Rework POW build so that we can use static libraries again.

svn path=/configure; revision=3602

1 files changed, 0 insertions, 2294 deletions

diff --git a/pow/POW-0.7/lib/_der.py b/pow/POW-0.7/lib/_der.py
deleted file mode 100644
index c7f58411..00000000
--- a/pow/POW-0.7/lib/_der.py
+++ /dev/null
@@ -1,2294 +0,0 @@
-#*****************************************************************************#
-#*                                                                           *#
-#*  Copyright (c) 2002, Peter Shannon                                        *#
-#*  All rights reserved.                                                     *#
-#*                                                                           *#
-#*  Redistribution and use in source and binary forms, with or without       *#
-#*  modification, are permitted provided that the following conditions       *#
-#*  are met:                                                                 *#
-#*                                                                           *#
-#*      * Redistributions of source code must retain the above               *#
-#*        copyright notice, this list of conditions and the following        *#
-#*        disclaimer.                                                        *#
-#*                                                                           *#
-#*      * 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.                                    *#
-#*                                                                           *#
-#*      * The name of the 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 REGENTS   *#
-#*  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.     *#
-#*                                                                           *#
-#*****************************************************************************#
-
-import exceptions, types, copy, string, time, base64, traceback, cStringIO
-
-DEBUG = 0
-
-# CLASS
-CLASS_UNIVERSAL   = 0x00
-CLASS_APPLICATION = 0x40
-CLASS_CONTEXT     = 0x80
-CLASS_PRIVATE     = 0xC0
-
-# FORM
-FORM_PRIMITIVE	   = 0x00
-FORM_CONSTRUCTED	= 0x20
-
-# TAG
-TAG_BOOLEAN          = 0x01
-TAG_INTEGER          = 0x02
-TAG_BITSTRING        = 0x03
-TAG_OCTETSTRING      = 0x04
-TAG_NULL             = 0x05
-TAG_OID              = 0x06
-TAG_OBJDESCRIPTOR    = 0x07
-TAG_EXTERNAL         = 0x08
-TAG_REAL             = 0x09
-TAG_ENUMERATED       = 0x0A
-TAG_EMBEDDED_PDV     = 0x0B
-TAG_UTF8STRING       = 0x0C
-TAG_SEQUENCE         = 0x10
-TAG_SET              = 0x11
-TAG_NUMERICSTRING    = 0x12
-TAG_PRINTABLESTRING  = 0x13
-TAG_T61STRING        = 0x14
-TAG_VIDEOTEXSTRING   = 0x15
-TAG_IA5STRING        = 0x16
-TAG_UTCTIME          = 0x17
-TAG_GENERALIZEDTIME  = 0x18
-TAG_GRAPHICSTRING    = 0x19
-TAG_VISIBLESTRING    = 0x1A
-TAG_GENERALSTRING    = 0x1B
-TAG_UNIVERSALSTRING  = 0x1C
-TAG_BMPSTRING        = 0x1E
-
-_fragments = []
-
-def _docset():
-   return _fragments
-
-def _addFragment(frag):
-   global _fragments
-   _fragments.append(frag)
-
-
-_addFragment('''
-<moduleDescription>
-   <header>
-      <name>POW.pkix</name>
-      <author>Peter Shannon</author>
-   </header>
-   <body>
-      <para>
-         This module is a solution to reading and writing X509v3 written
-         purely in Python.  It does use limited facilities from POW for
-         signing and verifying but these could be replaced easily.  It is
-         an abstract module and to use it successfully RFC3280 should be
-         referred to as well as the sourcecode where necessary.  The correct
-         use of many extensions often not clear from the definitions alone.
-         Do refer to the RFC for details.
-      </para>
-      <para>
-         Each constructed objects defined in the RFC is built from primitives
-         defined by the ASN1 recommedations.  Not all ASN1 primitive are available but all those
-         required for X509v3 should be.  The implementation is more or less
-         complete for DER encoding the only caveat, aside from a few
-         missing objects, is the behaviour of <classname>SET</classname> objects
-         and <classname>SET OF</classname> objects.  The order the objects are
-         written in should be determined at runtime by sorting their tags but this
-         library does not do this.  For X509 it isn't really necessary
-         since all the <classname>Set</classname> objects are simple and the
-         order they are written in is defined by the object's constructor.
-      </para>
-      <para>
-         Every documented object in this module supports the functions documented for
-         <classname>_GeneralObject</classname>.  In general the function
-         will only be documented in descendant classes if the class changes
-         the behaviour significantly from its ancestor.  This would
-         normally be <classname>_GeneralObject</classname> or
-         <classname>Sequence</classname>.
-      </para>
-   </body>
-</moduleDescription>
-''')
-
-class DerError(Exception):
-   def __init__(self, msg):
-      if not isinstance(msg, types.StringType):
-         raise Exception, 'argunment should be a string'
-      self.msg = msg
-
-   def __repr__(self):
-         return self.msg
-
-   __str__ = __repr__
-
-class _Tag(object):
-   def __init__(self):
-      self.tagclass = 0
-      self.tagform = 0
-      self.tagnumber = 0
-
-   def __repr__(self):
-      return '(%s, %s, %s)' % (self.tagclass, self.tagform, self.tagnumber)
-
-   def write(self, file):
-      if self.tagnumber < 31:
-         file.write( chr(self.tagclass | self.tagform | self.tagnumber) )
-      else:
-         val = copy.deepcopy(self.tagnumber)
-         bytes = []
-         while val:
-            byte = val & 0x7F
-            bytes.append(byte | 0x80)
-            val = val >> 7
-         bytes[0] = bytes[0] ^ 0x80
-         bytes.append( self.tagclass | self.tagform | 0x1F )
-         bytes.reverse()
-         file.write( string.join(map(chr, bytes), '') )
-
-   def read(self, file):
-      octet1 = ord( file.read(1) )
-      self.tagclass = octet1 & 0xC0
-      self.tagform = octet1 & 0x20
-      value = octet1 & 0x1F
-      if value < 31:
-         self.tagnumber = value
-      else:
-         total = 0
-         byte = 0x80
-         while byte & 0x80:
-            byte = ord( file.read(1) )
-            if byte & 0x80:
-               total = (total << 7) | byte ^ 0x80
-            else:
-               total = (total << 7) | byte
-         self.tagnumber = total
- 
-class _Length(object):
-   def __init__(self):
-      self.length = 0
-
-   def __repr__(self):
-      return '(%s)' % self.length
-
-   def write(self, file):
-      if self.length < 128:
-         file.write( chr(self.length) )
-      else:
-         val = copy.deepcopy(self.length)
-         bytes = []
-         while val:
-            byte = val & 0xFF
-            bytes.append(byte)
-            val = val >> 8
-         lengthOfLength = len(bytes)
-         if lengthOfLength > 126:
-            raise DerError, 'object is too long!'
