note 75495 added to language.operators.bitwise
| From: | kendsnyder at gmail dot com | Date: | Fri, 01 Jun 2007 22:30:45 +0000 |
| Subject: | note 75495 added to language.operators.bitwise | ||
| Groups: | php.notes | ||
| Request: | Send a blank email to php-notes+get-127112@lists.php.net to get a copy of this message | ||
I needed to perform a bitwise AND on floats and came up with this. There is probably a better way
to do this with bit rotation, but this works.
/**
* Perform a float-safe bitwise AND comparison
*
* @param int/float $number The number to which to perform a bitwise AND
* @param int/float $comparison The number with which to perform a bitwise AND
* @return bool
*/
function safeBitCheck($number,$comparison) {
if( $number < 2147483647 ) {
return ($number & $comparison)==$comparison;
} else {
$binNumber = strrev(base_convert($number,10,2));
$binComparison = strrev(base_convert($comparison,10,2));
for( $i=0; $i<strlen($binComparison); $i++ ) {
if( strlen($binNumber)<$i || ($binComparison{$i}==="1" &&
$binNumber{$i}==="0") ) {
return false;
}
}
return true;
}
}
safeBitCheck(17,16); // true
safeBitCheck(17,2); // false
safeBitCheck((4294967296+8589934592),4294967296); // true
safeBitCheck(2,8589934592); // false
----
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