mirror of https://github.com/bsnes-emu/bsnes.git
86 lines
2.3 KiB
C++
Executable File
86 lines
2.3 KiB
C++
Executable File
#pragma once
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#include <nall/stdint.hpp>
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namespace nall {
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template<uint bits> inline auto uclamp(const uintmax x) -> uintmax {
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enum : uintmax { b = 1ull << (bits - 1), y = b * 2 - 1 };
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return y + ((x - y) & -(x < y)); //min(x, y);
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}
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template<uint bits> inline auto uclip(const uintmax x) -> uintmax {
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enum : uintmax { b = 1ull << (bits - 1), m = b * 2 - 1 };
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return (x & m);
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}
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template<uint bits> inline auto sclamp(const intmax x) -> intmax {
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enum : intmax { b = 1ull << (bits - 1), m = b - 1 };
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return (x > m) ? m : (x < -b) ? -b : x;
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}
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template<uint bits> inline auto sclip(const intmax x) -> intmax {
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enum : uintmax { b = 1ull << (bits - 1), m = b * 2 - 1 };
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return ((x & m) ^ b) - b;
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}
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namespace bit {
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constexpr inline auto mask(const char* s, uintmax sum = 0) -> uintmax {
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return (
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*s == '0' || *s == '1' ? mask(s + 1, (sum << 1) | 1) :
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*s == ' ' || *s == '_' ? mask(s + 1, sum) :
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*s ? mask(s + 1, sum << 1) :
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sum
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);
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}
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constexpr inline auto test(const char* s, uintmax sum = 0) -> uintmax {
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return (
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*s == '0' || *s == '1' ? test(s + 1, (sum << 1) | (*s - '0')) :
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*s == ' ' || *s == '_' ? test(s + 1, sum) :
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*s ? test(s + 1, sum << 1) :
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sum
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);
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}
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//lowest(0b1110) == 0b0010
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constexpr inline auto lowest(const uintmax x) -> uintmax {
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return x & -x;
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}
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//clear_lowest(0b1110) == 0b1100
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constexpr inline auto clearLowest(const uintmax x) -> uintmax {
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return x & (x - 1);
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}
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//set_lowest(0b0101) == 0b0111
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constexpr inline auto setLowest(const uintmax x) -> uintmax {
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return x | (x + 1);
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}
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//count number of bits set in a byte
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constexpr inline auto count(uintmax x) -> uint {
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uint count = 0;
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while(x) x &= x - 1, count++; //clear the least significant bit
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return count;
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}
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//return index of the first bit set (or zero of no bits are set)
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//first(0b1000) == 3
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constexpr inline auto first(uintmax x) -> uint {
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uint first = 0;
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while(x) { if(x & 1) break; x >>= 1; first++; }
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return first;
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}
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//round up to next highest single bit:
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//round(15) == 16, round(16) == 16, round(17) == 32
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constexpr inline auto round(uintmax x) -> uintmax {
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if((x & (x - 1)) == 0) return x;
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while(x & (x - 1)) x &= x - 1;
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return x << 1;
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}
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}
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}
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