//C++ header - Open Scene Graph - Copyright (C) 1998-2001 Robert Osfield
//Distributed under the terms of the GNU Library General Public License (LGPL)
//as published by the Free Software Foundation.

#ifndef OSGDB_FIELDREADERITERATOR
#define OSGDB_FIELDREADERITERATOR 1

#include <osgDB/Field>
#include <osgDB/FieldReader>

namespace osgDB {


class OSGDB_EXPORT FieldReaderIterator
{
    public:

        enum {
            MINIMUM_FIELD_READER_QUEUE_SIZE = 10
        };

        FieldReaderIterator();
        FieldReaderIterator(const FieldReaderIterator& ic);
        virtual ~FieldReaderIterator();

        FieldReaderIterator& operator = (const FieldReaderIterator& ic);

        void attach(std::istream* input);
        void detach();

        virtual bool eof() const;

        FieldReader& getFieldReader() { return _reader; }

        void insert(int pos,Field* field);
        void insert(int pos,const char* str);

        Field& operator [] (int pos);
        Field& field (int pos);

        FieldReaderIterator& operator ++ ();
        FieldReaderIterator& operator += (int no);

        /** increments the iterator of the next simple field or
          * whole block if the current field[0] is an open bracket */
        void advanceOverCurrentFieldOrBlock();
        void advanceToEndOfCurrentBlock();
        void advanceToEndOfBlock(int noNestBrackets);

        bool matchSequence(const char* str);

    private:

        void _init();
        void _free();
        void _copy(const FieldReaderIterator& ic);

        FieldReader _reader;

        Field _blank;

        Field* _previousField;

        Field** _fieldQueue;
        int _fieldQueueSize;
        int _fieldQueueCapacity;

};

}

#endif                                            // __OSGDB_FIELD_READER_QUEUE_H