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#
# This file is part of pyasn1 software.
#
# Copyright (c) 2005-2017, Ilya Etingof <etingof@gmail.com>
# License: http://pyasn1.sf.net/license.html
#
from pyasn1.type import tag, univ, char, useful
from pyasn1.codec.ber import eoo
from pyasn1.compat.octets import int2oct, oct2int, ints2octs, null, str2octs
from pyasn1.compat.integer import to_bytes
from pyasn1 import debug, error
__all__ = ['encode']
class AbstractItemEncoder(object):
supportIndefLenMode = 1
# An outcome of otherwise legit call `encodeFun(eoo.endOfOctets)`
eooIntegerSubstrate = (0, 0)
eooOctetsSubstrate = ints2octs(eooIntegerSubstrate)
# noinspection PyMethodMayBeStatic
def encodeTag(self, singleTag, isConstructed):
tagClass, tagFormat, tagId = singleTag
encodedTag = tagClass | tagFormat
if isConstructed:
encodedTag |= tag.tagFormatConstructed
if tagId < 31:
return encodedTag | tagId,
else:
substrate = tagId & 0x7f,
tagId >>= 7
while tagId:
substrate = (0x80 | (tagId & 0x7f),) + substrate
tagId >>= 7
return (encodedTag | 0x1F,) + substrate
def encodeLength(self, length, defMode):
if not defMode and self.supportIndefLenMode:
return (0x80,)
if length < 0x80:
return length,
else:
substrate = ()
while length:
substrate = (length & 0xff,) + substrate
length >>= 8
substrateLen = len(substrate)
if substrateLen > 126:
raise error.PyAsn1Error('Length octets overflow (%d)' % substrateLen)
return (0x80 | substrateLen,) + substrate
def encodeValue(self, value, encodeFun, **options):
raise error.PyAsn1Error('Not implemented')
def encode(self, value, encodeFun, **options):
tagSet = value.tagSet
# untagged item?
if not tagSet:
substrate, isConstructed, isOctets = self.encodeValue(
value, encodeFun, **options
)
return substrate
defMode = options.get('defMode', True)
for idx, singleTag in enumerate(tagSet.superTags):
defModeOverride = defMode
# base tag?
if not idx:
substrate, isConstructed, isOctets = self.encodeValue(
value, encodeFun, **options
)
if options.get('ifNotEmpty', False) and not substrate:
return substrate
# primitive form implies definite mode
if not isConstructed:
defModeOverride = True
header = self.encodeTag(singleTag, isConstructed)
header += self.encodeLength(len(substrate), defModeOverride)
if isOctets:
substrate = ints2octs(header) + substrate
if not defModeOverride:
substrate += self.eooOctetsSubstrate
else:
substrate = header + substrate
if not defModeOverride:
substrate += self.eooIntegerSubstrate
if not isOctets:
substrate = ints2octs(substrate)
return substrate
class EndOfOctetsEncoder(AbstractItemEncoder):
def encodeValue(self, value, encodeFun, **options):
return null, False, True
class BooleanEncoder(AbstractItemEncoder):
supportIndefLenMode = False
def encodeValue(self, value, encodeFun, **options):
return value and (1,) or (0,), False, False
class IntegerEncoder(AbstractItemEncoder):
supportIndefLenMode = False
supportCompactZero = False
def encodeValue(self, value, encodeFun, **options):
if value == 0:
# de-facto way to encode zero
if self.supportCompactZero:
return (), False, False
else:
return (0,), False, False
return to_bytes(int(value), signed=True), False, True
class BitStringEncoder(AbstractItemEncoder):
def encodeValue(self, value, encodeFun, **options):
valueLength = len(value)
if valueLength % 8:
alignedValue = value << (8 - valueLength % 8)
else:
alignedValue = value
maxChunkSize = options.get('maxChunkSize', 0)
if not maxChunkSize or len(alignedValue) <= maxChunkSize * 8:
substrate = alignedValue.asOctets()
