617 lines
23 KiB
EmacsLisp
617 lines
23 KiB
EmacsLisp
;;; time-date.el --- Date and time handling functions -*- lexical-binding: t -*-
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;; Copyright (C) 1998-2024 Free Software Foundation, Inc.
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;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
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;; Masanobu Umeda <umerin@mse.kyutech.ac.jp>
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;; Keywords: mail news util
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;; This file is part of GNU Emacs.
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;; GNU Emacs is free software: you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation, either version 3 of the License, or
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;; (at your option) any later version.
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;; GNU Emacs is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>.
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;;; Commentary:
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;; Time values come in several formats. The oldest format is a cons
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;; cell of the form (HIGH . LOW). This format is obsolete, but still
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;; supported. The other formats are the lists (HIGH LOW), (HIGH LOW
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;; USEC), and (HIGH LOW USEC PSEC). These formats specify the time
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;; value equal to HIGH * 2^16 + LOW + USEC * 10^-6 + PSEC * 10^-12
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;; seconds, where missing components are treated as zero. HIGH can be
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;; negative, either because the value is a time difference, or because
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;; it represents a time stamp before the epoch. Typically, there are
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;; more time values than the underlying system time type supports,
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;; but the reverse can also be true.
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;;; Code:
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(require 'cl-lib)
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(require 'subr-x)
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(defmacro with-decoded-time-value (varlist &rest body)
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"Decode a time value and bind it according to VARLIST, then eval BODY.
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The value of the last form in BODY is returned.
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Each element of the list VARLIST is a list of the form
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\(HIGH-SYMBOL LOW-SYMBOL MICRO-SYMBOL [PICO-SYMBOL [TYPE-SYMBOL]] TIME-VALUE).
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The time value TIME-VALUE is decoded and the result is bound to
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the symbols HIGH-SYMBOL, LOW-SYMBOL and MICRO-SYMBOL.
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The optional PICO-SYMBOL is bound to the picoseconds part.
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The optional TYPE-SYMBOL is bound to the type of the time value.
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Type 0 is the cons cell (HIGH . LOW), type 1 is the list (HIGH
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LOW), type 2 is the list (HIGH LOW MICRO), and type 3 is the
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list (HIGH LOW MICRO PICO)."
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(declare (indent 1)
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(debug ((&rest (symbolp symbolp symbolp
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&or [symbolp symbolp form] [symbolp form] form))
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body)))
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(if varlist
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(let* ((elt (pop varlist))
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(high (pop elt))
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(low (pop elt))
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(micro (pop elt))
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(pico (unless (<= (length elt) 2)
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(pop elt)))
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(type (unless (eq (length elt) 1)
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(pop elt)))
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(time-value (car elt))
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(gensym (make-symbol "time")))
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`(let* ,(append `((,gensym (or ,time-value (time-convert nil 'list)))
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(,gensym
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(cond
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((integerp ,gensym)
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(list (ash ,gensym -16)
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(logand ,gensym 65535)))
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((floatp ,gensym)
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(let* ((usec (* 1000000 (mod ,gensym 1)))
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(ps (round (* 1000000 (mod usec 1))))
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(us (floor usec))
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(lo (floor (mod ,gensym 65536)))
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(hi (floor ,gensym 65536)))
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(if (eq ps 1000000)
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(progn
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(setq ps 0)
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(setq us (1+ us))
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(if (eq us 1000000)
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(progn
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(setq us 0)
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(setq lo (1+ lo))
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(if (eq lo 65536)
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(progn
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(setq lo 0)
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(setq hi (1+ hi))))))))
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(list hi lo us ps)))
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(t ,gensym)))
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(,high (pop ,gensym))
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,low ,micro)
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(when pico `(,pico))
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(when type `(,type)))
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(if (consp ,gensym)
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(progn
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(setq ,low (pop ,gensym))
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(if ,gensym
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(progn
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(setq ,micro (car ,gensym))
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,(cond (pico
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`(if (cdr ,gensym)
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,(append `(setq ,pico (cadr ,gensym))
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(when type `(,type 3)))
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,(append `(setq ,pico 0)
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(when type `(,type 2)))))
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(type
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`(setq type 2))))
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,(append `(setq ,micro 0)
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(when pico `(,pico 0))
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(when type `(,type 1)))))
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,(append `(setq ,low ,gensym ,micro 0)
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(when pico `(,pico 0))
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(when type `(,type 0))))
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(with-decoded-time-value ,varlist ,@body)))
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`(progn ,@body)))
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(defun encode-time-value (high low micro pico &optional type)
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"Encode HIGH, LOW, MICRO, and PICO into a time value of type TYPE.
