# CMBlockBufferProtocol A protocol for objects that operate on a range of a block buffer. ``` protocol CMBlockBufferProtocol ``` ## Topics ### Modifying a Block Buffer [`func copyDataBytes(to: UnsafeMutableRawBufferPointer) throws`](/documentation/CoreMedia/CMBlockBufferProtocol/copyDataBytes(to:)) [`func dataBytes() throws -> Data`](/documentation/CoreMedia/CMBlockBufferProtocol/dataBytes()) [`func fillDataBytes(with: UInt8) throws`](/documentation/CoreMedia/CMBlockBufferProtocol/fillDataBytes(with:)) [`func replaceDataBytes(with: UnsafeRawBufferPointer) throws`](/documentation/CoreMedia/CMBlockBufferProtocol/replaceDataBytes(with:)) [`var isContiguous: Bool`](/documentation/CoreMedia/CMBlockBufferProtocol/isContiguous) [`func makeContiguous(allocator: CMBlockBuffer.CustomBlockAllocator, deallocator: CMBlockBuffer.CustomBlockDeallocator, flags: CMBlockBuffer.Flags) throws -> CMBlockBuffer`](/documentation/CoreMedia/CMBlockBufferProtocol/makeContiguous(allocator:deallocator:flags:)) [`func makeContiguous(allocator: CFAllocator?, flags: CMBlockBuffer.Flags) throws -> CMBlockBuffer`](/documentation/CoreMedia/CMBlockBufferProtocol/makeContiguous(allocator:flags:)) [`func withContiguousStorage((UnsafeRawBufferPointer) throws -> R) throws -> R`](/documentation/CoreMedia/CMBlockBufferProtocol/withContiguousStorage(_:)) ### Inspecting a Block Buffer [`var dataLength: Int`](/documentation/CoreMedia/CMBlockBufferProtocol/dataLength) [`var startIndex: Int`](/documentation/CoreMedia/CMBlockBufferProtocol/startIndex) [`var endIndex: Int`](/documentation/CoreMedia/CMBlockBufferProtocol/endIndex) [`var owner: CMBlockBuffer`](/documentation/CoreMedia/CMBlockBufferProtocol/owner) ### Subscripts [`subscript(ClosedRange) -> CMBlockBuffer.Slice`](/documentation/CoreMedia/CMBlockBufferProtocol/subscript(_:)-7a30d) Creates a slice from a `ClosedRange`. [`subscript(Range) -> CMBlockBuffer.Slice`](/documentation/CoreMedia/CMBlockBufferProtocol/subscript(_:)-1go3) [`subscript(PartialRangeFrom) -> CMBlockBuffer.Slice`](/documentation/CoreMedia/CMBlockBufferProtocol/subscript(_:)-9ntfs) [`subscript(PartialRangeUpTo) -> CMBlockBuffer.Slice`](/documentation/CoreMedia/CMBlockBufferProtocol/subscript(_:)-6ghj4) [`subscript(PartialRangeThrough) -> CMBlockBuffer.Slice`](/documentation/CoreMedia/CMBlockBufferProtocol/subscript(_:)-532k5) [`subscript(UnboundedRange) -> CMBlockBuffer.Slice`](/documentation/CoreMedia/CMBlockBufferProtocol/subscript(_:)-8jilq) ## Relationships ### Conforming Types [`CMBlockBuffer`](/documentation/CoreMedia/CMBlockBuffer) [`Slice`](/documentation/CoreMedia/CMBlockBuffer/Slice) --- 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)