Use common base directory of given directories as basedir in phar mode

This fixes #63

src/Config.php

@@ -83,6 +83,10 @@ public function getBaseDirectory() {
             if ($this->baseDirectory !== NULL) {
                 return realpath($this->baseDirectory);
             }
+            if ($this->isPharMode()) {
+                $comparator = new PathComparator($this->directories);
+                return  $comparator->getCommondBase();
+            }
             if ($this->outputFile != 'STDOUT') {
                 return realpath(dirname($this->outputFile) ?: '.');
             }

src/PathComparator.php

@@ -0,0 +1,41 @@
+<?php
+namespace TheSeer\Autoload {
+
+    class PathComparator {
+
+        /**
+         * @var string[]
+         */
+        private $directories = array();
+
+        /**
+         * PathComparator constructor.
+         *
+         * @param array $directories
+         */
+        public function __construct(array $directories) {
+            foreach($directories as $dir) {
+                $this->directories[] = realpath($dir);
+            }
+        }
+
+        public function getCommondBase() {
+            if (count($this->directories) == 0) {
+                return '/';
+            }
+            $result = $this->directories[0];
+            foreach($this->directories as $dir) {
+                $result = substr($dir, 0, $this->commonPrefix($result, $dir));
+            }
+            return rtrim($result,'/');
+        }
+
+
+        private function commonPrefix( $s1, $s2, $i=0 ) {
+            return (
+                !empty($s1[$i]) && !empty($s2[$i]) && $s1[$i] == $s2[$i]
+            ) ? $this->commonPrefix( $s1, $s2, ++$i ) : $i;
+        }
+    }
+
+}

src/autoload.php

@@ -127,6 +127,7 @@ function($class) {
                 'theseer\\autoload\\parseresult' => '/ParseResult.php',
                 'theseer\\autoload\\parserexception' => '/Parser.php',
                 'theseer\\autoload\\parserinterface' => '/ParserInterface.php',
+                'theseer\\autoload\\pathcomparator' => '/PathComparator.php',
                 'theseer\\autoload\\pharbuilder' => '/PharBuilder.php',
                 'theseer\\autoload\\sourcefile' => '/SourceFile.php',
                 'theseer\\autoload\\staticrenderer' => '/StaticRenderer.php',
@@ -142,6 +143,8 @@ function($class) {
         if (isset($classes[$cn])) {
             require __DIR__ . $classes[$cn];
         }
-    }
+    },
+    true,
+    false
 );
 // @codeCoverageIgnoreEnd

tests/PathComparator.test.php

@@ -0,0 +1,35 @@
+<?php
+
+namespace TheSeer\Autoload\Tests {
+
+    use TheSeer\Autoload\PathComparator;
+
+    class PathComparatorTest extends \PHPUnit_Framework_TestCase {
+
+        /**
+         * @dataProvider directoriesProvider
+         */
+        public function testComparatorYieldsCorrectCommonBase(array $directories, $common) {
+            $comparator = new PathComparator($directories);
+            $this->assertEquals($common, $comparator->getCommondBase());
+        }
+
+        public function directoriesProvider() {
+            return [
+                'empty' => [
+                    [], '/'
+                ],
+                'single' => [
+                    array(__DIR__), __DIR__
+                ],
+                'two' => [
+                    array(__DIR__, dirname(__DIR__)), dirname(__DIR__)
+                ],
+                'partns' => [
+                    array(__DIR__ . '/../src', __DIR__ . '/../vendor/theseer'), dirname(__DIR__)
+                ]
+            ];
+        }
+    }
+
+}