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Factored out is_numeric computation. Borland still unhappy :(

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[SVN r9057]
This commit is contained in:
Dave Abrahams
2001-02-09 15:21:02 +00:00
parent 8174963a45
commit 490bee3a06
1 changed files with 25 additions and 23 deletions
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48
include/boost/counting_iterator.hpp
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@ -28,6 +28,8 @@
// Incrementable.
//
// Revision History
// 09 Feb 2001 Factored out is_numeric computation. Borland still
// unhappy :( (David Abrahams)
// 08 Feb 2001 Beginning of a failed attempt to appease Borland
// (David Abrahams)
// 07 Feb 2001 rename counting_iterator() -> make_counting_iterator()
@ -117,20 +119,29 @@ namespace detail {
};
};
// Try to detect numeric types at compile time in ways compatible with the
// limitations of the compiler and library.
template <class T>
struct is_numeric {
enum { value =
#ifndef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
std::numeric_limits<T>::is_specialized
#elif defined(__BORLANDC__)
::boost::is_integral<T>::value || ::boost::is_same<T,char>::value
#else
boost::is_convertible<int,T>::value && boost::is_convertible<T,int>::value
#endif
};
};
// Compute the distance over arbitrary numeric and/or iterator types
template <class Distance, class Incrementable>
Distance any_distance(Incrementable start, Incrementable finish, Distance* = 0)
{
return distance_policy_select<
#ifndef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
std::numeric_limits<Incrementable>::is_specialized
#else
// Causes warnings with GCC, but how else can I detect numeric types
// at compile-time?
(boost::is_convertible<int,Incrementable>::value &&
boost::is_convertible<Incrementable,int>::value)
#endif
>::template policy<Distance, Incrementable>::distance(start, finish);
return distance_policy_select<(
is_numeric<Incrementable>::value)>::template
policy<Distance, Incrementable>::distance(start, finish);
}
} // namespace detail
@ -138,19 +149,10 @@ namespace detail {
template <class Incrementable>
struct counting_iterator_traits {
private:
enum {
is_numeric =
#ifndef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
std::numeric_limits<Incrementable>::is_specialized
#else
// Try to detect numeric types at compile time
boost::is_convertible<int,Incrementable>::value
&& boost::is_convertible<Incrementable,int>::value
#endif
};
typedef typename detail::counting_iterator_traits_select<
is_numeric>::template traits<Incrementable> traits;
enum {numeric = detail::is_numeric<Incrementable>::value };
typedef typename detail::counting_iterator_traits_select<(
numeric
)>::template traits<Incrementable> traits;
public:
typedef Incrementable value_type;
typedef const Incrementable& reference;