Cody Taylor has a quick post to his blog about bit checking in PHP:
PHP makes life a lot easier for quick or dirty maintenance scripts, cron jobs or web applications but how does it do for older, not so straight forward problems dealing with bits and bytes? I was surprised how easy it was to manipulate bits in a byte with php. Here is an function that made my life a fair amount easier when having to check for a specific bit in a byte.
The function takes in the value and, after casting it to an int, checks to see how it compares to eight and returns it. This result can be passed through decbin function for output. A handy table of the bitwise operator definitions is also included.