Support higher-resolution time stamps.

Fixes: debbugs:9000

4 files changed, 153 insertions, 68 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 42342c60386..f99b3e4d32a 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,26 @@
+2012-06-22  Paul Eggert  <eggert@cs.ucla.edu>
+
+        Support higher-resolution time stamps (Bug#9000).
+
+        * calendar/time-date.el (with-decoded-time-value): New arg
+        PICO-SYMBOL in VARLIST.  It's optional, for backward compatibility.
+        (encode-time-value): New optional arg PICO.  New type 3.
+        (time-to-seconds) [!float-time]: Support the new picoseconds
+        component if it's used.
+        (seconds-to-time, time-subtract, time-add):
+        Support ps-resolution time stamps as well.
+
+        * emacs-lisp/timer.el (timer): New component psecs.  All uses changed.
+        (timerp): Timer vectors now have length 9, not 8.
+        (timer--time): Support new-style (4-part) time stamps.
+        (timer-next-integral-multiple-of-time): Time stamps now have
+        picosecond resolution, so take a bit more care about rounding.
+        (timer-relative-time, timer-inc-time): New optional arg psecs.
+        (timer-set-time-with-usecs): Set psecs to 0.
+        (timer--activate): Check psecs component, too.
+
+        * proced.el (proced-time-lessp): Support ps-resolution stamps.
+
 2012-06-22  Stefan Monnier  <monnier@iro.umontreal.ca>
 
         * icomplete.el (icomplete-minibuffer-setup, icomplete-completions):
diff --git a/lisp/calendar/time-date.el b/lisp/calendar/time-date.el
index 46e38ae46a8..38b766084c9 100644
--- a/lisp/calendar/time-date.el
+++ b/lisp/calendar/time-date.el
@@ -23,15 +23,15 @@
 
 ;;; Commentary:
 
-;; Time values come in three formats.  The oldest format is a cons
+;; Time values come in several formats.  The oldest format is a cons
 ;; cell of the form (HIGH . LOW).  This format is obsolete, but still
-;; supported.  The two other formats are the lists (HIGH LOW) and
-;; (HIGH LOW MICRO).  The first two formats specify HIGH * 2^16 + LOW
-;; seconds; the third format specifies HIGH * 2^16 + LOW + MICRO /
-;; 1000000 seconds.  We should have 0 <= MICRO < 1000000 and 0 <= LOW
-;; < 2^16.  If the time value represents a point in time, then HIGH is
-;; nonnegative.  If the time value is a time difference, then HIGH can
-;; be negative as well.  The macro `with-decoded-time-value' and the
+;; supported.  The other formats are the lists (HIGH LOW), (HIGH LOW
+;; USEC), and (HIGH LOW USEC PSEC).  These formats specify the time
+;; value equal to HIGH * 2^16 + LOW + USEC * 10^-6 + PSEC * 10^-12
+;; seconds, where missing components are treated as zero.  HIGH can be
+;; negative, either because the value is a time difference, or because
+;; the machine supports negative time stamps that fall before the
+;; epoch.  The macro `with-decoded-time-value' and the
 ;; function `encode-time-value' make it easier to deal with these
 ;; three formats.  See `time-subtract' for an example of how to use
 ;; them.
@@ -44,13 +44,15 @@
 The value of the last form in BODY is returned.
 
 Each element of the list VARLIST is a list of the form
-\(HIGH-SYMBOL LOW-SYMBOL MICRO-SYMBOL [TYPE-SYMBOL] TIME-VALUE).
+\(HIGH-SYMBOL LOW-SYMBOL MICRO-SYMBOL [PICO-SYMBOL [TYPE-SYMBOL]] TIME-VALUE).
 The time value TIME-VALUE is decoded and the result it bound to
 the symbols HIGH-SYMBOL, LOW-SYMBOL and MICRO-SYMBOL.
+The optional PICO-SYMBOL is bound to the picoseconds part.
 
