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lecture-operating-system-de…/c_os/user/lib/Iterator.h
2022-07-21 02:43:41 +02:00

62 lines
1.7 KiB
C++

#ifndef __Iterator_Include_H_
#define __Iterator_Include_H_
#include <cstddef>
namespace bse {
template<typename T>
class AbstractIterator {
public:
T* ptr;
// *this is always <= other
virtual std::size_t dist(const AbstractIterator& other) const = 0;
AbstractIterator(T* ptr) : ptr(ptr) {}
T* operator->() { return this->ptr; }
T& operator*() { return *this->ptr; }
bool operator==(const AbstractIterator& other) const { return this->ptr == other.ptr; }
bool operator!=(const AbstractIterator& other) const { return !(*this == other); }
friend std::size_t distance(const AbstractIterator& first, const AbstractIterator& last) {
return first.dist(last);
}
};
// This iterator works for structures where the elements are adjacent in memory.
template<typename T>
class ContinuousIterator : public AbstractIterator<T> {
public:
std::size_t dist(const AbstractIterator<T>& other) const override {
return other.ptr - this->ptr;
}
ContinuousIterator(T* ptr) : AbstractIterator<T>(ptr) {}
friend ContinuousIterator& operator++(ContinuousIterator& rhs) {
++rhs.ptr;
return rhs;
}
friend ContinuousIterator& operator--(ContinuousIterator& rhs) {
--rhs.ptr;
return rhs;
}
friend ContinuousIterator operator+(ContinuousIterator lhs, std::size_t add) {
lhs.ptr += add;
return lhs;
}
friend ContinuousIterator operator-(ContinuousIterator lhs, std::size_t sub) {
lhs.ptr -= sub;
return lhs;
}
};
} // namespace bse
#endif