Issue #118: First part of splitting

Pdf4QtLibCore/sources/pdfxreftable.h

@@ -0,0 +1,99 @@
+//    Copyright (C) 2018-2021 Jakub Melka
+//
+//    This file is part of PDF4QT.
+//
+//    PDF4QT 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
+//    with the written consent of the copyright owner, any later version.
+//
+//    PDF4QT 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 PDF4QT.  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:
+    inline explicit PDFXRefTable() = default;
+
+    // Enforce default copy constructor and default move constructor
+    inline PDFXRefTable(const PDFXRefTable&) = default;
+    inline PDFXRefTable(PDFXRefTable&&) = default;
+
+    // Enforce default copy assignment operator and move assignment operator
+    inline PDFXRefTable& operator=(const PDFXRefTable&) = default;
+    inline PDFXRefTable& operator=(PDFXRefTable&&) = default;
+
+    enum class EntryType
+    {
+        Free,           ///< Entry represents a free item (no object)
+        Occupied,       ///< Entry represents a occupied item (object)
+        InObjectStream  ///< Entry in object stream
+    };
+
+    struct Entry
+    {
+        PDFObjectReference reference;
+        PDFObjectReference objectStream;
+        PDFInteger offset = -1;
+        PDFInteger indexInObjectStream = -1;
+        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);
+
+    /// Filters only occupied entries and returns them
+    std::vector<Entry> getOccupiedEntries() const;
+
+    /// Filters only object stream entries and returns them
+    std::vector<Entry> getObjectStreamEntries() const;
+
+    /// 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;
+
+    /// Returns the trailer dictionary
+    const PDFObject& getTrailerDictionary() const { return m_trailerDictionary; }
+
+private:
+    /// Reference table entries
+    std::vector<Entry> m_entries;
+
+    /// Trailer dictionary
+    PDFObject m_trailerDictionary;
+};
+
+}   // namespace pdf
+
+#endif // PDFXREFTABLE_H