#pragma once
#include <vector>
namespace std {
template<class It>
class IteratorRange {
public:
IteratorRange(It b, It e) : begin_(b), end_(e), size_(std::distance(b, e)) {}
typedef It iterator;
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) {
auto lastPtr = begin;
while (true) {
if (lastPtr + page_size >= end) {
pages_.push_back(IteratorRange<It>(lastPtr, end));
break;
}
else {
pages_.push_back(IteratorRange<It>(lastPtr, lastPtr + page_size));
}
lastPtr += page_size;
}
}
typename vector<IteratorRange<It>>::iterator begin() {
return pages_.begin();
}
typename vector<IteratorRange<It>>::iterator end() {
return pages_.end();
}
size_t size() const {
return pages_.size();
}
private:
std::vector<IteratorRange<It>> pages_;
};
template<typename C>
Slicer<typename C::iterator> Slice(C& c, std::size_t page_size) {
return Slicer<typename C::iterator>(c.begin(), c.end(), page_size);
}
template<typename C>
Slicer<typename C::const_iterator> Slice(const C& c, std::size_t page_size) {
return Slicer<typename C::const_iterator>(c.begin(), c.end(), page_size);
}
}