Attachment 64022 Details for Bug 18356 – [SIGNED-OFF] Bug 18356: Fix date calculations for yearly frequencies in Serials

[patch] [SIGNED-OFF] Bug 18356: Fix date calculations for yearly frequencies in Serials

SIGNED-OFF-Bug-18356-Fix-date-calculations-for-yea.patch (text/plain), 5.83 KB, created by Josef Moravec on 2017-06-06 07:30:18 UTC

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Creator: Josef Moravec

Created: 2017-06-06 07:30:18 UTC

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patch

obsolete

>From a3e7938358746b161ad9e6a7fc5187d3bc8e9335 Mon Sep 17 00:00:00 2001
>From: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
>Date: Tue, 9 May 2017 17:01:46 +0200
>Subject: [PATCH] [SIGNED-OFF] Bug 18356: Fix date calculations for yearly
> frequencies in Serials
>
>The problem as described on BZ 18356 is a combination of an error in
>GetFictiveIssueNumber and GetNextDate for unit==year.
>
>[1] In GetNextDate the Add_Delta_YM calculation should be applied only to
>frequencies based on years per unit.
>In the case of multiple units per year we calculate the number of days to
>add. And if we have reached the end of a cycle, we correct the
>rounding applied in the cycle.
>NOTE 1: We obsolete the idea here of rebasing dates on firstacqui. In case
>of manual adjustments, we probably do not want it. And otherwise we do not
>need it anymore due to the correction at the end of a cycle.
>NOTE 2: The calls to Add_Delta_YM are intentionally not corrected for leap
>years. Say you start at 2016-02-29. If you use 1/yr or 1/2yr, you will
>switch to the Feb 28th in the following years. In 2020 there will be no
>switch to Feb 29 again; if someone should need it, please use a manual
>adjustment. This is probably highly exceptional.
>
>[2] In GetFictiveIssueNumber the year should be decreased by one if you
>have more units per year and you did not yet reach firstacqui day and
>month. This affects calculations in GetNextDate with irregularities.
>NOTE 1: I added a wrapper around Date::Calc::N_Delta_YMD in order to improve
>its results; this will especially be needed when we use it later for
>month units.
>NOTE 2: In case of manual adjustments this calculation does not really make
>sense. Another report should deal with improving irregularities.
>
>Test plan:
>[1] Verify that both GetNextDate.t as well as GetFictiveIssueNumber.t pass.
>[2] Look at the prediction pattern for a few frequencies.
>    For example: 1 iss/y, 1 iss/2y, 5 iss/y.
>
>Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
>
>Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
>---
> C4/Serials.pm | 57 +++++++++++++++++++++++++++++++++++++++++----------------
> 1 file changed, 41 insertions(+), 16 deletions(-)
>
>diff --git a/C4/Serials.pm b/C4/Serials.pm
>index c1316f2..7f91826 100644
>--- a/C4/Serials.pm
>+++ b/C4/Serials.pm
>@@ -2270,6 +2270,9 @@ depending on how many rows are in serial table.
> The issue number calculation is based on subscription frequency, first acquisition
> date, and $publisheddate.
> 
>+The routine is used to skip irregularities when calculating the next issue
>+date (in GetNextDate) or the next issue number (in GetNextSeq).
>+
> =cut
> 
> sub GetFictiveIssueNumber {
>@@ -2295,8 +2298,8 @@ sub GetFictiveIssueNumber {
>             $delta = ($fa_year == $year)
>                    ? ($month - $fa_month)
>                    : ( ($year-$fa_year-1)*12 + (12-$fa_month+$month) );
>-        } elsif($unit eq 'year') {
>-            $delta = $year - $fa_year;
>+        } elsif( $unit eq 'year' ) {
>+            $delta = _delta_units( [ $fa_year, $fa_month, $fa_day ], [ $year, $month, $day ], 'year' );
>         }
>         if($frequency->{'unitsperissue'} == 1) {
>             $issueno = $delta * $frequency->{'issuesperunit'} + $subscription->{'countissuesperunit'};
>@@ -2308,6 +2311,27 @@ sub GetFictiveIssueNumber {
>     return $issueno;
> }
> 
>+sub _delta_units {
>+# wrapper around N_Delta_YMD
>+# Note that N_Delta_YMD returns 29 days between e.g. 22-2-72 and 22-3-72
>+# while we expect 1 month.
>+    my ( $date1, $date2, $unit ) = @_;
>+    my @delta = N_Delta_YMD( @$date1, @$date2 );
>+    if( $delta[2] > 27 ) {
>+        # Check if we could add a month
>+        my @jump = Add_Delta_YM( @$date1, $delta[0], 1 + $delta[1] );
>+        if( Delta_Days( @jump, @$date2 ) >= 0 ) {
>+            $delta[1]++;
>+        }
>+    }
>+    if( $delta[1] >= 12 ) {
>+        $delta[0]++;
>+        $delta[1] -= 12;
>+    }
>+    # if unit is year, we only return full years
>+    return $unit eq 'month' ? $delta[0] * 12 + $delta[1] : $delta[0];
>+}
>+
> sub _get_next_date_day {
>     my ($subscription, $freqdata, $year, $month, $day) = @_;
> 
>@@ -2372,23 +2396,24 @@ sub _get_next_date_month {
> sub _get_next_date_year {
>     my ($subscription, $freqdata, $year, $month, $day) = @_;
> 
>-    my ($fa_year, $fa_month, $fa_day) = split /-/, $subscription->{firstacquidate};
>+    my @newissue; # ( yy, mm, dd )
>+    my $delta_days = int( 365 / $freqdata->{issuesperunit} );
> 
>-    if ($subscription->{countissuesperunit} + 1 > $freqdata->{issuesperunit}){
>-        $subscription->{countissuesperunit} = 1;
>-        ($year) = Add_Delta_YM($year,$month,$day, $freqdata->{"unitsperissue"},0);
>-        $month = $fa_month;
>-        my $days_in_month = Days_in_Month($year, $month);
>-        $day = $fa_day <= $days_in_month ? $fa_day : $days_in_month;
>-    } else {
>-        # Try to guess the next day in year
>-        my $days_in_year = Days_in_Year($year,12); #Sum the days of all the months of this year
>-        my $delta_days = int(($days_in_year - ($fa_day - 1)) / $freqdata->{issuesperunit});
>-        ($year,$month,$day) = Add_Delta_Days($year, $month, $day, $delta_days);
>+    if( $freqdata->{issuesperunit} == 1 ) {
>+        # Add full years
>+        @newissue = Add_Delta_YM( $year, $month, $day, $freqdata->{"unitsperissue"}, 0 );
>+    } elsif ( $subscription->{countissuesperunit} < $freqdata->{issuesperunit} ) {
>+        # Add rounded number of days based on frequency.
>+        @newissue = Add_Delta_Days( $year, $month, $day, $delta_days );
>         $subscription->{countissuesperunit}++;
>+    } else {
>+        # We finished a cycle of issues within a unit.
>+        # Subtract delta * (issues - 1), add 1 year
>+        @newissue = Add_Delta_Days( $year, $month, $day, -$delta_days * ($freqdata->{issuesperunit} - 1) );
>+        @newissue = Add_Delta_YM( @newissue, 1, 0 );
>+        $subscription->{countissuesperunit} = 1;
>     }
>-
>-    return ($year, $month, $day);
>+    return @newissue;
> }
> 
> =head2 GetNextDate
>-- 
>2.1.4

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