PDF4QT/PdfForQtLib/sources/pdfdocumentreader.h
2018-11-25 14:48:08 +01:00

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3.8 KiB
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// Copyright (C) 2018 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 PDFDOCUMENTREADER_H
#define PDFDOCUMENTREADER_H
#include "pdfglobal.h"
#include "pdfdocument.h"
#include <QtCore>
#include <QIODevice>
namespace pdf
{
/// This class is a reader of PDF document from various devices (file, io device,
/// byte buffer). This class doesn't throw exceptions, to check errors, use
/// appropriate functions.
class PDFFORQTLIBSHARED_EXPORT PDFDocumentReader
{
Q_DECLARE_TR_FUNCTIONS(pdf::PDFDocumentReader)
public:
explicit PDFDocumentReader();
constexpr inline PDFDocumentReader(const PDFDocumentReader&) = delete;
constexpr inline PDFDocumentReader(PDFDocumentReader&&) = delete;
constexpr inline PDFDocumentReader& operator=(const PDFDocumentReader&) = delete;
constexpr inline PDFDocumentReader& operator=(PDFDocumentReader&&) = delete;
/// Reads a PDF document from the specified file. If file doesn't exist,
/// cannot be opened or contain invalid pdf, empty PDF file is returned.
/// No exception is thrown.
PDFDocument readFromFile(const QString& fileName);
/// Reads a PDF document from the specified device. If device is not opened
/// for reading, then function tries it to open for reading. If it is opened,
/// but not for reading, empty PDF document is returned. This also occurs
/// when incorrect PDF is read. No exception is thrown.
PDFDocument readFromDevice(QIODevice* device);
/// Reads a PDF document from the specified buffer (byte array). If incorrect
/// PDF is read, then empty PDF document is returned. No exception is thrown.
PDFDocument readFromBuffer(const QByteArray& buffer);
/// Returns true, if document was successfully read from device
bool isSuccessfull() const { return m_successfull; }
/// Returns error message, if document reading was unsuccessfull
const QString& getErrorMessage() const { return m_errorMessage; }
private:
static constexpr const int FIND_NOT_FOUND_RESULT = -1;
/// Resets the internal state and prepares it for new reading cycle
void reset();
/// Find a last string in the byte array, scan only \p limit bytes. If string
/// is not found, then FIND_NOT_FOUND_RESULT is returned, if it is found, then
/// it position from the beginning of byte array is returned.
/// \param what String to be found
/// \param byteArray Byte array to be scanned from the end
/// \param limit Scan up to this value bytes from the end
/// \returns Position of string, or FIND_NOT_FOUND_RESULT
int findFromEnd(const char* what, const QByteArray& byteArray, int limit);
/// Mutex for access to variables of this reader from more threads
/// (providing thread safety)
QMutex m_mutex;
/// This bool flag is set, if pdf document was successfully read from the device
std::atomic<bool> m_successfull;
/// In case if error occurs, it is stored here
QString m_errorMessage;
/// Version of the scanned file
PDFVersion m_version;
};
} // namespace pdf
#endif // PDFDOCUMENTREADER_H