boost/convert/detail/range.hpp
// Copyright (c) 2009-2016 Vladimir Batov.
// Use, modification and distribution are subject to the Boost Software License,
// Version 1.0. See http://www.boost.org/LICENSE_1_0.txt.
#ifndef BOOST_CONVERT_DETAIL_RANGE_HPP
#define BOOST_CONVERT_DETAIL_RANGE_HPP
#include <boost/convert/detail/has_member.hpp>
#include <boost/convert/detail/char.hpp>
#include <boost/utility/enable_if.hpp>
#include <boost/range/iterator.hpp>
namespace boost { namespace cnv
{
namespace detail
{
template<typename T, bool is_class> struct is_range : std::false_type {};
template<typename T> struct is_range<T, /*is_class=*/true>
{
BOOST_DECLARE_HAS_MEMBER(has_begin, begin);
BOOST_DECLARE_HAS_MEMBER( has_end, end);
static bool const value = has_begin<T>::value && has_end<T>::value;
};
}
template<typename T> struct is_range : detail::is_range<typename boost::remove_const<T>::type, boost::is_class<T>::value> {};
template<typename T, typename enable =void> struct range;
template<typename T, typename enable =void> struct iterator;
template<typename T>
struct iterator<T, typename enable_if<is_range<T> >::type>
{
typedef typename boost::range_iterator<T>::type type;
typedef typename boost::range_iterator<T const>::type const_type;
typedef typename boost::iterator_value<type>::type value_type;
};
template<typename T>
struct iterator<T*, void>
{
typedef typename boost::remove_const<T>::type value_type;
typedef T* type;
typedef value_type const* const_type;
};
template<typename T>
struct range_base
{
typedef typename cnv::iterator<T>::value_type value_type;
typedef typename cnv::iterator<T>::type iterator;
typedef typename cnv::iterator<T>::const_type const_iterator;
typedef const_iterator sentry_type;
iterator begin () { return begin_; }
const_iterator begin () const { return begin_; }
void operator++ () { ++begin_; }
// void operator-- () { --end_; }
protected:
range_base (iterator b, iterator e) : begin_(b), end_(e) {}
iterator begin_;
iterator mutable end_;
};
template<typename T>
struct range<T, typename enable_if<is_range<T> >::type> : public range_base<T>
{
typedef range this_type;
typedef range_base<T> base_type;
typedef typename base_type::iterator iterator;
typedef typename base_type::const_iterator const_iterator;
typedef const_iterator sentry_type;
range (T& r) : base_type(r.begin(), r.end()) {}
iterator end () { return base_type::end_; }
const_iterator end () const { return base_type::end_; }
sentry_type sentry () const { return base_type::end_; }
std::size_t size () const { return base_type::end_ - base_type::begin_; }
bool empty () const { return base_type::begin_ == base_type::end_; }
};
template<typename T>
struct range<T*, typename enable_if<cnv::is_char<T> >::type> : public range_base<T*>
{
using this_type = range;
using base_type = range_base<T*>;
using value_type = typename boost::remove_const<T>::type;
using iterator = T*;
using const_iterator = value_type const*;
struct sentry_type
{
friend bool operator!=(iterator it, sentry_type) { return !!*it; }
};
range (iterator b, iterator e =0) : base_type(b, e) {}
iterator end () { return base_type::end_ ? base_type::end_ : (base_type::end_ = base_type::begin_ + size()); }
const_iterator end () const { return base_type::end_ ? base_type::end_ : (base_type::end_ = base_type::begin_ + size()); }
sentry_type sentry () const { return sentry_type(); }
std::size_t size () const { return std::char_traits<value_type>::length(base_type::begin_); }
bool empty () const { return !*base_type::begin_; }
};
template<typename T>
struct range<T* const, void> : public range<T*>
{
range (T* b, T* e =0) : range<T*>(b, e) {}
};
template <typename T, std::size_t N>
struct range<T [N], void> : public range<T*>
{
range (T* b, T* e =0) : range<T*>(b, e) {}
};
}}
#endif // BOOST_CONVERT_DETAIL_RANGE_HPP