function _field_ipaddress_minimum_cidr_prefix in IP address fields 7

Calculates the minimum CIDR prefix for a given IP address. The IP address is assumed to be the start of the block.

1 call to _field_ipaddress_minimum_cidr_prefix()

_field_ipaddress_validate_cidr in ./field_ipaddress.module

Validate a CIDR input.

File

./field_ipaddress.module, line 328

Code

function _field_ipaddress_minimum_cidr_prefix($ibase, $tbit) {
  while ($tbit > 0) {
    $im = pow(2, 32) - pow(2, 32 - ($tbit - 1));
    $imand = $ibase & $im;
    if ($imand != $ibase) {
      break;
    }
    $tbit--;
  }
  return $tbit;
}