diff --git a/src/Composer/Autoload/ClassMapGenerator.php b/src/Composer/Autoload/ClassMapGenerator.php
index f79c23526..bebf7c7e3 100644
--- a/src/Composer/Autoload/ClassMapGenerator.php
+++ b/src/Composer/Autoload/ClassMapGenerator.php
@@ -125,10 +125,10 @@ class ClassMapGenerator
 
         preg_match_all('{
             (?:
-                 \b(?<![\$:>])(?<type>class|interface'.$traits.') \s+ (?<name>[^\s\{]+)
-               | \b(?<![\$:>])(?<ns>namespace) (?<nsname>\s+[^\s;{}\\\\]+(?:\s*\\\\\s*[^\s;{}\\\\]+)*)? \s*[\{;]
+                 \b(?<![\$:>])(?<type>class|interface'.$traits.') \s+ (?<name>[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*)
+               | \b(?<![\$:>])(?<ns>namespace) (?<nsname>\s+[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*(?:\s*\\\\\s*[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*)*)? \s*[\{;]
             )
-        }iux', $contents, $matches);
+        }ix', $contents, $matches);
 
         $classes = array();
         $namespace = '';
diff --git a/tests/Composer/Test/Autoload/ClassMapGeneratorTest.php b/tests/Composer/Test/Autoload/ClassMapGeneratorTest.php
index 3aea3a730..2f05e60b6 100644
--- a/tests/Composer/Test/Autoload/ClassMapGeneratorTest.php
+++ b/tests/Composer/Test/Autoload/ClassMapGeneratorTest.php
@@ -54,7 +54,7 @@ class ClassMapGeneratorTest extends \PHPUnit_Framework_TestCase
                 'Foo\\LargeClass'         => realpath(__DIR__).'/Fixtures/classmap/LargeClass.php',
                 'Foo\\LargeGap'           => realpath(__DIR__).'/Fixtures/classmap/LargeGap.php',
                 'Foo\\MissingSpace'       => realpath(__DIR__).'/Fixtures/classmap/MissingSpace.php',
-                'Unicode\\↑'              => realpath(__DIR__).'/Fixtures/classmap/Unicode.php',
+                'Unicode\\↑\\↑'              => realpath(__DIR__).'/Fixtures/classmap/Unicode.php',
             )),
             array(__DIR__.'/Fixtures/template', array()),
         );
diff --git a/tests/Composer/Test/Autoload/Fixtures/classmap/Unicode.php b/tests/Composer/Test/Autoload/Fixtures/classmap/Unicode.php
index ddd9359cf..5f96dec59 100644
--- a/tests/Composer/Test/Autoload/Fixtures/classmap/Unicode.php
+++ b/tests/Composer/Test/Autoload/Fixtures/classmap/Unicode.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Unicode;
+namespace Unicode\↑;
 
 class ↑{
 }