vcglib/apps/pivoting/ring.h

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2007-05-10 10:36:46 +02:00
#ifndef RING_H
#define RING_H
// Making a "ring" data structure from the STL
#include <list>
using namespace std;
template<class T>
class ring {
list<T> lst;
public:
ring &operator=(const ring *r) {
lst = r->lst;
}
// Declaration necessary so the following
// 'friend' statement sees this 'iterator'
// instead of std::iterator:
class iterator;
friend class iterator;
class iterator :
public std::iterator<std::bidirectional_iterator_tag, T, ptrdiff_t> {
public:
typename list<T>::iterator it;
list<T>* r;
// "typename" necessary to resolve nesting:
iterator(): r(NULL) {}
iterator(list<T>& lst, const typename list<T>::iterator& i)
: r(&lst), it(i) {}
iterator &operator=(const iterator& x) {
it = x.it;
r = x.r;
return *this;
}
bool operator==(const iterator& x) const {
return it == x.it;
}
bool operator!=(const iterator& x) const {
return !(*this == x);
}
typename list<T>::reference operator*() const {
return *it;
}
iterator& operator++() {
++it;
if(it == r->end())
it = r->begin();
return *this;
}
iterator operator++(int) {
iterator tmp = *this;
++*this;
return tmp;
}
iterator& operator--() {
if(it == r->begin())
it = r->end();
--it;
return *this;
}
iterator operator--(int) {
iterator tmp = *this;
--*this;
return tmp;
}
iterator operator+(int i) {
iterator tmp = *this;
while(i--) ++tmp;
return tmp;
}
iterator operator-(int i) {
iterator tmp = *this;
while(i--) --tmp;
return tmp;
}
iterator insert(const T& x){
return iterator(*r, r->insert(it, x));
}
iterator erase() {
iterator tmp = iterator(*r, r->erase(it));
if (tmp.it == r->end()) tmp.it = r->begin();
return tmp;
}
};
iterator insert(iterator &i, const T& x) {
typename list<T>::iterator it;
it = lst.insert(i.it, x);
return iterator(lst, it);
}
iterator push_back(const T& x) {
typename list<T>::iterator it;
it = lst.insert(lst.end(), x);
return iterator(lst, it);
}
/* void push_back(const T& x) {
lst.push_back(x);
}*/
iterator begin() {
return iterator(lst, lst.begin());
}
int size() { return lst.size(); }
void clear() { lst.clear(); }
void reverse() { lst.reverse(); }
void erase(iterator &i) { lst.erase(i.it); }
};
#endif