bsnes/nall/primitives/bit-range.hpp

59 lines
2.6 KiB
C++

#pragma once
namespace nall {
template<int RequestedPrecision> struct BitRange {
enum : uint { Precision = RequestedPrecision < 1 ? 1 : RequestedPrecision > 64 ? 64 : RequestedPrecision };
static inline constexpr auto bits() -> uint { return Precision; }
using type =
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() -> type { return ~0ull >> 64 - bits(); }
inline BitRange(type& source, uint low, uint high)
: source(source), lo(low < high ? low : high), hi(high > low ? high : low) {}
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 uint64_t() 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 -> uint64_t {
const type rangeBits = hi - lo + 1;
const type rangeMask = (1ull << rangeBits) - 1 << lo & mask();
return (source & rangeMask) >> lo;
}
inline auto& set(const type& value) {
const type rangeBits = hi - lo + 1;
const type rangeMask = (1ull << rangeBits) - 1 << lo & mask();
source = source & ~rangeMask | value << lo & rangeMask;
return *this;
}
type& source;
const uint lo;
const uint hi;
};
}