// Filename: stl_iterator.h
// Comment By: 凝霜
// E-mail: mdl2009@vip.qq.com
// Blog: http://blog.csdn.net/mdl13412
/*
*
* 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) 1996,1997
* 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.
*/
/* NOTE: This is an internal header file, included by other STL headers.
* You should not attempt to use it directly.
*/
#ifndef __SGI_STL_INTERNAL_ITERATOR_H
#define __SGI_STL_INTERNAL_ITERATOR_H
__STL_BEGIN_NAMESPACE
////////////////////////////////////////////////////////////////////////////////
// STL迭代器定义
////////////////////////////////////////////////////////////////////////////////
// STL中有五种迭代器类型
// Input Iterator read only
// Output Iterator write only
// Forward Iterator 允许"写入型"算法在其指向区间进行操作
// Bidirectional Iterator 提供双向访问能力
// Random Access Iterator 支持原生指针具有的全部能力
////////////////////////////////////////////////////////////////////////////////
// 类型从属关系, 子类适用于接受父类类型的算法, 但是效率可能不佳
//
// Input Iterator
// ↑
// Forward Iterator
// ↑
// Bidirectional Iterator
// ↑
// Random Access Iterator
////////////////////////////////////////////////////////////////////////////////
// 用于标记迭代器类型
struct input_iterator_tag {};
struct output_iterator_tag {};
struct forward_iterator_tag : public input_iterator_tag {};
struct bidirectional_iterator_tag : public forward_iterator_tag {};
struct random_access_iterator_tag : public bidirectional_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;
typedef void value_type;
typedef void difference_type;
typedef void pointer;
typedef void reference;
};
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;
};
#ifdef __STL_USE_NAMESPACES
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 /* __STL_USE_NAMESPACES */
#ifdef __STL_CLASS_PARTIAL_SPECIALIZATION
////////////////////////////////////////////////////////////////////////////////
// iterator_traits定义
////////////////////////////////////////////////////////////////////////////////
// 用于traits出迭代其所指对象的型别
template <class Iterator>
struct iterator_traits
{
// 迭代器类型, STL提供五种迭代器
typedef typename Iterator::iterator_category iterator_category;
// 迭代器所指对象的型别
// 如果想与STL算法兼容, 那么在类内需要提供value_type定义
typedef typename Iterator::value_type value_type;
// 这个是用于处理两个迭代器间距离的类型
typedef typename Iterator::difference_type difference_type;
// 直接指向对象的原生指针类型
typedef typename Iterator::pointer pointer;
// 这个是对象的引用类型
typedef typename Iterator::reference reference;
};
// 针对指针提供特化版本
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;
};
// 针对指向常对象的指针提供特化
template <class T>
struct iterator_traits<const T*>
{
typedef random_access_iterator_tag iterator_category;
typedef T value_type;
typedef ptrdiff_t difference_type;
typedef const T* pointer;
typedef const T& reference;
};
////////////////////////////////////////////////////////////////////////////////
// iterator_traits支持函数
////////////////////////////////////////////////////////////////////////////////
// iterator_category(const Iterator&) 返回迭代器类别
// distance_type(const Iterator&) 返回表示迭代器距离的类型
// value_type(const Iterator&) 返回迭代器所指对象的类型
////////////////////////////////////////////////////////////////////////////////
template <class Iterator>
inline typename iterator_traits<Iterator>::iterator_category
iterator_category(const Iterator&)
{
typedef typename iterator_traits<Iterator>::iterator_category category;
return category();
}
template <class Iterator>
inline typename iterator_traits<Iterator>::difference_type*
distance_type(const Iterator&)
{
return static_cast<typename iterator_traits<Iterator>::difference_type*>(0);
}
template <class Iterator>
inline typename iterator_traits<Iterator>::value_type*
value_type(const Iterator&)
{
return static_cast<typename iterator_traits<Iterator>::value_type*>(0);
}
#else /* __STL_CLASS_PARTIAL_SPECIALIZATION */
// 编译器不支持partial specialization of class templates(模板类偏特化)
// 需要对所有迭代器类型都提供定义
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); }
#endif /* __STL_CLASS_PARTIAL_SPECIALIZATION */
////////////////////////////////////////////////////////////////////////////////
// template <class InputIterator, class Distance>
// inline void distance(InputIterator first, InputIterator last, Distance& n)
////////////////////////////////////////////////////////////////////////////////
// distance
// |
