# ArchiveStream An archive stream that reads from and writes to data blobs ``` class ArchiveStream ``` ## Topics ### Creating an Archive Stream [`init(object: _AAOptionalObjectWrapperWithFilter<_AAArchiveStreamTraits>.AAType?, owned: Bool, messageProc: ArchiveHeader._EntryFilterWrapper?)`](/documentation/AppleArchive/ArchiveStream/init(object:owned:messageProc:)) Returns a new archive stream from the specified traits and entry message processing callback. ### Reading and Writing Blobs ### Reading and Writing Headers ### Writing Directory Contents [`func writeDirectoryContents(archiveFrom: FilePath, path: FilePath?, keySet: ArchiveHeader.FieldKeySet, selectUsing: ArchiveHeader.EntryFilter?, flags: ArchiveFlags, threadCount: Int) throws`](/documentation/AppleArchive/ArchiveStream/writeDirectoryContents(archiveFrom:path:keySet:selectUsing:flags:threadCount:)) Writes all entries from a directory to the archive stream. ### Using Archive Streams ### Extracting Data [`static func extractStream(extractingTo: FilePath, selectUsing: ArchiveHeader.EntryFilter?, flags: ArchiveFlags, threadCount: Int) -> ArchiveStream?`](/documentation/AppleArchive/ArchiveStream/extractStream(extractingTo:selectUsing:flags:threadCount:)) Opens an extract output archive stream. [`static func withExtractStream(extractingTo: FilePath, selectUsing: ArchiveHeader.EntryFilter?, flags: ArchiveFlags, threadCount: Int, (ArchiveStream) throws -> E) throws -> E`](/documentation/AppleArchive/ArchiveStream/withExtractStream(extractingTo:selectUsing:flags:threadCount:_:)) Calls the given closure with an extract output archive stream. ### Encoding Data [`static func encodeStream(writingTo: ArchiveByteStream, selectUsing: ArchiveHeader.EntryFilter?, flags: ArchiveFlags, threadCount: Int) -> ArchiveStream?`](/documentation/AppleArchive/ArchiveStream/encodeStream(writingTo:selectUsing:flags:threadCount:)) Opens an encode output archive stream. [`static func withEncodeStream(writingTo: ArchiveByteStream, selectUsing: ArchiveHeader.EntryFilter?, flags: ArchiveFlags, threadCount: Int, (ArchiveStream) throws -> E) throws -> E`](/documentation/AppleArchive/ArchiveStream/withEncodeStream(writingTo:selectUsing:flags:threadCount:_:)) Calls the given closure with an encode output archive stream. ### Decoding Data [`static func decodeStream(readingFrom: ArchiveByteStream, selectUsing: ArchiveHeader.EntryFilter?, flags: ArchiveFlags, threadCount: Int) -> ArchiveStream?`](/documentation/AppleArchive/ArchiveStream/decodeStream(readingFrom:selectUsing:flags:threadCount:)) Opens a decode input archive stream. [`static func withDecodeStream(readingFrom: ArchiveByteStream, selectUsing: ArchiveHeader.EntryFilter?, flags: ArchiveFlags, threadCount: Int, (ArchiveStream) throws -> E) throws -> E`](/documentation/AppleArchive/ArchiveStream/withDecodeStream(readingFrom:selectUsing:flags:threadCount:_:)) Calls the given closure with a decode input archive stream. ### Converting Data [`static func convertStream(writingTo: ArchiveStream, insertKeySet: ArchiveHeader.FieldKeySet, removeKeySet: ArchiveHeader.FieldKeySet, selectUsing: ArchiveHeader.EntryFilter?, flags: ArchiveFlags, threadCount: Int) -> ArchiveStream?`](/documentation/AppleArchive/ArchiveStream/convertStream(writingTo:insertKeySet:removeKeySet:selectUsing:flags:threadCount:)) Opens a convert output archive stream. [`static func withConvertStream(writingTo: ArchiveStream, insertKeySet: ArchiveHeader.FieldKeySet, removeKeySet: ArchiveHeader.FieldKeySet, selectUsing: ArchiveHeader.EntryFilter?, flags: ArchiveFlags, threadCount: Int, (ArchiveStream) throws -> E) throws -> E`](/documentation/AppleArchive/ArchiveStream/withConvertStream(writingTo:insertKeySet:removeKeySet:selectUsing:flags:threadCount:_:)) Calls the given closure with a convert output archive stream. ### Processing Data [`static func process(readingFrom: ArchiveStream, writingTo: ArchiveStream, selectUsing: ArchiveHeader.EntryFilter?, flags: ArchiveFlags, threadCount: Int) throws -> Int`](/documentation/AppleArchive/ArchiveStream/process(readingFrom:writingTo:selectUsing:flags:threadCount:)) Processes archive elements between two archive streams. ### Using Custom Streams [`static func customStream(instance: C) -> ArchiveStream?`](/documentation/AppleArchive/ArchiveStream/customStream(instance:)) Returns a new archive stream instance mapped to an object that conforms to the archive stream protocol. [`static func withStream(wrapping: C, (ArchiveStream) throws -> E) throws -> E`](/documentation/AppleArchive/ArchiveStream/withStream(wrapping:_:)) Calls the given closure with an archive stream instance mapped to an object that conforms to the archive stream protocol. ## Relationships ### Conforms To [`ArchiveStreamProtocol`](/documentation/AppleArchive/ArchiveStreamProtocol) --- 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)