diff --git a/src/Composer/Autoload/ClassMapGenerator.php b/src/Composer/Autoload/ClassMapGenerator.php
index 85e14768d..61cfae4a5 100644
--- a/src/Composer/Autoload/ClassMapGenerator.php
+++ b/src/Composer/Autoload/ClassMapGenerator.php
@@ -92,10 +92,10 @@ class ClassMapGenerator
      */
     private static function findClasses($path)
     {
-        $contents = php_strip_whitespace($path);
         $traits = version_compare(PHP_VERSION, '5.4', '<') ? '' : '|trait';
 
         try {
+            $contents = php_strip_whitespace($path);
             if (!preg_match('{\b(?:class|interface'.$traits.')\b}i', $contents)) {
                 return array();
             }
@@ -105,7 +105,12 @@ class ClassMapGenerator
             // strip strings
             $contents = preg_replace('{"[^"\\\\]*(\\\\.[^"\\\\]*)*"|\'[^\'\\\\]*(\\\\.[^\'\\\\]*)*\'}', 'null', $contents);
 
-            preg_match_all('{(?:\b(?<![\$:>])(?<type>class|interface'.$traits.')\s+(?<name>\S+)|\b(?<![\$:>])(?<ns>namespace)(?<nsname>\s+[^\s;{}\\\\]+(?:\s*\\\\\s*[^\s;{}\\\\]+)*|\s*\{))}i', $contents, $matches);
+            preg_match_all('{
+                (?:
+                     \b(?<![\$:>])(?<type>class|interface'.$traits.') \s+ (?<name>\S+)
+                   | \b(?<![\$:>])(?<ns>namespace) (?<nsname>\s+[^\s;{}\\\\]+(?:\s*\\\\\s*[^\s;{}\\\\]+)*)? \s*[\{;]
+                )
+            }ix', $contents, $matches);
             $classes = array();
 
             $namespace = '';
diff --git a/tests/Composer/Test/Autoload/ClassMapGeneratorTest.php b/tests/Composer/Test/Autoload/ClassMapGeneratorTest.php
index 3937e8a99..f1394fd44 100644
--- a/tests/Composer/Test/Autoload/ClassMapGeneratorTest.php
+++ b/tests/Composer/Test/Autoload/ClassMapGeneratorTest.php
@@ -44,11 +44,11 @@ class ClassMapGeneratorTest extends \PHPUnit_Framework_TestCase
             array(__DIR__.'/Fixtures/classmap', array(
                 'Foo\\Bar\\A'             => realpath(__DIR__).'/Fixtures/classmap/sameNsMultipleClasses.php',
                 'Foo\\Bar\\B'             => realpath(__DIR__).'/Fixtures/classmap/sameNsMultipleClasses.php',
-                'A'                       => realpath(__DIR__).'/Fixtures/classmap/multipleNs.php',
                 'Alpha\\A'                => realpath(__DIR__).'/Fixtures/classmap/multipleNs.php',
                 'Alpha\\B'                => realpath(__DIR__).'/Fixtures/classmap/multipleNs.php',
-                'Beta\\A'                 => realpath(__DIR__).'/Fixtures/classmap/multipleNs.php',
-                'Beta\\B'                 => realpath(__DIR__).'/Fixtures/classmap/multipleNs.php',
+                'A'                       => realpath(__DIR__).'/Fixtures/classmap/multipleNs.php',
+                'Be\\ta\\A'               => realpath(__DIR__).'/Fixtures/classmap/multipleNs.php',
+                'Be\\ta\\B'               => realpath(__DIR__).'/Fixtures/classmap/multipleNs.php',
                 'ClassMap\\SomeInterface' => realpath(__DIR__).'/Fixtures/classmap/SomeInterface.php',
                 'ClassMap\\SomeParent'    => realpath(__DIR__).'/Fixtures/classmap/SomeParent.php',
                 'ClassMap\\SomeClass'     => realpath(__DIR__).'/Fixtures/classmap/SomeClass.php',
diff --git a/tests/Composer/Test/Autoload/Fixtures/classmap/multipleNs.php b/tests/Composer/Test/Autoload/Fixtures/classmap/multipleNs.php
index d19e07fc1..ab751a969 100644
--- a/tests/Composer/Test/Autoload/Fixtures/classmap/multipleNs.php
+++ b/tests/Composer/Test/Autoload/Fixtures/classmap/multipleNs.php
@@ -1,14 +1,14 @@
 <?php
-namespace {
-    class A {}
-}
-
 namespace Alpha {
     class A {}
     class B {}
 }
 
-namespace Beta {
+namespace {
+    class A {}
+}
+
+namespace Be \ ta {
     class A {}
     class B {}
 }