Add RandomDevice

src/Engine/RandomDevice.php

@@ -0,0 +1,35 @@
+<?php
+
+namespace Emonkak\Random\Engine;
+
+class RandomDevice extends AbstractEngine
+{
+    /**
+     * {@inheritDoc}
+     */
+    public function max()
+    {
+        return 0x7fffffff;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function min()
+    {
+        return 0;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function next()
+    {
+        $bytes = mcrypt_create_iv(4, MCRYPT_DEV_URANDOM);
+        if ($bytes === false || strlen($bytes) !== 4) {
+            throw new RuntimeException('Unable to get 4 bytes');
+        }
+        $array = unpack('Nint', $bytes);
+        return $array['int'] & 0x7FFFFFFF;   // 32-bit safe
+    }
+}

tests/Engine/RandomDeviceTest.php

@@ -0,0 +1,33 @@
+<?php
+
+namespace Emonkak\Random\Tests\Engine;
+
+use Emonkak\Random\Engine\RandomDevice;
+
+/**
+ * @requires extension mcrypt
+ */
+class RandomDeviceTest extends \PHPUnit_Framework_TestCase
+{
+    public function testMax()
+    {
+        return $this->assertSame(0x7fffffff, (new RandomDevice())->max());
+    }
+
+    public function testMin()
+    {
+        return $this->assertSame(0, (new RandomDevice())->min());
+    }
+
+    public function testNext()
+    {
+        $engine = new RandomDevice();
+
+        for ($i = 0; $i < 1000; $i++) {
+            $n = $engine->next();
+
+            $this->assertGreaterThanOrEqual($engine->min(), $n);
+            $this->assertLessThanOrEqual($engine->max(), $n);
+        }
+    }
+}