return int2oct(len(substrate) * 8 - valueLength) + substrate, False, True
# strip off explicit tags
alignedValue = alignedValue.clone(
tagSet=tag.TagSet(value.tagSet.baseTag, value.tagSet.baseTag)
)
stop = 0
substrate = null
while stop < valueLength:
start = stop
stop = min(start + maxChunkSize * 8, valueLength)
substrate += encodeFun(alignedValue[start:stop], **options)
return substrate, True, True
class OctetStringEncoder(AbstractItemEncoder):
def encodeValue(self, value, encodeFun, **options):
maxChunkSize = options.get('maxChunkSize', 0)
if not maxChunkSize or len(value) <= maxChunkSize:
return value.asOctets(), False, True
else:
# will strip off explicit tags
baseTagSet = tag.TagSet(value.tagSet.baseTag, value.tagSet.baseTag)
pos = 0
substrate = null
while True:
chunk = value.clone(value[pos:pos + maxChunkSize],
tagSet=baseTagSet)
if not chunk:
break
substrate += encodeFun(chunk, **options)
pos += maxChunkSize
return substrate, True, True
class NullEncoder(AbstractItemEncoder):
supportIndefLenMode = False
def encodeValue(self, value, encodeFun, **options):
return null, False, True
class ObjectIdentifierEncoder(AbstractItemEncoder):
supportIndefLenMode = False
def encodeValue(self, value, encodeFun, **options):
oid = value.asTuple()
# Build the first pair
try:
first = oid[0]
second = oid[1]
except IndexError:
raise error.PyAsn1Error('Short OID %s' % (value,))
if 0 <= second <= 39:
if first == 1:
oid = (second + 40,) + oid[2:]
elif first == 0:
oid = (second,) + oid[2:]
elif first == 2:
oid = (second + 80,) + oid[2:]
else:
raise error.PyAsn1Error('Impossible first/second arcs at %s' % (value,))
elif first == 2:
oid = (second + 80,) + oid[2:]
else:
raise error.PyAsn1Error('Impossible first/second arcs at %s' % (value,))
octets = ()
# Cycle through subIds
for subOid in oid:
if 0 <= subOid <= 127:
# Optimize for the common case
octets += (subOid,)
elif subOid > 127:
# Pack large Sub-Object IDs
res = (subOid & 0x7f,)
subOid >>= 7
while subOid:
res = (0x80 | (subOid & 0x7f),) + res
subOid >>= 7
# Add packed Sub-Object ID to resulted Object ID
octets += res
else:
raise error.PyAsn1Error('Negative OID arc %s at %s' % (subOid, value))
return octets, False, False
class RealEncoder(AbstractItemEncoder):
supportIndefLenMode = 0
binEncBase = 2 # set to None to choose encoding base automatically
@staticmethod
def _dropFloatingPoint(m, encbase, e):
ms, es = 1, 1
if m < 0:
ms = -1 # mantissa sign
if e < 0:
es = -1 # exponenta sign
m *= ms
if encbase == 8:
m *= 2 ** (abs(e) % 3 * es)
e = abs(e) // 3 * es
elif encbase == 16:
m *= 2 ** (abs(e) % 4 * es)
e = abs(e) // 4 * es
while True:
if int(m) != m:
m *= encbase
e -= 1
continue
break
return ms, int(m), encbase, e
def _chooseEncBase(self, value):
m, b, e = value
encBase = [2, 8, 16]
if value.binEncBase in encBase:
return self._dropFloatingPoint(m, value.binEncBase, e)
elif self.binEncBase in encBase:
return self._dropFloatingPoint(m, self.binEncBase, e)
# auto choosing base 2/8/16
mantissa = [m, m, m]
exponenta = [e, e, e]
sign = 1
encbase = 2
e = float('inf')
for i in range(3):
(sign,
mantissa[i],
encBase[i],
exponenta[i]) = self._dropFloatingPoint(mantissa[i], encBase[i], exponenta[i])
if abs(exponenta[i]) < abs(e) or (abs(exponenta[i]) == abs(e) and mantissa[i] < m):
e = exponenta[i]
m = int(mantissa[i])
encbase = encBase[i]
return sign, m, encbase, e
def encodeValue(self, value, encodeFun, **options):
if value.isPlusInf:
return (0x40,), False, False
if value.isMinusInf:
return (0x41,), False, False
m, b, e = value
if not m:
return null, False, True
if b == 10:
return str2octs('\x03%dE%s%d' % (m, e == 0 and '+' or '', e)), False, True
elif b == 2:
fo = 0x80 # binary encoding
ms, m, encbase, e = self._chooseEncBase(value)
if ms < 0: # mantissa sign
fo |= 0x40 # sign bit
# exponenta & mantissa normalization
if encbase == 2:
while m & 0x1 == 0:
m >>= 1
e += 1
elif encbase == 8:
while m & 0x7 == 0:
m >>= 3
e += 1
fo |= 0x10
else: # encbase = 16
while m & 0xf == 0:
m >>= 4
e += 1
fo |= 0x20
sf = 0 # scale factor
while m & 0x1 == 0:
m >>= 1
sf += 1
if sf > 3:
raise error.PyAsn1Error('Scale factor overflow') # bug if raised
fo |= sf << 2
eo = null
if e == 0 or e == -1:
eo = int2oct(e & 0xff)
else:
while e not in (0, -1):
eo = int2oct(e & 0xff) + eo
e >>= 8
if e == 0 and eo and oct2int(eo[0]) & 0x80:
eo = int2oct(0) + eo
if e == -1 and eo and not (oct2int(eo[0]) & 0x80):
eo = int2oct(0xff) + eo
n = len(eo)
if n > 0xff:
raise error.PyAsn1Error('Real exponent overflow')
if n == 1:
pass
elif n == 2:
fo |= 1
elif n == 3:
fo |= 2
else:
fo |= 3
eo = int2oct(n & 0xff) + eo
po = null
while m:
po = int2oct(m & 0xff) + po
m >>= 8
substrate = int2oct(fo) + eo + po
return substrate, False, True
else:
raise error.PyAsn1Error('Prohibited Real base %s' % b)
class SequenceEncoder(AbstractItemEncoder):
def encodeValue(self, value, encodeFun, **options):
value.verifySizeSpec()
namedTypes = value.componentType
substrate = null
idx = len(value)
while idx > 0:
idx -= 1
if namedTypes:
if namedTypes[idx].isOptional and not value[idx].isValue:
continue
if namedTypes[idx].isDefaulted and value[idx] == namedTypes[idx].asn1Object:
continue
substrate = encodeFun(value[idx], **options) + substrate
return substrate, True, True
class SequenceOfEncoder(AbstractItemEncoder):
def encodeValue(self, value, encodeFun, **options):
value.verifySizeSpec()
substrate = null
idx = len(value)
while idx > 0:
idx -= 1
substrate = encodeFun(value[idx], **options) + substrate
return substrate, True, True
class ChoiceEncoder(AbstractItemEncoder):
def encodeValue(self, value, encodeFun, **options):
return encodeFun(value.getComponent(), **options), True, True
class AnyEncoder(OctetStringEncoder):
def encodeValue(self, value, encodeFun, **options):
return value.asOctets(), not options.get('defMode', True), True
tagMap = {
eoo.endOfOctets.tagSet: EndOfOctetsEncoder(),
univ.Boolean.tagSet: BooleanEncoder(),
univ.Integer.tagSet: IntegerEncoder(),
univ.BitString.tagSet: BitStringEncoder(),
univ.OctetString.tagSet: OctetStringEncoder(),
univ.Null.tagSet: NullEncoder(),
univ.ObjectIdentifier.tagSet: ObjectIdentifierEncoder(),
univ.Enumerated.tagSet: IntegerEncoder(),
univ.Real.tagSet: RealEncoder(),
# Sequence & Set have same tags as SequenceOf & SetOf
univ.SequenceOf.tagSet: SequenceOfEncoder(),
univ.SetOf.tagSet: SequenceOfEncoder(),
univ.Choice.tagSet: ChoiceEncoder(),
# character string types
char.UTF8String.tagSet: OctetStringEncoder(),
char.NumericString.tagSet: OctetStringEncoder(),
char.PrintableString.tagSet: OctetStringEncoder(),
char.TeletexString.tagSet: OctetStringEncoder(),
char.VideotexString.tagSet: OctetStringEncoder(),
char.IA5String.tagSet: OctetStringEncoder(),
char.GraphicString.tagSet: OctetStringEncoder(),
char.VisibleString.tagSet: OctetStringEncoder(),
char.GeneralString.tagSet: OctetStringEncoder(),
char.UniversalString.tagSet: OctetStringEncoder(),
char.BMPString.tagSet: OctetStringEncoder(),
# useful types
useful.ObjectDescriptor.tagSet: OctetStringEncoder(),
useful.GeneralizedTime.tagSet: OctetStringEncoder(),
useful.UTCTime.tagSet: OctetStringEncoder()
}
# Put in ambiguous & non-ambiguous types for faster codec lookup
typeMap = {
