boostorg/iterator
1
0
Fork 1
mirror of https://github.com/boostorg/iterator.git synced 2025-07-29 20:37:17 +02:00
Code Issues Packages Projects Releases Wiki Activity

Updated pointee and indirect_reference so that pointee represents the

Browse Source 
immutability of the pointed-to type via const qualification.  The
pointee of a proxy-based iterator will be const qualified unless a
mutable reference to the value_type can be bound to the returned
proxy.

Added a test for pointee

Fixed iterator_facade so operator[] result type computation didn't
cause a problem with abstract types.

Updated iterator_facade operator[] docs for accuracy.

Allowed Borland to simply fail the indirect_iterator_member_types test
because of its lame const-dropping, instead of trying to work around
it.


[SVN r21579]
This commit is contained in:
Dave Abrahams
2004-01-11 00:03:09 +00:00
parent dd5fb425fa
commit 6c62f31f0a
7 changed files with 150 additions and 47 deletions
Download Patch File Download Diff File Expand all files Collapse all files

19
include/boost/iterator/iterator_facade.hpp
View File

@ -22,9 +22,11 @@
#include <boost/type_traits/add_pointer.hpp>
#include <boost/type_traits/remove_const.hpp>
#include <boost/type_traits/is_convertible.hpp>
#include <boost/type_traits/is_POD.hpp>
#include <boost/mpl/apply_if.hpp>
#include <boost/mpl/or.hpp>
#include <boost/mpl/and.hpp>
#include <boost/iterator/detail/config_def.hpp> // this goes last
@ -182,11 +184,21 @@ namespace boost
Iterator m_iter;
};
template <class Value, class Reference>
struct use_operator_brackets_proxy
: mpl::and_<
// Really we want an is_copy_constructible trait here,
// but is_POD will have to suffice in the meantime.
boost::is_POD<Value>
, iterator_writability_disabled<Value,Reference>
>
{};
template <class Iterator, class Value, class Reference>
struct operator_brackets_result
{
typedef typename mpl::if_<
iterator_writability_disabled<Value,Reference>
use_operator_brackets_proxy<Value,Reference>
, Value
, operator_brackets_proxy<Iterator>
>::type type;
@ -387,12 +399,11 @@ namespace boost
typename detail::operator_brackets_result<Derived,Value,Reference>::type
operator[](difference_type n) const
{
typedef detail::iterator_writability_disabled<Value,Reference>
not_writable;
typedef detail::use_operator_brackets_proxy<Value,Reference> use_proxy;
return detail::make_operator_brackets_result<Derived>(
this->derived() + n
, not_writable()
, use_proxy()
);
}

40
include/boost/pointee.hpp
View File

@ -9,7 +9,9 @@
# include <boost/detail/is_incrementable.hpp>
# include <boost/iterator/iterator_traits.hpp>
# include <boost/type_traits/add_const.hpp>
# include <boost/type_traits/remove_cv.hpp>
# include <boost/mpl/if.hpp>
# include <boost/mpl/apply_if.hpp>
namespace boost {
@ -17,9 +19,37 @@ namespace boost {
namespace detail
{
template <class P>
struct smart_ptr_value
struct smart_ptr_pointee
{
typedef typename remove_cv<typename P::element_type>::type type;
typedef typename P::element_type type;
};
template <class Iterator>
struct iterator_pointee
{
typedef typename iterator_traits<Iterator>::value_type value_type;
struct impl
{
template <class T>
static char test(T const&);
static char (& test(value_type&) )[2];
static Iterator& x;
};
BOOST_STATIC_CONSTANT(bool, is_constant = sizeof(impl::test(*impl::x)) == 1);
typedef typename mpl::if_c<
# if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x551))
::boost::detail::iterator_pointee<Iterator>::is_constant
# else
is_constant
# endif
, typename add_const<value_type>::type
, value_type
>::type type;
};
}
@ -27,11 +57,11 @@ template <class P>
struct pointee
{
typedef typename remove_cv<P>::type stripped;
typedef typename mpl::apply_if<
detail::is_incrementable<stripped>
, iterator_value<stripped>
, detail::smart_ptr_value<stripped>
, detail::iterator_pointee<stripped>
, detail::smart_ptr_pointee<stripped>
>::type type;
};