zone.lisp (timespec-seconds): Rewrite using a table of units.

diff --git a/zone.lisp b/zone.lisp
index f50c6d70e82766545478bda9c3b6b76ee635e876..d5d20724c43e7feeac90c4d1e3137f4b9bacc602 100644 (file)
--- a/zone.lisp
+++ b/zone.lisp
@@ -68,31 +68,42 @@ (defun to-mixed-base (base val)
        (push r a)
        (setf val q)))))
 
        (push r a)
        (setf val q)))))
 

-(export 'timespec-seconds)
-(defun timespec-seconds (ts)
-  "Convert a timespec TS to seconds.
-
-   A timespec may be a real count of seconds, or a list (COUNT UNIT).  UNIT
-   may be any of a number of obvious time units."
-  (cond ((null ts) 0)
-       ((realp ts) (floor ts))
-       ((atom ts)
-        (error "Unknown timespec format ~A" ts))
-       ((null (cdr ts))
-        (timespec-seconds (car ts)))
-       (t (+ (to-integer (* (car ts)
-                            (case (intern (string-upcase
-                                           (stringify (cadr ts)))
-                                          '#:zone)
-                              ((s sec secs second seconds) 1)
-                              ((m min mins minute minutes) 60)
-                              ((h hr hrs hour hours) #.(* 60 60))
-                              ((d dy dys day days) #.(* 24 60 60))
-                              ((w wk wks week weeks) #.(* 7 24 60 60))
-                              ((y yr yrs year years) #.(* 365 24 60 60))
-                              (t (error "Unknown time unit ~A"
-                                        (cadr ts))))))
-             (timespec-seconds (cddr ts))))))
+(let ((unit-scale (make-hash-table)))
+
+  (dolist (item `(((:second :seconds :sec :secs :s) ,1)
+                 ((:minute :minutes :min :mins :m) ,60)
+                 ((:hour :hours :hr :hrs :h) ,(* 60 60))
+                 ((:day :days :dy :dys :d) ,(* 24 60 60))
+                 ((:week :weeks :wk :wks :w) ,(* 7 24 60 60))))
+    (destructuring-bind (units scale) item
+      (dolist (unit units) (setf (gethash unit unit-scale) scale))))
+
+  (export 'timespec-seconds)
+  (defun timespec-seconds (ts)
+    "Convert a timespec TS to seconds.
+
+     A timespec may be a real count of seconds, or a list ({COUNT UNIT}*).
+     UNIT may be any of a number of obvious time units."
+    (labels ((convert (acc ts)
+              (cond ((null ts) acc)
+                    ((realp ts) (+ acc (floor ts)))
+                    ((atom ts) (error "Unknown timespec format ~A" ts))
+                    (t
+                     (destructuring-bind
+                         (count &optional unit &rest tail) ts
+                       (let ((scale
+                               (acond ((null unit) 1)
+                                      ((gethash (intern (string-upcase
+                                                         (stringify unit))
+                                                        :keyword)
+                                                unit-scale)
+                                       it)
+                                      (t
+                                       (error "Unknown time unit ~S"
+                                              unit)))))
+                         (convert (+ acc (to-integer (* count scale)))
+                                  tail)))))))
+      (convert 0 ts))))

 
 (defun hash-table-keys (ht)
   "Return a list of the keys in hashtable HT."
 
 (defun hash-table-keys (ht)
   "Return a list of the keys in hashtable HT."