| 1 | ### -*-bash-*- |
| 2 | ### |
| 3 | ### Common utilities for rsync-backup scripts |
| 4 | ### |
| 5 | ### (c) 2014 Mark Wooding |
| 6 | ### |
| 7 | |
| 8 | ###----- Licensing notice --------------------------------------------------- |
| 9 | ### |
| 10 | ### This file is part of the `rsync-backup' program. |
| 11 | ### |
| 12 | ### rsync-backup is free software; you can redistribute it and/or modify |
| 13 | ### it under the terms of the GNU General Public License as published by |
| 14 | ### the Free Software Foundation; either version 2 of the License, or |
| 15 | ### (at your option) any later version. |
| 16 | ### |
| 17 | ### rsync-backup is distributed in the hope that it will be useful, |
| 18 | ### but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 19 | ### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 20 | ### GNU General Public License for more details. |
| 21 | ### |
| 22 | ### You should have received a copy of the GNU General Public License |
| 23 | ### along with rsync-backup; if not, write to the Free Software Foundation, |
| 24 | ### Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 25 | |
| 26 | ###-------------------------------------------------------------------------- |
| 27 | ### Configuration. |
| 28 | |
| 29 | VERSION=@VERSION@ |
| 30 | pkgdatadir=@pkgdatadir@ |
| 31 | mntbkpdir=@mntbkpdir@ |
| 32 | logdir=@logdir@ |
| 33 | fshashdir=@fshashdir@ |
| 34 | conf=@sysconfdir@/rsync-backup.conf |
| 35 | |
| 36 | INDEXDB=@pkglocalstatedir@/index.db |
| 37 | |
| 38 | SNAPDIR=$mntbkpdir/snap |
| 39 | STOREDIR=$mntbkpdir/store |
| 40 | METADIR=$mntbkpdir/meta |
| 41 | |
| 42 | config () { |
| 43 | echo |
| 44 | cat <<EOF |
| 45 | conf = $conf |
| 46 | mntbkpdir = $mntbkpdir |
| 47 | fshashdir = $fshashdir |
| 48 | logdir = $logdir |
| 49 | EOF |
| 50 | } |
| 51 | |
| 52 | ###-------------------------------------------------------------------------- |
| 53 | ### Date hacking. |
| 54 | |
| 55 | parsedate () { |
| 56 | date=$1 |
| 57 | ## Parse an ISO8601 DATE, and set YEAR, MONTH, DAY appropriately (and |
| 58 | ## without leading zeros). |
| 59 | |
| 60 | ## Extract the components of the date and trim leading zeros (which will |
| 61 | ## cause things to be interpreted as octal and fail). |
| 62 | year=${date%%-*} rest=${date#*-}; month=${rest%%-*} day=${rest#*-} |
| 63 | year=${year#0} month=${month#0} day=${day#0} |
| 64 | } |
| 65 | |
| 66 | julian () { |
| 67 | date=$1 |
| 68 | ## Convert an ISO8601 DATE to a Julian Day Number. |
| 69 | |
| 70 | parsedate $date |
| 71 | |
| 72 | ## The actual calculation: convert a (proleptic) Gregorian calendar date |
| 73 | ## into a Julian day number. This is taken from Wikipedia's page |
| 74 | ## http://en.wikipedia.org/wiki/Julian_day#Calculation but the commentary |
| 75 | ## is mine. The epoch is 4713BC-01-01 (proleptic) Julian, or 4714BC-11-24 |
| 76 | ## proleptic Gregorian. |
| 77 | |
| 78 | ## If the MONTH is January or February then set a = 1, otherwise set a = 0. |
| 79 | a=$(( (14 - $month)/12 )) |
| 80 | |
| 81 | ## Compute a year offset relative to 4799BC-03-01. This puts the leap day |
| 82 | ## as the very last day in a year, which is very convenient. The offset |
| 83 | ## here is sufficient to make all y values positive (within the range of |
| 84 | ## the JDN calendar), and is a multiple of 400, which is the Gregorian |
| 85 | ## cycle length. |
| 86 | y=$(( $year + 4800 - $a )) |
| 87 | |
| 88 | ## Compute the offset month number in that year. These months count from |
| 89 | ## zero, not one. |
| 90 | m=$(( $month + 12*$a - 3 )) |
| 91 | |
| 92 | ## Now for the main event. The (153 m + 2)/5 term is a surprising but |
| 93 | ## correct trick for obtaining the number of days in the first m months of |
| 94 | ## the (shifted) year). The magic offset 32045 is what you get when you |
| 95 | ## plug the proper JDN epoch (year = -4713, month = 11, day = 24) into the |
| 96 | ## above machinery. |
| 97 | jdn=$(( $day + (153*$m + 2)/5 + 365*$y + $y/4 - $y/100 + $y/400 - 32045 )) |
| 98 | |
| 99 | echo $jdn |
| 100 | } |
| 101 | |
| 102 | ###----- That's all, folks -------------------------------------------------- |