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Type 0 is the cons cell (HIGH . LOW), type 1 is the list (HIGH LOW),
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type 2 is (HIGH LOW MICRO), and type 3 is (HIGH LOW MICRO PICO).
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For backward compatibility, if only four arguments are given,
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it is assumed that PICO was omitted and should be treated as zero."
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(when (null type)
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(setq type pico)
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(setq pico 0))
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(cond
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((eq type 0) (cons high low))
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((eq type 1) (list high low))
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((eq type 2) (list high low micro))
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((eq type 3) (list high low micro pico))))
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(make-obsolete 'encode-time-value nil "25.1")
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(make-obsolete 'with-decoded-time-value nil "25.1")
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(autoload 'parse-time-string "parse-time")
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(autoload 'timezone-make-date-arpa-standard "timezone")
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;;;###autoload
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(defun date-to-time (date)
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"Parse a string DATE that represents a date-time and return a time value.
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DATE should be in one of the forms recognized by `parse-time-string'.
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If DATE lacks time zone information, local time is assumed."
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(condition-case err
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;; Parse DATE. If it contains a year, use defaults for other components.
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;; Then encode the result; this signals an error if the year is missing,
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;; because encode-time signals if crucial time components are nil.
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;; This heuristic uses local time if the string lacks time zone info,
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;; because encode-time treats a nil time zone as local time.
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(let ((parsed (parse-time-string date)))
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(when (decoded-time-year parsed)
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(decoded-time-set-defaults parsed))
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(encode-time parsed))
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(error
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(if (equal err '(error "Specified time is not representable"))
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(signal (car err) (cdr err))
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(error "Invalid date: %s" date)))))
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;;;###autoload
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(defalias 'time-to-seconds #'float-time)
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;;;###autoload
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(defun seconds-to-time (seconds)
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"Convert SECONDS to a proper time, like `current-time' would."
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;; FIXME: Should we (declare (obsolete time-convert "27.1")) ?
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(time-convert seconds 'list))
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;;;###autoload
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(defun days-to-time (days)
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"Convert Emacs-epoch DAYS into a time value.
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Note that this does not use the same epoch as `time-to-days'; you
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must subtract (time-to-days 0) first to convert, and may get nil
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if the result is before the start."
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;; FIXME: We should likely just pass `t' to `time-convert'.
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;; All uses I could find in Emacs, GNU ELPA, and NonGNU ELPA can handle
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;; any valid time representation as return value.
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(let ((time (time-convert (* 86400 days) 'list)))
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;; Traditionally, this returned a two-element list if DAYS was an integer.
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;; Keep that tradition if time-convert outputs timestamps in list form.
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(if (and (integerp days) (consp (cdr time)))
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(setcdr (cdr time) nil))
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time))
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;;;###autoload
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(defun time-since (time)
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"Return the time elapsed since TIME.
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TIME should be either a time value or a date-time string."
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(when (stringp time)
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;; Convert date strings to internal time.
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(setq time (date-to-time time)))
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(time-subtract nil time))
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;;;###autoload
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(define-obsolete-function-alias 'subtract-time #'time-subtract "26.1")
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;;;###autoload
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(defun date-to-day (date)
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"Return the absolute date of DATE, a date-time string.
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The absolute date is the number of days elapsed since the imaginary
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Gregorian date Sunday, December 31, 1 BC."
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(time-to-days (date-to-time date)))
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;;;###autoload
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(defun days-between (date1 date2)
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"Return the number of days between DATE1 and DATE2.
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DATE1 and DATE2 should be date-time strings."