-         bytes.append(lengthOfLength)  
-         bytes.reverse()
-         bytes[0] = bytes[0] ^ 0x80
-         file.write( string.join(map(chr, bytes), '') )
-
-   def read(self, file):
-      octet1 = ord( file.read(1) )
-      if octet1 < 128:
-         self.length = octet1
-      else:
-         total = 0
-         byte = 0
-         for i in range(octet1 ^ 0x80):
-            byte = ord( file.read(1) )
-            total = (total << 8) | byte
-         self.length = total
- 
-class _TlvIo(_Tag, _Length):
-   def __init__(self, file):
-      self.file = file
-      self.offset = None
-      self.valueOffset = None
-
-   def __repr__(self):
-      return '<TAG:%s Length:%s>' % (_Tag.__repr__(self), _Length.__repr__(self))
-
-   def __nonzero__(self):
-      pos = self.file.tell()
-      self.file.seek(0,2)
-      if self.file.tell():
-         self.file.seek(pos)
-         return 1
-      else:
-         return 0
-
-   def read(self):
-      self.offset = self.file.tell()
-      _Tag.read( self, self.file )
-      _Length.read( self, self.file )
-      self.valueOffset = self.file.tell()
-      self.file.seek( self.length, 1 )
-
-   def readValue(self):
-      self.file.seek( self.valueOffset )
-      return self.file.read( self.length )
-
-   def write(self, val):
-      _Tag.write( self, self.file )
-      self.length = len(val)
-      _Length.write( self, self.file )
-      self.file.write(val)
-
-def _decodeBoolean(val):
-   'der encoded value not including tag or length'
-   if not isinstance(val, types.StringType):
-      raise DerError, 'argument should be a string'
-   if ord(val) == 0xFF:
-      return 1
-   elif ord(val) == 0x00:
-      return 0
-   else:
-      raise DerError, 'boolean should be encode as all 1s or all 0s'
-
-def _encodeBoolean(val):
-   'anything we can test for truth'
-   if val:
-      return chr(0xFF)
-   else:
-      return chr(0x00)
-
-def _decodeInteger(val):
-   'der encoded value not including tag or length'
-   if not isinstance(val, types.StringType):
-      raise DerError, 'argument should be a string'
-   total = 0L
-   if ord(val[0]) & 0x80:
-      val = map( lambda x : ord(x) ^ 0xFF, val )
-      for byte in val:
-         total = (total << 8) | byte
-      total = -(total+1) 
-   else:
-      for byte in val:
-         total = (total << 8) | ord(byte)
-   return total
-
-def _encodeInteger(val):
-   'python integer'
-   if not isinstance(val, types.IntType) and not isinstance(val, types.LongType):
-      raise DerError, 'argument should be an integer'
-   if val == 0:
-      return chr(0x00)
-   else:
-      val2 = copy.deepcopy(val)
-      if val2 < 0:
-         val2 = -(val2+1)
-      bytes = []
-      byte = 0
-      while val2:
-         byte = val2 & 0xFF
-         bytes.append(byte)
-         val2 = val2 >> 8
-      # if we have no used up the last byte to represent the value we need
-      # to add one more on to show if this is negative of positive.  Also,
-      # due to adding 1 and inverting -1 would be 0 or if 0 is the encoding
-      # value, so bytes would empty and this would lead to and empty value
-      # and this would not be working properly.  Adding this null byte
-      # fixes this, since it is inverted to -1 and preserved for 0.
-      if byte & 0x80 or not bytes:
-         bytes.append(0x00)
-      if val < 0:
-         bytes = map( lambda x : x ^ 0xFF, bytes )
-      bytes.reverse()
-
-      return string.join(map(chr, bytes), '')
-
-def _decodeBitString(val):
-   'der encoded value not including tag or length'
-   if not isinstance(val, types.StringType):
-      raise DerError, 'argument should be a string'
-   bitmasks = [0x80,0x40,0x20,0x10,0x08,0x04,0x02,0x01]
-   unused = ord( val[0] )
-   bits = []
-   for byte in val[1:]:
-      for j in range(8):
-         if ord(byte) & bitmasks[j]:
-            bits.append(1)
-         else:
-            bits.append(0)
-   if unused == 0:
-      return tuple(bits)
-   else:
-      return tuple(bits[:-unused])
- 
-def _encodeBitString(val):
-   'list of true/false objects ie [0,1,1,0,1,1]'
-   if not (isinstance(val, types.ListType) or isinstance(val, types.TupleType)):
-      raise DerError, 'argument should be a list or tuple'
-   bitmasks = [0x80,0x40,0x20,0x10,0x08,0x04,0x02,0x01]
-   bytes = []
-   fits, leftover = divmod(len(val), 8)
-   nobytes = fits
-   if leftover > 0:
-      nobytes = nobytes + 1
-   if leftover:
-      unused = 8 - leftover 
-   else:
-      unused = 0
-   bytes.append(unused)
-   for i in range(nobytes):
-      byte = 0
-      for j in range(8):
-         offset = j + i*8
-         if offset < len(val):
-            if val[offset]:
-               byte = byte | bitmasks[j]
-      bytes.append(byte)
-
-   return string.join(map(chr, bytes), '')
-
-def _decodeOid(val):
-   'der encoded value not including tag or length'
-   if not isinstance(val, types.StringType):
-      raise DerError, 'argument should be a string'
-   arc12 = ord( val[0] )
-   arc1, arc2 = divmod(arc12, 40)
-   oids = [arc1,arc2]
-
-   total = 0
-   for byte in val[1:]:
-      val = ord(byte)
-      if val & 0x80:
-         total = (total << 7) | (val ^ 0x80)
-      else:
-         total = (total << 7) | val
-         oids.append(total)
-         total = 0
-      
-   return tuple(oids)
-
-def _encodeOid(val):
-   'list of intgers'
-   if not (isinstance(val, types.ListType) or isinstance(val, types.TupleType)):
-      raise DerError, 'argument should be a list or tuple'
-   oids = []
-   oids.append( chr(40 * val[0] + val[1]) ) 
-   for val in val[2:]:
-      if val == 0:
-         oids.append( chr(0) )
-      else:
-         bytes = []
-         while val:
-            val, rem = divmod(val, 128)
-            bytes.append(rem | 0x80)
-         bytes[0] = bytes[0] ^ 0x80
-         bytes.reverse()
-         oids.append( string.join(map(chr, bytes), '') )
-
-   return string.join(oids, '')
-
-def _decodeSequence(val):
-   'der encoded value not including tag or length'
-   if not isinstance(val, types.StringType):
-      raise DerError, 'argument should be a string'
-   buf = cStringIO.StringIO(val)
-   buflen = len(val)
-   tvls = []
-   while buf.tell() < buflen:
-      t = _TlvIo(buf)
-      t.read()
-      tvls.append(t)
-   return tuple(tvls)
-
-def _encodeSequence(val):
-   'list of GenerlObjects'
-   if not (isinstance(val, types.ListType) or isinstance(val, types.TupleType)):
-      raise DerError, 'argument should be a list or tuple'
-   buf = cStringIO.StringIO()
-   for obj in val:
-      if obj or isinstance(obj, _GeneralObject):
-         obj.write(buf)
-      elif not obj.optional:
-         raise DerError, 'object not set which should be: %s' % obj
-         
-   return buf.getvalue()
-
-_addFragment('''
-<class>
-   <header>
-      <name>_GeneralObject</name>
-   </header>
-   <body>
-      <para>
-         <classname>_GeneralObject</classname> is the basis for all DER objects,
-         primitive or constructed.  It defines the basic behaviour of an
-         object which is serialised using the tag, length and value
-         approach of DER.  It is unlikely you would ever want to
-         instantiate one of these directly but I include a description
-         since many primatives don't override much of
-         <classname>_GeneralObject</classname>'s functions. 
-      </para>
-   </body>
-</class>
-''')
-
-class _GeneralObject(object):
-
-   _addFragment('''
-   <constructor>
-      <header>
-         <memberof>_GeneralObject</memberof>
-         <parameter>normclass</parameter>
-         <parameter>normform</parameter>
-         <parameter>normnumber</parameter>
-         <parameter>encRoutine</parameter>
-         <parameter>decRoutine</parameter>
-         <parameter>optional=0</parameter>
-         <parameter>default=''</parameter>
-      </header>
-      <body>
-         <para>
-            <parameter>normclass</parameter> is the class of the object,
-            ei: universal, application, context or private.
-            <parameter>normform</parameter> is the form of the object, ei
-            primitive or constructed.  <parameter>normnumber</parameter> is
-            the tag number of the object.
-            <parameter>encRoutine</parameter> is a function which takes a
-            value and encodes it according the appropriate DER rules.
-            <parameter>decRoutine</parameter> is a function which reads a
-            string value and returns a value which is more useful in
-            Python.  <parameter>optional</parameter> is a boolean
-            indicating if this object is optional.  The final parameter,
-            <parameter>default</parameter> is the base 64 encoded DER
-            value, which should be used as the default in leu of a value to
-            read or incase it is unset.
