// Copyright {Jagger Software Limited} 2003

#ifndef IO_FILE_ITERATOR_INCLUDED
#define IO_FILE_ITERATOR_INCLUDED

#include <cstdio>
#include <iterator>

namespace io
{
    class FILE_iterator // <<concrete>>
        : public 
            ::std::iterator<::std::random_access_iterator_tag, char>
    {
    public: // types

        typedef ::std::size_t    size_type;
        typedef ::std::ptrdiff_t difference_type;

    public: // 'tors

                 FILE_iterator();
        explicit FILE_iterator(FILE *);

        // compiler generated copy c'tor ok
        // compiler generated non virtual d'tor ok

    public: // assignment

        // compiler generated copy assignment ok

    public: // primitive comparison

        int compare(const FILE_iterator &) const;

    public: // dereference

        class reference;

        reference operator*();
             char operator*() const;

    public: // subscripting

        reference operator[](size_type);
             char operator[](size_type) const;

        reference operator[](difference_type);
             char operator[](difference_type) const;

    public: // movement

        FILE_iterator & operator+=(size_type);
        FILE_iterator & operator+=(difference_type);

        FILE_iterator & operator-=(size_type);
        FILE_iterator & operator-=(difference_type);

              FILE_iterator & operator++();
        const FILE_iterator   operator++(int);

              FILE_iterator & operator--();
        const FILE_iterator   operator--(int);

        difference_type operator-(const FILE_iterator &) const;

    private: // implementation
        
        bool is_end_sentinel() const;
        bool is_at_end() const;

        difference_type distance_to_start_of_stream() const;
        difference_type distance_to_end_of_stream() const;

    private: // validation

        void check_not_end_sentinel() const;
        void check_same_stream_as(const FILE_iterator &) const;

    private: // state

        FILE * stream; 
        long current_position, end_position;

    };

    // idiomatic comparisons
    
    bool operator==(const FILE_iterator &, const FILE_iterator &);
    bool operator!=(const FILE_iterator &, const FILE_iterator &);
    bool operator< (const FILE_iterator &, const FILE_iterator &);
    bool operator> (const FILE_iterator &, const FILE_iterator &);
    bool operator<=(const FILE_iterator &, const FILE_iterator &);
    bool operator>=(const FILE_iterator &, const FILE_iterator &);
    
    
    // idiomatic movement
    
    const FILE_iterator operator+(const FILE_iterator &, 
                                  FILE_iterator::size_type);
                                        
    const FILE_iterator operator+(FILE_iterator::size_type, 
                                  const FILE_iterator &);
    
    const FILE_iterator operator+(const FILE_iterator &, 
                                  FILE_iterator::difference_type);
                                        
    const FILE_iterator operator+(FILE_iterator::difference_type, 
                                  const FILE_iterator &);
    
    const FILE_iterator operator-(const FILE_iterator &,                                         
                                  FILE_iterator::size_type);

    const FILE_iterator operator-(FILE_iterator::size_type, 
                                  const FILE_iterator &);
    
    const FILE_iterator operator-(const FILE_iterator &, 
                                  FILE_iterator::difference_type);
                                        
    const FILE_iterator operator-(FILE_iterator::difference_type, 
                                  const FILE_iterator &);
}

    
namespace io 
{
    class FILE_iterator::reference
    {
    public: // 'tor

        reference(FILE *, long);
        // compiler generated copy c'tor ok
        // compiler generated non virtual d'tor ok

        // compiler generated copy assignment ok

    public: // dereference

        void operator=(char);
        operator char() const;

    private: // state

        FILE * stream;
        long position;
        
    };
}

#endif

//-------------------------------------------------
// Example of use

#if 0

#include "io/FILE_iterator.hpp"
#include "ownership/array_deleter.hpp"
#include "ownership/scoped.hpp"
#include "ownership/fcloser.hpp"
#include <cstdio>
#include <iostream>
#include <algorithm>

using namespace ::io;
using namespace ::ownership;
using namespace ::std;

int main(int argc, char * argv[])
{
    scoped<fcloser, FILE*> stream(fopen(argv[1], "rb"));
    
    const size_t file_size = file_size(stream.get());

    scoped<array_deleter, char*> source(new char[file_size]);

    copy(FILE_iterator(stream.get()), end, source.get());

    //...    

    return 0;
}

#endif