mirror of https://github.com/bsnes-emu/bsnes.git
68 lines
2.7 KiB
C++
68 lines
2.7 KiB
C++
#pragma once
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namespace nall {
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//warning: so that BitRange can modify the underlying number directly, it must bind a reference.
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//as a result, auto value = number.bits() will capture by-reference, rather than by-value.
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template<int Precision> struct BitRange {
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static_assert(Precision >= 1 && Precision <= 64);
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static inline constexpr auto bits() -> uint { return Precision; }
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using utype =
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conditional_t<bits() <= 8, uint8_t,
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conditional_t<bits() <= 16, uint16_t,
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conditional_t<bits() <= 32, uint32_t,
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conditional_t<bits() <= 64, uint64_t,
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void>>>>;
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static inline constexpr auto mask() -> utype { return ~0ull >> 64 - bits(); }
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inline BitRange(utype& source, int lo, int hi) : source(source) {
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if(lo < 0) lo = Precision + lo;
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if(hi < 0) hi = Precision + hi;
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if(lo > hi) swap(lo, hi);
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this->lo = lo;
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this->hi = hi;
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}
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inline auto& operator=(BitRange& source) { return set(source.get()); }
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inline operator utype() const { return get(); }
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inline auto operator++(int) { auto value = get(); set(value + 1); return value; }
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inline auto operator--(int) { auto value = get(); set(value - 1); return value; }
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inline auto& operator++() { return set(get() + 1); }
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inline auto& operator--() { return set(get() - 1); }
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template<typename T> inline auto& operator =(const T& value) { return set( value); }
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template<typename T> inline auto& operator *=(const T& value) { return set(get() * value); }
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template<typename T> inline auto& operator /=(const T& value) { return set(get() / value); }
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template<typename T> inline auto& operator %=(const T& value) { return set(get() % value); }
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template<typename T> inline auto& operator +=(const T& value) { return set(get() + value); }
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template<typename T> inline auto& operator -=(const T& value) { return set(get() - value); }
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template<typename T> inline auto& operator<<=(const T& value) { return set(get() << value); }
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template<typename T> inline auto& operator>>=(const T& value) { return set(get() >> value); }
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template<typename T> inline auto& operator &=(const T& value) { return set(get() & value); }
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template<typename T> inline auto& operator ^=(const T& value) { return set(get() ^ value); }
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template<typename T> inline auto& operator |=(const T& value) { return set(get() | value); }
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private:
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inline auto get() const -> utype {
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const utype rangeBits = hi - lo + 1;
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const utype rangeMask = (1ull << rangeBits) - 1 << lo & mask();
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return (source & rangeMask) >> lo;
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}
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inline auto& set(const utype& value) {
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const utype rangeBits = hi - lo + 1;
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const utype rangeMask = (1ull << rangeBits) - 1 << lo & mask();
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source = source & ~rangeMask | value << lo & rangeMask;
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return *this;
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}
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utype& source;
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uint lo;
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uint hi;
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};
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}
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