-         </para>
-      </body>
-   </constructor>
-   ''')
-
-   def __init__(self, normclass, normform, normnumber, encRoutine, decRoutine, optional=0, default=''):
-      if not isinstance(normclass, types.IntType):
-         raise DerError, 'nomrclass argument should be an integer : %s' % normclass
-      if not isinstance(normform, types.IntType):
-         raise DerError, 'normform argument should be an integer : %s' % normform
-      if not isinstance(normnumber, types.IntType):
-         raise DerError, 'normnumber argument should be an integer : %s' % normnumber
-      if not isinstance(encRoutine, types.FunctionType):
-         raise DerError, 'encRoutine argument should be an function : %s' % encRoutine
-      if not isinstance(decRoutine, types.FunctionType):
-         raise DerError, 'decRoutine argument should be an function : %s' % decRoutine 
-      if not isinstance(optional, types.IntType):
-         raise DerError, 'optional argument should be an integer : %s' % optional
-      if not isinstance(default, types.StringType):
-         raise DerError, 'default argument should be an String : %s' % default
-      self.normclass = normclass
-      self.normform = normform
-      self.normnumber = normnumber
-      self.encRoutine = encRoutine
-      self.decRoutine = decRoutine
-      self.value = None
-      self.optional = optional
-      self.default = default
-      self.reset()
-
-   def _ioSafe(self):
-      'is it safe to write this object'
-      if self.optional or self._isSet():
-         return 1
-      else:
-         return 0
-
-   def _isSet(self):
-      'are the values of this object set or not'
-      if self.value is not None:
-         return 1
-      else:
-         return 0
-
-   _addFragment('''
-   <method>
-      <header>
-         <memberof>_GeneralObject</memberof>
-         <name>reset</name>
-      </header>
-      <body>
-         <para>
-            This function re-initialises the object, clearing the value or
-            setting it to any default.
-         </para>
-      </body>
-   </method>
-   ''')
-   def reset(self):
-      self.value = None
-      if self.default:
-         buf = cStringIO.StringIO( base64.decodestring( self.default ) )
-         io = _TlvIo(buf)
-         io.read()
-         self.read(io)
-
-   _addFragment('''
-   <method>
-      <header>
-         <memberof>_GeneralObject</memberof>
-         <name>set</name>
-         <parameter>value</parameter>
-      </header>
-      <body>
-         <para>
-            This dosn't do much except store <parameter>value</parameter>,
-            presumably prior to writing the object.  The correct values to
-            use would be determined by the encoder or decoder this class is
-            instantiated with.  Be careful, there is some flexibility in
-            setting objects so you might find that once the object has been
-            written and read back in the value isn't identical.  A good
-            example would be anything which contains a sequence(list or
-            tuple), all sequence objects are returned as tuples.
-         </para>
-      </body>
-   </method>
-   ''')
-   def set(self, value):
-      if value is not None:
-         self.value = value
-
-   _addFragment('''
-   <method>
-      <header>
-         <memberof>_GeneralObject</memberof>
-         <name>get</name>
-      </header>
-      <body>
-         <para>
-            Gets the value stored presumably after reading the object.
-         </para>
-      </body>
-   </method>
-   ''')
-   def get(self):
-      return self.value
-
-   _addFragment('''
-   <method>
-      <header>
-         <memberof>_GeneralObject</memberof>
-         <name>implied</name>
-         <parameter>impclass</parameter>
-         <parameter>impform</parameter>
-         <parameter>impnumber</parameter>
-      </header>
-      <body>
-         <para>
-            This function is used to change how the tag is written or read
-            for a particular object and should be called in the constructor
-            for derived objects.  If you have an example of the structure you need to
-            process, Pete Gutmann's excellent
-            <application>dumpasn1</application> can be invaluable for
-            debugging objects.
-         </para>
-      </body>
-   </method>
-   ''')
-   def implied(self, impclass, impform, impnumber):
-      if not isinstance(impclass, types.IntType):
-         raise DerError, 'impclass argument should be an integer'
-      if not isinstance(impform, types.IntType):
-         raise DerError, 'impform argument should be an integer'
-      if not isinstance(impnumber, types.IntType):
-         raise DerError, 'impnumber argument should be an integer'
-      self.normclass = impclass
-      self.normform = impform
-      self.normnumber = impnumber
-
-   _addFragment('''
-   <method>
-      <header>
-         <memberof>_GeneralObject</memberof>
-         <name>read</name>
-         <parameter>io</parameter>
-      </header>
-      <body>
-         <para>
-            <parameter>io</parameter> should be a file like object.  If the
-            object being read matches the expected class, form and tag the
-            value is read and decoded using
-            <function>decRoutine</function>.  Else, if it has a default
-            that is read and stored.  
-         </para>
-         <para>
-            The return value of this function does not indicate success but
-            whether this TLV was processed successfully.  This bahaviour is
-            vital for processing constructed types since the object may be
-            optional or have a default.  Failure to decode would be indicated 
-            by an exception.  
-         </para>
-      </body>
-   </method>
-   ''')
-
-   def read(self, io=None):    
-
-      processDefOpt = 0
-      if io is None:
-         processDefOpt = 1
-      elif isinstance(io, _TlvIo):
-         if not io:
-            processDefOpt = 1
-      else:
-         pos = io.tell()
-         io.seek(0,2)
-         if io.tell():
-            io.seek(pos)
-         else:
-            processDefOpt = 1
-
-      if processDefOpt:
-         if self.optional or self.default:
-            self.reset()
-            return 0
-         else:
-            raise DerError, 'no TLV is available to read in non-optional/non-default object: %s' % repr(self)
-
-      if not isinstance(io, _TlvIo):
-         tmp = _TlvIo(io)
-         tmp.read()
-         io = tmp
-
-      if io.tagclass != self.normclass or io.tagform != self.normform or io.tagnumber != self.normnumber:
-         if self.default or self.optional:
-            self.reset()
-            return 0
-         else:
-            raise DerError, 'error in encoding, missing object:%s' % repr(self)
-      else:
-         derval = io.readValue()
-         self.value = self.decRoutine( derval )
-         return 1
-
-   _addFragment('''
-   <method>
-      <header>
-         <memberof>_GeneralObject</memberof>
-         <name>write</name>
-         <parameter>io</parameter>
-      </header>
-      <body>
-         <para>
-            If this object has not been set and is not optional and dosn't
-            have a default, a <classname>DerError</classname> exception will be raised
-         </para>
-         <para>
-            If no value has been set and this object is optional, nothing
-            is written.  If this object's value is equal to the default,
-            nothing is written as stipulated by DER.  Otherwise the value
-            is encoded and written.  
-         </para>
-      </body>
-   </method>
-   ''')
-
-   def write(self, file):
-      if not self._ioSafe():
-         raise DerError, 'object not set which must be: %s' % repr(self)
-      elif self.optional and self.value is None:
-         pass
-      else:
-         buf = cStringIO.StringIO()
-         io = _TlvIo(buf)
-         io.tagclass = self.normclass
-         io.tagform = self.normform
-         io.tagnumber = self.normnumber
-         derval = self.encRoutine( self.value )
-         io.length = len(derval)
-         io.write(derval)
-         if self.default:
-            if buf.getvalue() != base64.decodestring(self.default):
-               file.write( buf.getvalue() )
-         else:
-            file.write( buf.getvalue() )
-
-   _addFragment('''
-   <method>
-      <header>
-         <memberof>_GeneralObject</memberof>
-         <name>toString</name>
-      </header>
-      <body>
-         <para>
-            Encodes the value in DER and returns it as a string.
-         </para>
-      </body>
-   </method>
-   ''')
-
-   def toString(self):
-      buf = cStringIO.StringIO()
-      self.write(buf)
-      return buf.getvalue()
-
-   _addFragment('''
-   <method>
-      <header>
-         <memberof>_GeneralObject</memberof>
-         <name>fromString</name>
-      </header>
-      <body>
-         <para>
-            Decodes the string and sets the value of this object.
