src/tint/utils/enum_set.h - dawn - Git at Google

 // Copyright 2021 The Tint 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_TINT_UTILS_ENUM_SET_H_
 #define SRC_TINT_UTILS_ENUM_SET_H_

 #include <cstdint>
 #include <functional>
 #include <type_traits>
 #include <utility>

 #include "src/tint/utils/string_stream.h"

 namespace tint::utils {

 /// EnumSet is a set of enum values.
 /// @note As the EnumSet is backed by a single uint64_t value, it can only hold
 /// enum values in the range [0 .. 63].
 template <typename ENUM>
 struct EnumSet {
   public:
     /// Enum is the enum type this EnumSet wraps
     using Enum = ENUM;

     /// Constructor. Initializes the EnumSet with zero.
     constexpr EnumSet() = default;

     /// Copy constructor.
     /// @param s the set to copy
     constexpr EnumSet(const EnumSet& s) = default;

     /// Constructor. Initializes the EnumSet with the given values.
     /// @param values the enumerator values to construct the set with
     template <typename... VALUES>
     explicit constexpr EnumSet(VALUES... values) : set(Union(values...)) {}

     /// Copy assignment operator.
     /// @param set the set to assign to this set
     /// @return this set so calls can be chained
     inline EnumSet& operator=(const EnumSet& set) = default;

     /// Copy assignment operator.
     /// @param e the enum value
     /// @return this set so calls can be chained
     inline EnumSet& operator=(Enum e) { return *this = EnumSet{e}; }

     /// Adds all the given values to this set
     /// @param values the values to add
     /// @return this set so calls can be chained
     template <typename... VALUES>
     inline EnumSet& Add(VALUES... values) {
         return Add(EnumSet(std::forward<VALUES>(values)...));
     }

     /// Removes all the given values from this set
     /// @param values the values to remove
     /// @return this set so calls can be chained
     template <typename... VALUES>
     inline EnumSet& Remove(VALUES... values) {
         return Remove(EnumSet(std::forward<VALUES>(values)...));
     }

     /// Adds all of s to this set
     /// @param s the enum value
     /// @return this set so calls can be chained
     inline EnumSet& Add(EnumSet s) { return (*this = *this + s); }

     /// Removes all of s from this set
     /// @param s the enum value
     /// @return this set so calls can be chained
     inline EnumSet& Remove(EnumSet s) { return (*this = *this - s); }

     /// @param e the enum value
     /// @returns a copy of this set with e added
     inline EnumSet operator+(Enum e) const {
         EnumSet out;
         out.set = set | Bit(e);
         return out;
     }

     /// @param e the enum value
     /// @returns a copy of this set with e removed
     inline EnumSet operator-(Enum e) const {
         EnumSet out;
         out.set = set & ~Bit(e);
         return out;
     }

     /// @param s the other set
     /// @returns the union of this set with s (this ∪ rhs)
     inline EnumSet operator+(EnumSet s) const {
         EnumSet out;
         out.set = set | s.set;
         return out;
     }

     /// @param s the other set
     /// @returns the set of entries found in this but not in s (this \ s)
     inline EnumSet operator-(EnumSet s) const {
         EnumSet out;
         out.set = set & ~s.set;
         return out;
     }

     /// @param s the other set
     /// @returns the intersection of this set with s (this ∩ rhs)
     inline EnumSet operator&(EnumSet s) const {
         EnumSet out;
         out.set = set & s.set;
         return out;
     }

     /// @param e the enum value
     /// @return true if the set contains `e`
     inline bool Contains(Enum e) const { return (set & Bit(e)) != 0; }

     /// @return true if the set is empty
     inline bool Empty() const { return set == 0; }

     /// Equality operator
     /// @param rhs the other EnumSet to compare this to
     /// @return true if this EnumSet is equal to rhs
     inline bool operator==(EnumSet rhs) const { return set == rhs.set; }

     /// Inequality operator
     /// @param rhs the other EnumSet to compare this to
     /// @return true if this EnumSet is not equal to rhs
     inline bool operator!=(EnumSet rhs) const { return set != rhs.set; }

     /// Equality operator
     /// @param rhs the enum to compare this to
     /// @return true if this EnumSet only contains `rhs`
     inline bool operator==(Enum rhs) const { return set == Bit(rhs); }

     /// Inequality operator
     /// @param rhs the enum to compare this to
     /// @return false if this EnumSet only contains `rhs`
     inline bool operator!=(Enum rhs) const { return set != Bit(rhs); }

     /// @return the underlying value for the EnumSet
     inline uint64_t Value() const { return set; }

     /// Iterator provides read-only, unidirectional iterator over the enums of an
     /// EnumSet.
     class Iterator {
         static constexpr int8_t kEnd = 63;

         Iterator(uint64_t s, int8_t b) : set(s), pos(b) {}

         /// Make the constructor accessible to the EnumSet.
         friend struct EnumSet;

       public:
         /// @return the Enum value at this point in the iterator
         Enum operator*() const { return static_cast<Enum>(pos); }

