Adding code to detect whether this is a 32-bit or 64-bit PHP build

README.md

@@ -8,6 +8,18 @@ A PHP 5.3+ library for generating and working with [RFC 4122][rfc4122] version
 Much inspiration for this library came from the [Java][javauuid] and
 [Python][pyuuid] UUID libraries.
 
+## Requirements
+
+Rhumsaa\Uuid works on 64-bit builds of PHP 5.3.3+.
+
+Since, this library deals with large integers, so you will need to run it on a
+64-bit system with a 64-bit compiled version of PHP.
+
+**Warning:** The [Windows binaries located on PHP.net][phpwin] are 32-bit
+versions of PHP. Even if you run them on a 64-bit version of Windows, this
+library will not work. You will need to compile PHP on Windows yourself to
+build a 64-bit version.
+
 ## Examples
 
 ```php
@@ -51,4 +63,5 @@ and install the latest version of the Uuid library into your project:
 [rfc4122]: http://tools.ietf.org/html/rfc4122
 [javauuid]: http://docs.oracle.com/javase/6/docs/api/java/util/UUID.html
 [pyuuid]: http://docs.python.org/library/uuid.html
+[phpwin]: http://windows.php.net/download/
 [packagist]: http://packagist.org/

src/Rhumsaa/Uuid/Uuid.php

@@ -97,6 +97,13 @@ final class Uuid
      */
     protected function __construct($msb, $lsb)
     {
+        if (PHP_INT_SIZE == 4) {
+            throw new \OverflowException(
+                'Attempting to create a UUID on a 32-bit build of PHP. This '
+                . 'library requires a 64-bit build of PHP.'
+            );
+        }
+
         $this->msb = $msb;
         $this->lsb = $lsb;
     }

tests/Rhumsaa/Uuid/EnvironmentTest.php

@@ -0,0 +1,30 @@
+<?php
+namespace Rhumsaa\Uuid;
+
+/**
+ * This class tests the environment to ensure the library functions as designed
+ * on 32-bit and 64-bit environments.
+ */
+class EnvironmentTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * @covers Rhumsaa\Uuid\Uuid::__construct
+     */
+    public function testConstructorException()
+    {
+        if (PHP_INT_SIZE == 4) {
+
+            $this->setExpectedException(
+                'OverflowException',
+                'Attempting to create a UUID on a 32-bit build of PHP. This library requires a 64-bit build of PHP.'
+            );
+
+            $uuid = Uuid::uuid1();
+
+        } else {
+
+            $this->markTestSkipped('This test is only applicable on a 32-bit system.');
+
+        }
+    }
+}

tests/Rhumsaa/Uuid/UuidTest.php

@@ -3,6 +3,16 @@ namespace Rhumsaa\Uuid;
 
 class UuidTest extends \PHPUnit_Framework_TestCase
 {
+    protected function setUp()
+    {
+        // Skip these tests if run on a 32-bit build of PHP
+        if (PHP_INT_SIZE == 4) {
+            $this->markTestSkipped(
+                'Running tests on a 32-bit build of PHP; 64-bit build required.'
+            );
+        }
+    }
+
     /**
      * @covers Rhumsaa\Uuid\Uuid::fromString
      * @covers Rhumsaa\Uuid\Uuid::__construct