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swift-mirror/stdlib/public/core/RandomAccessCollection.swift

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1.6 KiB
Swift

//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2016 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See http://swift.org/LICENSE.txt for license information
// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
// TODO: swift-3-indexing-model - Add in RandomAccessCollection protocol documentation
public protocol RandomAccessCollection : BidirectionalCollection {
associatedtype Index : Strideable
// FIXME(compiler limitation): where Index.Distance == IndexDistance
// FIXME(swift-3-indexing-model, design): does this requirement to conform to
// `Strideable` limit possible collection designs?
// FIXME(compiler limitation):
// associatedtype SubSequence : RandomAccessCollection
// FIXME(compiler limitation):
// associatedtype Indices : RandomAccessCollection
}
/// Default implementation for random access collections.
extension RandomAccessCollection {
// TODO: swift-3-indexing-model - implement optimized version of the following
// advance(i: Index, by n: IndexDistance) -> Index
// advance(i: Index, by n: IndexDistance, limit: Index) -> Index
// distance(from start: Index, to end: Index) -> IndexDistance
/*
@warn_unused_result
public func advanced(by n: Distance, limit: Self) -> Self {
let d = self.distance(to: limit)
if d == 0 || (d > 0 ? d <= n : d >= n) {
return limit
}
return self.advanced(by: n)
}
*/
}