diff --git a/lib/zip_source_commit_write.c b/lib/zip_source_commit_write.c
new file mode 100644
index 0000000..09fe3da
--- /dev/null
+++ b/lib/zip_source_commit_write.c
@@ -0,0 +1,64 @@
+/*
+  zip_source_commit_write.c -- commit changes to file
+  Copyright (C) 2014 Dieter Baron and Thomas Klausner
+
+  This file is part of libzip, a library to manipulate ZIP archives.
+  The authors can be contacted at <libzip@nih.at>
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions
+  are met:
+  1. Redistributions of source code must retain the above copyright
+     notice, this list of conditions and the following disclaimer.
+  2. Redistributions in binary form must reproduce the above copyright
+     notice, this list of conditions and the following disclaimer in
+     the documentation and/or other materials provided with the
+     distribution.
+  3. The names of the authors may not be used to endorse or promote
+     products derived from this software without specific prior
+     written permission.
+ 
+  THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS
+  OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+  ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
+  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
+  GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
+  IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+  OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
+  IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+
+#include "zipint.h"
+
+
+int
+zip_source_commit_write(struct zip_source *src)
+{
+    if (!ZIP_SOURCE_IS_OPEN_WRITING(src)) {
+        zip_error_set(&src->error, ZIP_ER_INVAL, 0);
+        return -1;
+    }
+    
+    if (src->open_count > 1) {
+	zip_error_set(&src->error, ZIP_ER_INUSE, 0);
+	return -1;
+    }
+    else if (ZIP_SOURCE_IS_OPEN_READING(src)) {
+        if (zip_source_close(src) < 0) {
+	    return -1;
+	}
+    }
+    
+    if (_zip_source_call(src, NULL, 0, ZIP_SOURCE_COMMIT_WRITE) < 0) {
+        src->write_state = ZIP_SOURCE_WRITE_FAILED;
+        return -1;
+    }
+    
+    src->write_state = ZIP_SOURCE_WRITE_CLOSED;
+    
+    return 0;
+}