/*
 *
 * Copyright (c) 1994
 * Hewlett-Packard Company
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Hewlett-Packard Company makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 *
 *
 * Copyright (c) 1996
 * Silicon Graphics Computer Systems, Inc.
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Silicon Graphics makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 */

#ifndef __SGI_STL_ITERATOR_H
#define __SGI_STL_ITERATOR_H

#include <stddef.h>
#include <iostream.h>
#include <function.h>

struct input_iterator_tag {};
struct output_iterator_tag {};
struct forward_iterator_tag {};
struct bidirectional_iterator_tag {};
struct random_access_iterator_tag {};

template <class T, class Distance> struct input_iterator {
  typedef input_iterator_tag iterator_category;
  typedef T                  value_type;
  typedef Distance           difference_type;
  typedef T*                 pointer;
  typedef T&                 reference;
};

struct output_iterator {
  typedef output_iterator_tag iterator_category;
};

template <class T, class Distance> struct forward_iterator {
  typedef forward_iterator_tag iterator_category;
  typedef T                    value_type;
  typedef Distance             difference_type;
  typedef T*                   pointer;
  typedef T&                   reference;
};


template <class T, class Distance> struct bidirectional_iterator {
  typedef bidirectional_iterator_tag iterator_category;
  typedef T                          value_type;
  typedef Distance                   difference_type;
  typedef T*                         pointer;
  typedef T&                         reference;
};

template <class T, class Distance> struct random_access_iterator {
  typedef random_access_iterator_tag iterator_category;
  typedef T                          value_type;
  typedef Distance                   difference_type;
  typedef T*                         pointer;
  typedef T&                         reference;
};

#if 0
template <class Category, class T, class Distance = ptrdiff_t,
          class Pointer = T*, class Reference = T&>
struct iterator {
  typedef Category  iterator_category;
  typedef T         value_type;
  typedef Distance  difference_type;
  typedef Pointer   pointer;
  typedef Reference reference;
};
#endif

#ifdef __STL_CLASS_PARTIAL_SPECIALIZATION

template <class Iterator>
struct iterator_traits {
  typedef typename Iterator::iterator_category iterator_category;
  typedef typename Iterator::value_type        value_type;
  typedef typename Iterator::difference_type   difference_type;
  typedef typename Iterator::pointer           pointer;
  typedef typename Iterator::reference         reference;
};

template <class T>
struct iterator_traits<T*> {
  typedef random_access_iterator_tag iterator_category;
  typedef T                          value_type;
  typedef ptrdiff_t                  difference_type;
  typedef T*                         pointer;
  typedef T&                         reference;
};

#endif /* __STL_CLASS_PARTIAL_SPECIALIZATION */

template <class T, class Distance> 
inline input_iterator_tag 
iterator_category(const input_iterator<T, Distance>&) {
    return input_iterator_tag();
}

inline output_iterator_tag iterator_category(const output_iterator&) {
    return output_iterator_tag();
}

template <class T, class Distance> 
inline forward_iterator_tag
iterator_category(const forward_iterator<T, Distance>&) {
    return forward_iterator_tag();
}

template <class T, class Distance> 
inline bidirectional_iterator_tag
iterator_category(const bidirectional_iterator<T, Distance>&) {
    return bidirectional_iterator_tag();
}

template <class T, class Distance> 
inline random_access_iterator_tag
iterator_category(const random_access_iterator<T, Distance>&) {
    return random_access_iterator_tag();
}

template <class T>
inline random_access_iterator_tag iterator_category(const T*) {
    return random_access_iterator_tag();
}

template <class T, class Distance> 
inline T* value_type(const input_iterator<T, Distance>&) {
    return (T*)(0); 
}

template <class T, class Distance> 
inline T* value_type(const forward_iterator<T, Distance>&) {
    return (T*)(0);
}

template <class T, class Distance> 
inline T* value_type(const bidirectional_iterator<T, Distance>&) {
    return (T*)(0);
}

template <class T, class Distance> 
inline T* value_type(const random_access_iterator<T, Distance>&) {
    return (T*)(0);
}

template <class T>
inline T* value_type(const T*) { return (T*)(0); }

template <class T, class Distance> 
inline Distance* distance_type(const input_iterator<T, Distance>&) {
    return (Distance*)(0);
}

