;;; time-date.el --- Date and time handling functions
-;; Copyright (C) 1998 Free Software Foundation, Inc.
+;; Copyright (C) 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
;; Masanobu Umeda <umerin@mse.kyutech.ac.jp>
+;; Keywords: mail news util
+
;; This file is part of GNU Emacs.
;; GNU Emacs is free software; you can redistribute it and/or modify
;;; Code:
-(eval-and-compile
- (eval
- '(if (not (string-match "XEmacs" emacs-version))
- (require 'parse-time)
-
- (require 'timezone)
- (defun parse-time-string (date)
- "Convert DATE into time."
- (decode-time
- (condition-case ()
- (let* ((d1 (timezone-parse-date date))
- (t1 (timezone-parse-time (aref d1 3))))
- (apply 'encode-time
- (mapcar (lambda (el)
- (and el (string-to-number el)))
- (list
- (aref t1 2) (aref t1 1) (aref t1 0)
- (aref d1 2) (aref d1 1) (aref d1 0)
- (number-to-string
- (* 60 (timezone-zone-to-minute (aref d1 4))))))))
- ;; If we get an error, then we just return a 0 time.
- (error (list 0 0))))))))
+(eval-when-compile (require 'cl))
-(defun date-to-time (date)
- "Convert DATE into time."
- (apply 'encode-time (parse-time-string date)))
+(require 'parse-time)
-(defun time-to-float (time)
- "Convert TIME to a floating point number."
+(autoload 'timezone-make-date-arpa-standard "timezone")
+
+;;;###autoload
+(defun date-to-time (date)
+ "Parse a string that represents a date-time and return a time value."
+ (condition-case ()
+ (apply 'encode-time
+ (parse-time-string
+ ;; `parse-time-string' isn't sufficiently general or
+ ;; robust. It fails to grok some of the formats that
+ ;; timezone does (e.g. dodgy post-2000 stuff from some
+ ;; Elms) and either fails or returns bogus values. Lars
+ ;; reverted this change, but that loses non-trivially
+ ;; often for me. -- fx
+ (timezone-make-date-arpa-standard date)))
+ (error (error "Invalid date: %s" date))))
+
+(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)))
+ (cadr time)
+ (/ (or (nth 2 time) 0) 1000000.0)))
-(defun float-to-time (float)
- "Convert FLOAT (a floating point number) to an Emacs time structure."
- (list (floor float 65536)
- (floor (mod float 65536))))
+;;;###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))))
+;;;###autoload
(defun time-less-p (t1 t2)
- "Say whether time T1 is less than time 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)))))
+;;;###autoload
(defun days-to-time (days)
- "Convert DAYS into time."
+ "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))
(list ms (condition-case nil (round (- seconds (* ms rest)))
(range-error (expt 2 16))))))
+;;;###autoload
(defun time-since (time)
- "Return the time since TIME, which is either an internal time or a date."
+ "Return the time elapsed since TIME.
+TIME should be either a time value or a date-time string."
(when (stringp time)
;; Convert date strings to internal time.
(setq time (date-to-time time)))
(list (- (+ (car current) (if rest -1 0)) (car time))
(- (+ (or rest 0) (nth 1 current)) (nth 1 time)))))
-(defun subtract-time (t1 t2)
- "Subtract two internal times."
+;;;###autoload
+(defalias 'subtract-time 'time-subtract)
+
+;;;###autoload
+(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)))))
+;;;###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)))
+
+;;;###autoload
(defun date-to-day (date)
- "Return the number of days between year 1 and DATE."
- (time-to-day (date-to-time date)))
-
+ "Return the number of days between year 1 and DATE.
+DATE should be a date-time string."
+ (time-to-days (date-to-time date)))
+
+;;;###autoload
(defun days-between (date1 date2)
- "Return the number of days between DATE1 and DATE2."
+ "Return the number of days between DATE1 and DATE2.
+DATE1 and DATE2 should be date-time strings."
(- (date-to-day date1) (date-to-day date2)))
+;;;###autoload
(defun date-leap-year-p (year)
"Return t if YEAR is a leap year."
(or (and (zerop (% year 4))
(not (zerop (% year 100))))
(zerop (% year 400))))
+;;;###autoload
(defun time-to-day-in-year (time)
"Return the day number within the year of the date month/day/year."
(let* ((tim (decode-time time))
(setq day-of-year (1+ day-of-year))))
day-of-year))
-(defun time-to-day (time)
+;;;###autoload
+(defun time-to-days (time)
"The number of days between the Gregorian date 0001-12-31bce and TIME.
+TIME should be a time value.
The Gregorian date Sunday, December 31, 1bce is imaginary."
(let* ((tim (decode-time time))
(month (nth 4 tim))
(day (nth 3 tim))
(year (nth 5 tim)))
- (+ (time-to-day-in-year time) ; Days this year
+ (+ (time-to-day-in-year time) ; Days this year
(* 365 (1- year)) ; + Days in prior years
(/ (1- year) 4) ; + Julian leap years
(- (/ (1- year) 100)) ; - century years
(/ (1- year) 400)))) ; + Gregorian leap years
+(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)))
+
+;;;###autoload
+(defun safe-date-to-time (date)
+ "Parse a string that represents a date-time and return a time value.
+If DATE is malformed, return a time value of zeros."
+ (condition-case ()
+ (date-to-time date)
+ (error '(0 0))))
+
(provide 'time-date)
;;; time-date.el ends here