BLT/include/blt/std/iterator.h

327 lines
12 KiB
C++

#pragma once
/*
* Copyright (C) 2024 Brett Terpstra
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#ifndef BLT_ITERATOR_H
#define BLT_ITERATOR_H
#include <blt/std/types.h>
#include <blt/meta/meta.h>
#include <blt/meta/iterator.h>
#include <type_traits>
#include <iterator>
namespace blt
{
template<typename Iter, typename = std::void_t<>>
class enumerator;
template<typename Iter, typename = std::void_t<>>
class enumerator_rev;
namespace iterator
{
template<typename Iter, typename = std::void_t<>>
class enumerate_wrapper;
template<typename T>
struct enumerate_item
{
blt::size_t index;
T value;
};
template<typename Iter>
class enumerate_iterator_base
{
public:
explicit enumerate_iterator_base(Iter iter, blt::size_t place = 0): iter(std::move(iter)), index(place)
{}
enumerate_item<blt::meta::deref_return_t<Iter>> operator*() const
{
return {index, *this->iter};
}
friend bool operator==(const enumerate_iterator_base& a, const enumerate_iterator_base& b)
{
return a.iter == b.iter;
}
friend bool operator!=(const enumerate_iterator_base& a, const enumerate_iterator_base& b)
{
return a.iter != b.iter;
}
auto base() const
{
return iter;
}
auto get_index() const
{
return index;
}
protected:
Iter iter;
blt::size_t index;
};
template<typename Iter>
class enumerate_forward_iterator : public enumerate_iterator_base<Iter>
{
public:
using enumerate_iterator_base<Iter>::enumerate_iterator_base;
enumerate_forward_iterator& operator++()
{
++this->iter;
++this->index;
return *this;
}
enumerate_forward_iterator operator++(int)
{
auto tmp = *this;
++*this;
return tmp;
}
};
template<typename Iter>
class enumerate_bidirectional_iterator : public enumerate_forward_iterator<Iter>
{
public:
using enumerate_forward_iterator<Iter>::enumerate_forward_iterator;
enumerate_bidirectional_iterator& operator--()
{
--this->iter;
--this->index;
return *this;
}
enumerate_bidirectional_iterator operator--(int)
{
auto tmp = *this;
--*this;
return tmp;
}
};
template<typename Iter>
class enumerate_wrapper<Iter, std::enable_if_t<blt::meta::is_forward_iterator_v<Iter>, std::void_t<std::forward_iterator_tag>>>
: public enumerate_forward_iterator<Iter>
{
public:
using iterator_category = std::forward_iterator_tag;
using value_type = enumerate_item<blt::meta::deref_return_t<Iter>>;
using difference_type = typename std::iterator_traits<Iter>::difference_type;
using pointer = value_type;
using reference = value_type;
using iterator_type = Iter;
using enumerate_forward_iterator<Iter>::enumerate_forward_iterator;
};
template<typename Iter>
class enumerate_wrapper<Iter, std::enable_if_t<blt::meta::is_bidirectional_or_better_v<Iter>, std::void_t<std::bidirectional_iterator_tag>>>
: public enumerate_bidirectional_iterator<Iter>
{
public:
using iterator_category = typename std::iterator_traits<Iter>::iterator_category;
using value_type = enumerate_item<blt::meta::deref_return_t<Iter>>;
using difference_type = typename std::iterator_traits<Iter>::difference_type;
using pointer = value_type;
using reference = value_type;
using iterator_type = Iter;
using enumerate_bidirectional_iterator<Iter>::enumerate_bidirectional_iterator;
};
template<typename Iter, typename IterWrapper>
class enumerator_base
{
public:
explicit enumerator_base(Iter begin, Iter end): begin_(std::move(begin)), end_(std::move(end))
{}
explicit enumerator_base(IterWrapper begin, IterWrapper end): begin_(std::move(begin)), end_(std::move(end))
{}
auto begin()
{
return begin_;
}
auto end()
{
return end_;
}
protected:
IterWrapper begin_;
IterWrapper end_;
};
template<typename Iter, typename IterWrapper>
class enumerator_reversible : public enumerator_base<Iter, IterWrapper>
{
public:
explicit enumerator_reversible(Iter begin, Iter end, blt::size_t container_size):
enumerator_base<Iter, IterWrapper>{IterWrapper{enumerate_wrapper<Iter>{std::move(begin), 0}},
IterWrapper{enumerate_wrapper<Iter>{std::move(end), container_size}}},
container_size(container_size)
{}
explicit enumerator_reversible(Iter begin, Iter end, blt::size_t begin_index, blt::size_t end_index, blt::size_t container_size):