 The optional TYPE-SYMBOL is bound to the type of the time value.
 Type 0 is the cons cell (HIGH . LOW), type 1 is the list (HIGH
-LOW), and type 2 is the list (HIGH LOW MICRO)."
+LOW), type 2 is the list (HIGH LOW MICRO), and type 3 is the
+list (HIGH LOW MICRO PICO)."
   (declare (indent 1)
            (debug ((&rest (symbolp symbolp symbolp &or [symbolp form] form))
                    body)))
@@ -59,6 +61,8 @@ LOW), and type 2 is the list (HIGH LOW MICRO)."
              (high (pop elt))
              (low (pop elt))
              (micro (pop elt))
+             (pico (unless (<= (length elt) 2)
+                     (pop elt)))
              (type (unless (eq (length elt) 1)
                      (pop elt)))
              (time-value (car elt))
@@ -66,28 +70,44 @@ LOW), and type 2 is the list (HIGH LOW MICRO)."
         `(let* ,(append `((,gensym ,time-value)
                           (,high (pop ,gensym))
                           ,low ,micro)
+                        (when pico `(,pico))
                         (when type `(,type)))
            (if (consp ,gensym)
                (progn
                  (setq ,low (pop ,gensym))
                  (if ,gensym
-                     ,(append `(setq ,micro (car ,gensym))
-                              (when type `(,type 2)))
+                     (progn
+                       (setq ,micro (car ,gensym))
+                       ,(cond (pico
+                               `(if (cdr ,gensym)
+                                    ,(append `(setq ,pico (cadr ,gensym))
+                                             (when type `(,type 3)))
+                                  ,(append `(setq ,pico 0)
+                                           (when type `(,type 2)))))
+                              (type
+                               `(setq type 2))))
                    ,(append `(setq ,micro 0)
+                            (when pico `(,pico 0))
                             (when type `(,type 1)))))
              ,(append `(setq ,low ,gensym ,micro 0)
+                      (when pico `(,pico 0))
                       (when type `(,type 0))))
            (with-decoded-time-value ,varlist ,@body)))
     `(progn ,@body)))
 
-(defun encode-time-value (high low micro type)
-  "Encode HIGH, LOW, and MICRO into a time value of type TYPE.
+(defun encode-time-value (high low micro pico &optional type)
+  "Encode HIGH, LOW, MICRO, and PICO into a time value of type TYPE.
 Type 0 is the cons cell (HIGH . LOW), type 1 is the list (HIGH LOW),
-and type 2 is the list (HIGH LOW MICRO)."
+type 2 is (HIGH LOW MICRO), and type 3 is (HIGH LOW MICRO PICO).
+
+For backward compatibility, if only four arguments are given,
+it is assumed that PICO was omitted and should be treated as zero."
   (cond
    ((eq type 0) (cons high low))
    ((eq type 1) (list high low))
-   ((eq type 2) (list high low micro))))
+   ((eq type 2) (list high low micro))
+   ((eq type 3) (list high low micro pico))
+   ((null type) (encode-time-value high low micro 0 pico))))
 
 (autoload 'parse-time-string "parse-time")
 (autoload 'timezone-make-date-arpa-standard "timezone")
@@ -125,28 +145,45 @@ If DATE lacks timezone information, GMT is assumed."
            (subrp (symbol-function 'float-time)))
       (defun time-to-seconds (time)
         "Convert time value TIME to a floating point number."
-        (with-decoded-time-value ((high low micro time))
+        (with-decoded-time-value ((high low micro pico type time))
           (+ (* 1.0 high 65536)
              low
-             (/ micro 1000000.0))))))
+             (/ (+ (* micro 1e6) pico) 1e12))))))
 