-         </para>
-      </body>
-   </method>
-   ''')
-
-   def fromString(self, value):
-      buf = cStringIO.StringIO(value)
-      self.read(buf)
-
-class Any(_GeneralObject):
-
-   def __init__(self):
-      self.value = None
-      self.normclass = None
-      self.normform = None
-      self.normnumber = None
-
-   def _ioSafe(self):
-      if self.optional or (self._isSet() and self.normclass is not None and self.normform is not None and self.normnumber is not None):
-         return 1
-      else:
-         return 0
-
-   def setTag(self, klass, form, number):
-      self.normclass = klass
-      self.normform = form
-      self.normnumber = number
-
-   def reset(self):
-      self.value = None
-
-   def get(self):
-      return self.value
-
-   def set(self, value):
-      self.value = value
-
-   def write(self,file):
-      if not self._ioSafe():
-         raise DerError, 'object not set which must be: %s' % repr(self)
-      elif self.optional and self.value is None:
-         pass
-      else:
-         buf = cStringIO.StringIO()
-         io = _TlvIo(buf)
-         io.tagclass = self.normclass
-         io.tagform = self.normform
-         io.tagnumber = self.normnumber
-         io.length = len(self.value)
-         io.write(self.value)
-         file.write(buf.getvalue())
-
-   def read(self, io=None):    
-
-      processDefOpt = 0
-      if io is None:
-         processDefOpt = 1
-      elif isinstance(io, _TlvIo):
-         if not io:
-            processDefOpt = 1
-      else:
-         pos = io.tell()
-         io.seek(0,2)
-         if io.tell():
-            io.seek(pos)
-         else:
-            processDefOpt = 1
-      if processDefOpt:
-         if self.optional or self.default:
-            self.reset()
-            return 0
-         else:
-            raise DerError, 'no TLV is available to read in non-optional/non-default object: %s' % repr(self)
-
-      if not isinstance(io, _TlvIo):
-         tmp = _TlvIo(io)
-         tmp.read()
-         io = tmp
-
-      self.value = io.readValue()
-      self.normclass = io.tagclass
-      self.normform = io.tagform
-      self.normnumber = io.tagnumber
-
-_addFragment('''
-<class>
-   <header>
-      <name>Boolean</name>
-      <super>_GeneralObject</super>
-   </header>
-   <body>
-      <para>
-         This object represents the ASN1 BOOLEAN type.  It can be set
-         with any object which can be tested for truth. 
-      </para>
-   </body>
-</class>
-''')
-
-class Boolean(_GeneralObject):                            # 0x01
-
-   _addFragment('''
-   <constructor>
-      <header>
-         <memberof>Boolean</memberof>
-         <parameter>optional=0</parameter>
-         <parameter>default=''</parameter>
-      </header>
-   </constructor>
-   ''')
-   def __init__(self, optional=0, default=''):
-      _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_BOOLEAN, _encodeBoolean, _decodeBoolean, optional, default)
-
-_addFragment('''
-<class>
-   <header>
-      <name>Integer</name>
-      <super>_GeneralObject</super>
-   </header>
-   <body>
-      <para>
-         This object represents the ASN1 INTEGER type.  It should be set
-         with a Python integer.
-      </para>
-   </body>
-</class>
-''')
-
-class Integer(_GeneralObject):                            # 0x02
-
-   _addFragment('''
-   <constructor>
-      <header>
-         <memberof>Integer</memberof>
-         <parameter>optional=0</parameter>
-         <parameter>default=''</parameter>
-      </header>
-   </constructor>
-   ''')
-   def __init__(self, optional=0, default=''):
-      _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_INTEGER, _encodeInteger, _decodeInteger, optional, default)
-
-_addFragment('''
-<class>
-   <header>
-      <name>BitString</name>
-      <super>_GeneralObject</super>
-   </header>
-   <body>
-      <para>
-         This object represents the ASN1 BIT STRING type.  It should be set
-         with a sequence of integers.  A non-zero number will set the bit,
-         zero will leave the bit unset.
-      </para>
-   </body>
-</class>
-''')
-
-class BitString(_GeneralObject):                          # 0x03
-
-   _addFragment('''
-   <constructor>
-      <header>
-         <memberof>BitString</memberof>
-         <parameter>optional=0</parameter>
-         <parameter>default=''</parameter>
-      </header>
-   </constructor>
-   ''')
-   def __init__(self, optional=0, default=''):
-      _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_BITSTRING, _encodeBitString, _decodeBitString, optional, default)
-
-_addFragment('''
-<class>
-   <header>
-      <name>AltBitString</name>
-      <super>_GeneralObject</super>
-   </header>
-   <body>
-      <para>
-         This object represents the ASN1 BIT STRING type.  It differs from
-         the first <classname>BitString</classname> in that it's coding
-         routines treat values as binary data and do not interpret the data
-         in any way.  Some application treat the
-         <classname>BIT STRING</classname> in the same way as
-         <classname>OCTET STRING</classname> type, hence this extra object.
-      </para>
-   </body>
-</class>
-''')
-
-class AltBitString(_GeneralObject):                       # 0x03
-
-   _addFragment('''
-   <constructor>
-      <header>
-         <memberof>AltBitString</memberof>
-         <parameter>optional=0</parameter>
-         <parameter>default=''</parameter>
-      </header>
-   </constructor>
-   ''')
-
-   def __init__(self, optional=0, default=''):
-      _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_BITSTRING, lambda x : chr(0)+x, lambda x : x[1:], optional, default)
-
-_addFragment('''
-<class>
-   <header>
-      <name>OctetString</name>
-      <super>_GeneralObject</super>
-   </header>
-   <body>
-      <para>
-         This object represents the ASN1 OCTET STRING type.  This object
-         can be set with any binary data.
-      </para>
-   </body>
-</class>
-''')
-class OctetString(_GeneralObject):                        # 0x04
-
-   _addFragment('''
-   <constructor>
-      <header>
-         <memberof>OctetString</memberof>
-         <parameter>optional=0</parameter>
-         <parameter>default=''</parameter>
-      </header>
-   </constructor>
-   ''')
-
-   def __init__(self, optional=0, default=''):
-      _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_OCTETSTRING, lambda x : x, lambda x : x, optional, default)
-
-_addFragment('''
-<class>
-   <header>
-      <name>Null</name>
-      <super>_GeneralObject</super>
-   </header>
-   <body>
-      <para>
-         This object represents the ASN1 NULL type.  There is no point in
-         setting this object, the value will always be ignored when it is
-         written out.
-      </para>
-   </body>
-</class>
-''')
-class Null(_GeneralObject):                               # 0x05
-
-   _addFragment('''
-   <constructor>
-      <header>
-         <memberof>Null</memberof>
-         <parameter>optional=0</parameter>
-         <parameter>default=''</parameter>
-      </header>
-   </constructor>
-   ''')
-
-   def __init__(self, optional=0, default=''):
-      _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_NULL, lambda x : '', lambda x : '', optional, default)
-      self.value = '' 
-
-   def _ioSafe(self):
-      return 1
-
-   def reset(self):
-      self.value =  ''
-
-_addFragment('''
-<class>
-   <header>
-      <name>Oid</name>
-      <super>_GeneralObject</super>
-   </header>
-   <body>
-      <para>
-         This object represents the ASN1 OID type.  This object should be
-         set with a list or tuple of integers defining an objects oid.
-         Please note that the first three arcs have a restricted set of
-         values, so encoding (5, 3, 7, 1) will produce bad results.
-      </para>
-   </body>
-</class>
-''')
-class Oid(_GeneralObject):                                # 0x06
-
-   _addFragment('''
-   <constructor>
-      <header>
-         <memberof>Oid</memberof>
-         <parameter>optional=0</parameter>
-         <parameter>default=''</parameter>
-      </header>
-   </constructor>
-   ''')
-
-   def __init__(self, optional=0, default=''):
-      _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_OID, _encodeOid, _decodeOid, optional, default)
-
-_addFragment('''
-<class>
-   <header>
-      <name>Enum</name>
-      <super>_GeneralObject</super>
-   </header>
-   <body>
-      <para>
-         This object represents the ASN1 ENUM type.  This should be set
-         using a Python integer, the meaning should be described in the
-         ASN1 document for the object you are encoding.
-      </para>
-   </body>
-</class>
-''')
-class Enum(_GeneralObject):                               # 0x0A
-
-   _addFragment('''
-   <constructor>
-      <header>
-         <memberof>Enum</memberof>
-         <parameter>optional=0</parameter>
-         <parameter>default=''</parameter>
-      </header>
-   </constructor>
-   ''')
-
-   def __init__(self, optional=0, default=''):
-      _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_ENUMERATED, _encodeInteger, _decodeInteger, optional, default)
-
-_addFragment('''
-<class>
-   <header>
-      <name>Utf8String</name>
-      <super>_GeneralObject</super>
-   </header>
-   <body>
-      <para>
-         This object represents the ASN1 UTF8String type.  This object
-         should be set with a string.  It is up to the application to ensure
-         it only contains valid characters for this type.
