Commit 67475a59 authored by Paul Eggert's avatar Paul Eggert Committed by Paul Eggert

Fix timer.el minor rounding error

* lisp/emacs-lisp/timer.el (timer-next-integral-multiple-of-time):
Fix rounding error by using integers rather than floats.
* test/lisp/emacs-lisp/timer-tests.el (timer-test-multiple-of-time):
New test.
parent e9323956
......@@ -102,14 +102,14 @@ fire each time Emacs is idle for that many seconds."
"Yield the next value after TIME that is an integral multiple of SECS.
More precisely, the next value, after TIME, that is an integral multiple
of SECS seconds since the epoch. SECS may be a fraction."
(let* ((trillion 1e12)
(let* ((trillion 1000000000000)
(time-sec (+ (nth 1 time)
(* 65536.0 (nth 0 time))))
(* 65536 (nth 0 time))))
(delta-sec (mod (- time-sec) secs))
(next-sec (+ time-sec (ffloor delta-sec)))
(next-sec-psec (ffloor (* trillion (mod delta-sec 1))))
(next-sec (+ time-sec (floor delta-sec)))
(next-sec-psec (floor (* trillion (mod delta-sec 1))))
(sub-time-psec (+ (or (nth 3 time) 0)
(* 1e6 (nth 2 time))))
(* 1000000 (nth 2 time))))
(psec-diff (- sub-time-psec next-sec-psec)))
(if (and (<= next-sec time-sec) (< 0 psec-diff))
(setq next-sec-psec (+ sub-time-psec
......
......@@ -39,4 +39,9 @@
(if (fboundp 'debug-timer-check)
(should (debug-timer-check)) t))
(ert-deftest timer-test-multiple-of-time ()
(should (equal
(timer-next-integral-multiple-of-time '(0 0 0 1) (1+ (ash 1 53)))
(list (ash 1 (- 53 16)) 1 0 0))))
;;; timer-tests.el ends here
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