 ;;;###autoload
 (defun seconds-to-time (seconds)
   "Convert SECONDS (a floating point number) to a time value."
-  (list (floor seconds 65536)
-        (floor (mod seconds 65536))
-        (floor (* (- seconds (ffloor seconds)) 1000000))))
+  (let* ((usec (* 1000000 (mod seconds 1)))
+         (ps (round (* 1000000 (mod usec 1))))
+         (us (floor usec))
+         (lo (floor (mod seconds 65536)))
+         (hi (floor seconds 65536)))
+    (if (eq ps 1000000)
+        (progn
+          (setq ps 0)
+          (setq us (1+ us))
+          (if (eq us 1000000)
+              (progn
+                (setq us 0)
+                (setq lo (1+ lo))
+                (if (eq lo 65536)
+                    (progn
+                      (setq lo 0)
+                      (setq hi (1+ hi))))))))
+    (list hi lo us ps)))
 
 ;;;###autoload
 (defun time-less-p (t1 t2)
   "Return non-nil if time value T1 is earlier than time value T2."
-  (with-decoded-time-value ((high1 low1 micro1 t1)
-                            (high2 low2 micro2 t2))
+  (with-decoded-time-value ((high1 low1 micro1 pico1 type1 t1)
+                            (high2 low2 micro2 pico2 type2 t2))
     (or (< high1 high2)
         (and (= high1 high2)
              (or (< low1 low2)
                  (and (= low1 low2)
-                      (< micro1 micro2)))))))
+                      (or (< micro1 micro2)
+                          (and (= micro1 micro2)
+                               (< pico1 pico2)))))))))
 
 ;;;###autoload
 (defun days-to-time (days)
@@ -173,36 +210,44 @@ TIME should be either a time value or a date-time string."
 (defun time-subtract (t1 t2)
   "Subtract two time values, T1 minus T2.
 Return the difference in the format of a time value."
-  (with-decoded-time-value ((high low micro type t1)
-                            (high2 low2 micro2 type2 t2))
+  (with-decoded-time-value ((high low micro pico type t1)
+                            (high2 low2 micro2 pico2 type2 t2))
     (setq high (- high high2)
           low (- low low2)
           micro (- micro micro2)
+          pico (- pico pico2)
           type (max type type2))
+    (when (< pico 0)
+      (setq micro (1- micro)
+            pico (+ pico 1000000)))
     (when (< micro 0)
       (setq low (1- low)
             micro (+ micro 1000000)))
     (when (< low 0)
       (setq high (1- high)
             low (+ low 65536)))
-    (encode-time-value high low micro type)))
+    (encode-time-value high low micro pico type)))
 
 ;;;###autoload
 (defun time-add (t1 t2)
   "Add two time values T1 and T2.  One should represent a time difference."
-  (with-decoded-time-value ((high low micro type t1)
-                            (high2 low2 micro2 type2 t2))
+  (with-decoded-time-value ((high low micro pico type t1)
+                            (high2 low2 micro2 pico2 type2 t2))
     (setq high (+ high high2)
           low (+ low low2)
           micro (+ micro micro2)
+          pico (+ pico pico2)
           type (max type type2))
+    (when (>= pico 1000000)
+      (setq micro (1+ micro)
+            pico (- pico 1000000)))
     (when (>= micro 1000000)
       (setq low (1+ low)
             micro (- micro 1000000)))
     (when (>= low 65536)
       (setq high (1+ high)
             low (- low 65536)))
-    (encode-time-value high low micro type)))
+    (encode-time-value high low micro pico type)))
 
 ;;;###autoload
 (defun date-to-day (date)
diff --git a/lisp/emacs-lisp/timer.el b/lisp/emacs-lisp/timer.el
index 0b8480441c3..eab96fe202a 100644
--- a/lisp/emacs-lisp/timer.el
+++ b/lisp/emacs-lisp/timer.el
@@ -28,7 +28,7 @@
 ;;; Code:
 
