PDF4QT/PdfForQtLib/sources/pdfxreftable.h

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// Copyright (C) 2018-2019 Jakub Melka
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//
// 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 PDFXREFTABLE_H
#define PDFXREFTABLE_H
#include "pdfglobal.h"
#include "pdfobject.h"
#include <QtCore>
#include <vector>
namespace pdf
{
class PDFParsingContext;
/// Represents table of references in the PDF file. It contains
/// scanned table in the PDF file, together with information, if entry
/// is occupied, or it is free.
class PDFXRefTable
{
Q_DECLARE_TR_FUNCTIONS(pdf::PDFXRefTable)
public:
constexpr inline explicit PDFXRefTable() = default;
// Enforce default copy constructor and default move constructor
constexpr inline PDFXRefTable(const PDFXRefTable&) = default;
constexpr inline PDFXRefTable(PDFXRefTable&&) = default;
// Enforce default copy assignment operator and move assignment operator
constexpr inline PDFXRefTable& operator=(const PDFXRefTable&) = default;
constexpr inline PDFXRefTable& operator=(PDFXRefTable&&) = default;
enum class EntryType
{
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Free, ///< Entry represents a free item (no object)
Occupied, ///< Entry represents a occupied item (object)
InObjectStream ///< Entry in object stream
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};
struct Entry
{
PDFObjectReference reference;
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PDFObjectReference objectStream;
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PDFInteger offset = -1;
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PDFInteger indexInObjectStream = -1;
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EntryType type = EntryType::Free;
};
/// Tries to read reference table from the byte array. If error occurs, then exception
/// is raised. This fuction also checks redundant entries.
/// \param context Current parsing context
/// \param byteArray Input byte array (containing the PDF file)
/// \param startTableOffset Offset of first reference table
void readXRefTable(PDFParsingContext* context, const QByteArray& byteArray, PDFInteger startTableOffset);
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/// Filters only occupied entries and returns them
std::vector<Entry> getOccupiedEntries() const;
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/// Filters only object stream entries and returns them
std::vector<Entry> getObjectStreamEntries() const;
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/// Returns size of the reference table
std::size_t getSize() const { return m_entries.size(); }
/// Gets the entry for given reference. If entry for given reference is not found,
/// then free entry is returned.
const Entry& getEntry(PDFObjectReference reference) const;
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/// Returns the trailer dictionary
const PDFObject& getTrailerDictionary() const { return m_trailerDictionary; }
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private:
/// Reference table entries
std::vector<Entry> m_entries;
/// Trailer dictionary
PDFObject m_trailerDictionary;
};
} // namespace pdf
#endif // PDFXREFTABLE_H