PHP text size to byte

PHP text size to byte

function strBytes($str){
	// STRINGS ARE EXPECTED TO BE IN ASCII OR UTF-8 FORMAT

	// Number of characters in string
	$strlen_var = strlen($str);

	// string bytes counter
	$d = 0;

	/*
	* Iterate over every character in the string,
	* escaping with a slash or encoding to UTF-8 where necessary
	*/
	for($c = 0; $c < $strlen_var; ++$c){
		$ord_var_c = ord($str{$c});
		switch(true){
			case(($ord_var_c >= 0x20) && ($ord_var_c <= 0x7F)):
				// characters U-00000000 - U-0000007F (same as ASCII)
				$d++;
				break;
			case(($ord_var_c & 0xE0) == 0xC0):
				// characters U-00000080 - U-000007FF, mask 110XXXXX
				$d+=2;
				break;
			case(($ord_var_c & 0xF0) == 0xE0):
				// characters U-00000800 - U-0000FFFF, mask 1110XXXX
				$d+=3;
				break;
			case(($ord_var_c & 0xF8) == 0xF0):
				// characters U-00010000 - U-001FFFFF, mask 11110XXX
				$d+=4;
				break;
			case(($ord_var_c & 0xFC) == 0xF8):
				// characters U-00200000 - U-03FFFFFF, mask 111110XX
				$d+=5;
				break;
			case(($ord_var_c & 0xFE) == 0xFC):
				// characters U-04000000 - U-7FFFFFFF, mask 1111110X
				$d+=6;
				break;
			default:
				$d++;
		};
	};
	return $d;
}