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(- (date-to-day date1) (date-to-day date2)))
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;;;###autoload
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(defun date-leap-year-p (year)
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"Return t if YEAR is a leap year."
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(or (and (zerop (% year 4))
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(not (zerop (% year 100))))
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(zerop (% year 400))))
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(defun time-date--day-in-year (tim)
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"Return the day number within the year corresponding to the decoded time TIM."
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(let* ((month (decoded-time-month tim))
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(day (decoded-time-day tim))
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(year (decoded-time-year tim))
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(day-of-year (+ day (* 31 (1- month)))))
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(when (> month 2)
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(setq day-of-year (- day-of-year (/ (+ 23 (* 4 month)) 10)))
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(when (date-leap-year-p year)
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(setq day-of-year (1+ day-of-year))))
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day-of-year))
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;;;###autoload
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(defun time-to-day-in-year (time)
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"Return the day number within the year corresponding to TIME."
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(time-date--day-in-year (decode-time time)))
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;;;###autoload
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(defun time-to-days (time)
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"The absolute pseudo-Gregorian date for TIME, a time value.
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The absolute date is the number of days elapsed since the imaginary
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Gregorian date Sunday, December 31, 1 BC."
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(let* ((tim (decode-time time))
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(year (decoded-time-year tim)))
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(+ (time-date--day-in-year tim) ; Days this year
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(* 365 (1- year)) ; + Days in prior years
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(/ (1- year) 4) ; + Julian leap years
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(- (/ (1- year) 100)) ; - century years
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(/ (1- year) 400)))) ; + Gregorian leap years
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(defun time-to-number-of-days (time)
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"Return the number of days represented by TIME.
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Returns a floating point number."
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(/ (float-time time) (* 60 60 24)))
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;;;###autoload
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(defun safe-date-to-time (date)
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"Parse a string DATE that represents a date-time and return a time value.
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If DATE is malformed, return a time value of zero."
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(condition-case ()
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(date-to-time date)
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(error 0)))
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;;;###autoload
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(defun format-seconds (string seconds)
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"Use format control STRING to format the number SECONDS.
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The valid format specifiers are:
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%y is the number of (365-day) years.
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%d is the number of days.
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%h is the number of hours.
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%m is the number of minutes.
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%s is the number of seconds.
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%z is a non-printing control flag (see below).
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%% is a literal \"%\".
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Upper-case specifiers are followed by the unit-name (e.g. \"years\").
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Lower-case specifiers return only the unit.
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\"%\" may be followed by a number specifying a width, with an
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optional leading \".\" for zero-padding. For example, \"%.3Y\" will
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return something of the form \"001 year\".
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The \"%s\" spec takes an additional optional parameter,
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introduced by the \",\" character, to say how many decimals to
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use. \"%,1s\" means \"use one decimal\".
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The \"%z\" specifier does not print anything. When it is used, specifiers
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must be given in order of decreasing size. To the left of \"%z\", nothing
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is output until the first non-zero unit is encountered.
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The \"%x\" specifier does not print anything. When it is used,
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specifiers must be given in order of decreasing size. To the
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right of \"%x\", trailing zero units are not output."
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(let ((start 0)
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(units '(("y" "year" 31536000)
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("d" "day" 86400)
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("h" "hour" 3600)
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("m" "minute" 60)
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("s" "second" 1)
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("z")
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("x")))
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(case-fold-search t)
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spec match usedunits zeroflag larger prev name unit num
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leading-zeropos trailing-zeropos fraction
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chop-leading chop-trailing)
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(while (string-match "%\\.?[0-9]*\\(,[0-9]\\)?\\(.\\)" string start)
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(setq start (match-end 0)
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spec (match-string 2 string))
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(unless (string-equal spec "%")
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(or (setq match (assoc (downcase spec) units))
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(error "Bad format specifier: `%s'" spec))
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(if (assoc (downcase spec) usedunits)
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(error "Multiple instances of specifier: `%s'" spec))
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(if (or (string-equal (car match) "z")
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(string-equal (car match) "x"))
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(setq zeroflag t)
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(unless larger
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(setq unit (nth 2 match)
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larger (and prev (> unit prev))
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prev unit)))
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(push match usedunits)))
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(when (and zeroflag larger)
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(error "Units are not in decreasing order of size"))
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(unless (numberp seconds)
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(setq seconds (float-time seconds)))
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(setq fraction (mod seconds 1)
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seconds (round seconds))
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(dolist (u units)
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(setq spec (car u)
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name (cadr u)
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unit (nth 2 u))
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(when (string-match
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(format "%%\\(\\.?[0-9]+\\)?\\(,[0-9]+\\)?\\(%s\\)" spec)
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string)
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(cond
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((string-equal spec "z")
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(setq chop-leading
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(if leading-zeropos
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(min leading-zeropos (match-beginning 0))
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;; The entire spec is zero, get past "%z" to last 0.
