Determine if a day of week and time fall in a custom weekend period

I've been trying to come up with a method, that given a day of week and time of day, it will return if it falls under a custom weekend period.

The weekend period is saved in 4 variables as follows:

1. The day of week when it starts (0-6)
2. The time of day when it starts (0-23)
3. The day of week when it ends (0-6)
4. The time of day when it ends (0-23)

Based on these fields, the weekend period can be anything the user selected (even if it is well beyond a regular weekend)

I've been banging this one for awhile but to no avail. I'm trying this in delphi but any language will do, as I'm looking for the algorith开发者_StackOverflow中文版m and not the implementation.

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I assume there is also a constraint that the endpoint is >= beginpoint.

The easiest ways is to normalize to 'hours since week started'.

double interest = day * 24 + hours;
double startWeekend = startDay * 24 + startHours;
double endWeekend = endDay * 24 + endHours.
bool isInWeekend = interest >= startWeekend && interest < endWeekend;

Adjust <= and >= as desired.

Edit:

if the problem is that a Weekend could overlap the 7 * 24 hour boundary then it gets a little more interesting:

if startWeekend < endWeekend
then isInWeekend = interest >= startWeekend AND interest < endWeekend;
else isInWeekend = interest >= startWeekend OR interest < endWeekend;

(slightly mixed C / Pascal pseudo code)

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Call these four values d_start, d_end for the day and h_start, h_end for the hours. Then consider the total number of hours since day 0, hour 0, which is given by t_start = d_start * 24 + h_start, and likewise for t_end.

If the hour of the week that you're currently in is before t_end or after t_start, you're in the weekend period.

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If you want to handle intervals that wrap,

double hstart = startDay*24 + startHour;
double hend = endDay*24 + endHour;
double htest = testDay*24 + testHour;
return (hend-hstart)*(htest-hstart)*(hend-htest) > 0