template <class T, class Distance> 
inline Distance* distance_type(const forward_iterator<T, Distance>&) {
    return (Distance*)(0);
}

template <class T, class Distance> 
inline Distance* 
distance_type(const bidirectional_iterator<T, Distance>&) {
    return (Distance*)(0);
}

template <class T, class Distance> 
inline Distance* 
distance_type(const random_access_iterator<T, Distance>&) {
    return (Distance*)(0);
}

template <class T>
inline ptrdiff_t* distance_type(const T*) { return (ptrdiff_t*)(0); }

template <class Container>
class back_insert_iterator {
protected:
    Container* container;
public:
    typedef output_iterator_tag iterator_category;

    explicit back_insert_iterator(Container& x) : container(&x) {}
    back_insert_iterator<Container>&
    operator=(const typename Container::value_type& value) { 
        container->push_back(value);
        return *this;
    }
    back_insert_iterator<Container>& operator*() { return *this; }
    back_insert_iterator<Container>& operator++() { return *this; }
    back_insert_iterator<Container>& operator++(int) { return *this; }
};

template <class Container>
inline output_iterator_tag
iterator_category(const back_insert_iterator<Container>&)
{
  return output_iterator_tag();
}

template <class Container>
inline back_insert_iterator<Container> back_inserter(Container& x) {
  return back_insert_iterator<Container>(x);
}

template <class Container>
class front_insert_iterator {
protected:
    Container* container;
public:
    typedef output_iterator_tag iterator_category;

    explicit front_insert_iterator(Container& x) : container(&x) {}
    front_insert_iterator<Container>&
    operator=(const typename Container::value_type& value) { 
        container->push_front(value);
        return *this;
    }
    front_insert_iterator<Container>& operator*() { return *this; }
    front_insert_iterator<Container>& operator++() { return *this; }
    front_insert_iterator<Container>& operator++(int) { return *this; }
};

template <class Container>
inline output_iterator_tag
iterator_category(const front_insert_iterator<Container>&)
{
  return output_iterator_tag();
}

template <class Container>
inline front_insert_iterator<Container> front_inserter(Container& x) {
  return front_insert_iterator<Container>(x);
}

template <class Container>
class insert_iterator {
protected:
    Container* container;
    typename Container::iterator iter;
public:
    typedef output_iterator_tag iterator_category;

    insert_iterator(Container& x, typename Container::iterator i) 
        : container(&x), iter(i) {}
    insert_iterator<Container>&
    operator=(const typename Container::value_type& value) { 
        iter = container->insert(iter, value);
        ++iter;
        return *this;
    }
    insert_iterator<Container>& operator*() { return *this; }
    insert_iterator<Container>& operator++() { return *this; }
    insert_iterator<Container>& operator++(int) { return *this; }
};

template <class Container>
inline output_iterator_tag
iterator_category(const insert_iterator<Container>&)
{
  return output_iterator_tag();
}

template <class Container, class Iterator>
inline insert_iterator<Container> inserter(Container& x, Iterator i) {
  typedef typename Container::iterator iter;
  return insert_iterator<Container>(x, iter(i));
}

#ifndef __STL_LIMITED_DEFAULT_TEMPLATES
template <class BidirectionalIterator, class T, class Reference = T&, 
          class Distance = ptrdiff_t> 
#else
template <class BidirectionalIterator, class T, class Reference, 
          class Distance> 
#endif
class reverse_bidirectional_iterator {
    typedef reverse_bidirectional_iterator<BidirectionalIterator, T, Reference,
                                           Distance> self;
    friend bool operator==(const self& x, const self& y);
protected:
    BidirectionalIterator current;
public:
    typedef bidirectional_iterator_tag iterator_category;
    typedef T                          value_type;
    typedef Distance                   difference_type;
    typedef T*                         pointer;
    typedef Reference                  reference;

    reverse_bidirectional_iterator() {}
    explicit reverse_bidirectional_iterator(BidirectionalIterator x)
      : current(x) {}
    BidirectionalIterator base() { return current; }
    Reference operator*() const {
        BidirectionalIterator tmp = current;
        return *--tmp;
    }
    self& operator++() {
        --current;
        return *this;
    }
    self operator++(int) {
        self tmp = *this;
        --current;
        return tmp;
    }
    self& operator--() {
        ++current;
        return *this;
    }
    self operator--(int) {
        self tmp = *this;
        ++current;
        return tmp;
    }
};


