Add PDF writer.

src/publishing/pdf/PdfXRefTable.h

@@ -0,0 +1,37 @@
+#pragma once
+
+#include <string>
+#include <memory>
+#include <vector>
+
+struct XRefRecord
+{
+    unsigned mOffsetBytes{0};
+    unsigned mGenerationNumber{0};
+    bool mIsFree{false};
+};
+
+struct TableSubSection
+{
+    unsigned mStartIndex{0};
+    std::vector<XRefRecord> mRecords;
+};
+
+class PdfXRefTable
+{
+public:
+
+    PdfXRefTable();
+
+    std::string ToString();
+
+    unsigned GetNextOffset();
+
+    void AddRecord(unsigned numBytes, unsigned generation, unsigned isFree);
+
+    unsigned GetNumEntries();
+
+private:
+    unsigned mLastAddedBytes{0};
+    std::vector<TableSubSection> mSections;
+};