added base

include/library/Cana/Base36.php

@@ -0,0 +1,48 @@
+<?php
+
+/**
+ * base62 Decimal encoder
+ *
+ * @author		Devin Smith <devin@cana.la>
+ * @date		2009.12.09
+ *
+ * Convert a db index to a shorter one
+ *
+ */
+
+
+class Cana_Base36 {
+	private static $_chars = '0123456789abcdefghijklmnopqrstuvwxyz';
+	private static $_base = '36';
+
+	// encode the string
+	public static function encode($val) {
+		if ($val) {
+			$str = '';
+			do {
+				$i = $val % self::$_base;
+				$str = self::$_chars[$i] . $str;
+				$val = ($val - $i) / self::$_base;
+			} while($val > 0);
+			return strtoupper($str);
+		} else {
+			return '';
+		}
+	}
+	
+	// decode the string
+	public static function decode($str) {
+		if ($str) {
+			$str = strtolower($str);
+			$len = strlen($str);
+			$val = 0;
+			$arr = array_flip(str_split(self::$_chars));
+			for($i = 0; $i < $len; ++$i) {
+				$val += (isset($arr[$str[$i]]) ? $arr[$str[$i]] : 0) * pow(self::$_base, $len-$i-1);
+			}
+			return $val;
+		} else {
+			return '';
+		}
+	}
+}