template <class BidirectionalIterator, class T, class Reference, 
          class Distance>
inline bidirectional_iterator_tag
iterator_category(const reverse_bidirectional_iterator<BidirectionalIterator,
                                                       T,
                                                       Reference, Distance>&) {
  return bidirectional_iterator_tag();
}

template <class BidirectionalIterator, class T, class Reference, 
          class Distance>
inline T*
value_type(const reverse_bidirectional_iterator<BidirectionalIterator, T,
                                               Reference, Distance>&) {
  return (T*) 0;
}

template <class BidirectionalIterator, class T, class Reference, 
          class Distance>
inline Distance*
distance_type(const reverse_bidirectional_iterator<BidirectionalIterator, T,
                                                  Reference, Distance>&) {
  return (Distance*) 0;
}

template <class BidirectionalIterator, class T, class Reference,
          class Distance>
inline bool operator==(
    const reverse_bidirectional_iterator<BidirectionalIterator, T, Reference,
                                         Distance>& x, 
    const reverse_bidirectional_iterator<BidirectionalIterator, T, Reference,
                                         Distance>& y) {
    return x.current == y.current;
}

#ifndef __STL_LIMITED_DEFAULT_TEMPLATES
template <class RandomAccessIterator, class T, class Reference = T&,
          class Distance = ptrdiff_t> 
#else
template <class RandomAccessIterator, class T, class Reference,
          class Distance> 
#endif
class reverse_iterator {
    typedef reverse_iterator<RandomAccessIterator, T, Reference, Distance>
        self;
    friend bool operator==(const self& x, const self& y);
    friend bool operator<(const self& x, const self& y);
    friend Distance operator-(const self& x, const self& y);
    friend self operator+(Distance n, const self& x);
protected:
    RandomAccessIterator current;
public:
    typedef random_access_iterator_tag iterator_category;
    typedef T                          value_type;
    typedef Distance                   difference_type;
    typedef T*                         pointer;
    typedef Reference                  reference;

    reverse_iterator() {}
    explicit reverse_iterator(RandomAccessIterator x) : current(x) {}
    RandomAccessIterator base() { return current; }
    Reference operator*() const { return *(current - 1); }
    self& operator++() {
        --current;
        return *this;
    }
    self operator++(int) {
        self tmp = *this;
        --current;
        return tmp;
    }
    self& operator--() {
        ++current;
        return *this;
    }
    self operator--(int) {
        self tmp = *this;
        ++current;
        return tmp;
    }
    self operator+(Distance n) const {
        return self(current - n);
    }
    self& operator+=(Distance n) {
        current -= n;
        return *this;
    }
    self operator-(Distance n) const {
        return self(current + n);
    }
    self& operator-=(Distance n) {
        current += n;
        return *this;
    }
    Reference operator[](Distance n) { return *(*this + n); }
};

template <class RandomAccessIterator, class T, class Reference, class Distance>
inline random_access_iterator_tag
iterator_category(const reverse_iterator<RandomAccessIterator, T,
                                         Reference, Distance>&) {
  return random_access_iterator_tag();
}

template <class RandomAccessIterator, class T, class Reference, class Distance>
inline T* value_type(const reverse_iterator<RandomAccessIterator, T,
                                            Reference, Distance>&) {
  return (T*) 0;
}

template <class RandomAccessIterator, class T, class Reference, class Distance>
inline Distance* distance_type(const reverse_iterator<RandomAccessIterator, T,
                                                      Reference, Distance>&) {
  return (Distance*) 0;
}


template <class RandomAccessIterator, class T, class Reference, class Distance>
inline bool operator==(const reverse_iterator<RandomAccessIterator, T,
                                              Reference, Distance>& x, 
                       const reverse_iterator<RandomAccessIterator, T,
                                              Reference, Distance>& y) {
    return x.current == y.current;
}

template <class RandomAccessIterator, class T, class Reference, class Distance>
inline bool operator<(const reverse_iterator<RandomAccessIterator, T,
                                             Reference, Distance>& x, 
                      const reverse_iterator<RandomAccessIterator, T,
                                             Reference, Distance>& y) {
    return y.current < x.current;
}

