#pragma once
#include <vector>
template<class It>
class IteratorRange {
public:
IteratorRange(It b, It e) : begin_(b), end_(e), size_(std::distance(b, e)) {}
It begin() const {
return begin_;
}
It end() const {
return end_;
}
size_t size() const {
return size_;
}
private:
It begin_, end_;
size_t size_;
};
template <typename It>
class Slicer {
public:
Slicer(It begin, It end, size_t page_size) {
for (size_t left = distance(begin, end); left > 0; ) {
size_t current_page_size = std::min(page_size, left);
It current_page_end = next(begin, current_page_size);
pages_.push_back({begin, current_page_end});
left -= current_page_size;
begin = current_page_end;
}
}
auto begin() const {
return pages_.begin();
}
auto end() const {
return pages_.end();
}
size_t size() const {
return pages_.size();
}
private:
std::vector<IteratorRange<It>> pages_;
};
template <typename C>
auto Slice(C& c, size_t page_size) {
return Slicer(begin(c), end(c), page_size);
}