-      </para>
-   </body>
-</class>
-''')
-class Utf8String(_GeneralObject):                         # 0x0C
-
-   _addFragment('''
-   <constructor>
-      <header>
-         <memberof>Utf8String</memberof>
-         <parameter>optional=0</parameter>
-         <parameter>default=''</parameter>
-      </header>
-   </constructor>
-   ''')
-
-   def __init__(self, optional=0, default=''):
-      _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_UTF8STRING, lambda x : x, lambda x : x, optional, default)
-
-_addFragment('''
-<class>
-   <header>
-      <name>NumericString</name>
-      <super>_GeneralObject</super>
-   </header>
-   <body>
-      <para>
-         This object represents the ASN1 NumericString type.  This should
-  object should be set with a string.  It is up to the application to ensure
-  it only contains valid characters for this type.
-      </para>
-   </body>
-</class>
-''')
-class NumericString(_GeneralObject):                      # 0x12
-
-   _addFragment('''
-   <constructor>
-      <header>
-         <memberof>NumericString</memberof>
-         <parameter>optional=0</parameter>
-         <parameter>default=''</parameter>
-      </header>
-   </constructor>
-   ''')
-
-   def __init__(self, optional=0, default=''):
-      _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_NUMERICSTRING, lambda x : x, lambda x : x, optional, default)
-_addFragment('''
-<class>
-   <header>
-      <name>PrintableString</name>
-      <super>_GeneralObject</super>
-   </header>
-   <body>
-      <para>
-         This object represents the ASN1 PrintableString type.  This should
-  object should be set with a string.  It is up to the application to ensure
-  it only contains valid characters for this type.
-      </para>
-   </body>
-</class>
-''')
-class PrintableString(_GeneralObject):                    # 0x13
-
-   _addFragment('''
-   <constructor>
-      <header>
-         <memberof>PrintableString</memberof>
-         <parameter>optional=0</parameter>
-         <parameter>default=''</parameter>
-      </header>
-   </constructor>
-   ''')
-
-   def __init__(self, optional=0, default=''):
-      _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_PRINTABLESTRING, lambda x : x, lambda x : x, optional, default)
-
-_addFragment('''
-<class>
-   <header>
-      <name>T61String</name>
-      <super>_GeneralObject</super>
-   </header>
-   <body>
-      <para>
-         This object represents the ASN1 T61String type.  This object
-         should be set with a string.  It is up to the application to ensure
-         it only contains valid characters for this type.
-      </para>
-   </body>
-</class>
-''')
-class T61String(_GeneralObject):                          # 0x14
-
-   _addFragment('''
-   <constructor>
-      <header>
-         <memberof>T61String</memberof>
-         <parameter>optional=0</parameter>
-         <parameter>default=''</parameter>
-      </header>
-   </constructor>
-   ''')
-
-   def __init__(self, optional=0, default=''):
-      _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_T61STRING, lambda x : x, lambda x : x, optional, default)
-
-_addFragment('''
-<class>
-   <header>
-      <name>VideotexString</name>
-      <super>_GeneralObject</super>
-   </header>
-   <body>
-      <para>
-         This object represents the ASN1 VideotexString type.  This should
-  object should be set with a string.  It is up to the application to ensure
-  it only contains valid characters for this type.
-      </para>
-   </body>
-</class>
-''')
-class VideotexString(_GeneralObject):                     # 0x15
-
-   _addFragment('''
-   <constructor>
-      <header>
-         <memberof>VideotexString</memberof>
-         <parameter>optional=0</parameter>
-         <parameter>default=''</parameter>
-      </header>
-   </constructor>
-   ''')
-
-   def __init__(self, optional=0, default=''):
-      _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_VIDEOTEXSTRING, lambda x : x, lambda x : x, optional, default)
-
-_addFragment('''
-<class>
-   <header>
-      <name>IA5String</name>
-      <super>_GeneralObject</super>
-   </header>
-   <body>
-      <para>
-         This object represents the ASN1 IA5String type.  This object
-         should be set with a string.  It is up to the application to ensure
-         it only contains valid characters for this type.
-      </para>
-   </body>
-</class>
-''')
-class IA5String(_GeneralObject):                          # 0x16
-
-   _addFragment('''
-   <constructor>
-      <header>
-         <memberof>IA5String</memberof>
-         <parameter>optional=0</parameter>
-         <parameter>default=''</parameter>
-      </header>
-   </constructor>
-   ''')
-
-   def __init__(self, optional=0, default=''):
-      _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_IA5STRING, lambda x : x, lambda x : x, optional, default)
-
-_addFragment('''
-<class>
-   <header>
-      <name>UtcTime</name>
-      <super>_GeneralObject</super>
-   </header>
-   <body>
-      <para>
-         This object represents the ASN1 UTCTime type.  This object should
-         be set with a string of the general format YYMMDDhhmmssZ.  The
-         helper functions <function>time2utc</function> and
-         <function>utc2time</function> can be used to handle the conversion
-         from an integer to a string and back.
-      </para>
-   </body>
-</class>
-''')
-class UtcTime(_GeneralObject):                            # 0x17
-
-   _addFragment('''
-   <constructor>
-      <header>
-         <memberof>UtcTime</memberof>
-         <parameter>optional=0</parameter>
-         <parameter>default=''</parameter>
-      </header>
-   </constructor>
-   ''')
-
-   def __init__(self, optional=0, default=''):
-      _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_UTCTIME, lambda x : x, lambda x : x, optional, default)
-
-_addFragment('''
-<class>
-   <header>
-      <name>GeneralizedTime</name>
-      <super>_GeneralObject</super>
-   </header>
-   <body>
-      <para>
-         This object represents the ASN1 GeneralizedTime type.  This object should
-         be set with a string of the general format YYYYMMDDhhmmssZ.  The
-         helper functions <function>time2utc</function> and
-         <function>utc2time</function> can be used to handle the conversion
-         from an integer to a string and back.
-      </para>
-   </body>
-</class>
-''')
-class GeneralizedTime(_GeneralObject):                    # 0x18
-
-   _addFragment('''
-   <constructor>
-      <header>
-         <memberof>GeneralizedTime</memberof>
-         <parameter>optional=0</parameter>
-         <parameter>default=''</parameter>
-      </header>
-   </constructor>
-   ''')
-
-
-   def __init__(self, optional=0, default=''):
-      _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_GENERALIZEDTIME, lambda x : x, lambda x : x, optional, default)
-
-_addFragment('''
-<class>
-   <header>
-      <name>GraphicString</name>
-      <super>_GeneralObject</super>
-   </header>
-   <body>
-      <para>
-         This object represents the ASN1 GraphicString type.  This should
-         object should be set with a string.  It is up to the application to
-         ensure it only contains valid characters for this type.
-      </para>
-   </body>
-</class>
-''')
-class GraphicString(_GeneralObject):                      # 0x19
-
-   _addFragment('''
-   <constructor>
-      <header>
-         <memberof>GraphicString</memberof>
-         <parameter>optional=0</parameter>
-         <parameter>default=''</parameter>
-      </header>
-   </constructor>
-   ''')
-
-   def __init__(self, optional=0, default=''):
-      _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_GRAPHICSTRING, lambda x : x, lambda x : x, optional, default)
-
-_addFragment('''
-<class>
-   <header>
-      <name>VisibleString</name>
-      <super>_GeneralObject</super>
-   </header>
-   <body>
-      <para>
-         This object represents the ASN1 VisibleString type.  This should
-         object should be set with a string.  It is up to the application to
-         ensure it only contains valid characters for this type.
-      </para>
-   </body>
-</class>
-''')
-class VisibleString(_GeneralObject):                      # 0xC0
- 
-   _addFragment('''
-   <constructor>
-      <header>
-         <memberof>VisibleString</memberof>
-         <parameter>optional=0</parameter>
-         <parameter>default=''</parameter>
-      </header>
-   </constructor>
-   ''')
-
-   def __init__(self, optional=0, default=''):
-      _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_VISIBLESTRING, lambda x : x, lambda x : x, optional, default)
-
-_addFragment('''
-<class>
-   <header>
-      <name>GeneralString</name>
-      <super>_GeneralObject</super>
-   </header>
-   <body>
-      <para>
-         This object represents the ASN1 GeneralString type.  This should
-         object should be set with a string.  It is up to the application to
-         ensure it only contains valid characters for this type.