 ;; Layout of a timer vector:
-;; [triggered-p high-seconds low-seconds usecs repeat-delay
+;; [triggered-p high-seconds low-seconds usecs psecs repeat-delay
 ;;  function args idle-delay]
 ;; triggered-p is nil if the timer is active (waiting to be triggered),
 ;;  t if it is inactive ("already triggered", in theory)
@@ -42,27 +42,35 @@
             (:type vector)
             (:conc-name timer--))
   (triggered t)
-  high-seconds low-seconds usecs repeat-delay function args idle-delay)
+  high-seconds low-seconds usecs psecs repeat-delay function args idle-delay)
 
 (defun timerp (object)
   "Return t if OBJECT is a timer."
-  (and (vectorp object) (= (length object) 8)))
+  (and (vectorp object) (= (length object) 9)))
 
 ;; Pseudo field `time'.
 (defun timer--time (timer)
   (list (timer--high-seconds timer)
         (timer--low-seconds timer)
-        (timer--usecs timer)))
+        (timer--usecs timer)
+        (timer--psecs timer)))
 
 (gv-define-simple-setter timer--time
   (lambda (timer time)
     (or (timerp timer) (error "Invalid timer"))
     (setf (timer--high-seconds timer) (pop time))
-    (setf (timer--low-seconds timer)
-          (if (consp time) (car time) time))
-    (setf (timer--usecs timer) (or (and (consp time) (consp (cdr time))
-                                           (cadr time))
-                                      0))))
+    (let ((low time) (usecs 0) (psecs 0))
+      (if (consp time)
+          (progn
+            (setq low (pop time))
+            (if time
+                (progn
+                  (setq usecs (pop time))
+                  (if time
+                      (setq psecs (car time)))))))
+      (setf (timer--low-seconds timer) low)
+      (setf (timer--usecs timer) usecs)
+      (setf (timer--psecs timer) psecs))))
 
 
 (defun timer-set-time (timer time &optional delta)
@@ -77,7 +85,7 @@ fire repeatedly that many seconds apart."
 (defun timer-set-idle-time (timer secs &optional repeat)
   "Set the trigger idle time of TIMER to SECS.
 SECS may be an integer, floating point number, or the internal
-time format (HIGH LOW USECS) returned by, e.g., `current-idle-time'.
+time format returned by, e.g., `current-idle-time'.
 If optional third argument REPEAT is non-nil, make the timer
 fire each time Emacs is idle for that many seconds."
   (if (consp secs)
@@ -91,41 +99,46 @@ 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 ((time-base (ash 1 16)))
-    ;; Use floating point, taking care to not lose precision.
-    (let* ((float-time-base (float time-base))
-           (million 1000000.0)
-           (time-usec (+ (* million
-                            (+ (* float-time-base (nth 0 time))
-                               (nth 1 time)))
-                         (nth 2 time)))
-           (secs-usec (* million secs))
-           (mod-usec (mod time-usec secs-usec))
-           (next-usec (+ (- time-usec mod-usec) secs-usec))
-           (time-base-million (* float-time-base million)))
-      (list (floor next-usec time-base-million)
-            (floor (mod next-usec time-base-million) million)
-            (floor (mod next-usec million))))))
-
-(defun timer-relative-time (time secs &optional usecs)
-  "Advance TIME by SECS seconds and optionally USECS microseconds.
-SECS may be either an integer or a floating point number."
+  (let* ((trillion 1e12)
+         (time-sec (+ (nth 1 time)
+                      (* 65536.0 (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))))
+         (sub-time-psec (+ (or (nth 3 time) 0)
+                           (* 1e6 (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
+                               (mod (- psec-diff) (* trillion secs)))))
+    (setq next-sec (+ next-sec (floor next-sec-psec trillion)))
+    (setq next-sec-psec (mod next-sec-psec trillion))
+    (list (floor next-sec 65536)
+          (floor (mod next-sec 65536))
+          (floor next-sec-psec 1000000)
+          (floor (mod next-sec-psec 1000000)))))
+
+(defun timer-relative-time (time secs &optional usecs psecs)
+  "Advance TIME by SECS seconds and optionally USECS nanoseconds
+and PSECS picoseconds.  SECS may be either an integer or a
+floating point number."
   (let ((delta (if (floatp secs)
                    (seconds-to-time secs)
                  (list (floor secs 65536) (mod secs 65536)))))
-    (if usecs
-        (setq delta (time-add delta (list 0 0 usecs))))
+    (if (or usecs psecs)
+        (setq delta (time-add delta (list 0 0 (or usecs 0) (or psecs 0)))))
     (time-add time delta)))
 
