Sprout/sprout/iterator/generator_iterator.hpp
bolero-MURAKAMI f40ee0a2ff add generator_iterator
rename fix random/random_iterator.hpp -> random/iterator.hpp
2012-09-27 21:26:32 +09:00

157 lines
4.7 KiB
C++

#ifndef SPROUT_ITERATOR_GENERATOR_ITERATOR_HPP
#define SPROUT_ITERATOR_GENERATOR_ITERATOR_HPP
#include <cstddef>
#include <iterator>
#include <utility>
#include <stdexcept>
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/generator/functions.hpp>
namespace sprout {
//
// generator_iterator
//
template<typename Generator>
class generator_iterator
: public std::iterator<
std::forward_iterator_tag,
typename std::remove_reference<decltype(sprout::generators::generated_value(std::declval<Generator>()))>::type,
std::ptrdiff_t,
typename std::remove_reference<decltype(sprout::generators::generated_value(std::declval<Generator>()))>::type*,
decltype(sprout::generators::generated_value(std::declval<Generator>()))
>
{
public:
typedef Generator generator_type;
typedef std::forward_iterator_tag iterator_category;
typedef decltype(sprout::generators::generated_value(std::declval<Generator>())) reference;
typedef typename std::remove_reference<reference>::type value_type;
typedef std::ptrdiff_t difference_type;
typedef value_type* pointer;
private:
generator_type gen_;
difference_type count_;
public:
SPROUT_CONSTEXPR generator_iterator()
: gen_()
, count_()
{}
explicit SPROUT_CONSTEXPR generator_iterator(
generator_type const& gen,
difference_type count = -1
)
: gen_(gen)
, count_(count)
{}
generator_type& generator() {
return gen_;
}
SPROUT_CONSTEXPR generator_type const& generator() const {
return gen_;
}
SPROUT_CONSTEXPR difference_type count() const {
return count_;
}
SPROUT_CONSTEXPR generator_iterator operator()() const {
return count_ != 0
? generator_iterator(sprout::generators::next_generator(gen_)(), count_ > 0 ? count_ - 1 : count_)
: throw std::out_of_range("generator_iterator<>: increment at out of range")
;
}
SPROUT_CONSTEXPR generator_iterator next() const {
return (*this)();
}
SPROUT_CONSTEXPR reference generated_value() const {
return sprout::generators::generated_value(gen_);
}
SPROUT_CONSTEXPR generator_iterator next_generator() const {
return (*this)();
}
void swap(generator_iterator& other) {
using std::swap;
swap(gen_, other.gen_);
swap(count_, other.count_);
}
friend SPROUT_CONSTEXPR bool operator==(generator_iterator const& lhs, generator_iterator const& rhs) {
return lhs.count_ == rhs.count_;
}
friend SPROUT_CONSTEXPR bool operator!=(generator_iterator const& lhs, generator_iterator const& rhs) {
return !(lhs == rhs);
}
friend SPROUT_CONSTEXPR bool operator<(generator_iterator const& lhs, generator_iterator const& rhs) {
typedef typename std::make_unsigned<difference_type>::type unsigned_type;
return static_cast<unsigned_type>(lhs.count_) > static_cast<unsigned_type>(rhs.count_);
}
friend SPROUT_CONSTEXPR bool operator>(generator_iterator const& lhs, generator_iterator const& rhs) {
return rhs < lhs;
}
friend SPROUT_CONSTEXPR bool operator<=(generator_iterator const& lhs, generator_iterator const& rhs) {
return !(rhs < lhs);
}
friend SPROUT_CONSTEXPR bool operator>=(generator_iterator const& lhs, generator_iterator const& rhs) {
return !(lhs < rhs);
}
SPROUT_CONSTEXPR reference operator*() const {
return count_ != 0
? sprout::generators::generated_value(gen_)
: (throw std::out_of_range("generator_iterator<>: dereference at out of range"), gen_.result())
;
}
SPROUT_CONSTEXPR pointer operator->() const {
return &*(*this);
}
generator_iterator& operator++() {
generator_iterator temp((*this)());
temp.swap(*this);
return *this;
}
generator_iterator operator++(int) {
generator_iterator result(*this);
++*this;
return result;
}
friend SPROUT_CONSTEXPR difference_type operator-(generator_iterator const& lhs, generator_iterator const& rhs) {
return rhs.count_ - lhs.count_;
}
};
//
// swap
//
template<typename Generator>
void swap(
sprout::generator_iterator<Generator>& lhs,
sprout::generator_iterator<Generator>& rhs
)
{
lhs.swap(rhs);
}
//
// iterator_distance
//
template<typename Generator>
inline SPROUT_CONSTEXPR typename std::iterator_traits<sprout::generator_iterator<Generator> >::difference_type
iterator_distance(
sprout::generator_iterator<Generator> first,
sprout::generator_iterator<Generator> last
)
{
return last - first;
}
//
// iterator_next
//
template<typename Generator>
SPROUT_CONSTEXPR sprout::generator_iterator<Generator> iterator_next(
sprout::generator_iterator<Generator> const& it
)
{
return it.next();
}
} // namespace sprout
#endif // #ifndef SPROUT_ITERATOR_GENERATOR_ITERATOR_HPP