measurement.php

См. документацию.

<?php
 
class CSaleMeasure
{
    public static function GetList($category = false)
    {
        static $arMeasurementsTable;
 
        if (!is_array($arMeasurementsTable))
        {
            $tablePath = COption::GetOptionString('sale', 'measurement_path', '/bitrix/modules/sale/measurements.php');
            $fullPath = $_SERVER["DOCUMENT_ROOT"].$tablePath;
            if ($tablePath <> '' && file_exists($fullPath) && !is_dir($fullPath))
            {
                require_once($fullPath);
                
                if (!is_array($arMeasurementsTable)) 
                    return false;
            }
            else
                return false;
        }
 
        if (!$category)
            return $arMeasurementsTable;
        else
        {
            $arList = array();
            foreach ($arMeasurementsTable as $key => $arM)
            {
                if ($arM["CATEGORY"] == $category) $arList[$key] = $arM;
            }
            return $arList;
        }
    }
 
    public static function Convert($value, $measureFrom, $measureTo = "G")
    {
        if (!is_numeric($value)) 
            return false;
 
        if (!$arMeasurementsTable = CSaleMeasure::GetList())
            return false;
        
        if (is_set($arMeasurementsTable, $measureFrom) && is_set($arMeasurementsTable, $measureTo))
            return $value * $arMeasurementsTable[$measureFrom]['KOEF'] / $arMeasurementsTable[$measureTo]['KOEF'];
        else
            return false;
    }
}