         /// Increments the iterator
         /// @returns this iterator
         Iterator& operator++() {
             while (pos < kEnd) {
                 pos++;
                 if (set & (static_cast<uint64_t>(1) << static_cast<uint64_t>(pos))) {
                     break;
                 }
             }
             return *this;
         }

         /// Equality operator
         /// @param rhs the Iterator to compare this to
         /// @return true if the two iterators are equal
         bool operator==(const Iterator& rhs) const { return set == rhs.set && pos == rhs.pos; }

         /// Inequality operator
         /// @param rhs the Iterator to compare this to
         /// @return true if the two iterators are different
         bool operator!=(const Iterator& rhs) const { return !(*this == rhs); }

       private:
         const uint64_t set;
         int8_t pos;
     };

     /// @returns an read-only iterator to the beginning of the set
     Iterator begin() const {
         auto it = Iterator{set, -1};
         ++it;  // Move to first set bit
         return it;
     }

     /// @returns an iterator to the beginning of the set
     Iterator end() const { return Iterator{set, Iterator::kEnd}; }

   private:
     static constexpr uint64_t Bit(Enum value) {
         return static_cast<uint64_t>(1) << static_cast<uint64_t>(value);
     }

     static constexpr uint64_t Union() { return 0; }

     template <typename FIRST, typename... VALUES>
     static constexpr uint64_t Union(FIRST first, VALUES... values) {
         return Bit(first) | Union(values...);
     }

     uint64_t set = 0;
 };

 /// Writes the EnumSet to the stream.
 /// @param out the stream to write to
 /// @param set the EnumSet to write
 /// @returns out so calls can be chained
 template <typename ENUM>
 inline utils::StringStream& operator<<(utils::StringStream& out, EnumSet<ENUM> set) {
     out << "{";
     bool first = true;
     for (auto e : set) {
         if (!first) {
             out << ", ";
         }
         first = false;
         out << e;
     }
     return out << "}";
 }

 }  // namespace tint::utils

 namespace std {

 /// Custom std::hash specialization for tint::utils::EnumSet<T>
 template <typename T>
 class hash<tint::utils::EnumSet<T>> {
   public:
     /// @param e the EnumSet to create a hash for
     /// @return the hash value
     inline std::size_t operator()(const tint::utils::EnumSet<T>& e) const {
         return std::hash<uint64_t>()(e.Value());
     }
 };

 }  // namespace std

 #endif  // SRC_TINT_UTILS_ENUM_SET_H_
	// Copyright 2021 The Tint 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_TINT_UTILS_ENUM_SET_H_
	#define SRC_TINT_UTILS_ENUM_SET_H_

	#include <cstdint>
	#include <functional>
	#include <type_traits>
	#include <utility>

	#include "src/tint/utils/string_stream.h"

	namespace tint::utils {

	/// EnumSet is a set of enum values.
	/// @note As the EnumSet is backed by a single uint64_t value, it can only hold
	/// enum values in the range [0 .. 63].
	template <typename ENUM>
	struct EnumSet {
	public:
	/// Enum is the enum type this EnumSet wraps
	using Enum = ENUM;

	/// Constructor. Initializes the EnumSet with zero.
	constexpr EnumSet() = default;

	/// Copy constructor.
	/// @param s the set to copy
	constexpr EnumSet(const EnumSet& s) = default;

	/// Constructor. Initializes the EnumSet with the given values.
	/// @param values the enumerator values to construct the set with
	template <typename... VALUES>
	explicit constexpr EnumSet(VALUES... values) : set(Union(values...)) {}

	/// Copy assignment operator.
	/// @param set the set to assign to this set
	/// @return this set so calls can be chained
	inline EnumSet& operator=(const EnumSet& set) = default;

	/// Copy assignment operator.
	/// @param e the enum value
	/// @return this set so calls can be chained
	inline EnumSet& operator=(Enum e) { return *this = EnumSet{e}; }

	/// Adds all the given values to this set
	/// @param values the values to add
	/// @return this set so calls can be chained
	template <typename... VALUES>
	inline EnumSet& Add(VALUES... values) {
	return Add(EnumSet(std::forward<VALUES>(values)...));
	}

	/// Removes all the given values from this set
	/// @param values the values to remove
	/// @return this set so calls can be chained
	template <typename... VALUES>
	inline EnumSet& Remove(VALUES... values) {
	return Remove(EnumSet(std::forward<VALUES>(values)...));
	}

	/// Adds all of s to this set
	/// @param s the enum value
	/// @return this set so calls can be chained
	inline EnumSet& Add(EnumSet s) { return (this = this + s); }

	/// Removes all of s from this set
	/// @param s the enum value
	/// @return this set so calls can be chained
	inline EnumSet& Remove(EnumSet s) { return (this = this - s); }

	/// @param e the enum value
	/// @returns a copy of this set with e added
	inline EnumSet operator+(Enum e) const {
	EnumSet out;
	out.set = set \| Bit(e);
	return out;
	}

