;;; time-date.el --- Date and time handling functions
-;; Copyright (C) 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
+;; Copyright (C) 1998, 1999, 2000, 2001, 2002, 2004, 2005 Free Software Foundation, Inc.
;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
;; Masanobu Umeda <umerin@mse.kyutech.ac.jp>
;;; Commentary:
+;; Time values come in three 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 This format is obsolete, but still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
+;; function `encode-time-value' make it easier to deal with these
+;; three formats. See `time-subtract' for an example of how to use
+;; them.
+
;;; Code:
-(require 'parse-time)
+(defmacro with-decoded-time-value (varlist &rest body)
+ "Decode a time value and bind it according to VARLIST, then eval BODY.
+
+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).
+The time value TIME-VALUE is decoded and the result it bound to
+the symbols HIGH-SYMBOL, LOW-SYMBOL and MICRO-SYMBOL.
+
+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 3 is the list (HIGH LOW MICRO)."
+ (declare (indent 1)
+ (debug ((&rest (symbolp symbolp symbolp &or [symbolp form] form))
+ body)))
+ (if varlist
+ (let* ((elt (pop varlist))
+ (high (pop elt))
+ (low (pop elt))
+ (micro (pop elt))
+ (type (unless (eq (length elt) 1)
+ (pop elt)))
+ (time-value (car elt))
+ (gensym (make-symbol "time")))
+ `(let* ,(append `((,gensym ,time-value)
+ (,high (pop ,gensym))
+ ,low ,micro)
+ (when type `(,type)))
+ (if (consp ,gensym)
+ (progn
+ (setq ,low (pop ,gensym))
+ (if ,gensym
+ ,(append `(setq ,micro (car ,gensym))
+ (when type `(,type 2)))
+ ,(append `(setq ,micro 0)
+ (when type `(,type 1)))))
+ ,(append `(setq ,low ,gensym ,micro 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.
+Type 0 is the cons cell (HIGH . LOW), type 1 is the list (HIGH LOW),
+and type 3 is the list (HIGH LOW MICRO)."
+ (cond
+ ((eq type 0) (cons high low))
+ ((eq type 1) (list high low))
+ ((eq type 2) (list high low micro))))
(autoload 'timezone-make-date-arpa-standard "timezone")
(defun time-to-seconds (time)
"Convert time value TIME to a floating point number.
You can use `float-time' instead."
- (+ (* (car time) 65536.0)
- (cadr time)
- (/ (or (nth 2 time) 0) 1000000.0)))
+ (with-decoded-time-value ((high low micro time))
+ (+ (* 1.0 high #x10000)
+ low
+ (/ micro 1000000.0))))
;;;###autoload
(defun seconds-to-time (seconds)
"Convert SECONDS (a floating point number) to a time value."
- (list (floor seconds 65536)
- (floor (mod seconds 65536))
+ (list (floor seconds #x10000)
+ (floor (mod seconds #x10000))
(floor (* (- seconds (ffloor seconds)) 1000000))))
;;;###autoload
(defun time-less-p (t1 t2)
"Say whether time value T1 is less than time value T2."
- (or (< (car t1) (car t2))
- (and (= (car t1) (car t2))
- (< (nth 1 t1) (nth 1 t2)))))
+ (with-decoded-time-value ((high1 low1 micro1 t1)
+ (high2 low2 micro2 t2))
+ (or (< high1 high2)
+ (and (= high1 high2)
+ (or (< low1 low2)
+ (and (= low1 low2)
+ (< micro1 micro2)))))))
;;;###autoload
(defun days-to-time (days)
"Convert DAYS into a time value."
(let* ((seconds (* 1.0 days 60 60 24))
- (rest (expt 2 16))
- (ms (condition-case nil (floor (/ seconds rest))
- (range-error (expt 2 16)))))
- (list ms (condition-case nil (round (- seconds (* ms rest)))
- (range-error (expt 2 16))))))
+ (high (condition-case nil (floor (/ seconds #x10000))
+ (range-error most-positive-fixnum))))
+ (list high (condition-case nil (floor (- seconds (* 1.0 high #x10000)))
+ (range-error #xffff)))))
;;;###autoload
(defun time-since (time)
(when (stringp time)
;; Convert date strings to internal time.
(setq time (date-to-time time)))
- (let* ((current (current-time))
- (rest (when (< (nth 1 current) (nth 1 time))
- (expt 2 16))))
- (list (- (+ (car current) (if rest -1 0)) (car time))
- (- (+ (or rest 0) (nth 1 current)) (nth 1 time)))))
+ (time-subtract (current-time) time))
;;;###autoload
(defalias 'subtract-time 'time-subtract)
(defun time-subtract (t1 t2)
"Subtract two time values.
Return the difference in the format of a time value."
- (let ((borrow (< (cadr t1) (cadr t2))))
- (list (- (car t1) (car t2) (if borrow 1 0))
- (- (+ (if borrow 65536 0) (cadr t1)) (cadr t2)))))
+ (with-decoded-time-value ((high low micro type t1)
+ (high2 low2 micro2 type2 t2))
+ (setq high (- high high2)
+ low (- low low2)
+ micro (- micro micro2)
+ type (max type type2))
+ (when (< micro 0)
+ (setq low (1- low)
+ micro (+ micro 1000000)))
+ (when (< low 0)
+ (setq high (1- high)
+ low (+ low #x10000)))
+ (encode-time-value high low micro type)))
;;;###autoload
(defun time-add (t1 t2)
"Add two time values. One should represent a time difference."
- (let ((high (car t1))
- (low (if (consp (cdr t1)) (nth 1 t1) (cdr t1)))
- (micro (if (numberp (car-safe (cdr-safe (cdr t1))))
- (nth 2 t1)
- 0))
- (high2 (car t2))
- (low2 (if (consp (cdr t2)) (nth 1 t2) (cdr t2)))
- (micro2 (if (numberp (car-safe (cdr-safe (cdr t2))))
- (nth 2 t2)
- 0)))
- ;; Add
- (setq micro (+ micro micro2))
- (setq low (+ low low2))
- (setq high (+ high high2))
-
- ;; Normalize
- ;; `/' rounds towards zero while `mod' returns a positive number,
- ;; so we can't rely on (= a (+ (* 100 (/ a 100)) (mod a 100))).
- (setq low (+ low (/ micro 1000000) (if (< micro 0) -1 0)))
- (setq micro (mod micro 1000000))
- (setq high (+ high (/ low 65536) (if (< low 0) -1 0)))
- (setq low (logand low 65535))
-
- (list high low micro)))
+ (with-decoded-time-value ((high low micro type t1)
+ (high2 low2 micro2 type2 t2))
+ (setq high (+ high high2)
+ low (+ low low2)
+ micro (+ micro micro2)
+ type (max type type2))
+ (when (>= micro 1000000)
+ (setq low (1+ low)
+ micro (- micro 1000000)))
+ (when (>= low #x10000)
+ (setq high (1+ high)
+ low (- low #x10000)))
+ (encode-time-value high low micro type)))
;;;###autoload
(defun date-to-day (date)
(defun time-to-number-of-days (time)
"Return the number of days represented by TIME.
The number of days will be returned as a floating point number."
- (/ (+ (* 1.0 65536 (car time)) (cadr time)) (* 60 60 24)))
+ (/ (time-to-seconds time) (* 60 60 24)))
;;;###autoload
(defun safe-date-to-time (date)
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