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skip working

v1
Brett 2024-09-30 18:15:59 -04:00
parent a66fc586fd
commit 4bdaa3481b
2 changed files with 33 additions and 67 deletions
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2
CMakeLists.txt
View File

@ -1,6 +1,6 @@
cmake_minimum_required(VERSION 3.20)
include(cmake/color.cmake)
set(BLT_VERSION 1.1.3)
set(BLT_VERSION 1.1.4)
set(BLT_TARGET BLT)

98
include/blt/iterator/common.h
View File

@ -131,77 +131,49 @@ namespace blt::iterator
namespace impls
{
template<typename Iter>
struct skip_wrapper : public passthrough_wrapper<Iter, skip_wrapper<Iter>>
template<typename Derived>
class skip_t
{
public:
using iterator_category = typename std::iterator_traits<Iter>::iterator_category;
using value_type = typename std::iterator_traits<Iter>::value_type;
using difference_type = typename std::iterator_traits<Iter>::difference_type;
using pointer = typename std::iterator_traits<Iter>::pointer;
using reference = typename std::iterator_traits<Iter>::reference;
explicit skip_wrapper(Iter iter, blt::size_t n): passthrough_wrapper<Iter, skip_wrapper<Iter>>(std::move(iter)), skip(n)
{}
meta::deref_return_t<Iter> operator*() const
{
BLT_TRACE("Dereference Skip");
forward_skip();
return *this->iter;
}
skip_wrapper& operator++()
{
BLT_TRACE("Forward Skip");
forward_skip();
++this->iter;
return *this;
}
skip_wrapper& operator--()
{
BLT_TRACE("Backward Skip");
forward_skip();
--this->iter;
return *this;
}
friend skip_wrapper operator+(const skip_wrapper& a, blt::ptrdiff_t n)
{
static_assert(std::is_same_v<iterator_category, std::random_access_iterator_tag>,
"Iterator must allow random access");
return {a.base() + static_cast<blt::ptrdiff_t>(a.skip) + n, 0};
}
friend skip_wrapper operator-(const skip_wrapper& a, blt::ptrdiff_t n)
{
static_assert(std::is_same_v<iterator_category, std::random_access_iterator_tag>,
"Iterator must allow random access");
return {a.base() - static_cast<blt::ptrdiff_t>(a.skip) - n, 0};
}
private:
void forward_skip() const
template<bool check>
auto skip_base(blt::size_t n)
{
if constexpr (std::is_same_v<iterator_category, std::random_access_iterator_tag>)
auto* d = static_cast<Derived*>(this);
auto begin = d->begin();
auto end = d->end();
if constexpr (std::is_same_v<typename Derived::iterator_category, std::forward_iterator_tag> ||
std::is_same_v<typename Derived::iterator_category, std::bidirectional_iterator_tag>)
{
if (skip > 0)
for (blt::size_t i = 0; i < n; i++)
{
this->iter = this->iter + skip;
skip = 0;
if constexpr (check)
{
if (begin == end)
break;
}
++begin;
}
} else
return Derived{std::move(begin), std::move(end)};
} else if constexpr (std::is_same_v<typename Derived::iterator_category, std::random_access_iterator_tag>)
{
while (skip > 0)
// random access iterators can have math directly applied to them.
if constexpr (check)
{
++this->iter;
--skip;
return Derived{begin + std::min(static_cast<blt::ptrdiff_t>(n), std::distance(begin, end)), end};
} else
{
return Derived{begin + n, end};
}
}
}
public:
auto skip(blt::size_t n)
{ return skip_base<false>(n); }
mutable blt::size_t skip;
auto skip_or(blt::size_t n)
{ return skip_base<true>(n); }
};
template<typename Derived>
@ -256,7 +228,7 @@ namespace blt::iterator
}
template<typename IterBase>
class iterator_container : public impls::take_t<iterator_container<IterBase>>
class iterator_container : public impls::take_t<iterator_container<IterBase>>, public impls::skip_t<iterator_container<IterBase>>
{
public:
using iterator_category = typename IterBase::iterator_category;
@ -277,12 +249,6 @@ namespace blt::iterator
std::reverse_iterator<IterBase>{begin()}};
}
auto skip(blt::size_t n)
{
return iterator_container<impls::skip_wrapper<IterBase>>{impls::skip_wrapper<IterBase>{begin(), n},
impls::skip_wrapper<IterBase>{end(), n}};
}
auto begin() const
{
return m_begin;