-      </para>
-   </body>
-</class>
-''')
-class GeneralString(_GeneralObject):                      # 0xC0
-
-   _addFragment('''
-   <constructor>
-      <header>
-         <memberof>GeneralString</memberof>
-         <parameter>optional=0</parameter>
-         <parameter>default=''</parameter>
-      </header>
-   </constructor>
-   ''')
-
-   def __init__(self, optional=0, default=''):
-      _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_GENERALSTRING, lambda x : x, lambda x : x, optional, default)
-
-_addFragment('''
-<class>
-   <header>
-      <name>UniversalString</name>
-      <super>_GeneralObject</super>
-   </header>
-   <body>
-      <para>
-         This object represents the ASN1 UniversalString type.  This should
-         object should be set with a string.  It is up to the application to
-         ensure it only contains valid characters for this type.
-      </para>
-   </body>
-</class>
-''')
-class UniversalString(_GeneralObject):                    # 0xC0
-
-   _addFragment('''
-   <constructor>
-      <header>
-         <memberof>UniversalString</memberof>
-         <parameter>optional=0</parameter>
-         <parameter>default=''</parameter>
-      </header>
-   </constructor>
-   ''')
-
-   def __init__(self, optional=0, default=''):
-      _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_UNIVERSALSTRING, lambda x : x, lambda x : x, optional, default)
-
-_addFragment('''
-<class>
-   <header>
-      <name>BmpString</name>
-      <super>_GeneralObject</super>
-   </header>
-   <body>
-      <para>
-         This object represents the ASN1 BMPString type.  This object
-         should be set with a string.  It is up to the application to ensure
-         it only contains valid characters for this type.
-      </para>
-   </body>
-</class>
-''')
-class BmpString(_GeneralObject):                          # 0xC0
- 
-   _addFragment('''
-   <constructor>
-      <header>
-         <memberof>BmpString</memberof>
-         <parameter>optional=0</parameter>
-         <parameter>default=''</parameter>
-      </header>
-   </constructor>
-   ''')
-
-   def __init__(self, optional=0, default=''):
-      _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_BMPSTRING, lambda x : x, lambda x : x, optional, default)
-
-_addFragment('''
-<class>
-   <header>
-      <name>Sequence</name>
-      <super>_GeneralObject</super>
-   </header>
-   <body>
-      <para>
-         This object represents the ASN1 SEQUENCE type.  
-      </para>
-   </body>
-</class>
-''')
-class Sequence(_GeneralObject):                           # 0x10
-
-   _addFragment('''
-   <constructor>
-      <header>
-         <memberof>Sequence</memberof>
-         <super>_GeneralObject</super>
-         <parameter>contents</parameter>
-         <parameter>optional=0</parameter>
-         <parameter>default=''</parameter>
-      </header>
-      <body>
-         <para>
-            The <parameter>contents</parameter> should be a list or tuple containing
-            the contents of the sequence.
-            Two important members are initialised this this constructor.
-            First <constant>self.next</constant> this is used to keep track
-            of which TLVs in this sequence has been read succesfully.  The second,
-            <constant>self.contents</constant> should be set to the list of
-            objects stored in this sequence.  Note that the order they are
-            specified in is the order in which they are written or read.
-         </para>
-      </body>
-   </constructor>
-   ''')
-
-   def __init__(self, contents, optional=0, default=''):
-      self.contents = contents
-      self.next = 0
-      _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_CONSTRUCTED, TAG_SEQUENCE, _encodeSequence, _decodeSequence, optional, default)
-
-   def _childRead(self, obj):
-      if self.next < len(self.value):
-         if obj.read( self.value[self.next] ):
-            self.next += 1
-      else:
-         obj.read()
-
-   _addFragment('''
-   <method>
-      <header>
-         <memberof>Sequence</memberof>
-         <name>readContents</name>
-         <parameter>io</parameter>
-         <parameter>contents</parameter>
-      </header>
-      <body>
-         <para>
-            This function implements basic SEQUENCE like reading behaviour.
-            It will attempt to read each of the objects in
-            <parameter>contents</parameter> in turn from
-            <parameter>io</parameter>.  It exists as a function, separate
-            from <function>read</function> for the benefit of the SEQUENCE
-            OF implementation.
-         </para>
-         <para>
-            The TLV of this SEQUENCE is read and parsed into a list of
-            TLVs, which are store in <constant>self.value</constant>, by
-            <classname>_GeneralObject</classname>.<function>read</function>.
-            Then <function>read</function> is called on each member to
-            process each TLV in turn.  The next TLV is moved onto only when
-            a member returns TRUE from the read call.
-         </para>
-      </body>
-   </method>
-   ''')
-
-   def readContents(self, io, contents):    
-      if _GeneralObject.read( self, io ):
-         for item in contents:
-            Sequence._childRead( self, item )
-         return 1
-      else:
-         return 0
-
-   _addFragment('''
-   <method>
-      <header>
-         <memberof>Sequence</memberof>
-         <name>read</name>
-         <parameter>io</parameter>
-      </header>
-      <body>
-         <para>
-            Most of the logic for reading is implemented in <function>readContents</function>
-            so it can be reused for <classname>SequenceOf</classname>'s
-            <function>read</function> function.
-         </para>
-      </body>
-   </method>
-   ''')
-
-   def read(self, io=None):    
-      self.next = 0
-      return self.readContents(io, self.contents)
-
-   _addFragment('''
-   <method>
-      <header>
-         <memberof>Sequence</memberof>
-         <name>write</name>
-         <parameter>file</parameter>
-      </header>
-      <body>
-         <para>
-            <constant>self.value</constant> is set to the contents of this
-            SEQUENCE and then written by calling
-            <classname>_GeneralObject</classname>.<function>write</function>
-            whos encoder will call <function>write</function> of
-            each element in the list of contents in turn.
-         </para>
-      </body>
-   </method>
-   ''')
-
-   def write(self, file):
-      if self._ioSafe(): 
-         if self._isSet(): 
-            _GeneralObject.set( self, self.contents )
-            _GeneralObject.write( self, file )
-      elif self.optional:
-         pass
-      else:
-         prob = self.findUnset()
-         raise DerError, '%s is not in a state which can be written, %s is unset' % (repr(self), repr(prob) )
-
-   _addFragment('''
-   <method>
-      <header>
-         <memberof>Sequence</memberof>
-         <name>set</name>
-         <parameter>values</parameter>
-      </header>
-      <body>
-         <para>
-            Accessing and setting values for ASN1 objects is a bit of a
-            thorny issue.  The problem stems from the arbitrary complexity
-            of the data and the possible levels of nesting, which in
-            practice are used and are quite massive.  Designing a good general
-            approach is a bit tricky, perhaps nearly
-            impossible.  I choose to use a most compact
-            form which is excellent for simple objects and is very concise.
-         </para>
-         <para>
-            <parameter>value</parameter> should be a list or tuple of
-            values.  Each element of the list (or tuple) will be used in
-            turn to set a member.  Defaults can be specified by using the
-            default value itself or <constant>None</constant>.  Hence, for
-            SEQUENCES of SEQUENCES, SEQUENCES OF, SET and so on
-            <parameter>values</parameter> should consist of nested lists or
-            tuples.  Look at the ASN1 specs for that object to figure out
-            exactly what these should look like.
-         </para>
-      </body>
-   </method>
-   ''')
-
-   def set(self, values):
-      if self.contents is None:
-         raise DerError, 'the contents attribute should be set before using this object'
-      if not( isinstance(values, types.ListType) or isinstance(values, types.TupleType) ):
-         raise DerError, 'a sequence should be set with a list or tuple of values' 
-      if len(values) != len(self.contents):
-         raise DerError, 'wrong number of values have been supplied to set %s. Expecting %i, got %i' % \
-                  (self.__class__.__name__, len(self.contents), len(values) )
-
-      i = 0
-      for val in values:
-         self.contents[i].set(val) 
-         i = i + 1
-
-   _addFragment('''
-   <method>
-      <header>
-         <memberof>Sequence</memberof>
-         <name>get</name>
-      </header>
-      <body>
-         <para>
-            A tuple of the values of the contents of this sequence will be
-            returned.  Hence, for SEQUENCES of SEQUENCES, SEQUENCES OF, SET
-            and so on nested tuples will be returned.
