#pragma once
#include <vector>
template<typename It>
class IteratorRange {
public:
IteratorRange(It b, It e) :
begin_(b), end_(e), size_(std::distance(b, e)) {}
[[nodiscard]] It begin() const {
return begin_;
}
[[nodiscard]] It end() const {
return end_;
}
[[nodiscard]] std::size_t size() const {
return size_;
}
private:
It begin_, end_;
std::size_t size_;
};
template <typename It>
class Slicer {
public:
Slicer(It b, It e, std::size_t page_size) {
std::size_t i = 0;
It begin = b, end = b;
for (; end != e;) {
++i;
++end;
if (i == page_size) {
pages_.push_back(IteratorRange<It>(begin, end));
i = 0;
begin = end;
continue;
}
}
if (i > 0) {
pages_.push_back(IteratorRange<It>(begin, end));
}
}
[[nodiscard]] auto begin() const {
return pages_.begin();
}
[[nodiscard]] auto end() const {
return pages_.end();
}
std::size_t size() {
return pages_.size();
}
private:
// It begin_, end_;
std::vector<IteratorRange<It>> pages_;
};
template<typename C>
auto Slice(C &c, std::size_t page_size) {
return Slicer<typename C::iterator>(c.begin(), c.end(), page_size);
}
template<typename C>
auto Slice(const C &c, std::size_t page_size) {
return Slicer<typename C::const_iterator>(c.begin(), c.end(), page_size);
}
template<>
auto Slice(const IteratorRange<std::vector<int>::iterator> &c, std::size_t page_size) {
return Slicer<std::vector<int>::iterator>(c.begin(), c.end(), page_size);
}