enumerator_base<Iter, IterWrapper>(IterWrapper{enumerate_wrapper<Iter>{std::move(begin), begin_index}},
IterWrapper{enumerate_wrapper<Iter>{std::move(end), end_index}}),
container_size(container_size)
{}
auto rev() const
{
return enumerator_rev<Iter>{this->end_.base(), this->begin_.base(), this->container_size, this->begin_.get_index(),
this->container_size};
}
protected:
blt::size_t container_size;
};
template<typename Iter, typename IterWrapper>
class enumerator_reversible_rev : public enumerator_reversible<Iter, IterWrapper>
{
public:
using enumerator_reversible<Iter, IterWrapper>::enumerator_reversible;
auto rev() const
{
return enumerator<Iter>{this->end_.base().base(), this->begin_.base().base(), this->end_.base().get_index(),
this->begin_.base().get_index(), this->container_size};
}
};
}
template<typename Iter>
class enumerator<Iter, std::enable_if_t<blt::meta::is_forward_iterator_v<Iter>, std::void_t<std::forward_iterator_tag>>>
: public iterator::enumerator_base<Iter, iterator::enumerate_wrapper<Iter>>
{
public:
using iterator::enumerator_base<Iter, iterator::enumerate_wrapper<Iter>>::enumerator_base;
};
template<typename Iter>
class enumerator<Iter, std::enable_if_t<blt::meta::is_bidirectional_iterator_v<Iter>, std::void_t<std::bidirectional_iterator_tag>>>
: public iterator::enumerator_reversible<Iter, iterator::enumerate_wrapper<Iter>>
{
public:
using iterator::enumerator_reversible<Iter, iterator::enumerate_wrapper<Iter>>::enumerator_reversible;
auto skip(blt::size_t offset)
{
}
};
template<typename Iter>
class enumerator<Iter, std::enable_if_t<blt::meta::is_random_access_iterator_v<Iter>, std::void_t<std::random_access_iterator_tag>>>
: public iterator::enumerator_reversible<Iter, iterator::enumerate_wrapper<Iter>>
{
public:
using iterator::enumerator_reversible<Iter, iterator::enumerate_wrapper<Iter>>::enumerator_reversible;
auto skip(blt::size_t offset)
{
return enumerator<Iter>{this->begin_.base() + offset,
this->end_.base(),
this->begin_.get_index() + offset,
this->end_.get_index(),
this->container_size};
}
};
template<typename Iter>
class enumerator_rev<Iter, std::enable_if_t<blt::meta::is_bidirectional_iterator_v<Iter>, std::void_t<std::bidirectional_iterator_tag>>>
: public iterator::enumerator_reversible_rev<Iter, std::reverse_iterator<iterator::enumerate_wrapper<Iter>>>
{
public:
using iterator::enumerator_reversible_rev<Iter, std::reverse_iterator<iterator::enumerate_wrapper<Iter>>>::enumerator_reversible_rev;
};
template<typename Iter>
class enumerator_rev<Iter, std::enable_if_t<blt::meta::is_random_access_iterator_v<Iter>, std::void_t<std::random_access_iterator_tag>>>
: public iterator::enumerator_reversible_rev<Iter, std::reverse_iterator<iterator::enumerate_wrapper<Iter>>>
{
public:
using iterator::enumerator_reversible_rev<Iter, std::reverse_iterator<iterator::enumerate_wrapper<Iter>>>::enumerator_reversible_rev;
auto skip(blt::size_t offset)
{
return enumerator_rev<Iter>{this->begin_.base().base() - offset,
this->end_.base().base(),
this->begin_.base().get_index() - offset,
this->end_.base().get_index(), this->container_size};
}
};
template<typename Iter>
enumerator(Iter, Iter) -> enumerator<Iter>;
template<typename Iter>
enumerator(Iter, Iter, blt::size_t) -> enumerator<Iter>;
template<typename Iter>
enumerator(Iter, Iter, blt::size_t, blt::size_t) -> enumerator<Iter>;
template<typename T>
static inline auto enumerate(const T& container)
{
return enumerator{container.begin(), container.end(), container.size()};
}
template<typename T, blt::size_t size>
static inline auto enumerate(const T(& container)[size])
{
return enumerator{&container[0], &container[size], size};
}
template<typename T, blt::size_t size>
static inline auto enumerate(T(& container)[size])
{
return enumerator{&container[0], &container[size], size};
}
template<typename T>
static inline auto enumerate(T& container)
{
return enumerator{container.begin(), container.end(), container.size()};
}
template<typename T>
static inline auto enumerate(T&& container)
{
return enumerator{container.begin(), container.end(), container.size()};
}
}
#endif //BLT_ITERATOR_H