Question about implementation of bitDateRange

[strongeye]

I am looking at the source code of Bitter and had a question about it.

in the function bitDateRange in Bitter.php (line 137+) it looks like you get two different DatePeriods, then do two array_diffs, and it looks like this sometimes will result in bitOfOr being performed twice for the $hoursTo array.

What is the purpose of doing two different calls to DatePeriod::createForHour ?

Here is my analysis of what you are doing (in words):

• IF the date period is within the same day
  • With $hoursFrom, get all hours within the day
  • With $hoursTo, get just the hours between the start of this day and the $to hour value
• ELSE // the date period overlaps more than one day
  • With both $hoursFrom and $hoursTo, get actual hours between $from and $to

Is this meaningful? Why do you do anything other than return the actual hour span in all cases? Why do the bitOfOr twice?

Code below

// Hours
$hoursFrom = DatePeriod::createForHour($from, $to, DatePeriod::CREATE_FROM);
foreach ($hoursFrom as $date) {
$this->bitOpOr($destKey, new Hour($key, $date), $destKey);
}
$hoursTo = DatePeriod::createForHour($from, $to, DatePeriod::CREATE_TO);
if (array_diff($hoursTo->toArray(true), $hoursFrom->toArray(true)) !== array_diff($hoursFrom->toArray(true), $hoursTo->toArray(true))) {
foreach ($hoursTo as $date) {
$this->bitOpOr($destKey, new Hour($key, $date), $destKey);
}
}

[jeremyFreeAgent]

The aim of doing it "twice" is for doing the following with a dateFrom 2005-06-20 16:53:00 and a dateTo 2007-03-10 08:32:00 as example:

We want the data for theses hours:

• 2005-06-20 16
• 2005-06-20 17
• 2005-06-20 18
• 2005-06-20 19
• 2005-06-20 20
• 2005-06-20 21
• 2005-06-20 22
• 2005-06-20 23

Then data for theses days:

• 2005-06-21
• 2005-06-22
• 2005-06-23
• 2005-06-24
• 2005-06-25
• 2005-06-26
• 2005-06-27
• 2005-06-28
• 2005-06-29
• 2005-06-30

Then data for theses months:

• 2005-07
• 2005-08
• 2005-09
• 2005-10
• 2005-11
• 2005-12

Then data for these year:

• 2006

Then data for theses months:

• 2007-01
• 2007-02

Then data for theses days:

• 2007-03-01
• 2007-03-02
• 2007-03-03
• 2007-03-04
• 2007-03-05
• 2007-03-06
• 2007-03-07
• 2007-03-08
• 2007-03-09

Then data for theses hours:

• 2007-03-10 00
• 2007-03-10 01
• 2007-03-10 02
• 2007-03-10 03
• 2007-03-10 04
• 2007-03-10 05
• 2007-03-10 06
• 2007-03-10 07
• 2007-03-10 08

I hope that help you.

[strongeye]

So I guess it seems that the idea is to capture only for granular time units where the next-level-up unit is not 100% covered, ie. hours that are not a full day, days that are not a full month, months that do not cover a full year, etc.

[jeremyFreeAgent]

Yes, that the point. We could get all the data with the smallest part (hours) but that not really good. Remember that bit works as: does something happened on that day? on that hour? on that year? If something happened this hour, it happened this day so this month so this year.