michael@0: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* vim: set ts=8 sts=2 et sw=2 tw=80: */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: /* A set abstraction for enumeration values. */
michael@0: 
michael@0: #ifndef mozilla_EnumSet_h
michael@0: #define mozilla_EnumSet_h
michael@0: 
michael@0: #include "mozilla/Assertions.h"
michael@0: 
michael@0: #include <stdint.h>
michael@0: 
michael@0: namespace mozilla {
michael@0: 
michael@0: /**
michael@0:  * EnumSet<T> is a set of values defined by an enumeration. It is implemented
michael@0:  * using a 32 bit mask for each value so it will only work for enums with an int
michael@0:  * representation less than 32. It works both for enum and enum class types.
michael@0:  */
michael@0: template<typename T>
michael@0: class EnumSet
michael@0: {
michael@0:   public:
michael@0:     EnumSet()
michael@0:       : mBitField(0)
michael@0:     { }
michael@0: 
michael@0:     EnumSet(T aEnum)
michael@0:       : mBitField(aEnum)
michael@0:     { }
michael@0: 
michael@0:     EnumSet(T aEnum1, T aEnum2)
michael@0:       : mBitField(bitFor(aEnum1) |
michael@0:                   bitFor(aEnum2))
michael@0:     { }
michael@0: 
michael@0:     EnumSet(T aEnum1, T aEnum2, T aEnum3)
michael@0:       : mBitField(bitFor(aEnum1) |
michael@0:                   bitFor(aEnum2) |
michael@0:                   bitFor(aEnum3))
michael@0:     { }
michael@0: 
michael@0:     EnumSet(T aEnum1, T aEnum2, T aEnum3, T aEnum4)
michael@0:      : mBitField(bitFor(aEnum1) |
michael@0:                  bitFor(aEnum2) |
michael@0:                  bitFor(aEnum3) |
michael@0:                  bitFor(aEnum4))
michael@0:     { }
michael@0: 
michael@0:     EnumSet(const EnumSet& aEnumSet)
michael@0:      : mBitField(aEnumSet.mBitField)
michael@0:     { }
michael@0: 
michael@0:     /**
michael@0:      * Add an element
michael@0:      */
michael@0:     void operator+=(T aEnum) {
michael@0:       mBitField |= bitFor(aEnum);
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Add an element
michael@0:      */
michael@0:     EnumSet<T> operator+(T aEnum) const {
michael@0:       EnumSet<T> result(*this);
michael@0:       result += aEnum;
michael@0:       return result;
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Union
michael@0:      */
michael@0:     void operator+=(const EnumSet<T> aEnumSet) {
michael@0:       mBitField |= aEnumSet.mBitField;
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Union
michael@0:      */
michael@0:     EnumSet<T> operator+(const EnumSet<T> aEnumSet) const {
michael@0:       EnumSet<T> result(*this);
michael@0:       result += aEnumSet;
michael@0:       return result;
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Remove an element
michael@0:      */
michael@0:     void operator-=(T aEnum) {
michael@0:       mBitField &= ~(bitFor(aEnum));
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Remove an element
michael@0:      */
michael@0:     EnumSet<T> operator-(T aEnum) const {
michael@0:       EnumSet<T> result(*this);
michael@0:       result -= aEnum;
michael@0:       return result;
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Remove a set of elements
michael@0:      */
michael@0:     void operator-=(const EnumSet<T> aEnumSet) {
michael@0:       mBitField &= ~(aEnumSet.mBitField);
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Remove a set of elements
michael@0:      */
michael@0:     EnumSet<T> operator-(const EnumSet<T> aEnumSet) const {
michael@0:       EnumSet<T> result(*this);
michael@0:       result -= aEnumSet;
michael@0:       return result;
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Intersection
michael@0:      */
michael@0:     void operator&=(const EnumSet<T> aEnumSet) {
michael@0:       mBitField &= aEnumSet.mBitField;
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Intersection
michael@0:      */
michael@0:     EnumSet<T> operator&(const EnumSet<T> aEnumSet) const {
michael@0:       EnumSet<T> result(*this);
michael@0:       result &= aEnumSet;
michael@0:       return result;
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Equality
michael@0:      */
michael@0: 
michael@0:     bool operator==(const EnumSet<T> aEnumSet) const {
michael@0:       return mBitField == aEnumSet.mBitField;
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Test is an element is contained in the set
michael@0:      */
michael@0:     bool contains(T aEnum) const {
michael@0:       return mBitField & bitFor(aEnum);
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Return the number of elements in the set
michael@0:      */
michael@0: 
michael@0:     uint8_t size() {
michael@0:       uint8_t count = 0;
michael@0:       for (uint32_t bitField = mBitField; bitField; bitField >>= 1) {
michael@0:         if (bitField & 1)
michael@0:           count++;
michael@0:       }
michael@0:       return count;
michael@0:     }
michael@0: 
michael@0:   private:
michael@0:     static uint32_t bitFor(T aEnum) {
michael@0:       uint32_t bitNumber(aEnum);
michael@0:       MOZ_ASSERT(bitNumber < 32);
michael@0:       return 1U << bitNumber;
michael@0:     }
michael@0: 
michael@0:     uint32_t mBitField;
michael@0: };
michael@0: 
michael@0: } // namespace mozilla
michael@0: 
michael@0: #endif /* mozilla_EnumSet_h_*/