62 lines
1.5 KiB
Swift
62 lines
1.5 KiB
Swift
//
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// Copyright (c) 2020 Open Whisper Systems. All rights reserved.
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//
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import Foundation
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public struct OrderedSet<Element> where Element: Hashable {
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public private(set) var orderedMembers: [Element] = []
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private var set: Set<Element> = []
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public init(_ members: [Element]) {
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set = []
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orderedMembers = []
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for element in members {
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append(element)
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}
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}
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@discardableResult
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public mutating func append(_ element: Element) -> (Bool, Element) {
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let (wasInserted, elementAfterInsert) = set.insert(element)
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if wasInserted {
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orderedMembers.append(element)
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}
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return (wasInserted, elementAfterInsert)
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}
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public mutating func remove(_ element: Element) {
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set.remove(element)
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orderedMembers = orderedMembers.filter { $0 != element }
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}
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public func contains(_ element: Element) -> Bool {
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return set.contains(element)
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}
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public var isEmpty: Bool {
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return set.isEmpty
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}
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public var count: Int {
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return set.count
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}
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public var first: Element? {
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return orderedMembers.first
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}
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// TODO: I only implemented the minimum API that I needed. There's lots more that could
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// reasonably be added to an OrderedSet (union, etc.)
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}
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extension OrderedSet: ExpressibleByArrayLiteral {
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public typealias ArrayLiteralElement = Element
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public init(arrayLiteral elements: Element...) {
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self.init(elements)
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}
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}
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