yuyue/Modules/Lib/Length.class.php

<?php
namespace Lib;
class Length {
	private $lengths = array();

	public function __construct($registry) {
		
		$length_class_query = M()->query("SELECT * FROM " . C('DB_PREFIX') . "length_class");		
		foreach ($length_class_query as $result) {
			$this->lengths[$result['length_class_id']] = array(
				'length_class_id' => $result['length_class_id'],
				'title'           => $result['title'],
				'unit'            => $result['unit'],
				'value'           => $result['value']
			);
		}
	}

	public function convert($value, $from, $to) {
		if ($from == $to) {
			return $value;
		}

		if (isset($this->lengths[$from])) {
			$from = $this->lengths[$from]['value'];
		} else {
			$from = 1;
		}

		if (isset($this->lengths[$to])) {
			$to = $this->lengths[$to]['value'];
		} else {
			$to = 1;
		}

		return $value * ($to / $from);
	}

	public function format($value, $length_class_id, $decimal_point = '.', $thousand_point = ',') {
		if (isset($this->lengths[$length_class_id])) {
			return number_format($value, 2, $decimal_point, $thousand_point) . $this->lengths[$length_class_id]['unit'];
		} else {
			return number_format($value, 2, $decimal_point, $thousand_point);
		}
	}

	public function getUnit($length_class_id) {
		if (isset($this->lengths[$length_class_id])) {
			return $this->lengths[$length_class_id]['unit'];
		} else {
			return '';
		}
	}
}