PHP Util::pow方法代码示例

 /**
  * Handle the AJAX request for setting value for a single variable
  *
  * @return void
  */
 public function setValueAction()
 {
     $value = $_REQUEST['varValue'];
     $matches = array();
     if (isset($this->variable_doc_links[$_REQUEST['varName']][3]) && $this->variable_doc_links[$_REQUEST['varName']][3] == 'byte' && preg_match('/^\\s*(\\d+(\\.\\d+)?)\\s*(mb|kb|mib|kib|gb|gib)\\s*$/i', $value, $matches)) {
         $exp = array('kb' => 1, 'kib' => 1, 'mb' => 2, 'mib' => 2, 'gb' => 3, 'gib' => 3);
         $value = floatval($matches[1]) * Util::pow(1024, $exp[mb_strtolower($matches[3])]);
     } else {
         $value = Util::sqlAddSlashes($value);
     }
     if (!is_numeric($value)) {
         $value = "'" . $value . "'";
     }
     if (!preg_match("/[^a-zA-Z0-9_]+/", $_REQUEST['varName']) && $this->dbi->query('SET GLOBAL ' . $_REQUEST['varName'] . ' = ' . $value)) {
         // Some values are rounded down etc.
         $varValue = $this->dbi->fetchSingleRow('SHOW GLOBAL VARIABLES WHERE Variable_name="' . Util::sqlAddSlashes($_REQUEST['varName']) . '";', 'NUM');
         $this->response->addJSON('variable', htmlspecialchars($this->_formatVariable($_REQUEST['varName'], $varValue[1])));
     } else {
         $this->response->setRequestStatus(false);
         $this->response->addJSON('error', __('Setting variable failed'));
     }
 }

 /**
  * Returns a point that is guaranteed to be on the surface of the ring.
  * (for simple closed rings)
  *
  * @param array $ring array of points forming the ring
  *
  * @return array|void a point on the surface of the ring
  * @access public
  * @static
  */
 public static function getPointOnSurface($ring)
 {
     // Find two consecutive distinct points.
     for ($i = 0, $nb = count($ring) - 1; $i < $nb; $i++) {
         if ($ring[$i]['y'] != $ring[$i + 1]['y']) {
             $x0 = $ring[$i]['x'];
             $x1 = $ring[$i + 1]['x'];
             $y0 = $ring[$i]['y'];
             $y1 = $ring[$i + 1]['y'];
             break;
         }
     }
     if (!isset($x0)) {
         return false;
     }
     // Find the mid point
     $x2 = ($x0 + $x1) / 2;
     $y2 = ($y0 + $y1) / 2;
     // Always keep $epsilon < 1 to go with the reduction logic down here
     $epsilon = 0.1;
     $denominator = sqrt(Util::pow($y1 - $y0, 2) + Util::pow($x0 - $x1, 2));
     $pointA = array();
     $pointB = array();
     while (true) {
         // Get the points on either sides of the line
         // with a distance of epsilon to the mid point
         $pointA['x'] = $x2 + $epsilon * ($y1 - $y0) / $denominator;
         $pointA['y'] = $y2 + ($pointA['x'] - $x2) * ($x0 - $x1) / ($y1 - $y0);
         $pointB['x'] = $x2 + $epsilon * ($y1 - $y0) / (0 - $denominator);
         $pointB['y'] = $y2 + ($pointB['x'] - $x2) * ($x0 - $x1) / ($y1 - $y0);
         // One of the points should be inside the polygon,
         // unless epsilon chosen is too large
         if (GISPolygon::isPointInsidePolygon($pointA, $ring)) {
             return $pointA;
         }
         if (GISPolygon::isPointInsidePolygon($pointB, $ring)) {
             return $pointB;
         }
         //If both are outside the polygon reduce the epsilon and
         //recalculate the points(reduce exponentially for faster convergence)
         $epsilon = Util::pow($epsilon, 2);
         if ($epsilon == 0) {
             return false;
         }
     }
 }

/**
 * Returns the column number based on the Excel name.
 * So "A" = 1, "Z" = 26, "AA" = 27, etc.
 *
 * Basically this is a base26 (A-Z) to base10 (0-9) conversion.
 * It iterates through all characters in the column name and
 * calculates the corresponding value, based on character value
 * (A = 1, ..., Z = 26) and position in the string.
 *
 * @param string $name column name(i.e. "A", or "BC", etc.)
 *
 * @return int The column number
 * @access  public
 */
function PMA_getColumnNumberFromName($name)
{
    if (empty($name)) {
        return 0;
    }
    $name = mb_strtoupper($name);
    $num_chars = mb_strlen($name);
    $column_number = 0;
    for ($i = 0; $i < $num_chars; ++$i) {
        // read string from back to front
        $char_pos = $num_chars - 1 - $i;
        // convert capital character to ASCII value
        // and subtract 64 to get corresponding decimal value
        // ASCII value of "A" is 65, "B" is 66, etc.
        // Decimal equivalent of "A" is 1, "B" is 2, etc.
        $number = (int) (mb_ord($name[$char_pos]) - 64);
        // base26 to base10 conversion : multiply each number
        // with corresponding value of the position, in this case
        // $i=0 : 1; $i=1 : 26; $i=2 : 676; ...
        $column_number += $number * PMA\libraries\Util::pow(26, $i);
    }
    return $column_number;
}