Function: emerge-find-difference1

emerge-find-difference1 is a byte-compiled function defined in emerge.el.gz.

Signature

(emerge-find-difference1 ARG LOCATION BEGIN END)

Source Code

;; Defined in /usr/src/emacs/lisp/vc/emerge.el.gz
(defun emerge-find-difference1 (arg location begin end)
  (let* ((index
	  ;; find first difference containing or after the current position
	  (catch 'search
	    (let ((n 0))
	      (while (< n emerge-number-of-differences)
		(let ((diff-vector (aref emerge-difference-list n)))
		  (if (<= location (marker-position (aref diff-vector end)))
		      (throw 'search n)))
		(setq n (1+ n))))
	    emerge-number-of-differences))
	 (contains
	  ;; whether the found difference contains the current position
	  (and (< index emerge-number-of-differences)
	       (<= (marker-position (aref (aref emerge-difference-list index)
					  begin))
		   location)))
	 (arg-value
	  ;; numeric value of prefix argument
	  (prefix-numeric-value arg)))
    (emerge-unselect-and-select-difference
     (cond
      ;; if the point is in a difference, select it
      (contains index)
      ;; if the arg is nil and the point is not in a difference, error
      ((null arg) (error "No difference contains point"))
      ;; if the arg is positive, select the following difference
      ((> arg-value 0)
       (if (< index emerge-number-of-differences)
	   index
	 (error "No difference contains or follows point")))
      ;; if the arg is negative, select the preceding difference
      (t
       (if (> index 0)
	   (1- index)
	 (error "No difference contains or precedes point")))))))