Convert decimal to hexadecimal (base A-Z)

Convert decimal to hexadecimal (base A-Z), convert decimal numbers into hexadecimal data with Z-A as base.
Used to get the index of the specified column in excel

/**
 * Get the name index of the specified cell in the excel table:
 * For example, row 1, column 1:
 * Return A1
 * Row 27, second column:
 * Return AA1:
 *
 * @param int $row No. How many rows
 * @param int $col Which column
 *
 * @author mingche
 * @since 2014-05-31
*/
function getExcelCeilIndex($row, $col) {
 if($row > 0 && $col > 0 )
 {
 $str = " ZABCDEFGHIGKLMNOPQRSTUVWXY";
 $col_str = "";
 do
 {
 $col_tmp = $col % 26;
 $col = $col_tmp == 0 ? intval($col / 26) - 1 : intval($col / 26) ;
 $col_str = $str[$col_tmp].$col_str;
 }while( $col );
 return $col_str.$row;
 }
 return false;
}
?>