XFA: xfa engine basics

Pdf4QtLib/sources/pdfxfaengine.h

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+//    Copyright (C) 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 PDFXFAENGINE_H
+#define PDFXFAENGINE_H
+
+#include "pdfglobal.h"
+
+#include <optional>
+#include <memory>
+
+namespace pdf
+{
+
+namespace xfa
+{
+struct XFA_InplaceTag;
+struct XFA_SharedMemoryTag;
+
+template<typename Value, struct Tag>
+class PDFXFAValueHolder
+{
+public:
+    constexpr inline bool hasValue() const { return false; }
+    constexpr const Value* getValue() const { return nullptr; }
+};
+
+template<typename Value>
+class PDFXFAValueHolder<Value, XFA_InplaceTag>
+{
+public:
+    inline constexpr PDFXFAValueHolder(std::optional<Value> value) :
+        m_value(std::move(value))
+    {
+
+    }
+
+    constexpr inline bool hasValue() const { return m_value.has_value(); }
+    constexpr const Value* getValue() const { return m_value.has_value() ? &m_value.value() : nullptr; }
+
+private:
+    std::optional<Value> m_value;
+};
+
+template<typename Value>
+class PDFXFAValueHolder<Value, XFA_SharedMemoryTag>
+{
+public:
+    inline constexpr PDFXFAValueHolder(std::optional<Value> value) :
+        m_value()
+    {
+        if (value)
+        {
+            m_value = std::make_shared(std::move(*value));
+        }
+    }
+
+    constexpr inline bool hasValue() const { return m_value; }
+    constexpr const Value* getValue() const { return m_value.get(); }
+
+private:
+    std::shared_ptr<Value> m_value;
+};
+
+template<typename Value>
+using XFA_Attribute = PDFXFAValueHolder<Value, XFA_InplaceTag>;
+
+template<typename Value>
+using XFA_Node = PDFXFAValueHolder<Value, typename Value::StorageTag>;
+
+class XFA_Measurement
+{
+public:
+    enum Type
+    {
+        in,
+        cm,
+        mm,
+        pt,
+        em,
+        percent
+    };
+
+    constexpr inline XFA_Measurement() :
+        m_value(0.0),
+        m_type(in)
+    {
+
+    }
+
+    constexpr inline XFA_Measurement(PDFReal value, Type type) :
+        m_value(value),
+        m_type(type)
+    {
+
+    }
+
+    constexpr inline XFA_Measurement(PDFReal value) :
+        m_value(value),
+        m_type(in)
+    {
+
+    }
+
+    constexpr PDFReal getValue() const { return m_value; }
+    constexpr Type getType() const { return m_type; }
+
+private:
+    PDFReal m_value;
+    Type m_type;
+};
+
+class XFA_AbstractNode
+{
+public:
+    constexpr inline XFA_AbstractNode() = default;
+    virtual ~XFA_AbstractNode();
+};
+
+}   // namespace xfa
+
+class PDFXFAEngine
+{
+public:
+    PDFXFAEngine();
+
+private:
+};
+
+/* START GENERATED CODE */
+
+/* END GENERATED CODE */
+
+}   // namespace pdf
+
+#endif // PDFXFAENGINE_H