libraries/tbs/plugins/tbs_plugin_opentbs.php
function Misc_ColNum($ColRef, $IsODF) {

		if ($IsODF) {
			$p = strpos($ColRef, '.');
			if ($p!==false) $ColRef = substr($ColRef, $p); // delete the table name wich is in prefix
			$ColRef = str_replace( array('.','$'), '', $ColRef);
			$ColRef = explode(':', $ColRef);
			$ColRef = $ColRef[0];
		}

		$num = 0;
		$rank = 0;
		for ($i=strlen($ColRef)-1;$i>=0;$i--) {
			$l = $ColRef[$i];
			if (!is_numeric($l)) {
				$l = ord(strtoupper($l)) -64;
				if ($l>0 && $l<27) {
					$num = $num + $l*pow(26,$rank);
				} else {
					return $this->RaiseError('(Sheet) Reference of cell \''.$ColRef.'\' cannot be recognized.');
				}
				$rank++;
			}
		}

		return $num;

	}
function Misc_ColNum($ColRef, $IsODF) {

		if ($IsODF) {
			$p = strpos($ColRef, '.');
			if ($p!==false) $ColRef = substr($ColRef, $p); // delete the table name wich is in prefix
			$ColRef = str_replace( array('.','$'), '', $ColRef);
			$ColRef = explode(':', $ColRef);
			$ColRef = $ColRef[0];
		}

		$num = 0;
		$rank = 0;
		for ($i=strlen($ColRef)-1;$i>=0;$i--) {
			$l = $ColRef[$i];
			if (!is_numeric($l)) {
				$l = ord(strtoupper($l)) -64;
				if ($l>0 && $l<27) {
					$num = $num + $l*pow(26,$rank);
				} else {
					return $this->RaiseError('(Sheet) Reference of cell \''.$ColRef.'\' cannot be recognized.');
				}
				$rank++;
			}
		}

		return $num;

	}
Return the column number from a cell reference like "B3".