Executes a closure on the collection’s contiguous storage.
mutating func withContiguousMutableStorageIfAvailable<R>(_ body: (inout UnsafeMutableBufferPointer<Self.Element>) throws -> R) rethrows -> R?
A closure that receives an in-out
UnsafeMutableBufferPointerto the collection’s contiguous storage.
The value returned from
body, unless the collection doesn’t support contiguous storage, in which case the method ignores
body and returns
This method calls
buffer provides access to the contiguous mutable storage of the entire collection. If the contiguous storage doesn’t exist, the collection creates it. If the collection doesn’t support an internal representation in the form of contiguous mutable storage, this method doesn’t call
body — it immediately returns
The optimizer can often eliminate bounds- and uniqueness-checking within an algorithm. When that fails, however, invoking the same algorithm on the
buffer argument may let you trade safety for speed.
Always perform any necessary cleanup in the closure, because the method makes no guarantees about the state of the collection if the closure throws an error. Your changes to the collection may be absent from the collection after throwing the error, because the closure could receive a temporary copy rather than direct access to the collection’s storage.
Successive calls to this method may provide a different pointer on each call. Don’t store
buffer outside of this method.
Collection that provides its own implementation of this method must provide contiguous storage to its elements in the same order as they appear in the collection. This guarantees that it’s possible to generate contiguous mutable storage to any of its subsequences by slicing
buffer with a range formed from the distances to the subsequence’s