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Diffstat (limited to 'include/EASTL/bit.h')
| -rw-r--r-- | include/EASTL/bit.h | 172 |
1 files changed, 0 insertions, 172 deletions
diff --git a/include/EASTL/bit.h b/include/EASTL/bit.h deleted file mode 100644 index 0eeeed0..0000000 --- a/include/EASTL/bit.h +++ /dev/null @@ -1,172 +0,0 @@ -///////////////////////////////////////////////////////////////////////////// -// Copyright (c) Electronic Arts Inc. All rights reserved. -///////////////////////////////////////////////////////////////////////////// - -#ifndef EASTL_BIT_H -#define EASTL_BIT_H - -#include <EASTL/internal/config.h> - -#if defined(EA_PRAGMA_ONCE_SUPPORTED) - #pragma once -#endif - -#include <EASTL/internal/memory_base.h> -#include <EASTL/type_traits.h> -#include <string.h> // memcpy - -namespace eastl -{ - // eastl::bit_cast - // Obtains a value of type To by reinterpreting the object representation of 'from'. - // Every bit in the value representation of the returned To object is equal to the - // corresponding bit in the object representation of 'from'. - // - // In order for bit_cast to be constexpr, the compiler needs to explicitly support - // it by providing the __builtin_bit_cast builtin. If that builtin is not available, - // then we memcpy into aligned storage at runtime and return that instead. - // - // Both types To and From must be equal in size, and must be trivially copyable. - - #if defined(EASTL_CONSTEXPR_BIT_CAST_SUPPORTED) && EASTL_CONSTEXPR_BIT_CAST_SUPPORTED - - template<typename To, typename From, - typename = eastl::enable_if_t< - sizeof(To) == sizeof(From) - && eastl::is_trivially_copyable<To>::value - && eastl::is_trivially_copyable<From>::value - > - > - EA_CONSTEXPR To bit_cast(const From& from) EA_NOEXCEPT - { - return __builtin_bit_cast(To, from); - } - - #else - - template<typename To, typename From, - typename = eastl::enable_if_t< - sizeof(To) == sizeof(From) - && eastl::is_trivially_copyable<To>::value - && eastl::is_trivially_copyable<From>::value - > - > - inline To bit_cast(const From& from) EA_NOEXCEPT - { - typename eastl::aligned_storage<sizeof(To), alignof(To)>::type to; - ::memcpy(eastl::addressof(to), eastl::addressof(from), sizeof(To)); - return reinterpret_cast<To&>(to); - } - - #endif // EASTL_CONSTEXPR_BIT_CAST_SUPPORTED - - #if defined(EA_COMPILER_CPP20_ENABLED) - #ifndef EASTL_COUNT_LEADING_ZEROES - #if defined(__GNUC__) - #if (EA_PLATFORM_PTR_SIZE == 8) - #define EASTL_COUNT_LEADING_ZEROES __builtin_clzll - #else - #define EASTL_COUNT_LEADING_ZEROES __builtin_clz - #endif - #endif - - #ifndef EASTL_COUNT_LEADING_ZEROES - static inline int eastl_count_leading_zeroes(uint64_t x) - { - if(x) - { - int n = 0; - if(x & UINT64_C(0xFFFFFFFF00000000)) { n += 32; x >>= 32; } - if(x & 0xFFFF0000) { n += 16; x >>= 16; } - if(x & 0xFFFFFF00) { n += 8; x >>= 8; } - if(x & 0xFFFFFFF0) { n += 4; x >>= 4; } - if(x & 0xFFFFFFFC) { n += 2; x >>= 2; } - if(x & 0xFFFFFFFE) { n += 1; } - return 63 - n; - } - return 64; - } - - static inline int eastl_count_leading_zeroes(uint32_t x) - { - if(x) - { - int n = 0; - if(x <= 0x0000FFFF) { n += 16; x <<= 16; } - if(x <= 0x00FFFFFF) { n += 8; x <<= 8; } - if(x <= 0x0FFFFFFF) { n += 4; x <<= 4; } - if(x <= 0x3FFFFFFF) { n += 2; x <<= 2; } - if(x <= 0x7FFFFFFF) { n += 1; } - return n; - } - return 32; - } - - #define EASTL_COUNT_LEADING_ZEROES eastl_count_leading_zeroes - #endif - #endif - - template <typename T, typename = eastl::enable_if_t<eastl::is_unsigned_v<T>>> - EA_CONSTEXPR int countl_zero(const T num) EA_NOEXCEPT - { - EA_CONSTEXPR auto DIGITS = eastl::numeric_limits<T>::digits; - EA_CONSTEXPR auto DIGITS_U = eastl::numeric_limits<unsigned>::digits; - EA_CONSTEXPR auto DIGITS_ULL = eastl::numeric_limits<unsigned long long>::digits; - - if (num == 0) - { - return DIGITS; - } - - if constexpr (DIGITS <= DIGITS_U) - { - EA_CONSTEXPR auto DIFF = DIGITS_U - DIGITS; - return EASTL_COUNT_LEADING_ZEROES(static_cast<uint32_t>(num)) - DIFF; - } - else - { - EA_CONSTEXPR auto DIFF = DIGITS_ULL - DIGITS; - return EASTL_COUNT_LEADING_ZEROES(static_cast<uint64_t>(num)) - DIFF; - } - } - - template <typename T, typename = eastl::enable_if_t<eastl::is_unsigned_v<T>>> - EA_CONSTEXPR bool has_single_bit(const T num) EA_NOEXCEPT - { - return num != 0 && (num & (num - 1)) == 0; - } - - template <typename T, typename = eastl::enable_if_t<eastl::is_unsigned_v<T>>> - EA_CONSTEXPR T bit_ceil(const T num) EA_NOEXCEPT - { - if (num <= 1U) - { - return T(1); - } - - const auto shift = eastl::numeric_limits<T>::digits - eastl::countl_zero(static_cast<T>(num - 1)); - return static_cast<T>(T(1) << shift); - } - - template <typename T, typename = eastl::enable_if_t<eastl::is_unsigned_v<T>>> - EA_CONSTEXPR T bit_floor(const T num) EA_NOEXCEPT - { - if (num == 0) - { - return T(0); - } - - const auto shift = eastl::numeric_limits<T>::digits - eastl::countl_zero(num) - 1; - return static_cast<T>(T(1) << shift); - } - - template <typename T, typename = eastl::enable_if_t<eastl::is_unsigned_v<T>>> - EA_CONSTEXPR T bit_width(const T num) EA_NOEXCEPT - { - return static_cast<T>(eastl::numeric_limits<T>::digits - eastl::countl_zero(num)); - } - #endif - -} // namespace eastl - -#endif // EASTL_BIT_H |