Hi,
Is there a way to make mem-aref work with CL's complex numbers? I don't need anything else from CFFI (no complex function arguments, return types, etc), just mem-aref, eg something like
(mem-aref ptr :complex-float 11) (setf (mem-aref ptr :complex-float 12) #C(1s0 2s0))
with complex numbers stored as per the C99 standard (basically, two single or double floats next to each other) and the offset properly calculated.
Doing this would allow me to dispose of some ugly workaround code.
Thanks,
Tamas
On Sun, Aug 16, 2009 at 5:14 PM, Tamas K Papptkpapp@gmail.com wrote:
Is there a way to make mem-aref work with CL's complex numbers? I don't need anything else from CFFI (no complex function arguments, return types, etc), just mem-aref, eg something like
(mem-aref ptr :complex-float 11)
That is doable with something like:
(defmethod translate-from-foreign (ptr (type complex-float-type)) (complex (mem-aref ptr :float 0) (mem-aref ptr :float 1)))
(setf (mem-aref ptr :complex-float 12) #C(1s0 2s0))
But that isn't. Would defining your own setter work for you?
(defun complex-float-aref (ptr index c) (let ((p (* (foreign-type-size :complex-float) index))) (setf (mem-aref p :float 0) (realpart c) (mem-aref p :float 1) (imagpart c))))
To do that with plain MEM-AREF as you wanted, I think we would need some sort of TRANSLATE-INTO-FOREIGN hook.
HTH.
On Sun, 16 Aug 2009 17:43:04 +0100, Luís Oliveira wrote:
On Sun, Aug 16, 2009 at 5:14 PM, Tamas K Papptkpapp@gmail.com wrote:
Is there a way to make mem-aref work with CL's complex numbers? I don't need anything else from CFFI (no complex function arguments, return types, etc), just mem-aref, eg something like
(mem-aref ptr :complex-float 11)
That is doable with something like:
(defmethod translate-from-foreign (ptr (type complex-float-type)) (complex (mem-aref ptr :float 0) (mem-aref ptr :float 1)))
(setf (mem-aref ptr :complex-float 12) #C(1s0 2s0))
But that isn't. Would defining your own setter work for you?
(defun complex-float-aref (ptr index c) (let ((p (* (foreign-type-size :complex-float) index))) (setf (mem-aref p :float 0) (realpart c) (mem-aref p :float 1) (imagpart c))))
To do that with plain MEM-AREF as you wanted, I think we would need some sort of TRANSLATE-INTO-FOREIGN hook.
Thanks for the quick reply. Yes, my own setter works, and I managed to prettify my code by writing a wrapper around mem-aref that calls the setter above when necessary. But if mem-ref and mem-aref could be extended to handle C99 complex types in the future, that would be neat (that means that my code would more more standard, and I would benefit from optimizations like compiler macros, etc).
Tamas
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Luís Oliveira -
Tamas K Papp