// |---------------- 判断迭代器类型
// Input Iterator ↓ Random Access Iterator
// -------------------------------------------
// | |
// | |
// ↓ |
// __distance(..., input_iterator_tag) |
// while (first != last) { ++first; ++n; } |
// ↓
// __distance(..., random_access_iterator_tag)
// n += last - first;
////////////////////////////////////////////////////////////////////////////////
template <class InputIterator, class Distance>
inline void __distance(InputIterator first, InputIterator last, Distance& n,
input_iterator_tag)
{
while (first != last) { ++first; ++n; }
}
template <class RandomAccessIterator, class Distance>
inline void __distance(RandomAccessIterator first, RandomAccessIterator last,
Distance& n, random_access_iterator_tag)
{
n += last - first;
}
template <class InputIterator, class Distance>
inline void distance(InputIterator first, InputIterator last, Distance& n)
{
__distance(first, last, n, iterator_category(first));
}
#ifdef __STL_CLASS_PARTIAL_SPECIALIZATION
////////////////////////////////////////////////////////////////////////////////
// template <class InputIterator>
// inline iterator_traits<InputIterator>::difference_type
// distance(InputIterator first, InputIterator last)
////////////////////////////////////////////////////////////////////////////////
// distance
// |
// |---------------- 判断迭代器类型
// Input Iterator ↓ Random Access Iterator
// -------------------------------------------
// | |
// | |
// ↓ |
// __distance(..., input_iterator_tag) |
// while (first != last) { |
// ++first; ++n; |
// } |
// return n; |
// ↓
// __distance(..., random_access_iterator_tag)
// return last - first;
////////////////////////////////////////////////////////////////////////////////
template <class InputIterator>
inline iterator_traits<InputIterator>::difference_type
__distance(InputIterator first, InputIterator last, input_iterator_tag)
{
iterator_traits<InputIterator>::difference_type n = 0;
while (first != last) {
++first; ++n;
}
return n;
}
template <class RandomAccessIterator>
inline iterator_traits<RandomAccessIterator>::difference_type
__distance(RandomAccessIterator first, RandomAccessIterator last,
random_access_iterator_tag)
{
return last - first;
}
template <class InputIterator>
inline iterator_traits<InputIterator>::difference_type
distance(InputIterator first, InputIterator last)
{
typedef typename iterator_traits<InputIterator>::iterator_category category;
return __distance(first, last, category());
}
#endif /* __STL_CLASS_PARTIAL_SPECIALIZATION */
////////////////////////////////////////////////////////////////////////////////
// advance()实现部分
////////////////////////////////////////////////////////////////////////////////
// advance
// |
// |---------------- 判断迭代器类型
// Input Iterator ↓
// ---------------------------------------------------------------------
// | Random Access Iterator | Bidirectional Iterator |
// | | |
// ↓ | |
// __advance(..., input_iterator_tag) | |
// while (n--) ++i; | |
// | |
// ↓ |
// __advance(..., random_access_iterator_tag) |
// i += n; |
// |
// ↓
// __advance(..., bidirectional_iterator_tag)
// if (n >= 0)
// while (n--) ++i;
// else
// while (n++) --i;
////////////////////////////////////////////////////////////////////////////////
template <class InputIterator, class Distance>
inline void __advance(InputIterator& i, Distance n, input_iterator_tag)
{
while (n--) ++i;
}
#if defined(__sgi) && !defined(__GNUC__) && (_MIPS_SIM != _MIPS_SIM_ABI32)
#pragma set woff 1183
#endif
template <class BidirectionalIterator, class Distance>
inline void __advance(BidirectionalIterator& i, Distance n,
bidirectional_iterator_tag)
{
if (n >= 0)
while (n--) ++i;
else
while (n++) --i;
}
#if defined(__sgi) && !defined(__GNUC__) && (_MIPS_SIM != _MIPS_SIM_ABI32)
#pragma reset woff 1183
#endif
template <class RandomAccessIterator, class Distance>
inline void __advance(RandomAccessIterator& i, Distance n,
random_access_iterator_tag)
{
i += n;
}
template <class InputIterator, class Distance>
inline void advance(InputIterator& i, Distance n)
{
__advance(i, n, iterator_category(i));
}
////////////////////////////////////////////////////////////////////////////////
// back_insert_iterator实现部分
////////////////////////////////////////////////////////////////////////////////