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(+ 2 (match-beginning 0)))))
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((string-equal spec "x")
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(setq chop-trailing t))
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(t
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;; Cf article-make-date-line in gnus-art.
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(setq num (floor seconds unit)
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seconds (- seconds (* num unit)))
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(let ((is-zero (zerop (if (= unit 1)
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(+ num fraction)
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num))))
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;; Start position of the first non-zero unit.
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(when (and (not leading-zeropos)
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(not is-zero))
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(setq leading-zeropos (match-beginning 0)))
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(unless is-zero
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(setq trailing-zeropos nil))
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(when (and (not trailing-zeropos)
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is-zero)
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(setq trailing-zeropos (match-beginning 0))))
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(setq string
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(replace-match
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(format (if (match-string 2 string)
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(concat
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"%"
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(and (match-string 1 string)
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(if (= (elt (match-string 1 string) 0) ?.)
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(concat "0" (substring
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(match-string 1 string) 1))
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(match-string 1 string)))
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(concat "." (substring
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(match-string 2 string) 1))
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"f%s")
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(concat "%" (match-string 1 string) "d%s"))
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(if (= unit 1)
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(+ num fraction)
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num)
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(if (string-equal (match-string 3 string) spec)
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"" ; lower-case, no unit-name
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(format " %s%s" name
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(if (= num 1) "" "s"))))
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t t string))))))
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(let ((pre string))
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(when (and chop-trailing trailing-zeropos)
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(setq string (substring string 0 trailing-zeropos)))
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(when chop-leading
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(setq string (substring string chop-leading)))
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;; If we ended up removing everything, return the formatted
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;; string in full.
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(when (equal string "")
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(setq string pre)))
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(setq string (replace-regexp-in-string "%[zx]" "" string)))
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(string-trim (string-replace "%%" "%" string)))
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(defvar seconds-to-string
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(list (list 1 "ms" 0.001)
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(list 100 "s" 1)
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(list (* 60 100) "m" 60.0)
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(list (* 3600 30) "h" 3600.0)
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(list (* 3600 24 400) "d" (* 3600.0 24.0))
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(list nil "y" (* 365.25 24 3600)))
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"Formatting used by the function `seconds-to-string'.")
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;;;###autoload
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(defun seconds-to-string (delay)
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;; FIXME: There's a similar (tho fancier) function in mastodon.el!
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"Convert the time interval in seconds to a short string."
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(cond ((> 0 delay) (concat "-" (seconds-to-string (- delay))))
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((= 0 delay) "0s")
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(t (let ((sts seconds-to-string) here)
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(while (and (car (setq here (pop sts)))
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(<= (car here) delay)))
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(concat (format "%.2f" (/ delay (car (cddr here)))) (cadr here))))))
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(defun date-days-in-month (year month)
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"The number of days in MONTH in YEAR."
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(unless (and (numberp month) (<= 1 month 12))
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(error "Month %s is invalid" month))
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(if (= month 2)
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(if (date-leap-year-p year)
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29
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28)
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(if (memq month '(1 3 5 7 8 10 12))
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31
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30)))
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(defun date-ordinal-to-time (year ordinal)
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"Convert a YEAR/ORDINAL to the equivalent `decoded-time' structure.
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ORDINAL is the number of days since the start of the year, with
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January 1st being 1."
