BLT/include/blt/std/iterator.h

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#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>
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#include <blt/std/logging.h>
#include <blt/meta/meta.h>
#include <blt/meta/iterator.h>
#include <type_traits>
#include <iterator>
namespace blt
{
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// forward declare useful types
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;
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// struct which is returned by the enumerator
template<typename T>
struct enumerate_item
{
blt::size_t index;
T value;
};
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template<typename Iter1, typename Iter2>
class pair_iterator_base
{
public:
explicit pair_iterator_base(Iter1 iter1, Iter2 iter2): m_iter1(std::move(iter1)), m_iter2(std::move(iter2))
{}
friend bool operator==(const pair_iterator_base& a, const pair_iterator_base& b)
{
return a.m_iter1 == b.m_iter1;
}
friend bool operator!=(const pair_iterator_base& a, const pair_iterator_base& b)
{
return a.m_iter1 != b.m_iter1;
}
auto iter1() const
{
return m_iter1;
}
auto iter2() const
{
return m_iter2;
}
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protected:
Iter1 m_iter1;
Iter2 m_iter2;
};
template<typename Iter>
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class enumerate_iterator_base : public pair_iterator_base<Iter, blt::size_t>
{
public:
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explicit enumerate_iterator_base(Iter iter, blt::size_t place = 0):
pair_iterator_base<Iter, blt::size_t>(std::move(iter), place)
{}
enumerate_item<blt::meta::deref_return_t<Iter>> operator*() const
{
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return {this->m_iter2, *this->m_iter1};
}
auto base() const
{
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return this->iter1();
}
auto get_index() const
{
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return this->iter2();
}
};
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++()
{
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++this->m_iter1;
++this->m_iter2;
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--()
{
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--this->m_iter1;
--this->m_iter2;
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}},
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IterWrapper{enumerate_wrapper<Iter>{std::move(end), container_size}}}
{}
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explicit enumerator_reversible(Iter begin, Iter end, blt::size_t begin_index, blt::size_t end_index):
enumerator_base<Iter, IterWrapper>(IterWrapper{enumerate_wrapper<Iter>{std::move(begin), begin_index}},
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IterWrapper{enumerate_wrapper<Iter>{std::move(end), end_index}})
{}
auto rev() const
{
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return enumerator_rev<Iter>{this->end_.base(),
this->begin_.base(),
this->end_.get_index(),
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this->begin_.get_index()};
}
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auto skip(blt::size_t amount)
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{
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auto begin = this->begin_;
for (blt::size_t i = 0; i < amount; i++)
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++begin;
return enumerator<Iter>{begin.base(),
this->end_.base(),
begin.get_index(),
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this->end_.get_index()};
}
auto take(blt::size_t amount)
{
auto end = this->begin();
for (blt::size_t i = 0; i < amount; i++)
++end;
return enumerator<Iter>{this->begin_.base(),
end.base(),
this->begin_.get_index(),
end.get_index()};
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}
};
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
{
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return enumerator<Iter>{this->end_.base().base(),
this->begin_.base().base(),
this->end_.base().get_index(),
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this->begin_.base().get_index()};
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}
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auto skip(blt::size_t amount)
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{
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auto begin = this->begin_.base();
for (blt::size_t i = 0; i < amount; i++)
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--begin;
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return enumerator_rev<Iter>{begin.base(),
this->end_.base().base(),
begin.get_index(),
this->end_.base().get_index()};
}
auto take(blt::size_t amount)
{
auto end = this->begin_.base();
for (blt::size_t i = 0; i < amount; i++)
--end;
return enumerator_rev<Iter>{
this->begin_.base().base(),
end.base(),
this->begin_.base().get_index(),
end.get_index()};
}
};
}
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;
};
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;
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auto skip(blt::size_t amount)
{
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return enumerator<Iter>{this->begin_.base() + amount,
this->end_.base(),
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this->begin_.get_index() + amount,
this->end_.get_index()};
}
auto take(blt::size_t amount)
{
return enumerator<Iter>{this->begin_.base(),
this->begin_.base() + amount,
this->begin_.get_index(),
this->begin_.get_index() + amount};
}
};
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;
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auto skip(blt::size_t amount)
{
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return enumerator_rev<Iter>{this->begin_.base().base() - amount,
this->end_.base().base(),
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this->begin_.base().get_index() - amount,
this->end_.base().get_index()};
}
auto take(blt::size_t amount)
{
return enumerator_rev<Iter>{this->begin_.base().base(),
this->begin_.base().base() - amount,
this->begin_.base().get_index(),
this->begin_.base().get_index() - amount};
}
};
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