template <class Container>
class back_insert_iterator
{
protected:
Container* container;
public:
typedef output_iterator_tag iterator_category;
typedef void value_type;
typedef void difference_type;
typedef void pointer;
typedef void reference;
explicit back_insert_iterator(Container& x) : container(&x) {}
// 只有提供了push_back()操作的容器才能使用back_insert_iterator
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; }
};
#ifndef __STL_CLASS_PARTIAL_SPECIALIZATION
// 用于traits出back_insert_iterator的迭代器类别
template <class Container>
inline output_iterator_tag
iterator_category(const back_insert_iterator<Container>&)
{
return output_iterator_tag();
}
#endif /* __STL_CLASS_PARTIAL_SPECIALIZATION */
template <class Container>
inline back_insert_iterator<Container> back_inserter(Container& x)
{
return back_insert_iterator<Container>(x);
}
////////////////////////////////////////////////////////////////////////////////
// front_insert_iterator实现部分
////////////////////////////////////////////////////////////////////////////////
template <class Container>
class front_insert_iterator
{
protected:
Container* container;
public:
typedef output_iterator_tag iterator_category;
typedef void value_type;
typedef void difference_type;
typedef void pointer;
typedef void reference;
explicit front_insert_iterator(Container& x) : container(&x) {}
// 只有提供了push_front()操作的容器才能使用front_insert_iterator
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; }
};
#ifndef __STL_CLASS_PARTIAL_SPECIALIZATION
template <class Container>
inline output_iterator_tag
iterator_category(const front_insert_iterator<Container>&)
{
return output_iterator_tag();
}
#endif /* __STL_CLASS_PARTIAL_SPECIALIZATION */
template <class Container>
inline front_insert_iterator<Container> front_inserter(Container& x)
{
return front_insert_iterator<Container>(x);
}
////////////////////////////////////////////////////////////////////////////////
// insert_iterator实现部分
////////////////////////////////////////////////////////////////////////////////
template <class Container>
class insert_iterator
{
protected:
Container* container;
typename Container::iterator iter;
public:
typedef output_iterator_tag iterator_category;
typedef void value_type;
typedef void difference_type;
typedef void pointer;
typedef void reference;
insert_iterator(Container& x, typename Container::iterator i)
: container(&x), iter(i) {}
// 只有提供了insert操作的容器才能使用insert_iterator
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; }
};
#ifndef __STL_CLASS_PARTIAL_SPECIALIZATION
template <class Container>
inline output_iterator_tag
iterator_category(const insert_iterator<Container>&)
{
return output_iterator_tag();
}
#endif /* __STL_CLASS_PARTIAL_SPECIALIZATION */
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));
}
////////////////////////////////////////////////////////////////////////////////
// reverse_bidirectional_iterator实现部分
////////////////////////////////////////////////////////////////////////////////
// reverse_bidirectional_iterator使用的是BidirectionalIterator
// 所以要对operator *(), ++(), ++(int)都提供处理
// 同时因为是反向迭代器, 所以重载运算符的操作要特殊处理
#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;
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() const { return current; }
Reference operator*() const {
BidirectionalIterator tmp = current;
return *--tmp;
}
#ifndef __SGI_STL_NO_ARROW_OPERATOR
pointer operator->() const { return &(operator*()); }
#endif /* __SGI_STL_NO_ARROW_OPERATOR */
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;
}
};
#ifndef __STL_CLASS_PARTIAL_SPECIALIZATION
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;
}
#endif /* __STL_CLASS_PARTIAL_SPECIALIZATION */
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.base() == y.base();
}
#ifdef __STL_CLASS_PARTIAL_SPECIALIZATION
////////////////////////////////////////////////////////////////////////////////
// reverse_iterator实现部分
////////////////////////////////////////////////////////////////////////////////
// This is the new version of reverse_iterator, as defined in the
// draft C++ standard. It relies on the iterator_traits template,
// which in turn relies on partial specialization. The class
// reverse_bidirectional_iterator is no longer part of the draft
// standard, but it is retained for backward compatibility.
