分享：用四十种语言分别写一个MD5算法 之4 Common Lisp语言MD5算法

分享：用四十种语言分别写一个MD5算法 之4 Common Lisp语言MD5算法

(require #+sbcl 'sb-md5 #-sbcl 'md5)
 
(defvar +letters+ "0123456789abcdef")
 
(defun octets->letters (octet-vector)
  (with-output-to-string (stream)
    (loop for i across octet-vector
          do (flet ((foo (x) (aref +letters+ (ldb (byte x (- x 4)) i))))
               (princ (foo 8) stream)
               (princ (foo 4) stream)))))
 
(defun md5 (string)
  (octets->letters #+sbcl (sb-md5:md5sum-string string)
                   #-sbcl (with-input-from-string (stream string)
                            (md5:md5sum-stream stream))))</pre>
 
  CL-USER> (md5 "foo")