Merge pull request #833 from terrafrost/sftp-endless-loop

SFTP.php : prevent endless loop when upload completed with non-zero $start or $local_start for 1.0

* terrafrost/sftp-endless-loop:
  SFTP: don't start in local file middle when uploading to middle of the remote file
  Tests/SFTP: updates to newly added unit test
  SFTP: backport DavidAnderson684's changes to 1.0 branch
  add unit test demo'ing issue # 830

phpseclib/Net/SFTP.php

@@ -1917,10 +1917,7 @@ class Net_SFTP extends Net_SSH2
 
             if ($local_start >= 0) {
                 fseek($fp, $local_start);
-            } elseif ($mode & NET_SFTP_RESUME_START) {
+                $size-= $local_start;
-                // do nothing
-            } else {
-                fseek($fp, $offset);
             }
         } elseif ($dataCallback) {
             $size = 0;

tests/Functional/Net/SFTPUserStoryTest.php

@@ -649,5 +649,28 @@ class Functional_Net_SFTPUserStoryTest extends PhpseclibFunctionalTestCase
         $this->assertSame($stat['type'], NET_SFTP_TYPE_SYMLINK);
 
         $sftp->enableStatCache();
+
+        return $sftp;
+    }
+
+    /**
+     * @depends testStatVsLstat
+     * @group github830
+     */
+    public function testUploadOffsets($sftp)
+    {
+        $sftp->put('offset.txt', 'res.txt', NET_SFTP_LOCAL_FILE, 0, 10);
+        $this->assertSame(
+            substr(self::$exampleData, 10),
+            $sftp->get('offset.txt'),
+            'Failed asserting that portions of a file could be uploaded.'
+        );
+
+        $sftp->put('offset.txt', 'res.txt', NET_SFTP_LOCAL_FILE, self::$exampleDataLength - 100);
+        $this->assertSame(
+            substr(self::$exampleData, 10, -90) . self::$exampleData,
+            $sftp->get('offset.txt'),
+            'Failed asserting that you could upload into the middle of a file.'
+        );
     }
 }