bsnes/nall/primitives/bit-range.hpp

64 lines
2.6 KiB
C++

#pragma once
namespace nall {
template<int Precision> struct BitRange {
static_assert(Precision >= 1 && Precision <= 64);
static inline constexpr auto bits() -> uint { return Precision; }
using utype =
typename conditional<bits() <= 8, uint8_t,
typename conditional<bits() <= 16, uint16_t,
typename conditional<bits() <= 32, uint32_t,
typename conditional<bits() <= 64, uint64_t,
void>::type>::type>::type>::type;
static inline constexpr auto mask() -> utype { return ~0ull >> 64 - bits(); }
inline BitRange(utype& source, int lo, int hi) : source(source) {
if(lo < 0) lo = Precision + lo;
if(hi < 0) hi = Precision + hi;
if(lo > hi) swap(lo, hi);
this->lo = lo;
this->hi = hi;
}
inline auto& operator=(BitRange& source) { return set(source.get()); }
inline auto operator++(int) { auto value = get(); set(value + 1); return value; }
inline auto operator--(int) { auto value = get(); set(value - 1); return value; }
inline auto& operator++() { return set(get() + 1); }
inline auto& operator--() { return set(get() - 1); }
inline operator utype() const { return get(); }
template<typename T> inline auto& operator =(const T& value) { return set( value); }
template<typename T> inline auto& operator *=(const T& value) { return set(get() * value); }
template<typename T> inline auto& operator /=(const T& value) { return set(get() / value); }
template<typename T> inline auto& operator %=(const T& value) { return set(get() % value); }
template<typename T> inline auto& operator +=(const T& value) { return set(get() + value); }
template<typename T> inline auto& operator -=(const T& value) { return set(get() - value); }
template<typename T> inline auto& operator<<=(const T& value) { return set(get() << value); }
template<typename T> inline auto& operator>>=(const T& value) { return set(get() >> value); }
template<typename T> inline auto& operator &=(const T& value) { return set(get() & value); }
template<typename T> inline auto& operator ^=(const T& value) { return set(get() ^ value); }
template<typename T> inline auto& operator |=(const T& value) { return set(get() | value); }
private:
inline auto get() const -> utype {
const utype rangeBits = hi - lo + 1;
const utype rangeMask = (1ull << rangeBits) - 1 << lo & mask();
return (source & rangeMask) >> lo;
}
inline auto& set(const utype& value) {
const utype rangeBits = hi - lo + 1;
const utype rangeMask = (1ull << rangeBits) - 1 << lo & mask();
source = source & ~rangeMask | value << lo & rangeMask;
return *this;
}
utype& source;
uint lo;
uint hi;
};
}