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| public struct Zip <Sequence1: Sequence, Sequence2: Sequence> { | |
| public struct ShortestSequence: Sequence { | |
| internal let sequence1: Sequence1 | |
| internal let sequence2: Sequence2 | |
| internal init (_ sequence1: Sequence1, _ sequence2: Sequence2) { | |
| (self.sequence1, self.sequence2) = (sequence1, sequence2) | |
| } | |
| public struct Iterator: IteratorProtocol { | |
| internal var iterator1: Sequence1.Iterator | |
| internal var iterator2: Sequence2.Iterator | |
| internal var reachedEnd = false | |
| internal init (_ iterator1: Sequence1.Iterator, _ iterator2: Sequence2.Iterator) { | |
| (self.iterator1, self.iterator2) = (iterator1, iterator2) | |
| } | |
| public mutating func next() -> (Sequence1.Iterator.Element, Sequence2.Iterator.Element)? { | |
| if self.reachedEnd { | |
| return nil | |
| } | |
| guard let element1 = self.iterator1.next(), let element2 = self.iterator2.next() else { | |
| self.reachedEnd.toggle() | |
| return nil | |
| } | |
| return (element1, element2) | |
| } | |
| } | |
| public func makeIterator () -> Iterator { | |
| return Iterator(self.sequence1.makeIterator(), self.sequence2.makeIterator()) | |
| } | |
| } | |
| public struct LongestSequence: Sequence { | |
| internal let sequence1: Sequence1 | |
| internal let sequence2: Sequence2 | |
| internal init (_ sequence1: Sequence1, _ sequence2: Sequence2) { | |
| (self.sequence1, self.sequence2) = (sequence1, sequence2) | |
| } | |
| public struct Iterator: IteratorProtocol { | |
| internal var iterator1: Sequence1.Iterator | |
| internal var iterator2: Sequence2.Iterator | |
| internal var reachedEnd = false | |
| internal init (_ iterator1: Sequence1.Iterator, _ iterator2: Sequence2.Iterator) { | |
| (self.iterator1, self.iterator2) = (iterator1, iterator2) | |
| } | |
| public mutating func next() -> (Sequence1.Iterator.Element?, Sequence2.Iterator.Element?)? { | |
| if self.reachedEnd { | |
| return nil | |
| } | |
| let element1 = self.iterator1.next() | |
| let element2 = self.iterator2.next() | |
| if element1 == nil && element2 == nil { | |
| self.reachedEnd.toggle() | |
| return nil | |
| } | |
| return (element1, element2) | |
| } | |
| } | |
| public func makeIterator () -> Iterator { | |
| return Iterator(self.sequence1.makeIterator(), self.sequence2.makeIterator()) | |
| } | |
| } | |
| } | |
| public func zip <Sequence1: Sequence, Sequence2: Sequence> (_ sequence1: Sequence1, _ sequence2: Sequence2) -> | |
| Zip<Sequence1, Sequence2>.ShortestSequence { | |
| return Zip.ShortestSequence(sequence1, sequence2) | |
| } | |
| public func zipLongest <Sequence1: Sequence, Sequence2: Sequence> (_ sequence1: Sequence1, _ sequence2: Sequence2) -> | |
| Zip<Sequence1, Sequence2>.LongestSequence { | |
| return Zip.LongestSequence(sequence1, sequence2) | |
| } | |
| extension Sequence { | |
| public func unzip <Type1, Type2> () -> ([Type1], [Type2]) where Self.Element == (Type1, Type2) { | |
| return self.reduce(into: ([Type1](), [Type2]())) { (result, element) in | |
| result.0.append(element.0) | |
| result.1.append(element.1) | |
| } | |
| } | |
| } | |
| @available(*, deprecated, renamed: "Zip.ShortestSequence") | |
| public typealias Zip2Sequence<Sequence1, Sequence2> = Zip<Sequence1, Sequence2>.ShortestSequence where | |
| Sequence1: Sequence, Sequence2: Sequence | |
| @available(*, deprecated, renamed: "Zip.ShortestSequence.Iterator") | |
| public typealias Zip2Iterator<Sequence1, Sequence2> = Zip<Sequence1, Sequence2>.ShortestSequence.Iterator where | |
| Sequence1: Sequence, Sequence2: Sequence |
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