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improve bit slice, take care of edge case, move BitSliceType

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This commit is contained in:
CocoSimone
2022-05-09 10:22:12 +02:00
parent a2a6de65a1
commit 429541ab0c
2 changed files with 23 additions and 14 deletions
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11
src/core/common.hpp
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@@ -20,14 +20,3 @@ using m128 = __m128i;
#define INT128_MAX ((u128)0x7FFF'FFFF'FFFF'FFFF << 64) | 0xFFFF'FFFF'FFFF'FFFF #define INT128_MAX ((u128)0x7FFF'FFFF'FFFF'FFFF << 64) | 0xFFFF'FFFF'FFFF'FFFF
#define INT128_MIN (-INT128_MAX - 1LL) #define INT128_MIN (-INT128_MAX - 1LL)
template <u8 start, u8 end>
using BitSliceType =
std::conditional<(end - start) <= 7, u8,
std::conditional<(end - start) <= 15, u16,
std::conditional<(end - start) <= 31, u32,
std::conditional<(end - start) <= 63, u64,
std::conditional<(end - start) <= 127, u128, u128>
>
>
>
>;

26
src/core/util.hpp
View File

@@ -1,12 +1,32 @@
#pragma once #pragma once
#include <common.hpp> #include <common.hpp>
#include <type_traits> #include <type_traits>
#include <cassert>
namespace natsukashii::util { namespace natsukashii::util {
template <u8 start, u8 end>
using BitSliceType =
typename std::conditional<(end - start) <= 7, u8,
typename std::conditional<(end - start) <= 15, u16,
typename std::conditional<(end - start) <= 31, u32,
typename std::conditional<(end - start) <= 63, u64,
typename std::conditional<(end - start) <= 127, u128, void>::type
>::type
>::type
>::type
>::type;
template <u8 start, u8 end, typename T> template <u8 start, u8 end, typename T>
BitSliceType<start, end> BitSlice(const T& num) { BitSliceType<start, end> BitSlice(const T& num) {
static_assert(end - start > 127); static_assert(end < (sizeof(T) * 8) && start < (sizeof(T) * 8));
static_assert(end - start > sizeof(T)); constexpr auto correctedEnd = end == (sizeof(T) * 8) - 1 ? end : end + 1;
return (num >> start) & ((1 << end) - 1); return (num >> start) & ((1 << correctedEnd) - 1);
}
template <typename T>
T BitSlice(const T& num, int start, int end) {
assert(end < (sizeof(T) * 8) && start < (sizeof(T) * 8));
auto correctedEnd = end == (sizeof(T) * 8) - 1 ? end : end + 1;
return (num >> start) & ((1 << correctedEnd) - 1);
} }
} }