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PDF4QT/Pdf4QtLibCore/sources/pdfnametreeloader.h
2025-04-27 12:39:06 +02:00

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// MIT License
//
// Copyright (c) 2018-2025 Jakub Melka and Contributors
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
#ifndef PDFNAMETREELOADER_H
#define PDFNAMETREELOADER_H
#include "pdfdocument.h"
#include <map>
#include <functional>
namespace pdf
{
/// This class can load a number tree into the array
template<typename Type>
class PDFNameTreeLoader
{
public:
explicit PDFNameTreeLoader() = delete;
using MappedObjects = std::map<QByteArray, Type>;
using LoadMethod = std::function<Type(const PDFObjectStorage*, const PDFObject&)>;
/// Parses the name tree and loads its items into the map. Some errors are ignored,
/// e.g. when kid is null. Objects are retrieved by \p loadMethod.
/// \param storage Object storage
/// \param root Root of the name tree
/// \param loadMethod Parsing method, which retrieves parsed object
static MappedObjects parse(const PDFObjectStorage* storage, const PDFObject& root, const LoadMethod& loadMethod)
{
MappedObjects result;
parseImpl(result, storage, root, loadMethod);
return result;
}
private:
static void parseImpl(MappedObjects& objects, const PDFObjectStorage* storage, const PDFObject& root, const LoadMethod& loadMethod)
{
if (const PDFDictionary* dictionary = storage->getDictionaryFromObject(root))
{
// Jakub Melka: First, load the objects into the map
const PDFObject& namedItems = storage->getObject(dictionary->get("Names"));
if (namedItems.isArray())
{
const PDFArray* namedItemsArray = namedItems.getArray();
const size_t count = namedItemsArray->getCount() / 2;
for (size_t i = 0; i < count; ++i)
{
const size_t numberIndex = 2 * i;
const size_t valueIndex = 2 * i + 1;
const PDFObject& name = storage->getObject(namedItemsArray->getItem(numberIndex));
if (!name.isString())
{
continue;
}
objects[name.getString()] = loadMethod(storage, namedItemsArray->getItem(valueIndex));
}
}
// Then, follow the kids
const PDFObject& kids = storage->getObject(dictionary->get("Kids"));
if (kids.isArray())
{
const PDFArray* kidsArray = kids.getArray();
const size_t count = kidsArray->getCount();
for (size_t i = 0; i < count; ++i)
{
parseImpl(objects, storage, kidsArray->getItem(i), loadMethod);
}
}
}
}
};
} // namespace pdf
#endif // PDFNAMETREELOADER_H