JsonReader.h

/*
   Copyright (C) 2015-2023 by Dr. Marc Boris Duerner
  
   This library 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 2.1 of the License, or (at your option) any later version.
   
   As a special exception, you may use this file as part of a free
   software library without restriction. Specifically, if other files
   instantiate templates or use macros or inline functions from this
   file, or you compile this file and link it with other files to
   produce an executable, this file does not by itself cause the
   resulting executable to be covered by the GNU General Public
   License. This exception does not however invalidate any other
   reasons why the executable file might be covered by the GNU Library
   General Public License.
   
   This library 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 this library; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, 
   MA 02110-1301 USA
*/
 
#ifndef PT_JSON_JSON_READER_H
#define PT_JSON_JSON_READER_H
 
#include <Pt/Json/Api.h>
#include <Pt/Json/Node.h>
#include <Pt/IOStream.h>
#include <Pt/String.h>
#include <Pt/NonCopyable.h>
 
namespace Pt {
 
namespace Json {
 
class Node;
class InputSource;
class InputIterator;
class JsonReaderImpl;

class PT_JSON_API JsonReader : private NonCopyable
{
    public:
        JsonReader();

        explicit JsonReader(std::basic_istream<Pt::Char>& is);

        ~JsonReader();

        std::basic_istream<Pt::Char>* input();

        void attach(std::basic_istream<Pt::Char>& is);

        void reset();

        void reset(std::basic_istream<Pt::Char>& is);

        void setChunkSize(std::size_t n);

        void setMaxSize(std::size_t n);

        std::size_t maxSize() const;

        std::size_t usedSize() const;

        std::size_t line() const;

        InputIterator current();

        InputIterator end() const;

        Node& get();

        Node& next();

        Node* advance();
 
    public:
        JsonReaderImpl* impl()
        { return _impl; }
 
    private:
        JsonReaderImpl* _impl;
};

class InputIterator
{
    public:
        InputIterator()
        : _stream(0)
        , _node(0)
        { }

        explicit InputIterator(JsonReader& xis)
        : _stream(&xis)
        , _node(0)
        { _node = &_stream->get(); }

        InputIterator(const InputIterator& it)
        : _stream(it._stream), _node(it._node)
        { }

        ~InputIterator()
        { }

        InputIterator& operator=(const InputIterator& it)
        {
            _stream = it._stream;
            _node = it._node;
            return *this;
        }

        inline Node& operator*()
        { return *_node; }

        inline Node* operator->()
        { return _node; }

        InputIterator& operator++()
        {
            if(_node->type() == Node::EndDocument)
                _node = 0;
            else
                _node = &_stream->next();
 
            return *this;
        }

        inline bool operator==(const InputIterator& it) const
        { return _node == it._node; }

        inline bool operator!=(const InputIterator& it) const
        { return _node != it._node; }
 
    private:
        JsonReader* _stream;
        Node*       _node;
};
 
 
inline InputIterator JsonReader::current()
{
    return InputIterator(*this); 
}
 
 
inline InputIterator JsonReader::end() const
{
    return InputIterator(); 
}
 
} // namespace
 
} // namespace
 
#endif // include guard