diff -r f9f4d4d6f162 -r 51d14b0c68c0 tools/outputfile.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/outputfile.py	Sat Aug 03 01:18:56 2019 +0300
@@ -0,0 +1,61 @@
+#!/usr/bin/env python
+# coding: utf-8
+#
+#    Copyright 2015 Teemu Piippo
+#    All rights reserved.
+#
+#    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. Neither the name of the copyright holder nor the names of its
+#       contributors may be used to endorse or promote products derived from
+#       this software without specific prior written permission.
+#
+#    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+#    "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 COPYRIGHT HOLDER
+#    OR CONTRIBUTORS 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.
+#
+
+class OutputFile:
+    def __init__ (self, filename):
+        self.filename = filename
+        try:
+            with open (self.filename, "r") as file:
+                self.oldsum = file.readline()
+                self.oldsum = self.oldsum.replace ('// ', '').strip()
+        except IOError:
+            self.oldsum = ''
+        self.body = ''
+
+    def write(self, text):
+        self.body += text
+
+    def save(self, verbose = False):
+        from hashlib import sha256
+        checksum = sha256(self.body.encode('utf-8')).hexdigest()
+        if checksum == self.oldsum:
+            if verbose:
+                print ('%s is up to date' % self.filename)
+            pass
+        else:
+            with open (self.filename, "w") as file:
+                file.write('// %s\n' % checksum)
+                file.write('// This file has been automatically generated. Do not edit by hand\n')
+                file.write('\n')
+                file.write(self.body)
+                if verbose:
+                    print('%s written' % self.filename)