68 lines
1.7 KiB
C++
68 lines
1.7 KiB
C++
/*
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* Copyright (c) Facebook, Inc. and its affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*/
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#pragma once
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#include <cstdio>
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#include <cstdint>
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#include "YGEnums.h"
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namespace facebook {
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namespace yoga {
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namespace detail {
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constexpr size_t log2ceilFn(size_t n) {
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return n < 1 ? 0 : (1 + log2ceilFn(n / 2));
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}
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constexpr int mask(size_t bitWidth, size_t index) {
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return ((1 << bitWidth) - 1) << index;
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}
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// The number of bits necessary to represent enums defined with YG_ENUM_SEQ_DECL
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template <typename Enum>
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constexpr size_t bitWidthFn() {
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static_assert(
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enums::count<Enum>() > 0, "Enums must have at least one entries");
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return log2ceilFn(enums::count<Enum>() - 1);
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}
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template <typename Enum>
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constexpr Enum getEnumData(int flags, size_t index) {
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return static_cast<Enum>((flags & mask(bitWidthFn<Enum>(), index)) >> index);
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}
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template <typename Enum>
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void setEnumData(uint32_t& flags, size_t index, int newValue) {
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flags = (flags & ~mask(bitWidthFn<Enum>(), index)) |
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((newValue << index) & (mask(bitWidthFn<Enum>(), index)));
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}
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template <typename Enum>
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void setEnumData(uint8_t& flags, size_t index, int newValue) {
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flags = (flags & ~static_cast<uint8_t>(mask(bitWidthFn<Enum>(), index))) |
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((newValue << index) &
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(static_cast<uint8_t>(mask(bitWidthFn<Enum>(), index))));
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}
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constexpr bool getBooleanData(int flags, size_t index) {
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return (flags >> index) & 1;
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}
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inline void setBooleanData(uint8_t& flags, size_t index, bool value) {
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if (value) {
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flags |= 1 << index;
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} else {
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flags &= ~(1 << index);
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}
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}
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} // namespace detail
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} // namespace yoga
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} // namespace facebook
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