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(let ((month 1))
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(while (> ordinal (date-days-in-month year month))
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(setq ordinal (- ordinal (date-days-in-month year month))
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month (1+ month)))
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(list nil nil nil ordinal month year nil nil nil)))
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(defun decoded-time-add (time delta)
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"Add DELTA to TIME, both of which are `decoded-time' structures.
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TIME should represent a time, while DELTA should have non-nil
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entries only for the values that should be altered.
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For instance, if you want to \"add two months\" to TIME, then
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leave all other fields but the month field in DELTA nil, and make
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the month field 2. For instance:
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(decoded-time-add (decode-time) (make-decoded-time :month 2))
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The values in DELTA can be negative.
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If applying a month/year delta leaves the time spec invalid, it
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is decreased to be valid (\"add one month\" to January 31st 2019
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will yield a result of February 28th 2019 and \"add one year\" to
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February 29th 2020 will result in February 28th 2021).
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Fields are added in a most to least significant order, so if the
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adjustment described above happens, it happens before adding
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days, hours, minutes or seconds.
|
||
|
||
When changing the time bits in TIME (i.e., second/minute/hour),
|
||
changes in daylight saving time are not taken into account."
|
||
(let ((time (copy-sequence time))
|
||
seconds)
|
||
;; Years are simple.
|
||
(when (decoded-time-year delta)
|
||
(cl-incf (decoded-time-year time) (decoded-time-year delta)))
|
||
|
||
;; Months are pretty simple, but start at 1 (for January).
|
||
(when (decoded-time-month delta)
|
||
(let ((new (+ (1- (decoded-time-month time)) (decoded-time-month delta))))
|
||
(setf (decoded-time-month time) (1+ (mod new 12)))
|
||
(cl-incf (decoded-time-year time) (/ new 12))))
|
||
|
||
;; Adjust for month length (as described in the doc string).
|
||
(setf (decoded-time-day time)
|
||
(min (date-days-in-month (decoded-time-year time)
|
||
(decoded-time-month time))
|
||
(decoded-time-day time)))
|
||
|
||
;; Days are iterative.
|
||
(when-let* ((days (decoded-time-day delta)))
|
||
(let ((increase (> days 0))
|
||
(days (abs days)))
|
||
(while (> days 0)
|
||
(decoded-time--alter-day time increase)
|
||
(cl-decf days))))
|
||
|
||
;; Do the time part, which is pretty simple (except for leap
|
||
;; seconds, I guess).
|
||
;; Time zone adjustments are basically the same as time adjustments.
|
||
(setq seconds (time-convert (or (decoded-time-second delta) 0) t))
|
||
(setq seconds
|
||
(time-add seconds
|
||
(time-convert (+ (* (or (decoded-time-hour delta) 0) 3600)
|
||
(* (or (decoded-time-minute delta) 0) 60)
|
||
(or (decoded-time-zone delta) 0))
|
||
(cdr seconds))))
|
||
|
||
(decoded-time--alter-second time seconds)
|
||
time))
|
||
|
||
(defun decoded-time--alter-month (time increase)
|
||
"Increase or decrease the month in TIME by 1."
|
||
(if increase
|
||
(progn
|
||
(cl-incf (decoded-time-month time))
|
||
(when (> (decoded-time-month time) 12)
|
||
(setf (decoded-time-month time) 1)
|
||
(cl-incf (decoded-time-year time))))
|
||
(cl-decf (decoded-time-month time))
|
||
(when (zerop (decoded-time-month time))
|
||
(setf (decoded-time-month time) 12)
|
||
(cl-decf (decoded-time-year time)))))
|
||
|
||
(defun decoded-time--alter-day (time increase)
|
||
"Increase or decrease the day in TIME by 1."
|
||
(if increase
|
||
(progn
|
||
(cl-incf (decoded-time-day time))
|
||
(when (> (decoded-time-day time)
|
||
(date-days-in-month (decoded-time-year time)
|
||
(decoded-time-month time)))
|
||
(setf (decoded-time-day time) 1)
|
||
(decoded-time--alter-month time t)))
|
||
(cl-decf (decoded-time-day time))
|
||
(when (zerop (decoded-time-day time))
|
||
(decoded-time--alter-month time nil)
|
||
(setf (decoded-time-day time)
|
||
(date-days-in-month (decoded-time-year time)
|
||
(decoded-time-month time))))))
|
||
|
||
(defun decoded-time--alter-second (time seconds)
|
||
"Increase the time in TIME by SECONDS."
