From d5d1fab3bdd7f4dc65118a0fe0bc875a050e1914 Mon Sep 17 00:00:00 2001
From: Rossen Georgiev <zoorty@gmail.com>
Date: Tue, 30 Dec 2014 15:34:58 +0000
Subject: [PATCH] added pass generation function

---
 aprslib/__init__.py    |  6 +++++-
 aprslib/passcode.py    | 34 ++++++++++++++++++++++++++++++++++
 tests/test_passcode.py | 30 ++++++++++++++++++++++++++++++
 3 files changed, 69 insertions(+), 1 deletion(-)
 create mode 100644 aprslib/passcode.py
 create mode 100644 tests/test_passcode.py

diff --git a/aprslib/__init__.py b/aprslib/__init__.py
index d0a1637..50fd689 100644
--- a/aprslib/__init__.py
+++ b/aprslib/__init__.py
@@ -29,12 +29,16 @@ del _date
 
 __version__ = "0.6.31"
 __author__ = "Rossen Georgiev"
-__all__ = ['IS', 'parse']
+__all__ = ['IS', 'parse', 'passcode']
 
 from .parse import parse as refparse
 parse = refparse
 del refparse
 
+from .passcode import passcode as refpasscode
+passcode = refpasscode
+del refpasscode
+
 from .IS import IS as refIS
 
 
diff --git a/aprslib/passcode.py b/aprslib/passcode.py
new file mode 100644
index 0000000..c164bf6
--- /dev/null
+++ b/aprslib/passcode.py
@@ -0,0 +1,34 @@
+# aprs - Python library for dealing with APRS
+# Copyright (C) 2013-2014 Rossen Georgiev
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+"""
+Contains a function for generating passcode from callsign
+"""
+
+
+def passcode(callsign):
+    """
+    Takes a CALLSIGN and returns passcode
+    """
+    assert isinstance(callsign, str)
+
+    callsign = callsign.split('-')[0].upper()
+
+    code = 0x73e2
+    for i, char in enumerate(callsign):
+        code ^= ord(char) << (8 if not i % 2 else 0)
+
+    return code & 0x7fff
diff --git a/tests/test_passcode.py b/tests/test_passcode.py
new file mode 100644
index 0000000..af51566
--- /dev/null
+++ b/tests/test_passcode.py
@@ -0,0 +1,30 @@
+import unittest
+from aprslib import passcode
+
+
+class TC_pascode(unittest.TestCase):
+    def test_nonstring(self):
+        with self.assertRaises(AssertionError):
+            passcode(5)
+
+    def test_valid_input(self):
+        testData = [
+            ['TESTCALL', 31742],
+            ['testcall', 31742],
+            ['tEsTcAlL', 31742],
+            ['tEsTcAlL', 31742],
+            ['TESTCALL-', 31742],
+            ['TESTCALL-12', 31742],
+            ['TESTCALL-0', 31742],
+            ['N0CALL', 13023],
+            ['SUCHCALL', 27890],
+            ['MUCHSIGN', 27128],
+            ['WOW', 29613],
+            ]
+
+        results = []
+
+        for callsign, x in testData:
+            results.append([callsign, passcode(callsign)])
+
+        self.assertEqual(testData, results)