Support microtime in returned DateTimeInterface instances

Fixes #90 and supersedes #93.

src/Type/Decimal.php

@@ -0,0 +1,64 @@
+<?php
+
+/**
+ * This file is part of the ramsey/uuid library
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * @copyright Copyright (c) Ben Ramsey <ben@benramsey.com>
+ * @license http://opensource.org/licenses/MIT MIT
+ */
+
+declare(strict_types=1);
+
+namespace Ramsey\Uuid\Type;
+
+use Ramsey\Uuid\Exception\InvalidArgumentException;
+
+/**
+ * A value object representing a decimal
+ *
+ * This class exists for type-safety purposes, to ensure that decimals
+ * returned from ramsey/uuid methods as strings are truly decimals and not some
+ * other kind of string.
+ *
+ * To support values as true decimals and not as floats or doubles, we store the
+ * decimals as strings.
+ *
+ * @psalm-immutable
+ */
+final class Decimal implements NumberInterface
+{
+    /**
+     * @var string
+     */
+    private $value;
+
+    /**
+     * @param mixed $value The decimal value to store
+     */
+    public function __construct($value)
+    {
+        $value = (string) $value;
+
+        if (!is_numeric($value)) {
+            throw new InvalidArgumentException(
+                'Value must be a signed decimal or a string containing only '
+                . 'digits 0-9 and, optionally, a decimal point or sign (+ or -)'
+            );
+        }
+
+        $this->value = $value;
+    }
+
+    public function toString(): string
+    {
+        return $this->value;
+    }
+
+    public function __toString(): string
+    {
+        return $this->toString();
+    }
+}