diff --git a/lib/zip_source_function.c b/lib/zip_source_function.c
new file mode 100644
index 0000000..083ecfc
--- /dev/null
+++ b/lib/zip_source_function.c
@@ -0,0 +1,59 @@
+/*
+  $NiH: zip_source_function.c,v 1.17 2004/11/17 21:55:13 wiz Exp $
+
+  zip_source_function.c -- create zip data source from callback function
+  Copyright (C) 1999, 2003, 2004 Dieter Baron and Thomas Klausner
+
+  This file is part of libzip, a library to manipulate ZIP archives.
+  The authors can be contacted at <nih@giga.or.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 <stdlib.h>
+
+#include "zip.h"
+#include "zipint.h"
+
+
+
+struct zip_source *
+zip_source_function(struct zip *za, zip_read_func zrf, void *ud)
+{
+    struct zip_source *zs;
+
+    if ((zs=malloc(sizeof(*zs))) == NULL) {
+	_zip_error_set(&za->error, ZIP_ER_MEMORY, 0);
+	return NULL;
+    }
+
+    zs->f = zrf;
+    zs->ud = ud;
+    
+    return zs;
+}