|
|
|
private:
|
|
bool m_dirty;
|
|
T m_object;
|
|
};
|
|
|
|
/// Bit-reader, which can read n-bit unsigned integers from the stream.
|
|
/// Number of bits can be set in the constructor and is constant.
|
|
class PDFBitReader
|
|
{
|
|
public:
|
|
using Value = uint64_t;
|
|
|
|
explicit PDFBitReader(QDataStream* stream, Value bitsPerComponent);
|
|
|
|
/// Returns maximal value of n-bit unsigned integer.
|
|
Value max() const { return m_maximalValue; }
|
|
|
|
/// Reads single n-bit value from the stream. If stream hasn't enough data,
|
|
/// then exception is thrown.
|
|
Value read();
|
|
|
|
/// Seeks the desired position in the data stream. If position can't be seeked,
|
|
/// then exception is thrown.
|
|
void seek(qint64 position);
|
|
|
|
private:
|
|
QDataStream* m_stream;
|
|
|
|
const Value m_bitsPerComponent;
|
|
const Value m_maximalValue;
|
|
|
|
Value m_buffer;
|
|
Value m_bitsInBuffer;
|
|
};
|
|
|
|
/// Performs linear mapping of value x in interval [x_min, x_max] to the interval [y_min, y_max].
|
|
/// \param x Value to be linearly remapped from interval [x_min, x_max] to the interval [y_min, y_max].
|
|
/// \param x_min Start of the input interval
|
|
/// \param x_max End of the input interval
|
|
/// \param y_min Start of the output interval
|
|
/// \param y_max End of the output interval
|
|
static inline constexpr PDFReal interpolate(PDFReal x, PDFReal x_min, PDFReal x_max, PDFReal y_min, PDFReal y_max)
|
|
{
|
|
return y_min + (x - x_min) * (y_max - y_min) / (x_max - x_min);
|
|
}
|
|
|
|
} // namespace pdf
|
|
|
|
#endif // PDFUTILS_H
|