blob: 2436c8aa6565bb0303bf385fd6cad773aa857865 [file] [log] [blame]
/*
* Copyright 2021 Google LLC
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkEnumBitMask_DEFINED
#define SkEnumBitMask_DEFINED
#include "include/private/base/SkAttributes.h"
/**
* Wraps an enum that is used for flags, and enables masking with type safety. Example:
*
* enum class MyFlags {
* kNone = 0,
* kA = 1,
* kB = 2,
* kC = 4,
* };
*
* SK_MAKE_BITMASK_OPS(MyFlags)
*
* ...
*
* SkEnumBitMask<MyFlags> flags = MyFlags::kA | MyFlags::kB;
*
* if (flags & MyFlags::kB) {}
*
* ...
*/
template<typename E>
class SkEnumBitMask {
public:
SK_ALWAYS_INLINE constexpr SkEnumBitMask(E e) : SkEnumBitMask((int)e) {}
SK_ALWAYS_INLINE constexpr explicit operator bool() const { return fValue; }
SK_ALWAYS_INLINE constexpr int value() const { return fValue; }
SK_ALWAYS_INLINE constexpr bool operator==(SkEnumBitMask m) const { return fValue == m.fValue; }
SK_ALWAYS_INLINE constexpr bool operator!=(SkEnumBitMask m) const { return fValue != m.fValue; }
SK_ALWAYS_INLINE constexpr SkEnumBitMask operator|(SkEnumBitMask m) const {
return SkEnumBitMask(fValue | m.fValue);
}
SK_ALWAYS_INLINE constexpr SkEnumBitMask operator&(SkEnumBitMask m) const {
return SkEnumBitMask(fValue & m.fValue);
}
SK_ALWAYS_INLINE constexpr SkEnumBitMask operator^(SkEnumBitMask m) const {
return SkEnumBitMask(fValue ^ m.fValue);
}
SK_ALWAYS_INLINE constexpr SkEnumBitMask operator~() const { return SkEnumBitMask(~fValue); }
SK_ALWAYS_INLINE SkEnumBitMask& operator|=(SkEnumBitMask m) { return *this = *this | m; }
SK_ALWAYS_INLINE SkEnumBitMask& operator&=(SkEnumBitMask m) { return *this = *this & m; }
SK_ALWAYS_INLINE SkEnumBitMask& operator^=(SkEnumBitMask m) { return *this = *this ^ m; }
private:
SK_ALWAYS_INLINE constexpr explicit SkEnumBitMask(int value) : fValue(value) {}
int fValue;
};
/**
* Defines functions that make it possible to use bitwise operators on an enum.
*/
#define SK_MAKE_BITMASK_OPS(E) \
[[maybe_unused]] constexpr SkEnumBitMask<E> operator|(E a, E b) { \
return SkEnumBitMask<E>(a) | b; \
} \
[[maybe_unused]] constexpr SkEnumBitMask<E> operator&(E a, E b) { \
return SkEnumBitMask<E>(a) & b; \
} \
[[maybe_unused]] constexpr SkEnumBitMask<E> operator^(E a, E b) { \
return SkEnumBitMask<E>(a) ^ b; \
} \
[[maybe_unused]] constexpr SkEnumBitMask<E> operator~(E e) { \
return ~SkEnumBitMask<E>(e); \
}
#define SK_DECL_BITMASK_OPS_FRIENDS(E) \
friend constexpr SkEnumBitMask<E> operator|(E, E); \
friend constexpr SkEnumBitMask<E> operator&(E, E); \
friend constexpr SkEnumBitMask<E> operator^(E, E); \
friend constexpr SkEnumBitMask<E> operator~(E);
#endif // SkEnumBitMask_DEFINED