26.5. Types of measurements

Some popular binary conventions, include terms like kilo-, mega-, giga, etc. in normal language use imply base 10, such as 1000 or 10³. However, in the binary format for computers these terms have to be seen for a conversion factor of 1024 instead of 1000. To preclude confusions a few years ago the notation BI was introduced. Instead of kilobyte, kibibyte for kilo-binary-byte should be used.

In the class BINARY both notations can be found, such as KILOBYTE = 1024 - binary conputer conversion KIBIBYTE = 1024 - new notation KILO_BINARY_BYTE = 1024 - new, or the notation, long format KILOBYTE_SI = 1000 - SI notation for kilo (1000). DVDs for example are marked with the SI-notation, but almost all harddisks are marked in computer binary notation.

The best known number format is the decimal system. Additionally this class supports the octal system, the hexadecimal system, the binary system, the roman number system and some other less popular systems. Note that only the decimal part of numbers is handled. Any fractional part will be stripped.

For the roman number system digits greater 4000 are supported. In reality these digits are shown with a crossbeam on top of the digit. As the crossbeam can not be shown within the computer, an underline has to be used instead of it.

$great = '_X';
$locale = new Zend_Locale('en');
$unit = new Zend_Measure_Number($great,Zend_Measure_Number::ROMAN, $locale);

// convert to the decimal system
echo $unit->convertTo(Zend_Measure_Number::DECIMAL);