## Documentation

- uses binary search to find the index of key in vector.
- vector must be sorted
- returns : (nil index) if key not found and search stoped at index
(index index) if key was found

## Source

(defun vector-search (key vector &key (key-fn #'identity) (start 0)
(end (1- (length vector)))
(comparator (number-comparator)))
"- uses binary search to find the index of key in vector.
- vector must be sorted
- returns : (nil index) if key not found and search stoped at index
(index index) if key was found"
(let* ((mid (round (+ start end) 2))
(k (funcall key-fn (aref vector mid))))
(cond ((comp-= key k comparator) (values mid mid))
((<= end start) (values nil start))
(t (let ((left (if (comp-< key k comparator)
start
(if (= start mid) end mid)))
(right (if (comp-> key k comparator)
end
(if (= end mid) start mid))))
(vector-search key vector :key-fn key-fn
:start left :end right
:comparator comparator))))))

Source Context