Re: bit wise math? Is there a function to easily return the bits?

At 1/25/2007 11:16 AM, blackwater dev wrote:

Is there a php function I can call to pass in a number and get the values returned? For example, pass in 7 and get 1,2,4 ?

Here's a slightly more off-the-wall contribution: ==================================== function bin2array($iDecimal) {

        $aResult = array_reverse(explode("\r\n", chunk_split (decbin($iDecimal), 1)));

        array_walk($aResult, 'doPower');

        return $aResult;

} function doPower(&$iValue, $iIndex) {

        $iValue = $iValue * pow(2, $iIndex);

} ==================================== Here's the break-down of that eye-crossing first statement: array_reverse(explode("\r\n", trim(chunk_split (decbin($iDecimal), 1)))); using $iDecimal = 6: $a = decbin($iDecimal) --> '110' $b = chunk_split($a, 1) --> '1\r\n1\r\n0'

$c = explode("\r\n", $b);       // array(1,1,0)

$d = array_reverse($c); // array(0,1,1) (If you're using PHP5 you can use split() instead of chunk_split() and explode().) The doPower function performs this transform on each member of the array: $iValue = $iValue * pow(2, $iIndex);

Ix      Val     Math
0       0       0 * 2^0 = 0
1       1       1 * 2^1 = 2
2       1       1 * 2^2 = 4

Regards, Paul __________________________ Juniper Webcraft Ltd. http://juniperwebcraft.com