如何定义CFFI外部类型，以便可以在接受不同外来类型作为参数的函数中使用它

Question

我有3个defcfuns，用于OpenCV函数（C ++）已经包含在C中（已包含C和C +++函数定义），前2，%brisk和surf0都可以用作底部(self feature-detector)中的%feat-detect-detect参数self。如果前两个的输出和feat-detect-detect的{​​{1}}参数只是：指针，但我需要将它们的所有三种类型定义为与页面底部的类型相似，这样我才能使用终结者。这三个的所有终结器和类型都是相同的，只需在页面底部的四个函数中替换brisk和surf feature-detector，您就会知道每个看起来是什么喜欢。我应该只调用brisk和surf的输出类型以及feat-detect-detect的输入类型，并使它们全部使用相同的4函数类型/终结器组合页面的底部，或者有更好的方法。

    ;; BRISK::BRISK(int thresh=30, int octaves=3, float patternScale=1.0f)
    ;; BRISK* cv_create_BRISK(int thresh, int octaves, float patternScale)
    (defcfun ("cv_create_BRISK" %brisk) brisk
      (thresh :int)
      (octaves :int)
      (pattern-scale :float))

    ;; SURF::SURF()
    ;; SURF* cv_create_SURF() 
    (defcfun ("cv_create_SURF" surf0) surf)

    ;; void FeatureDetector::detect(const Mat& image, vector<KeyPoint>& keypoints, const Mat& mask=Mat() ) const
    ;; void cv_FeatureDetector_detect3(FeatureDetector* self, Mat* image, vector_KeyPoint* keypoints, Mat* mask)
    (defcfun ("cv_FeatureDetector_detect3" %feat-detector-detect) :void
      (self feature-detector)
      (image mat)
      (keypoints (:pointer vector-keypoint))
      (mask mat))




    (define-foreign-type feature-detector ()
      ((garbage-collect  :reader garbage-collect :initform nil :initarg 
                         :garbage-collect))
      (:actual-type :pointer)
      (:simple-parser feature-detector))


    (defclass cv-feature-detector ()
      ((c-pointer :reader c-pointer :initarg :c-pointer)))


    (defmethod translate-to-foreign ((lisp-value cv-feature-detector) (c-type feature-detector))
      (c-pointer lisp-value))


    (defmethod translate-from-foreign (c-pointer (c-type feature-detector))
      (let ((feature-detector (make-instance 'cv-feature-detector :c-pointer c-pointer)))
        (when (garbage-collect c-type)
          (tg:finalize feature-detector (lambda () (del-feature-detector c-pointer))))
        feature-detector))
    ound matches of keypoints from two images."
       (%draw-matches img1 keypoints1 img2 keypoints2 matches1to2 outimg match-color single-point-color matches-mask flags))