90 lines
2.4 KiB
Swift
90 lines
2.4 KiB
Swift
/*
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* Splitflap
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*
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* Copyright 2015-present Yannick Loriot.
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* http://yannickloriot.com
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*
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*/
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import Foundation
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/**
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A TokenGenerator helps the flap view by choosing the right token rescpecting the
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initial order.
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*/
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final class TokenGenerator: IteratorProtocol {
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typealias Element = String
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let tokens: [String]
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required init(tokens: [String]) {
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self.tokens = tokens
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}
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// MARK: - Implementing GeneratorType
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/// Current element index
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fileprivate var currentIndex = 0
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/// Returns the current element of the generator, nil otherwise.
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var currentElement: Element? {
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get {
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if currentIndex < tokens.count {
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return tokens[currentIndex]
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}
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return nil
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}
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set(newValue) {
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if let value = newValue {
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currentIndex = tokens.index(of: value) ?? currentIndex
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}
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else {
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currentIndex = 0
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}
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}
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}
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/// Advance to the next element and return it, or `nil` if no next.
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/// element exists.
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@discardableResult
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func next() -> Element? {
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let tokenCount = tokens.count
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guard tokenCount > 0 else {
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return nil
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}
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currentIndex = (currentIndex + 1) % tokens.count
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return tokens[currentIndex]
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}
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// MARK: - Convenience Methods
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/// Returns the first token, or `nil` if no token.
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var firstToken: String? {
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get {
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return tokens.first
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}
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}
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}
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