# MutableDataProtocol A protocol that provides consistent data access to the bytes underlying contiguous and noncontiguous mutable data buffers. ``` protocol MutableDataProtocol : DataProtocol, MutableCollection, RangeReplaceableCollection ``` ## Topics ### Resetting Backing Storage [`func resetBytes(in: R)`](/documentation/Foundation/MutableDataProtocol/resetBytes(in:)) Replaces the contents of the data buffer with zeros for the provided range. ## Relationships ### Inherits From [`Collection`](/documentation/Swift/Collection) [`Sequence`](/documentation/Swift/Sequence) [`BidirectionalCollection`](/documentation/Swift/BidirectionalCollection) [`DataProtocol`](/documentation/Foundation/DataProtocol) [`RangeReplaceableCollection`](/documentation/Swift/RangeReplaceableCollection) [`MutableCollection`](/documentation/Swift/MutableCollection) [`RandomAccessCollection`](/documentation/Swift/RandomAccessCollection) ### Conforming Types [`Data`](/documentation/Foundation/Data) --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)