Added shuffleString and shuffleArray to the CryptLib class

examples/CryptLib.php

@@ -76,6 +76,29 @@
 
 printf("\nHere's a random array element: %s\n", $element);
 
+/**
+ * And we can randomize an array
+ */
+$array = array('a', 'b', 'c', 'd', 'e', 'f');
+$newArray = $cryptLib->shuffleArray($array);
+
+printf("\nHere's a randomized array: \n");
+
+print_r($newArray);
+
+printf("\nAnd here's the same arrays with incremental keys:\n");
+
+print_r(array_values($newArray));
+
+/**
+ * And we can randomize a string
+ */
+
+$string = 'abcdef';
+$newString = $cryptLib->shuffleString($string);
+
+printf("\nHere's our randomized string: %s\n", $newString);
+
 /**
  * Now, lets do some password hashing.
  */

lib/CryptLib/CryptLib.php

@@ -119,4 +119,46 @@ public function getRandomToken($size) {
         return $generator->generateString($size);
     }
 
+    /**
+     * Shuffle an array.  This will preserve key => value relationships, and return
+     * a new array that has been randomized in order.
+     *
+     * To get keys randomized, simply pass the result through array_values()...
+     *
+     * @param array $array The input array to randomize
+     *
+     * @return array The suffled array
+     */
+    public function shuffleArray(array $array) {
+        $factory   = new RandomFactory;
+        $generator = $factory->getMediumStrengthGenerator();
+        $result    = array();
+        $values    = array_values($array);
+        $keys      = array_keys($array);
+        $max       = count($array);
+        for ($i = $max - 1; $i >= 0; $i--) {
+            $int                 = $generator->generateInt(0, $i);
+            $result[$keys[$int]] = $values[$int];
+            unset($keys[$int], $values[$int]);
+            $keys   = array_values($keys);
+            $values = array_values($values);
+        }
+        return $result;
+    }
+
+    /**
+     * Shuffle a string and return the randomized string
+     *
+     * @param string $string The string to randomize
+     *
+     * @return string The shuffled string
+     */
+    public function shuffleString($string) {
+        $factory   = new RandomFactory;
+        $generator = $factory->getMediumStrengthGenerator();
+        $array     = str_split($string);
+        $result    = $this->shuffleArray($array);
+        return implode('', $result);
+    }
+
 }

test/Unit/CryptLibTest.php

@@ -51,4 +51,22 @@ public function testGetRandomToken() {
         $string = $crypt->getRandomToken(10);
         $this->assertEquals(10, strlen($string));
     }
+
+    public function testShuffleArray() {
+        $crypt = new CryptLib;
+        $array = array(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+        $newArray = $crypt->shuffleArray($array);
+        $this->assertNotEquals($array, array_values($newArray));
+        $this->assertEquals($array, $newArray);
+    }
+
+    public function testShuffleString() {
+        $crypt = new CryptLib;
+        $string = 'abcdefghijklmnopqrstuvwxyz';
+        $newString = $crypt->shuffleString($string);
+        $this->assertNotEquals($string, $newString);
+        $cnt = count_chars($string, 1);
+        $cnt2 = count_chars($newString, 1);
+        $this->assertEquals($cnt, $cnt2);
+    }
 }