template <class RandomAccessIterator, class T, class Reference, class Distance>
inline Distance operator-(const reverse_iterator<RandomAccessIterator, T,
                                                 Reference, Distance>& x, 
                          const reverse_iterator<RandomAccessIterator, T,
                                                 Reference, Distance>& y) {
    return y.current - x.current;
}

template <class RandomAccessIterator, class T, class Reference, class Distance>
inline reverse_iterator<RandomAccessIterator, T, Reference, Distance> 
operator+(Distance n,
          const reverse_iterator<RandomAccessIterator, T, Reference,
                                 Distance>& x) {
    return reverse_iterator<RandomAccessIterator, T, Reference, Distance>
        (x.current - n);
}


template <class ForwardIterator, class T>
class raw_storage_iterator {
protected:
    ForwardIterator iter;
public:
    typedef output_iterator_tag iterator_category;

    explicit raw_storage_iterator(ForwardIterator x) : iter(x) {}
    raw_storage_iterator<ForwardIterator, T>& operator*() { return *this; }
    raw_storage_iterator<ForwardIterator, T>& operator=(const T& element) {
        construct(&*iter, element);
        return *this;
    }        
    raw_storage_iterator<ForwardIterator, T>& operator++() {
        ++iter;
        return *this;
    }
    raw_storage_iterator<ForwardIterator, T> operator++(int) {
        raw_storage_iterator<ForwardIterator, T> tmp = *this;
        ++iter;
        return tmp;
    }
};

template <class ForwardIterator, class T>
inline output_iterator_tag
iterator_category(const raw_storage_iterator<ForwardIterator, T>&)
{
  return output_iterator_tag();
}

template <class T, class Distance = ptrdiff_t> 
class istream_iterator {
friend bool operator==(const istream_iterator<T, Distance>& x,
                       const istream_iterator<T, Distance>& y);
protected:
    istream* stream;
    T value;
    bool end_marker;
    void read() {
        end_marker = (*stream) ? true : false;
        if (end_marker) *stream >> value;
        end_marker = (*stream) ? true : false;
    }
public:
    typedef input_iterator_tag iterator_category;
    typedef T                  value_type;
    typedef Distance           difference_type;
    typedef T*                 pointer;
    typedef T&                 reference;

    istream_iterator() : stream(&cin), end_marker(false) {}
    istream_iterator(istream& s) : stream(&s) { read(); }
    const T& operator*() const { return value; }
    istream_iterator<T, Distance>& operator++() { 
        read(); 
        return *this;
    }
    istream_iterator<T, Distance> operator++(int)  {
        istream_iterator<T, Distance> tmp = *this;
        read();
        return tmp;
    }
};

template <class T, class Distance>
inline input_iterator_tag 
iterator_category(const istream_iterator<T, Distance>&) {
  return input_iterator_tag();
}

template <class T, class Distance>
inline T* value_type(const istream_iterator<T, Distance>&) { return (T*) 0; }

template <class T, class Distance>
inline Distance* distance_type(const istream_iterator<T, Distance>&) {
  return (Distance*) 0;
}

template <class T, class Distance>
bool operator==(const istream_iterator<T, Distance>& x,
                const istream_iterator<T, Distance>& y) {
    return x.stream == y.stream && x.end_marker == y.end_marker ||
        x.end_marker == false && y.end_marker == false;
}

template <class T>
class ostream_iterator {
protected:
    ostream* stream;
    const char* string;
public:
    typedef output_iterator_tag iterator_category;

    ostream_iterator(ostream& s) : stream(&s), string(0) {}
    ostream_iterator(ostream& s, const char* c) : stream(&s), string(c)  {}
    ostream_iterator<T>& operator=(const T& value) { 
        *stream << value;
        if (string) *stream << string;
        return *this;
    }
    ostream_iterator<T>& operator*() { return *this; }
    ostream_iterator<T>& operator++() { return *this; } 
    ostream_iterator<T>& operator++(int) { return *this; } 
};

template <class T>
inline output_iterator_tag 
iterator_category(const ostream_iterator<T>&) {
  return output_iterator_tag();
}

#endif /* __SGI_STL_ITERATOR_H */