def writeLength(value: int) -> bytes:
"""
Pack a PER length indicator
"""
if value > 0x7f:
return Uint16BE.pack(value | 0x8000)
else:
return Uint8.pack(value)
def writeLength(length: int) -> bytes:
"""
Pack structure length as expected in BER specification
:param length: structure length.
"""
if length > 0x7f:
return Uint8.pack(0x82) + Uint16BE.pack(length)
else:
return Uint8.pack(length)
def writeInteger(value: int) -> bytes:
"""
Pack a PER integer
"""
if value <= 0xff:
return writeLength(1) + Uint8.pack(value)
elif value < 0xffff:
return writeLength(2) + Uint16BE.pack(value)
else:
return writeLength(4) + Uint32BE.pack(value)
def writeLength(value):
"""
Pack a PER length indicator
:type value: int
:return: str
"""
if value > 0x7f:
return Uint16BE.pack(value | 0x8000)
else:
return Uint8.pack(value)
def writeInteger(value):
"""
Pack a PER integer
:type value: int
:return: str
"""
if value <= 0xff:
return writeLength(1) + Uint8.pack(value)
elif value < 0xffff:
return writeLength(2) + Uint16BE.pack(value)
else:
return writeLength(4) + Uint32BE.pack(value)
def writeInteger(value):
"""
Pack a BER integer
:type value: int
:return: str
"""
if value <= 0xff:
return writeUniversalTag(Tag.BER_TAG_INTEGER, False) + writeLength(1) + Uint8.pack(value)
elif value <= 0xffff:
return writeUniversalTag(Tag.BER_TAG_INTEGER, False) + writeLength(2) + Uint16BE.pack(value)
else:
return writeUniversalTag(Tag.BER_TAG_INTEGER, False) + writeLength(4) + Uint32BE.pack(value)
def readInteger(s: BinaryIO) -> int:
"""
Unpack a BER integer
:param s: stream
"""
if not readUniversalTag(s, Tag.BER_TAG_INTEGER, False):
raise ValueError("Bad integer tag")
size = readLength(s)
if size == 1:
return Uint8.unpack(s.read(1))
elif size == 2:
return Uint16BE.unpack(s.read(2))
elif size == 3:
integer1 = Uint8.unpack(s.read(1))
integer2 = Uint16BE.unpack(s.read(2))
return (integer1 << 16) + integer2
elif size == 4:
return Uint32BE.unpack(s.read(4))
else:
raise ValueError("Wrong integer size")
def readInteger(s: BinaryIO) -> int:
"""
Unpack a PER integer
:param s: stream
@raise InvalidValue: if the size of the integer is invalid
"""
size = readLength(s)
if size == 1:
return Uint8.unpack(s.read(1))
elif size == 2:
return Uint16BE.unpack(s.read(2))
elif size == 4:
return Uint32BE.unpack(s.read(4))
else:
raise ValueError("invalid integer size %d" % size)
def readLength(s: BinaryIO) -> int:
"""
Read length of BER structure
Length is on 1, 2 or 3 bytes
:param s: stream
"""
byte = Uint8.unpack(s.read(1))
if byte & 0x80:
byte &= ~0x80
if byte == 1:
return Uint8.unpack(s.read(1))
elif byte == 2:
return Uint16BE.unpack(s.read(2))
else:
raise ValueError("BER length must be 1 or 2")
else:
return byte