BEncoded integers for the Bittorrent stuff.

svn path=/trunk/boinc/; revision=12640

html/bt/inc/binteger.php

@@ -0,0 +1,32 @@
+<?php
+/**
+ * A BInteger takes care of the BEncoding and BDecoding of integers for the 
+ * Bittorrent features.
+ * An integer starts with "i", has the value and then ends with "e".
+ */
+class BInteger {
+    private function __construct(){
+    }
+    
+    /**
+     * Returns the ordinary value decoded from $str
+     * @throws an IllegalArgumentException in the case
+     * that the string is malformed.
+     */
+    public static function toInteger($str){
+        if (substr($str, 0, 1)!="i" || substr($str, -1, 1)!="e") throw new IllegalArgumentException("BEncoded integer value does not start with i or end with e.");
+        $value = substr($str, 1,-1);
+        if (!is_numeric($value)) throw new IllegalArgumentException("BEncoded string has non-numeric length specification.");
+        return $value;
+    }				
+
+    /**
+     * Returns a BEncoded integer value
+     */
+    public static function toEncoded($value){
+	return "i".$value."e";
+    }    
+}
+
+
+?>