Document builder basics

PdfForQtLib/PdfForQtLib.pro

@@ -42,6 +42,7 @@ SOURCES += \
     sources/pdfccittfaxdecoder.cpp \
     sources/pdfcms.cpp \
     sources/pdfcompiler.cpp \
+    sources/pdfdocumentbuilder.cpp \
     sources/pdfexecutionpolicy.cpp \
     sources/pdffile.cpp \
     sources/pdfitemmodels.cpp \
@@ -87,6 +88,7 @@ HEADERS += \
     sources/pdfccittfaxdecoder.h \
     sources/pdfcms.h \
     sources/pdfcompiler.h \
+    sources/pdfdocumentbuilder.h \
     sources/pdfdocumentdrawinterface.h \
     sources/pdfexecutionpolicy.h \
     sources/pdffile.h \

PdfForQtLib/sources/pdfdocumentbuilder.cpp

@@ -0,0 +1,130 @@
+//    Copyright (C) 2020 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/>.
+
+#include "pdfdocumentbuilder.h"
+
+namespace pdf
+{
+
+void PDFObjectFactory::beginArray()
+{
+    m_items.emplace_back(ItemType::Array, PDFArray());
+}
+
+void PDFObjectFactory::endArray()
+{
+    Item topItem = qMove(m_items.back());
+    Q_ASSERT(topItem.type == ItemType::Array);
+    m_items.pop_back();
+    addObject(PDFObject::createArray(std::make_shared<PDFArray>(qMove(std::get<PDFArray>(topItem.object)))));
+}
+
+void PDFObjectFactory::beginDictionary()
+{
+    m_items.emplace_back(ItemType::Dictionary, PDFDictionary());
+}
+
+void PDFObjectFactory::endDictionary()
+{
+    Item topItem = qMove(m_items.back());
+    Q_ASSERT(topItem.type == ItemType::Dictionary);
+    m_items.pop_back();
+    addObject(PDFObject::createDictionary(std::make_shared<PDFDictionary>(qMove(std::get<PDFDictionary>(topItem.object)))));
+}
+
+void PDFObjectFactory::beginDictionaryItem(const QByteArray& name)
+{
+    m_items.emplace_back(ItemType::DictionaryItem, name, PDFObject());
+}
+
+void PDFObjectFactory::endDictionaryItem()
+{
+    Item topItem = qMove(m_items.back());
+    Q_ASSERT(topItem.type == ItemType::DictionaryItem);
+    m_items.pop_back();
+
+    Item& dictionaryItem = m_items.back();
+    Q_ASSERT(dictionaryItem.type == ItemType::Dictionary);
+    std::get<PDFDictionary>(dictionaryItem.object).addEntry(qMove(topItem.itemName), qMove(std::get<PDFObject>(topItem.object)));
+}
+
+void PDFObjectFactory::addObject(PDFObject object)
+{
+    if (m_items.empty())
+    {
+        m_items.emplace_back(ItemType::Object, qMove(object));
+        return;
+    }
+
+    Item& topItem = m_items.back();
+    switch (topItem.type)
+    {
+        case ItemType::Object:
+            // Just override the object
+            topItem.object = qMove(object);
+            break;
+
+        case ItemType::Dictionary:
+            // Do not do anything - we are inside dictionary
+            break;
+
+        case ItemType::DictionaryItem:
+            // Add item to dictionary item
+            topItem.object = qMove(object);
+            break;
+
+        case ItemType::Array:
+            std::get<PDFArray>(topItem.object).appendItem(qMove(object));
+            break;
+
+        default:
+            Q_ASSERT(false);
+            break;
+    }
+}
+
+PDFObjectFactory& PDFObjectFactory::operator<<(std::nullptr_t)
+{
+    addObject(PDFObject::createNull());
+    return *this;
+}
+
+PDFObjectFactory& PDFObjectFactory::operator<<(bool value)
+{
+    addObject(PDFObject::createBool(value));
+    return *this;
+}
+
+PDFObjectFactory& PDFObjectFactory::operator<<(PDFReal value)
+{
+    addObject(PDFObject::createReal(value));
+    return *this;
+}
+
+PDFObjectFactory& PDFObjectFactory::operator<<(PDFInteger value)
+{
+    addObject(PDFObject::createInteger(value));
+    return *this;
+}
+
+PDFObjectFactory& PDFObjectFactory::operator<<(PDFObjectReference value)
+{
+    addObject(PDFObject::createReference(value));
+    return *this;
+}
+
+}   // namespace pdf

PdfForQtLib/sources/pdfdocumentbuilder.h

@@ -0,0 +1,119 @@
+//    Copyright (C) 2020 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 PDFDOCUMENTBUILDER_H
+#define PDFDOCUMENTBUILDER_H
+
+#include "pdfobject.h"
+
+namespace pdf
+{
+
+/// Factory for creating various PDF objects, such as simple objects,
+/// dictionaries, arrays etc.
+class PDFObjectFactory
+{
+public:
+    inline explicit PDFObjectFactory() = default;
+
+    void beginArray();
+    void endArray();
+
+    void beginDictionary();
+    void endDictionary();
+
+    void beginDictionaryItem(const QByteArray& name);
+    void endDictionaryItem();
+
+    PDFObjectFactory& operator<<(std::nullptr_t);
+    PDFObjectFactory& operator<<(bool value);
+    PDFObjectFactory& operator<<(PDFReal value);
+    PDFObjectFactory& operator<<(PDFInteger value);
+    PDFObjectFactory& operator<<(PDFObjectReference value);
+
+    /// Treat containers - write them as array
+    template<typename Container, typename ValueType = decltype(*std::begin(std::declval<Container>()))>
+    PDFObjectFactory& operator<<(Container container)
+    {
+        beginArray();
+
+        auto it = std::begin(container);
+        auto itEnd = std::end(container);
+        for (; it != itEnd; ++it)
+        {
+            *this << *it;
+        }
+
+        endArray();
+
+        return *this;
+    }
+
+private:
+    void addObject(PDFObject object);
+
+    enum class ItemType
+    {
+        Object,
+        Dictionary,
+        DictionaryItem,
+        Array
+    };
+
+    /// What is stored in this structure, depends on the type.
+    /// If type is 'Object', then single simple object is in object,
+    /// if type is dictionary, then PDFDictionary is stored in object,
+    /// if type is dictionary item, then object and item name is stored
+    /// in the data, if item is array, then array is stored in the data.
+    struct Item
+    {
+        inline Item() = default;
+
+        template<typename T>
+        inline Item(ItemType type, T&& data) :
+            type(type),
+            object(qMove(data))
+        {
+
+        }
+
+        template<typename T>
+        inline Item(ItemType type, const QByteArray& itemName, T&& data) :
+            type(type),
+            itemName(qMove(itemName)),
+            object(qMove(data))
+        {
+
+        }
+
+        ItemType type = ItemType::Object;
+        QByteArray itemName;
+        std::variant<PDFObject, PDFArray, PDFDictionary> object;
+    };
+
+    std::vector<Item> m_items;
+};
+
+class PDFDocumentBuilder
+{
+public:
+    PDFDocumentBuilder();
+};
+
+}   // namespace pdf
+
+#endif // PDFDOCUMENTBUILDER_H

PdfForQtLib/sources/pdfobject.h

@@ -55,7 +55,7 @@ public:
 class PDFFORQTLIBSHARED_EXPORT PDFObject
 {
 public:
-    enum class Type
+    enum class Type : uint8_t
     {
         // Simple PDF objects
         Null,