CFDataCreateWithBytesNoCopy(_:_:_:_:)
Creates an immutable CFData object from an external (client-owned) byte buffer.
Declaration
func CFDataCreateWithBytesNoCopy(_ allocator: CFAllocator!, _ bytes: UnsafePointer<UInt8>!, _ length: CFIndex, _ bytesDeallocator: CFAllocator!) -> CFData!Parameters
- allocator:
The allocator to use to allocate memory for the new object. Pass
NULLor kCFAllocatorDefault to use the current default allocator. - bytes:
A pointer to the byte buffer to be used as the backing store of the CFData object.
- length:
The number of bytes in the buffer
bytes. - bytesDeallocator:
The allocator to use to deallocate the external buffer when the CFData object is deallocated. If the default allocator is suitable for this purpose, pass
NULLor kCFAllocatorDefault. If you do not want the created CFData object to deallocate the buffer (that is, you assume responsibility for freeing it yourself), pass kCFAllocatorNull.
Return Value
A new CFData object, or NULL if there was a problem creating the object. On a NULL return, the bytes buffer is left intact. Ownership follows the The Create Rule.
Discussion
This function creates an immutable CFData object from a buffer of unstructured bytes. Unless the situation warrants otherwise, the created object does not copy the external buffer to internal storage but instead uses the buffer as its backing store. However, you should never count on the object using the external buffer since it could copy the buffer to internal storage or might even dump the buffer altogether and use alternative means for storing the bytes.