univ.Boolean.typeId: BooleanEncoder(),
univ.Integer.typeId: IntegerEncoder(),
univ.BitString.typeId: BitStringEncoder(),
univ.OctetString.typeId: OctetStringEncoder(),
univ.Null.typeId: NullEncoder(),
univ.ObjectIdentifier.typeId: ObjectIdentifierEncoder(),
univ.Enumerated.typeId: IntegerEncoder(),
univ.Real.typeId: RealEncoder(),
# Sequence & Set have same tags as SequenceOf & SetOf
univ.Set.typeId: SequenceEncoder(),
univ.SetOf.typeId: SequenceOfEncoder(),
univ.Sequence.typeId: SequenceEncoder(),
univ.SequenceOf.typeId: SequenceOfEncoder(),
univ.Choice.typeId: ChoiceEncoder(),
univ.Any.typeId: AnyEncoder(),
# character string types
char.UTF8String.typeId: OctetStringEncoder(),
char.NumericString.typeId: OctetStringEncoder(),
char.PrintableString.typeId: OctetStringEncoder(),
char.TeletexString.typeId: OctetStringEncoder(),
char.VideotexString.typeId: OctetStringEncoder(),
char.IA5String.typeId: OctetStringEncoder(),
char.GraphicString.typeId: OctetStringEncoder(),
char.VisibleString.typeId: OctetStringEncoder(),
char.GeneralString.typeId: OctetStringEncoder(),
char.UniversalString.typeId: OctetStringEncoder(),
char.BMPString.typeId: OctetStringEncoder(),
# useful types
useful.ObjectDescriptor.typeId: OctetStringEncoder(),
useful.GeneralizedTime.typeId: OctetStringEncoder(),
useful.UTCTime.typeId: OctetStringEncoder()
}
class Encoder(object):
fixedDefLengthMode = None
fixedChunkSize = None
# noinspection PyDefaultArgument
def __init__(self, tagMap, typeMap={}):
self.__tagMap = tagMap
self.__typeMap = typeMap
def __call__(self, value, **options):
if debug.logger & debug.flagEncoder:
logger = debug.logger
else:
logger = None
if logger:
logger('encoder called in %sdef mode, chunk size %s for type %s, value:\n%s' % (not options.get('defMode', True) and 'in' or '', options.get('maxChunkSize', 0), value.prettyPrintType(), value.prettyPrint()))
if self.fixedDefLengthMode is not None:
options.update(defMode=self.fixedDefLengthMode)
if self.fixedChunkSize is not None:
options.update(maxChunkSize=self.fixedChunkSize)
tagSet = value.tagSet
try:
concreteEncoder = self.__typeMap[value.typeId]
except KeyError:
# use base type for codec lookup to recover untagged types
baseTagSet = tag.TagSet(value.tagSet.baseTag, value.tagSet.baseTag)
try:
concreteEncoder = self.__tagMap[baseTagSet]
except KeyError:
raise error.PyAsn1Error('No encoder for %s' % (value,))
if logger:
logger('using value codec %s chosen by %s' % (concreteEncoder.__class__.__name__, tagSet))
substrate = concreteEncoder.encode(value, self, **options)
if logger:
logger('codec %s built %s octets of substrate: %s\nencoder completed' % (concreteEncoder, len(substrate), debug.hexdump(substrate)))
return substrate
#: Turns ASN.1 object into BER octet stream.
#:
#: Takes any ASN.1 object (e.g. :py:class:`~pyasn1.type.base.PyAsn1Item` derivative)
#: walks all its components recursively and produces a BER octet stream.
#:
#: Parameters
#: ----------
# value: any pyasn1 object (e.g. :py:class:`~pyasn1.type.base.PyAsn1Item` derivative)
#: A pyasn1 object to encode
#:
#: defMode: :py:class:`bool`
#: If `False`, produces indefinite length encoding
#:
#: maxChunkSize: :py:class:`int`
#: Maximum chunk size in chunked encoding mode (0 denotes unlimited chunk size)
#:
#: Returns
#: -------
#: : :py:class:`bytes` (Python 3) or :py:class:`str` (Python 2)
#: Given ASN.1 object encoded into BER octetstream
#:
#: Raises
#: ------
#: : :py:class:`pyasn1.error.PyAsn1Error`
#: On encoding errors
encode = Encoder(tagMap, typeMap)