archive

rfc1982_serial_number.py

@@ -0,0 +1,40 @@
+#!/usr/bin/env python3
+
+class Serial:
+
+    def __init__(self, val):
+        self._val = int(val) & (2**32)
+
+    def __int__(self):
+        return self._val
+
+    def __add__(self, val):
+        return Serial(self._val + int(val))
+
+    def __eq__(self, other):
+        return int(self) == int(other)
+
+    def __ne__(self, other):
+        return int(self) != int(other)
+
+    def __lt__(self, other):
+        return self != other and (
+            (self._val < other._val and other._val - self._val < 2**31) or
+            (self._val > other._val and self._val - other._val > 2**31))
+
+    def __gt__(self, other):
+        return self != other and (
+            (self._val < other._val and other._val - self._val > 2**31) or
+            (self._val > other._val and self._val - other._val < 2**31))
+
+if __name__ == "__main__":
+    from random import randint
+
+    for test in range(100):
+        i1 = randint(0, 2**32-1)
+        i2 = randint(0, 2**32-1)
+
+        assert i1 == i2 or \
+            (i1 < i2 and not (i1 > i2)) or \
+            (i1 > i2 and not (i1 < i2)) or \
+            int(i1) & int(i2) == 0x80000000