/**
* Returns a conversion table which has conversion factors to normalize
* any given measurement unit to one of only a few others, to simplify
* the challenge of unit conversion
*
* @since 3.0
* @return array of conversion factors
*/
public static function get_normalize_table()
{
if (is_null(self::$normalize_table)) {
self::$normalize_table = apply_filters('wc_measurement_price_calculator_normalize_table', array('in' => array('factor' => 12, 'unit' => 'ft', 'inverse' => true), 'ft' => array('factor' => 1, 'unit' => 'ft'), 'yd' => array('factor' => 3, 'unit' => 'ft'), 'mi' => array('factor' => 5280, 'unit' => 'ft'), 'mm' => array('factor' => 0.001, 'unit' => 'm'), 'cm' => array('factor' => 0.01, 'unit' => 'm'), 'm' => array('factor' => 1, 'unit' => 'm'), 'km' => array('factor' => 1000, 'unit' => 'm'), 'sq. in.' => array('factor' => 144, 'unit' => 'sq. ft.', 'inverse' => true), 'sq. ft.' => array('factor' => 1, 'unit' => 'sq. ft.'), 'sq. yd.' => array('factor' => 9, 'unit' => 'sq. ft.'), 'acs' => array('factor' => 43560, 'unit' => 'sq. ft.'), 'sq. mi.' => array('factor' => 27878400, 'unit' => 'sq. ft.'), 'sq mm' => array('factor' => 1.0E-6, 'unit' => 'sq m'), 'sq cm' => array('factor' => 0.0001, 'unit' => 'sq m'), 'sq m' => array('factor' => 1, 'unit' => 'sq m'), 'ha' => array('factor' => 10000, 'unit' => 'sq m'), 'sq km' => array('factor' => 1000000, 'unit' => 'sq m'), 'fl. oz.' => array('factor' => 1, 'unit' => 'fl. oz.'), 'cup' => array('factor' => 8, 'unit' => 'fl. oz.'), 'pt' => array('factor' => 16, 'unit' => 'fl. oz.'), 'qt' => array('factor' => 32, 'unit' => 'fl. oz.'), 'gal' => array('factor' => 128, 'unit' => 'fl. oz.'), 'cu. in.' => array('factor' => 1728, 'unit' => 'cu. ft.', 'inverse' => true), 'cu. ft.' => array('factor' => 1, 'unit' => 'cu. ft.'), 'cu. yd.' => array('factor' => 27, 'unit' => 'cu. ft.'), 'ml' => array('factor' => 1.0E-6, 'unit' => 'cu m'), 'cu cm' => array('factor' => 1.0E-6, 'unit' => 'cu m'), 'l' => array('factor' => 0.001, 'unit' => 'cu m'), 'cu m' => array('factor' => 1, 'unit' => 'cu m'), 'oz' => array('factor' => 16, 'unit' => 'lbs', 'inverse' => true), 'lbs' => array('factor' => 1, 'unit' => 'lbs'), 'tn' => array('factor' => 2000, 'unit' => 'lbs'), 'g' => array('factor' => 0.001, 'unit' => 'kg'), 'kg' => array('factor' => 1, 'unit' => 'kg'), 't' => array('factor' => 1000, 'unit' => 'kg')));
}
return self::$normalize_table;
}