-            <function>get</function> always returns tuples even if a list
-            was used to set and object.
-         </para>
-      </body>
-   </method>
-   ''')
-
-   def get(self):
-      if self.contents is None:
-         return _GeneralObject.get(self)   
-      else:
-         results = []
-         for obj in self.contents:
-            results.append( obj.get() )
-         return tuple(results)
-
-   def reset(self):
-      if self.contents is None:
-         raise DerError, 'this object has no members to set'
-      self.next = 0
-      for obj in self.contents:
-         obj.reset() # clear all child objects prior to possible setting
-                     # via default
-      _GeneralObject.reset(self)
-
-   def _isSet(self):
-      if self.contents is None:
-         raise DerError, 'this object has no members to set'
-      for obj in self.contents:
-         if not obj._ioSafe():
-            return 0
-      return 1
-
-   def findUnset(self):
-      if self.contents is None:
-         raise DerError, 'this object has no members to check'
-      for obj in self.contents:
-         if not obj._ioSafe():
-            return obj
-
-   def _ioSafe(self):
-      if self.optional or self._isSet():
-         return 1
-      else:
-         for obj in self.contents:
-            if not obj._ioSafe():
-               return 0
-         return 1
-
-_addFragment('''
-<class>
-   <header>
-      <name>SequenceOf</name>
-      <super>Sequence</super>
-   </header>
-   <body>
-      <para>
-         This object represents the ASN1 SEQUENCE OF construct.  
-      </para>
-   </body>
-</class>
-''')           
-class SequenceOf(Sequence):
-
-   _addFragment('''
-   <constructor>
-      <header>
-         <memberof>SequenceOf</memberof>
-         <super>Sequence</super>
-         <parameter>contains</parameter>
-         <parameter>optional=0</parameter>
-         <parameter>default=''</parameter>
-      </header>
-      <body>
-         <para>
-            The <parameter>contains</parameter> should be the constructor
-            for the objects which this SEQUENCE OF contains.
-         </para>
-      </body>
-   </constructor>
-   ''')
-
-   def __init__(self, contains, optional=0, default=''):
-      self.contains = contains
-      self.sequenceOf = []
-      Sequence.__init__(self, [], optional, default)
-
-   def _ioSafe(self):
-      return 1
-
-   def reset(self):
-      if self.contents is None:
-         raise DerError, 'this object has no members to set'
-      self.next = 0
-      self.sequenceOf = []
-      _GeneralObject.reset(self)
-
-   def _isSet(self):
-      if self.sequenceOf:
-         for obj in self.contents:
-            if not obj._ioSafe():
-               return 0
-         return 1
-      else:
-         return 0
-
-   def set(self, values):
-      if isinstance(values, types.NoneType):
-         return
-      objects = []
-      for val in values:
-         obj = self.contains()
-         obj.set(val)
-         objects.append(obj)
-      self.sequenceOf = objects
-
-   def get(self):
-      results = []
-      for obj in self.sequenceOf:
-         results.append( obj.get() )
-      return tuple(results)
-
-   def read(self, io=None):    
-      self.sequenceOf = []
-      self.next = 0
-      if _GeneralObject.read( self, io ):
-         for tagio in _GeneralObject.get(self):
-            value = self.contains()
-            value.read(tagio)
-            self.sequenceOf.append(value)
-         return 1
-      else:
-         return 0
-
-   def write(self, file):
-      if not self._isSet() and self.optional: 
-         pass
-      else:
-         _GeneralObject.set( self, self.sequenceOf )
-         _GeneralObject.write( self, file )
-
-   def __len__(self):
-      return len(self.sequenceOf)
-
-   def __getitem__(self, key):
-      return self.sequenceOf[key]
-
-   def __iter__(self):
-      for i in self.sequenceOf:
-         yield(i)
-
-   def __contains__(self, item):
-      return item in self.sequenceOf
-
-_addFragment('''
-<class>
-   <header>
-      <name>Set</name>
-      <super>Sequence</super>
-   </header>
-   <body>
-      <para>
-         This object represents the ASN1 Set type.  
-      </para>
-   </body>
-</class>
-''')
-class Set(Sequence):                                     # 0x11
- 
-   _addFragment('''
-   <constructor>
-      <header>
-         <memberof>Set</memberof>
-         <super>Sequence</super>
-         <parameter>contents</parameter>
-         <parameter>optional=0</parameter>
-         <parameter>default=''</parameter>
-      </header>
-      <body>
-         <para>
-            The <parameter>contents</parameter> should be a list containing
-            the contents of the sequence.
-         </para>
-      </body>
-   </constructor>
-   ''')
-
-   def __init__(self, contents, optional=0, default=''):
-      Sequence.__init__(self, contents, optional, default)
-      self.normnumber = TAG_SET
-
-_addFragment('''
-<class>
-   <header>
-      <name>SetOf</name>
-      <super>SequenceOf</super>
-   </header>
-   <body>
-      <para>
-         This object represents the ASN1 SET OF construct.  
-      </para>
-   </body>
-</class>
-''')
-class SetOf(SequenceOf):
-
-   _addFragment('''
-   <constructor>
-      <header>
-         <memberof>SetOf</memberof>
-         <super>SequenceOf</super>
-         <parameter>contains</parameter>
-         <parameter>optional=0</parameter>
-         <parameter>default=''</parameter>
-      </header>
-      <body>
-         <para>
-            The <parameter>contains</parameter> should be the constructor
-            for the objects which this SET OF contains.
-         </para>
-      </body>
-   </constructor>
-   ''')
-
-   def __init__(self, contains, optional=0, default=''):
-      SequenceOf.__init__(self, contains, optional, default)
-      self.normnumber = TAG_SET
-
-_addFragment('''
-<class>
-   <header>
-      <name>Explicit</name>
-      <super>Sequence</super>
-   </header>
-   <body>
-      <para>
-         Explicit objects support the DER concept of explicit tagging.  In
-         general they behave just like a SEQUENCE which must have only one
-         element.  See below for other differences.
-      </para>
-   </body>
-</class>
-''')
-class Explicit(Sequence):           
-
-   _addFragment('''
-   <constructor>
-      <header>
-         <memberof>Explicit</memberof>
-         <super>Sequence</super>
-         <parameter>expclass</parameter>
-         <parameter>expform</parameter>
-         <parameter>expnumber</parameter>
-         <parameter>contents</parameter>
-         <parameter>optional=0</parameter>
-         <parameter>default=''</parameter>
-      </header>
-      <body>
-         <para>
-            <parameter>expclass</parameter>,
-            <parameter>expform</parameter>,
-            <parameter>expnumber</parameter> should be as
-            specified in the ASN1 documentation for this object.
-            <parameter>contents</parameter> should be an object instance
-            such as <classname>Integer</classname>,
-            <classname>Oid</classname> or a derived object which supports
-            the <classname>_GeneralObjec</classname> interface.
-         </para>
-      </body>
-   </constructor>
-   ''')
-
-   def __init__(self, expclass, expform, expnumber, contents, optional=0, default=''):
-      self.contents = [contents]
-      self.next = 0
-      _GeneralObject.__init__(self, expclass, expform, expnumber, _encodeSequence, _decodeSequence, optional, default)
-
-   _addFragment('''
-   <method>
-      <header>
-         <memberof>Explicit</memberof>
-         <name>set</name>
-         <parameter>value</parameter>
-      </header>
-      <body>
-         <para>
-            <parameter>value</parameter> is passed direct to
-            <function>set</function> of the explicit object, so it should
-            not be placed in a list or tuple(unless you are setting a constructed
-            object).  
-         </para>
-      </body>
-   </method>
-   ''')
-   def set(self, value):
-      return Sequence.set(self, [value])
-
-   _addFragment('''
-   <method>
-      <header>
-         <memberof>Explicit</memberof>
-         <name>get</name>
-      </header>
-      <body>
-         <para>
-            The value of explicit object is returned and not
-            put in a tuple.   