	/// @param e the enum value
	/// @returns a copy of this set with e removed
	inline EnumSet operator-(Enum e) const {
	EnumSet out;
	out.set = set & ~Bit(e);
	return out;
	}

	/// @param s the other set
	/// @returns the union of this set with s (this ∪ rhs)
	inline EnumSet operator+(EnumSet s) const {
	EnumSet out;
	out.set = set \| s.set;
	return out;
	}

	/// @param s the other set
	/// @returns the set of entries found in this but not in s (this \ s)
	inline EnumSet operator-(EnumSet s) const {
	EnumSet out;
	out.set = set & ~s.set;
	return out;
	}

	/// @param s the other set
	/// @returns the intersection of this set with s (this ∩ rhs)
	inline EnumSet operator&(EnumSet s) const {
	EnumSet out;
	out.set = set & s.set;
	return out;
	}

	/// @param e the enum value
	/// @return true if the set contains `e`
	inline bool Contains(Enum e) const { return (set & Bit(e)) != 0; }

	/// @return true if the set is empty
	inline bool Empty() const { return set == 0; }

	/// Equality operator
	/// @param rhs the other EnumSet to compare this to
	/// @return true if this EnumSet is equal to rhs
	inline bool operator==(EnumSet rhs) const { return set == rhs.set; }

	/// Inequality operator
	/// @param rhs the other EnumSet to compare this to
	/// @return true if this EnumSet is not equal to rhs
	inline bool operator!=(EnumSet rhs) const { return set != rhs.set; }

	/// Equality operator
	/// @param rhs the enum to compare this to
	/// @return true if this EnumSet only contains `rhs`
	inline bool operator==(Enum rhs) const { return set == Bit(rhs); }

	/// Inequality operator
	/// @param rhs the enum to compare this to
	/// @return false if this EnumSet only contains `rhs`
	inline bool operator!=(Enum rhs) const { return set != Bit(rhs); }

	/// @return the underlying value for the EnumSet
	inline uint64_t Value() const { return set; }

	/// Iterator provides read-only, unidirectional iterator over the enums of an
	/// EnumSet.
	class Iterator {
	static constexpr int8_t kEnd = 63;

	Iterator(uint64_t s, int8_t b) : set(s), pos(b) {}

	/// Make the constructor accessible to the EnumSet.
	friend struct EnumSet;

	public:
	/// @return the Enum value at this point in the iterator
	Enum operator*() const { return static_cast<Enum>(pos); }

	/// Increments the iterator
	/// @returns this iterator
	Iterator& operator++() {
	while (pos < kEnd) {
	pos++;
	if (set & (static_cast<uint64_t>(1) << static_cast<uint64_t>(pos))) {
	break;
	}
	}
	return *this;
	}

	/// Equality operator
	/// @param rhs the Iterator to compare this to
	/// @return true if the two iterators are equal
	bool operator==(const Iterator& rhs) const { return set == rhs.set && pos == rhs.pos; }

	/// Inequality operator
	/// @param rhs the Iterator to compare this to
	/// @return true if the two iterators are different
	bool operator!=(const Iterator& rhs) const { return !(*this == rhs); }

	private:
	const uint64_t set;
	int8_t pos;
	};

	/// @returns an read-only iterator to the beginning of the set
	Iterator begin() const {
	auto it = Iterator{set, -1};
	++it; // Move to first set bit
	return it;
	}

	/// @returns an iterator to the beginning of the set
	Iterator end() const { return Iterator{set, Iterator::kEnd}; }

	private:
	static constexpr uint64_t Bit(Enum value) {
	return static_cast<uint64_t>(1) << static_cast<uint64_t>(value);
	}

	static constexpr uint64_t Union() { return 0; }

	template <typename FIRST, typename... VALUES>
	static constexpr uint64_t Union(FIRST first, VALUES... values) {
	return Bit(first) \| Union(values...);
	}

	uint64_t set = 0;
	};

	/// Writes the EnumSet to the stream.
	/// @param out the stream to write to
	/// @param set the EnumSet to write
	/// @returns out so calls can be chained
	template <typename ENUM>
	inline utils::StringStream& operator<<(utils::StringStream& out, EnumSet<ENUM> set) {
	out << "{";
	bool first = true;
	for (auto e : set) {
	if (!first) {
	out << ", ";
	}
	first = false;
	out << e;
	}
	return out << "}";
	}

	} // namespace tint::utils

	namespace std {

	/// Custom std::hash specialization for tint::utils::EnumSet<T>
	template <typename T>
	class hash<tint::utils::EnumSet<T>> {
	public:
	/// @param e the EnumSet to create a hash for
	/// @return the hash value
	inline std::size_t operator()(const tint::utils::EnumSet<T>& e) const {
	return std::hash<uint64_t>()(e.Value());
	}
	};

	} // namespace std

	#endif // SRC_TINT_UTILS_ENUM_SET_H_