How to round unix timestamp up and down to nearest half hour?

Question

Ok so I am working on a calendar application within my CRM system and I need to find the upper and lower bounds of the half an hour surrorunding the timestamp at which someb

Answer 1

You could use the modulo operator.

$time -= $time % 3600; // nearest hour (always rounds down)

Hopefully this is enough to point you in the right direction, if not please add a comment and I'll try to craft a more specific example.