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#pragma once
#include <nall/maybe.hpp>
namespace nall {
template<typename T = s64>
struct range_t {
struct iterator {
iterator(T position, T step = 0) : position(position), step(step) {}
auto operator*() const -> T { return position; }
auto operator!=(const iterator& source) const -> bool { return step > 0 ? position < source.position : position > source.position; }
auto operator++() -> iterator& { position += step; return *this; }
private:
T position;
const T step;
};
struct reverse_iterator {
reverse_iterator(T position, T step = 0) : position(position), step(step) {}
auto operator*() const -> T { return position; }
auto operator!=(const reverse_iterator& source) const -> bool { return step > 0 ? position > source.position : position < source.position; }
auto operator++() -> reverse_iterator& { position -= step; return *this; }
private:
T position;
const T step;
};
auto begin() const -> iterator { return {origin, stride}; }
auto end() const -> iterator { return {target}; }
auto rbegin() const -> reverse_iterator { return {target - stride, stride}; }
auto rend() const -> reverse_iterator { return {origin - stride}; }
T origin;
T target;
T stride;
};
template<typename T = s64>
inline auto range(s64 size) {
return range_t<T>{0, size, 1};
}
template<typename T = s64>
inline auto range(s64 offset, s64 size) {
return range_t<T>{offset, size, 1};
}
template<typename T = s64>
inline auto range(s64 offset, s64 size, s64 step) {
return range_t<T>{offset, size, step};
}
//returns true if {offset ... offset+length-1} is within {min ... max} in range {lo ... hi}
template<s64 lo, s64 hi>
inline auto within(s64 offset, s64 length, s64 min, s64 max) -> bool {
static_assert(lo <= hi);
static constexpr s64 range = hi - lo + 1;
s64 lhs = (offset - lo) % range;
s64 rhs = (offset + length - 1) % range;
min = (min - lo) % range;
max = (max - lo) % range;
if(rhs < lhs) {
return lhs <= max || rhs >= min;
} else {
return max >= lhs && min <= rhs;
}
}
//returns index of target within {offset ... offset+length-1} in range {lo ... hi}
template<s64 lo, s64 hi>
inline auto within(s64 offset, s64 length, s64 target) -> maybe<u64> {
static_assert(lo <= hi);
static constexpr s64 range = hi - lo + 1;
s64 start = (offset - lo) % range;
s64 index = (target - lo) % range - start;
if(index < 0) index += range;
if(index < length) return index;
return {};
}
}
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