ファイルの内容を全部読む処理のベンチマーク #xyzzy

gistfile1.cl

;; ファイルの内容を全部読む処理のベンチマーク #xyzzy
;;
;; 参考
;;
;; * SLURP-FILE Performance Comparison
;;   http://cybertiggyr.com/gene/sfpc/
;; * Slurping a file in Common Lisp | The Lambda meme - all things Lisp, and more
;;   http://www.ymeme.com/node/83

(defun slurp-buffer (filename)
  (let ((buf (create-new-buffer "slurp")))
    (unwind-protect
        (with-set-buffer
          (set-buffer buf)
          (insert-file-contents filename)
          (buffer-substring (point-min) (point-max)))
      (delete-buffer buf))))

(defun slurp-read-into (file)
  (let* ((len (file-length file))
         (buf (make-vector len :element-type 'character :fill-pointer 0)))
    (with-open-file (s file :direction :input)
      (read-into buf s))))

(defun slurp-read-line (file)
  (with-open-file (in file :direction :input)
    (with-output-to-string (out)
      (loop
        (multiple-value-bind (line nl)
            (read-line in nil :eof)
          (when (eq line :eof)
            (return))
          (write line :stream out)
          (unless nl
            (write-char #\LFD out)))))))

gistfile2.cl

;; 実行結果
;; benchmark は http://gist.github.com/507687 と同じ。
;; 上から 1) 3 回分の処理速度、2) 3 回分の平均、3) 実行結果(今回は常に nil)

(setf *file* (merge-pathnames "XTAGS" (si:system-root)))
(format nil "~:D" (file-length *file*))
"1,201,715"

(benchmark
 (slurp-buffer *file*)
 nil)
(0.031 0.047 0.031)
0.03633333
nil

(benchmark
 (slurp-read-into  *file*)
 nil)
(0.25 0.25 0.234)
0.2446667
nil

(benchmark
 (slurp-read-line *file*)
 nil)
(30.375 29.906 29.907)
30.06267
nil