InlineEnumSet.kt

package inlineEnumSet

import java.util.EnumSet

inline class InlineEnumSet<T : Enum<T>>(val set: UInt) {
    companion object
}


//bit extraction functions

fun <T : Enum<T>> T.enumPosition() = 1u shl ordinal

inline fun <reified T : Enum<T>> allValuesMask() =
    generateSequence(1u) { (it shl 1) + 1u }.elementAt(enumValues<T>().lastIndex)


//creation functions

inline fun <T : Enum<T>> T.toSet() = InlineEnumSet<T>(enumPosition())

inline fun <T : Enum<T>> InlineEnumSet.Companion.emptySet() = InlineEnumSet<T>(0u)

inline fun <reified T : Enum<T>> InlineEnumSet.Companion.allValues() = InlineEnumSet<T>(allValuesMask<T>())

inline fun <T : Enum<T>> InlineEnumSet.Companion.from(vararg values: T): InlineEnumSet<T> =
    InlineEnumSet(values.fold(0u) { acc, curr -> acc or curr.enumPosition() })


//check functions

inline operator fun <T : Enum<T>> InlineEnumSet<T>.contains(value: T): Boolean = (set and value.enumPosition()) != 0u

inline fun <T : Enum<T>> InlineEnumSet<T>.containsAll(other: InlineEnumSet<T>): Boolean = (other - this).isEmpty()

inline fun <T : Enum<T>> InlineEnumSet<T>.isEmpty(): Boolean = set == 0u

inline fun <reified T : Enum<T>> InlineEnumSet<T>.containsAllElements(): Boolean = set == allValuesMask<T>()


//bitwise functions

inline infix fun <T : Enum<T>> T.or(other: T): InlineEnumSet<T> =
    InlineEnumSet(enumPosition() or other.enumPosition())

inline infix fun <T : Enum<T>> InlineEnumSet<T>.or(other: T): InlineEnumSet<T> =
    InlineEnumSet(set or other.enumPosition())

inline infix fun <T : Enum<T>> InlineEnumSet<T>.or(other: InlineEnumSet<T>): InlineEnumSet<T> =
    InlineEnumSet(set or other.set)

inline infix fun <T : Enum<T>> InlineEnumSet<T>.xor(other: T): InlineEnumSet<T> =
    InlineEnumSet((set xor other.enumPosition()))

inline infix fun <T : Enum<T>> InlineEnumSet<T>.xor(other: InlineEnumSet<T>): InlineEnumSet<T> =
    InlineEnumSet((set xor other.set))

inline infix fun <T : Enum<T>> InlineEnumSet<T>.and(other: InlineEnumSet<T>): InlineEnumSet<T> =
    InlineEnumSet(set and other.set)

inline fun <reified T : Enum<T>> InlineEnumSet<T>.negate(): InlineEnumSet<T> =
    InlineEnumSet(set.inv() and allValuesMask<T>())


//arithmetic functions

inline operator fun <T : Enum<T>> InlineEnumSet<T>.plus(other: T): InlineEnumSet<T> = this or other

inline operator fun <T : Enum<T>> InlineEnumSet<T>.plus(other: InlineEnumSet<T>): InlineEnumSet<T> = this or other

inline operator fun <T : Enum<T>> InlineEnumSet<T>.minus(other: T): InlineEnumSet<T> =
    InlineEnumSet((set or other.enumPosition()) - other.enumPosition())

inline operator fun <T : Enum<T>> InlineEnumSet<T>.minus(other: InlineEnumSet<T>): InlineEnumSet<T> =
    InlineEnumSet((set or other.set) - other.set)


//space operation functions

inline infix fun <T : Enum<T>> InlineEnumSet<T>.intersect(other: InlineEnumSet<T>): InlineEnumSet<T> =
    this and other

inline infix fun <T : Enum<T>> InlineEnumSet<T>.union(other: InlineEnumSet<T>): InlineEnumSet<T> =
    this or other

inline infix fun <T : Enum<T>> InlineEnumSet<T>.symDiff(other: InlineEnumSet<T>): InlineEnumSet<T> =
    this xor other


//convert back to usual collections

inline fun <reified T : Enum<T>> InlineEnumSet<T>.toList(): List<T> = enumValues<T>().filter { it in this }

inline fun <reified T : Enum<T>> InlineEnumSet<T>.toBoxedSet(): EnumSet<T> = EnumSet.copyOf(toList())


fun main() {
    val set = Color.Red or Color.Blue
    val altSet = InlineEnumSet.from(Color.Green, Color.Blue)
    println(Color.Green in set)
}

enum class Color {
    Red,
    Green,
    Blue
}