template <class Iterator>
class reverse_iterator
{
protected:
Iterator current;
public:
typedef typename iterator_traits<Iterator>::iterator_category
iterator_category;
typedef typename iterator_traits<Iterator>::value_type
value_type;
typedef typename iterator_traits<Iterator>::difference_type
difference_type;
typedef typename iterator_traits<Iterator>::pointer
pointer;
typedef typename iterator_traits<Iterator>::reference
reference;
typedef Iterator iterator_type;
typedef reverse_iterator<Iterator> self;
public:
reverse_iterator() {}
explicit reverse_iterator(iterator_type x) : current(x) {}
reverse_iterator(const self& x) : current(x.current) {}
#ifdef __STL_MEMBER_TEMPLATES
template <class Iter>
reverse_iterator(const reverse_iterator<Iter>& x) : current(x.current) {}
#endif /* __STL_MEMBER_TEMPLATES */
iterator_type base() const { return current; }
reference operator*() const {
Iterator tmp = current;
return *--tmp;
}
#ifndef __SGI_STL_NO_ARROW_OPERATOR
pointer operator->() const { return &(operator*()); }
#endif /* __SGI_STL_NO_ARROW_OPERATOR */
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+(difference_type n) const {
return self(current - n);
}
self& operator+=(difference_type n) {
current -= n;
return *this;
}
self operator-(difference_type n) const {
return self(current + n);
}
self& operator-=(difference_type n) {
current += n;
return *this;
}
reference operator[](difference_type n) const { return *(*this + n); }
};
template <class Iterator>
inline bool operator==(const reverse_iterator<Iterator>& x,
const reverse_iterator<Iterator>& y)
{
return x.base() == y.base();
}
template <class Iterator>
inline bool operator<(const reverse_iterator<Iterator>& x,
const reverse_iterator<Iterator>& y)
{
return y.base() < x.base();
}
template <class Iterator>
inline typename reverse_iterator<Iterator>::difference_type
operator-(const reverse_iterator<Iterator>& x,
const reverse_iterator<Iterator>& y)
{
return y.base() - x.base();
}
template <class Iterator>
inline reverse_iterator<Iterator>
operator+(reverse_iterator<Iterator>::difference_type n,
const reverse_iterator<Iterator>& x)
{
return reverse_iterator<Iterator>(x.base() - n);
}
#else /* __STL_CLASS_PARTIAL_SPECIALIZATION */
// 如果不支持partial specialization of class templates(模板类偏特化)
// 则使用HP STL的实现
// This is the old version of reverse_iterator, as found in the original
// HP STL. It does not use partial specialization.
#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;
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() const { return current; }
Reference operator*() const { return *(current - 1); }
#ifndef __SGI_STL_NO_ARROW_OPERATOR
pointer operator->() const { return &(operator*()); }
#endif /* __SGI_STL_NO_ARROW_OPERATOR */
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) const { 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.base() == y.base();
}
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.base() < x.base();
}
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.base() - x.base();
}
template <class RandomAccessIter, class T, class Ref, class Dist>
inline reverse_iterator<RandomAccessIter, T, Ref, Dist>
operator+(Dist n, const reverse_iterator<RandomAccessIter, T, Ref, Dist>& x)
{
return reverse_iterator<RandomAccessIter, T, Ref, Dist>(x.base() - n);
}
#endif /* __STL_CLASS_PARTIAL_SPECIALIZATION */
////////////////////////////////////////////////////////////////////////////////
// istream_iterator实现部分
////////////////////////////////////////////////////////////////////////////////
template <class T, class Distance = ptrdiff_t>
class istream_iterator
{
friend bool
operator== __STL_NULL_TMPL_ARGS (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 const T* pointer;
typedef const T& reference;
istream_iterator() : stream(&cin), end_marker(false) {}
istream_iterator(istream& s) : stream(&s) { read(); }
reference operator*() const { return value; }
#ifndef __SGI_STL_NO_ARROW_OPERATOR
pointer operator->() const { return &(operator*()); }
#endif /* __SGI_STL_NO_ARROW_OPERATOR */
istream_iterator<T, Distance>& operator++() {
read();
return *this;
}
istream_iterator<T, Distance> operator++(int) {
istream_iterator<T, Distance> tmp = *this;
read();
return tmp;
}
};
#ifndef __STL_CLASS_PARTIAL_SPECIALIZATION
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;
}
#endif /* __STL_CLASS_PARTIAL_SPECIALIZATION */
template <class T, class Distance>
inline 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;
}
////////////////////////////////////////////////////////////////////////////////
// ostream_iterator实现部分
////////////////////////////////////////////////////////////////////////////////
template <class T>
class ostream_iterator
{
protected:
ostream* stream;
const char* string;
public:
typedef output_iterator_tag iterator_category;
typedef void value_type;
typedef void difference_type;
typedef void pointer;
typedef void reference;
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; }
};
#ifndef __STL_CLASS_PARTIAL_SPECIALIZATION
template <class T>
inline output_iterator_tag
iterator_category(const ostream_iterator<T>&)
{
return output_iterator_tag();
}
#endif /* __STL_CLASS_PARTIAL_SPECIALIZATION */
__STL_END_NAMESPACE
#endif /* __SGI_STL_INTERNAL_ITERATOR_H */
// Local Variables:
// mode:C++
// End:
