CoreFoundation

FFI based wrappers for a subset of core foundation: various bits of
CFString, CFData, CFArray, CFDictionary are available.

Although the CF collection classes can store arbitrary pointer sized values
this wrapper only supports storing CFTypes.

The CF namespace has the raw FFI generated method calls but it's usually
easier to use the wrapper classes: CF::String, CF::Date, CF::Array,
CF::Dictionary, CF::Boolean which try to present a rubyish view of the world
(for example CF::Array implements Enumerable).

These implement methods for creating new instances from ruby objects (eg
CF::String.from_string("hello world")) but you can also pass build them from
an FFI::Pointer).