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// Copyright 2017 The Dawn Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef SRC_DAWN_COMMON_MATH_H_
#define SRC_DAWN_COMMON_MATH_H_
#include <cstddef>
#include <cstdint>
#include <cstring>
#include <limits>
#include <optional>
#include <type_traits>
#include "dawn/common/Assert.h"
// The following are not valid for 0
uint32_t ScanForward(uint32_t bits);
uint32_t Log2(uint32_t value);
uint32_t Log2(uint64_t value);
bool IsPowerOfTwo(uint64_t n);
uint64_t RoundUp(uint64_t n, uint64_t m);
constexpr uint32_t ConstexprLog2(uint64_t v) {
return v <= 1 ? 0 : 1 + ConstexprLog2(v / 2);
}
constexpr uint32_t ConstexprLog2Ceil(uint64_t v) {
return v <= 1 ? 0 : ConstexprLog2(v - 1) + 1;
}
inline uint32_t Log2Ceil(uint32_t v) {
return v <= 1 ? 0 : Log2(v - 1) + 1;
}
inline uint32_t Log2Ceil(uint64_t v) {
return v <= 1 ? 0 : Log2(v - 1) + 1;
}
uint64_t NextPowerOfTwo(uint64_t n);
bool IsPtrAligned(const void* ptr, size_t alignment);
void* AlignVoidPtr(void* ptr, size_t alignment);
bool IsAligned(uint32_t value, size_t alignment);
template <typename T>
T Align(T value, size_t alignment) {
ASSERT(value <= std::numeric_limits<T>::max() - (alignment - 1));
ASSERT(IsPowerOfTwo(alignment));
ASSERT(alignment != 0);
T alignmentT = static_cast<T>(alignment);
return (value + (alignmentT - 1)) & ~(alignmentT - 1);
}
template <typename T, size_t Alignment>
constexpr size_t AlignSizeof() {
static_assert(Alignment != 0 && (Alignment & (Alignment - 1)) == 0,
"Alignment must be a valid power of 2.");
static_assert(sizeof(T) <= std::numeric_limits<size_t>::max() - (Alignment - 1));
return (sizeof(T) + (Alignment - 1)) & ~(Alignment - 1);
}
// Returns an aligned size for an n-sized array of T elements. If the size would overflow, returns
// nullopt instead.
template <typename T, size_t Alignment>
std::optional<size_t> AlignSizeofN(uint64_t n) {
constexpr uint64_t kMaxCountWithoutOverflows =
(std::numeric_limits<size_t>::max() - Alignment + 1) / sizeof(T);
if (n > kMaxCountWithoutOverflows) {
return std::nullopt;
}
return Align(sizeof(T) * n, Alignment);
}
template <typename T>
DAWN_FORCE_INLINE T* AlignPtr(T* ptr, size_t alignment) {
ASSERT(IsPowerOfTwo(alignment));
ASSERT(alignment != 0);
return reinterpret_cast<T*>((reinterpret_cast<size_t>(ptr) + (alignment - 1)) &
~(alignment - 1));
}
template <typename T>
DAWN_FORCE_INLINE const T* AlignPtr(const T* ptr, size_t alignment) {
ASSERT(IsPowerOfTwo(alignment));
ASSERT(alignment != 0);
return reinterpret_cast<const T*>((reinterpret_cast<size_t>(ptr) + (alignment - 1)) &
~(alignment - 1));
}
template <typename destType, typename sourceType>
destType BitCast(const sourceType& source) {
static_assert(sizeof(destType) == sizeof(sourceType), "BitCast: cannot lose precision.");
destType output;
std::memcpy(&output, &source, sizeof(destType));
return output;
}
uint16_t Float32ToFloat16(float fp32);
float Float16ToFloat32(uint16_t fp16);
bool IsFloat16NaN(uint16_t fp16);
template <typename T>
T FloatToUnorm(float value) {
return static_cast<T>(value * static_cast<float>(std::numeric_limits<T>::max()));
}
float SRGBToLinear(float srgb);
template <typename T1,
typename T2,
typename Enable = typename std::enable_if<sizeof(T1) == sizeof(T2)>::type>
constexpr bool IsSubset(T1 subset, T2 set) {
T2 bitsAlsoInSet = subset & set;
return bitsAlsoInSet == subset;
}
#endif // SRC_DAWN_COMMON_MATH_H_