Split out policy code from net/tools/testserver.

net/tools/testserver/asn1der.py

-# Copyright (c) 2011 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-"""Helper module for ASN.1/DER encoding."""
-
-import binascii
-import struct
-
-# Tags as defined by ASN.1.
-INTEGER = 2
-BIT_STRING = 3
-NULL = 5
-OBJECT_IDENTIFIER = 6
-SEQUENCE = 0x30
-
-def Data(tag, data):
-  """Generic type-length-value encoder.
-
-  Args:
-    tag: the tag.
-    data: the data for the given tag.
-  Returns:
-    encoded TLV value.
-  """
-  if len(data) == 0:
-    return struct.pack(">BB", tag, 0);
-  assert len(data) <= 0xffff;
-  return struct.pack(">BBH", tag, 0x82, len(data)) + data;
-
-def Integer(value):
-  """Encodes an integer.
-
-  Args:
-    value: the long value.
-  Returns:
-    encoded TLV value.
-  """
-  data = '%x' % value
-  return Data(INTEGER, binascii.unhexlify('00' + '0' * (len(data) % 2) + data))
-
-def Bitstring(value):
-  """Encodes a bit string.
-
-  Args:
-    value: a string holding the binary data.
-  Returns:
-    encoded TLV value.
-  """
-  return Data(BIT_STRING, '\x00' + value)
-
-def Sequence(values):
-  """Encodes a sequence of other values.
-
-  Args:
-    values: the list of values, must be strings holding already encoded data.
-  Returns:
-    encoded TLV value.
-  """
-  return Data(SEQUENCE, ''.join(values))