On 01/08/19 12:36 +0200, Daniel Krügler wrote:
Am Do., 1. Aug. 2019 um 11:57 Uhr schrieb Jonathan Wakely <jwak...@redhat.com>:
More comments inline below ...
[..]
>François
>
>On 6/19/19 7:32 PM, François Dumont wrote:
>>I wanted to implement Debug overloads for those already existing
>>overloads but then realized that those algos could be generalized.
>>This way we will benefit from the memmove replacement when operating
>>with C array or std::array or std::vector iterators.
>>
>>I might do the same for lexicographical_compare one day.
>>
>>The ChangeLog below is quite huge so I attached it. I wonder if I
>>could use deque::iterator and deque::const_iterator in place of the
>>_Deque_iterator<> to reduce it ?
>>
>>Tested under Linux x86_64 normal and debug modes, ok to commit ?
>>
>>François
>>
>
>diff --git a/libstdc++-v3/include/bits/deque.tcc
b/libstdc++-v3/include/bits/deque.tcc
>index 3f77b4f079c..9db869fb666 100644
>--- a/libstdc++-v3/include/bits/deque.tcc
>+++ b/libstdc++-v3/include/bits/deque.tcc
>@@ -967,155 +967,507 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
> this->_M_impl._M_finish._M_set_node(__new_nstart + __old_num_nodes - 1);
> }
>
[..]
And anyway, isn't _Deque_iterator<T, T&, T*>::_Self just the same type as
_Deque_iterator<T, T&, T*> ? It should be something like:
typedef typename _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*> _Iter;
>+ template<typename _II, typename _Tp>
>+ typename enable_if<
>+ is_same<typename std::iterator_traits<_II>::iterator_category,
>+ std::random_access_iterator_tag>::value,
Use is_base_of<random_access_iterator_tag, ...::iterator_category> so
it works for types derived from random_access_iterator_tag too.
Interesting. Traditional type tag dispatching approaches (as function
parameters) do have more in a manner that would be equivalent to an
implicit conversion (Being used as "by-value-parameters"), so I'm
wondering whether this should not instead refer to is_convertible? I
also found examples where this trait is currently used in <stl_algo.h>
such as
static_assert(
__or_<is_convertible<__pop_cat, forward_iterator_tag>,
is_convertible<__samp_cat, random_access_iterator_tag>>::value,
"output range must use a RandomAccessIterator when input range"
" does not meet the ForwardIterator requirements");
Should possibly this trait be preferred?
Hmm, I don't know why I did it that way in sample.
The standard requires derivation in a couple of places today, see
[reverse.iterator] bullet 2.1 and [move.iterator] bullet 1.1 which use
DerivedFrom<random_access_iterator_tag> to check whether the base
iterator is random access or not.