 (defun timer--time-less-p (t1 t2)
   "Say whether time value T1 is less than time value T2."
   (time-less-p (timer--time t1) (timer--time t2)))
 
-(defun timer-inc-time (timer secs &optional usecs)
-  "Increment the time set in TIMER by SECS seconds and USECS microseconds.
-SECS may be a fraction.  If USECS is omitted, that means it is zero."
+(defun timer-inc-time (timer secs &optional usecs psecs)
+  "Increment the time set in TIMER by SECS seconds, USECS nanoseconds,
+and PSECS picoseconds.  SECS may be a fraction.  If USECS or PSECS are
+omitted, they are treated as zero."
   (setf (timer--time timer)
-        (timer-relative-time (timer--time timer) secs usecs)))
+        (timer-relative-time (timer--time timer) secs usecs psecs)))
 
 (defun timer-set-time-with-usecs (timer time usecs &optional delta)
   "Set the trigger time of TIMER to TIME plus USECS.
@@ -135,6 +148,7 @@ If optional fourth argument DELTA is a positive number, make the timer
 fire repeatedly that many seconds apart."
   (setf (timer--time timer) time)
   (setf (timer--usecs timer) usecs)
+  (setf (timer--psecs timer) 0)
   (setf (timer--repeat-delay timer) (and (numberp delta) (> delta 0) delta))
   timer)
 (make-obsolete 'timer-set-time-with-usecs
@@ -154,6 +168,7 @@ fire repeatedly that many seconds apart."
            (integerp (timer--high-seconds timer))
            (integerp (timer--low-seconds timer))
            (integerp (timer--usecs timer))
+           (integerp (timer--psecs timer))
            (timer--function timer))
       (let ((timers (if idle timer-idle-list timer-list))
             last)
@@ -386,7 +401,7 @@ This function is for compatibility; see also `run-with-timer'."
   "Perform an action the next time Emacs is idle for SECS seconds.
 The action is to call FUNCTION with arguments ARGS.
 SECS may be an integer, a floating point number, or the internal
-time format (HIGH LOW USECS) returned by, e.g., `current-idle-time'.
+time format returned by, e.g., `current-idle-time'.
 If Emacs is currently idle, and has been idle for N seconds (N < SECS),
 then it will call FUNCTION in SECS - N seconds from now.
 
diff --git a/lisp/proced.el b/lisp/proced.el
index 930f7d99f9e..78afcac9f50 100644
--- a/lisp/proced.el
+++ b/lisp/proced.el
@@ -1170,14 +1170,16 @@ Return nil otherwise."
 (defun proced-time-lessp (t1 t2)
   "Return t if time value T1 is less than time value T2.
 Return `equal' if T1 equals T2.  Return nil otherwise."
-  (with-decoded-time-value ((high1 low1 micro1 t1)
-                            (high2 low2 micro2 t2))
+  (with-decoded-time-value ((high1 low1 micro1 pico1 type1 t1)
+                            (high2 low2 micro2 pico2 type2 t2))
     (cond ((< high1 high2))
           ((< high2 high1) nil)
           ((< low1 low2))
           ((< low2 low1) nil)
           ((< micro1 micro2))
           ((< micro2 micro1) nil)
+          ((< pico1 pico2))
+          ((< pico2 pico1) nil)
           (t 'equal))))
 
 ;;; Sorting