+(defun nearest-power-of-two (n)
+ (labels ((power (p n)
+ (cond ((> (* p 2) n) p)
+ (t (power (* p 2) n)))))
+ (power 1 n)))
+
+(defmacro secured-eval (form &optional output-stream)
+ (let ((error-handler #'si::universal-error-handler))
+ `(block secure
+ (defun si::universal-error-handler (error-name correctable function-name continue-format-string error-format-string &rest args)
+ ,(when output-stream `(format ,output-stream error-format-string))
+ (setf (symbol-function 'si::universal-error-handler) ,error-handler)
+ (return-from secure))
+ (let (result-eval)
+ (setq result-eval (eval ,form))
+ (setf (symbol-function 'si::universal-error-handler) ,error-handler)
+ result-eval))))
+