[movitz-cvs] CVS update: movitz/losp/muerte/integers.lisp

[Frode Vatvedt Fjeld]

Update of /project/movitz/cvsroot/movitz/losp/muerte
In directory common-lisp.net:/tmp/cvs-serv1920

Modified Files:
	integers.lisp 
Log Message:
Added floor.

Date: Wed May 19 11:42:08 2004
Author: ffjeld

Index: movitz/losp/muerte/integers.lisp
diff -u movitz/losp/muerte/integers.lisp:1.9 movitz/losp/muerte/integers.lisp:1.10
--- movitz/losp/muerte/integers.lisp:1.9	Wed May 19 11:09:05 2004
+++ movitz/losp/muerte/integers.lisp	Wed May 19 11:42:08 2004
@@ -9,7 +9,7 @@
 ;;;; Created at:    Wed Nov  8 18:44:57 2000
 ;;;; Distribution:  See the accompanying file COPYING.
 ;;;;                
-;;;; $Id: integers.lisp,v 1.9 2004/05/19 15:09:05 ffjeld Exp $
+;;;; $Id: integers.lisp,v 1.10 2004/05/19 15:42:08 ffjeld Exp $
 ;;;;                
 ;;;;------------------------------------------------------------------
 
@@ -1132,3 +1132,19 @@
 		(gcd gcd (car rest)))
 	   (rest (cdr numbers) (cdr rest)))
 	  ((null rest) gcd)))))
+
+(defun floor (n &optional (divisor 1))
+  "This is floor written in terms of truncate."
+  (numargs-case
+   (1 (n) n)
+   (2 (n divisor)
+      (multiple-value-bind (q r)
+	  (truncate n divisor)
+	(cond
+	 ((<= 0 q)
+	  (values q r))
+	 ((= 0 r)
+	  (values q 0))
+	 (t (values (1- q) (+ r divisor))))))
+   (t (n &optional (divisor 1))
+      (floor n divisor))))
\ No newline at end of file