|
||
(let* ((time-sec (time-convert (or (decoded-time-second time) 0) t))
|
||
(time-hz (cdr time-sec))
|
||
(old (time-add time-sec
|
||
(time-convert
|
||
(+ (* 3600 (or (decoded-time-hour time) 0))
|
||
(* 60 (or (decoded-time-minute time) 0)))
|
||
time-hz)))
|
||
(new (time-convert (time-add old seconds) t))
|
||
(new-hz (cdr new))
|
||
(secsperday (time-convert 86400 new-hz)))
|
||
;; Hm... DST...
|
||
(while (time-less-p new 0)
|
||
(decoded-time--alter-day time nil)
|
||
(setq new (time-add new secsperday)))
|
||
(while (not (time-less-p new secsperday))
|
||
(decoded-time--alter-day time t)
|
||
(setq new (time-subtract new secsperday)))
|
||
(let ((sec (time-convert new 'integer)))
|
||
(setf (decoded-time-second time) (time-add
|
||
(time-convert (% sec 60) new-hz)
|
||
(time-subtract
|
||
new (time-convert sec new-hz)))
|
||
(decoded-time-minute time) (% (/ sec 60) 60)
|
||
(decoded-time-hour time) (/ sec 3600)))))
|
||
|
||
(cl-defun make-decoded-time (&key second minute hour
|
||
day month year
|
||
(dst -1) zone)
|
||
"Return a `decoded-time' structure with only the keywords given filled out."
|
||
(list second minute hour day month year nil dst zone))
|
||
|
||
(defun decoded-time-set-defaults (time &optional default-zone)
|
||
"Set most nil values in `decoded-time' TIME to default values.
|
||
This can set TIME's year, month, day, hour, minute and second.
|
||
The default value is based on January 1st, 1970 at midnight.
|
||
This year is used to guarantee portability; see Info
|
||
node `(elisp) Time of Day'.
|
||
|
||
Optional argument DEFAULT-ZONE specifies what time zone to
|
||
default to when TIME's time zone is nil (meaning local time).
|
||
|
||
TIME is modified and returned."
|
||
(unless (decoded-time-second time)
|
||
(setf (decoded-time-second time) 0))
|
||
(unless (decoded-time-minute time)
|
||
(setf (decoded-time-minute time) 0))
|
||
(unless (decoded-time-hour time)
|
||
(setf (decoded-time-hour time) 0))
|
||
|
||
(unless (decoded-time-day time)
|
||
(setf (decoded-time-day time) 1))
|
||
(unless (decoded-time-month time)
|
||
(setf (decoded-time-month time) 1))
|
||
(unless (decoded-time-year time)
|
||
(setf (decoded-time-year time) 1970))
|
||
|
||
(unless (decoded-time-zone time)
|
||
(setf (decoded-time-zone time) default-zone))
|
||
|
||
;; Do not set decoded-time-weekday or decoded-time-dst,
|
||
;; as encode-time can infer them well enough when unknown.
|
||
|
||
time)
|
||
|
||
(defun decoded-time-period (time)
|
||
"Interpret TIME as a period and return its length in seconds.
|
||
For computational purposes, years are 365 days long and months
|
||
are 30 days long."
|
||
(+ (if (consp (decoded-time-second time))
|
||
;; Fractional second.
|
||
(/ (float (car (decoded-time-second time)))
|
||
(cdr (decoded-time-second time)))
|
||
(or (decoded-time-second time) 0))
|
||
(* (or (decoded-time-minute time) 0) 60)
|
||
(* (or (decoded-time-hour time) 0) 60 60)
|
||
(* (or (decoded-time-day time) 0) 60 60 24)
|
||
(* (or (decoded-time-month time) 0) 60 60 24 30)
|
||
(* (or (decoded-time-year time) 0) 60 60 24 365)))
|
||
|
||
(provide 'time-date)
|
||
|
||
;;; time-date.el ends here
|