-         </para>
-      </body>
-   </method>
-   ''')
-   def get(self):
-      return Sequence.get(self)[0]
-
-_addFragment('''
-<class>
-   <header>
-      <name>Choice</name>
-   </header>
-   <body>
-      <para>
-         This object represents the ASN1 Choice type.  
-      </para>
-   </body>
-</class>
-''')
-class Choice(object):
-
-   _addFragment('''
-   <constructor>
-      <header>
-         <memberof>Choice</memberof>
-         <parameter>choices</parameter>
-         <parameter>optional=0</parameter>
-         <parameter>default=''</parameter>
-      </header>
-      <body>
-         <para>
-            <parameter>choices</parameter> should be a dictionary of 
-            objects which support the <classname>_GeneralObject</classname>
-            interface.  The key being the name of the choice specified in the
-            ASN1 documentation.  <parameter>optional</parameter> is a boolean
-            indicating if this object is optional.  The final parameter,
-            <parameter>default</parameter> is the base 64 encoded DER
-            value, which should be used as the default in leu of a value to
-            read or incase it is unset.  If neither
-            <parameter>optional</parameter> or
-            <parameter>default</parameter> is not set then the first choice
-            which is optional or has a default will be honored.
-         </para>
-      </body>
-   </constructor>
-   ''')
-
-   def __init__(self, choices, optional=0, default=''):
-      self.value = None
-      self.choices = choices
-      self.optional = optional
-      self.default = default
-      self.choice = None
-      self.reset()
-
-   def _ioSafe(self):
-      if self.optional or self._isSet():
-         return 1
-      elif self.choice and self.choices[ self.choice ]._ioSafe():
-         return 1
-      else:
-         return 0
-
-   def _isSet(self):
-      if self.choice and self.choices[self.choice]._isSet():
-         return 1
-      else:
-         return 0
-
-   _addFragment('''
-   <method>
-      <header>
-         <memberof>Choice</memberof>
-         <name>reset</name>
-      </header>
-      <body>
-         <para>
-            This function re-initialises the object, clearing the value or
-            setting it to any default.
-         </para>
-      </body>
-   </method>
-   ''')
-   def reset(self):
-      self.value = None
-      self.choice = None
-      if self.default:
-         buf = cStringIO.StringIO( base64.decodestring( self.default ) )
-         io = _TlvIo(buf)
-         io.read()
-         self.read(io)
-      else:
-         for key in self.choices.keys():
-            self.choices[key].reset()
-            if self.choices[key]._ioSafe():
-               self.choice = key
-               break;
-            
-
-   _addFragment('''
-   <method>
-      <header>
-         <memberof>Choice</memberof>
-         <name>set</name>
-         <parameter>value</parameter>
-      </header>
-      <body>
-         <para>
-            <parameter>value</parameter> should be a list or tuple with two
-            elements. The first value should be the name of the choice to
-            be set and the second the value to set it with.
-         </para>
-      </body>
-   </method>
-   ''')
-   def set(self, val):
-      if val is None:
-         return
-      if not (isinstance(val, types.ListType) or isinstance(val, types.TupleType)):
-         raise DerError, 'argument should be a list or tuple'
-      if not self.choices.has_key( val[0] ):
-         raise DerError, 'unknown choice: %s' % val[0]
-      self.choices[ val[0] ].set(val[1])
-      self.choice = val[0]
-
-   _addFragment('''
-   <method>
-      <header>
-         <memberof>Choice</memberof>
-         <name>get</name>
-      </header>
-      <body>
-         <para>
-            This function will return tuple with two elements. The first
-            value will be the name of the choice which was set and the second
-            the value it was set to.
-         </para>
-      </body>
-   </method>
-   ''')
-
-   def get(self):
-      if self._isSet():
-         return (self.choice, self.choices[ self.choice ].get())
-      else:
-         return None
-
-   _addFragment('''
-   <method>
-      <header>
-         <memberof>Choice</memberof>
-         <name>toString</name>
-      </header>
-      <body>
-         <para>
-            Encodes the value in DER and returns it as a string.
-         </para>
-      </body>
-   </method>
-   ''')
-
-   def toString(self):
-      buf = cStringIO.StringIO()
-      self.write(buf)
-      return buf.getvalue()
-
-   _addFragment('''
-   <method>
-      <header>
-         <memberof>Choice</memberof>
-         <name>fromString</name>
-      </header>
-      <body>
-         <para>
-            Decodes the string and sets the value of this object.
-         </para>
-      </body>
-   </method>
-   ''')
-
-   def fromString(self, value):
-      buf = cStringIO.StringIO(value)
-      self.read(buf)
-
-   _addFragment('''
-   <method>
-      <header>
-         <memberof>Choice</memberof>
-         <name>read</name>
-         <parameter>io</parameter>
-      </header>
-      <body>
-         <para>
-            <parameter>io</parameter> should be a file like object.  If the
-            object being read matches the expected class, form and tag the
-            value is read and decoded using
-            <function>decRoutine</function>.  Else, if it has a default
-            that is read and stored.  
-         </para>
-         <para>
-            The return value of this function does not indicate success but
-            whether this TLV was processed successfully.  This bahaviour is
-            vital for processing constructed types since the object may be
-            optional or have a default.  Failure to decode would be indicated 
-            by an exception.  
-         </para>
-      </body>
-   </method>
-   ''')
-
-   def _readChoices(self, io):
-      for key in self.choices.keys():
-         try:
-            readindicator = self.choices[key].read(io)
-            self.choice = key
-            break;
-         except DerError:
-            if DEBUG:
-               traceback.print_exc()
-      return readindicator
- 
-   def read(self, io=None):    
-
-      self.choice = None
-      processDefOpt = 0
-      readindicator = 0
-
-      if io is None:
-         processDefOpt = 1
-      elif isinstance(io, _TlvIo):
-         if not io:
-            processDefOpt = 1
-      else:
-         pos = io.tell()
-         io.seek(0,2)
-         if io.tell():
-            io.seek(pos)
-         else:
-            processDefOpt = 1
-
-      if processDefOpt:
-         if self.optional or self.default:
-            self.reset()
-            return 0
-         else:
-            readindicator = self._readChoices(io)
-            for key in self.choices.keys():
-               try:
-                  readindicator = self.choices[key].read(io)
-                  self.choice = key
-                  break;
-               except DerError:
-                  if DEBUG:
-                     traceback.print_exc()
-            if not self._isSet():
-               raise DerError, 'no TLV is available to read in non-optional/non-default object: %s' % repr(self)
-            else:
-               return readindicator
-
-      if not isinstance(io, _TlvIo):
-         tmp = _TlvIo(io)
-         tmp.read()
-         io = tmp
-
-      for key in self.choices.keys():
-         try:
-            if self.choices[key].read(io):
-               self.choice = key
-               readindicator = 1
-               break;
-         except DerError:
-            if DEBUG:
-               traceback.print_exc()
- 
-      if not self._isSet():
-         self.reset()
-      else:
-         return readindicator
-
-   _addFragment('''
-   <method>
-      <header>
-         <memberof>Choice</memberof>
-         <name>write</name>
-         <parameter>file</parameter>
-      </header>
-      <body>
-         <para>
-            If this object has not been set and is not optional and dosn't
-            have a default, a <classname>DerError</classname> exception will be raised
-         </para>
-         <para>
-            If no value has been set and this object is optional, nothing
-            is written.  If this object's value is equal to the default,
-            nothing is written as stipulated by DER.  Otherwise the value
-            is encoded and written.  
-         </para>
-      </body>
-   </method>
-   ''')
-   def write(self,file):
-      if self.optional and not self.choice:
-         pass
-      elif not self.choice:
-         raise DerError, 'choice not set'
-      elif self.choice:
-         if self.default:
-            defval = base64.decodestring( self.default )
-            if defval != self.choices[ self.choice ].toString():
-               self.choices[ self.choice ].write(file)
-         else:
-            self.choices[ self.choice ].write(file)
-      else:
-         raise DerError, 'an internal error has occured: %s' % repr(self)
-
-