trx_toolkit: check in simple declarative codec
Change-Id: I7ff46b278c59af3720ee7f3950ea5a8b2f1313e1 Related: OS#4006, SYS#4895
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# -*- coding: utf-8 -*-
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'''
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Very simple (performance oriented) declarative message codec.
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Inspired by Pycrate and Scapy.
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'''
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# TRX Toolkit
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#
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# (C) 2021 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
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# Author: Vadim Yanitskiy <vyanitskiy@sysmocom.de>
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#
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# All Rights Reserved
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License along
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# with this program; if not, write to the Free Software Foundation, Inc.,
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# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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from typing import Optional, Callable, Tuple, Any
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import abc
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class ProtocolError(Exception):
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''' Error in a protocol definition. '''
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class DecodeError(Exception):
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''' Error during decoding of a field/message. '''
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class EncodeError(Exception):
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''' Error during encoding of a field/message. '''
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class Codec(abc.ABC):
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''' Base class providing encoding and decoding API. '''
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@abc.abstractmethod
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def from_bytes(self, vals: dict, data: bytes) -> int:
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''' Decode value(s) from the given buffer of bytes. '''
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@abc.abstractmethod
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def to_bytes(self, vals: dict) -> bytes:
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''' Encode value(s) into bytes. '''
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class Field(Codec):
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''' Base class representing one field in a Message. '''
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# Default length (0 means the whole buffer)
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DEF_LEN: int = 0
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# Default parameters
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DEF_PARAMS: dict = { }
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# Presence of a field during decoding and encoding
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get_pres: Callable[[dict], bool]
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# Length of a field for self.from_bytes()
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get_len: Callable[[dict, bytes], int]
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# Value of a field for self.to_bytes()
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get_val: Callable[[dict], Any]
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def __init__(self, name: str, **kw) -> None:
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self.name = name
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self.len = kw.get('len', self.DEF_LEN)
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if self.len == 0: # flexible field
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self.get_len = lambda _, data: len(data)
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else: # fixed length
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self.get_len = lambda vals, _: self.len
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# Field is unconditionally present by default
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self.get_pres = lambda vals: True
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# Field takes its value from the given dict by default
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self.get_val = lambda vals: vals[self.name]
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# Additional parameters for derived field types
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self.p = { key : kw.get(key, self.DEF_PARAMS[key])
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for key in self.DEF_PARAMS }
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def from_bytes(self, vals: dict, data: bytes) -> int:
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if self.get_pres(vals) is False:
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return 0
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length = self.get_len(vals, data)
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if len(data) < length:
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raise DecodeError('Short read')
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self._from_bytes(vals, data[:length])
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return length
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def to_bytes(self, vals: dict) -> bytes:
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if self.get_pres(vals) is False:
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return b''
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data = self._to_bytes(vals)
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if self.len > 0 and len(data) != self.len:
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raise EncodeError('Field length mismatch')
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return data
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@abc.abstractmethod
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def _from_bytes(self, vals: dict, data: bytes) -> None:
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''' Decode value(s) from the given buffer of bytes. '''
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raise NotImplementedError
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@abc.abstractmethod
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def _to_bytes(self, vals: dict) -> bytes:
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''' Encode value(s) into bytes. '''
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raise NotImplementedError
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class Buf(Field):
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''' A sequence of octets. '''
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def _from_bytes(self, vals: dict, data: bytes) -> None:
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vals[self.name] = data
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def _to_bytes(self, vals: dict) -> bytes:
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# TODO: handle len(self.get_val()) < self.get_len()
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return self.get_val(vals)
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class Spare(Field):
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''' Spare filling for RFU fields or padding. '''
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# Default parameters
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DEF_PARAMS = {
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'filler' : b'\x00',
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}
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def _from_bytes(self, vals: dict, data: bytes) -> None:
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pass # Just ignore it
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def _to_bytes(self, vals: dict) -> bytes:
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return self.p['filler'] * self.get_len(vals, b'')
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class Uint(Field):
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''' An integer field: unsigned, N bits, big endian. '''
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# Uint8 by default
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DEF_LEN = 1
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# Default parameters
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DEF_PARAMS = {
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'offset' : 0,
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'mult' : 1,
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}
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# Big endian, unsigned
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SIGN = False
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BO = 'big'
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def _from_bytes(self, vals: dict, data: bytes) -> None:
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val = int.from_bytes(data, self.BO, signed=self.SIGN)
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vals[self.name] = val * self.p['mult'] + self.p['offset']
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def _to_bytes(self, vals: dict) -> bytes:
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val = (self.get_val(vals) - self.p['offset']) // self.p['mult']
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return val.to_bytes(self.len, self.BO, signed=self.SIGN)
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class Uint16BE(Uint):
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DEF_LEN = 16 // 8
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class Uint16LE(Uint16BE):
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BO = 'little'
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class Uint32BE(Uint):
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DEF_LEN = 32 // 8
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class Uint32LE(Uint32BE):
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BO = 'little'
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class Int(Uint):
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SIGN = True
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class Int16BE(Int):
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DEF_LEN = 16 // 8
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class Int16LE(Int16BE):
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BO = 'little'
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class Int32BE(Int):
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DEF_LEN = 32 // 8
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class Int32LE(Int32BE):
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BO = 'little'
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class BitFieldSet(Field):
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''' A set of bit-fields. '''
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# Default parameters
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DEF_PARAMS = {
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# Default field order (MSB first)
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'order' : 'big',
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}
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# To be defined by derived types
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STRUCT: Tuple['BitField', ...] = ()
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def __init__(self, **kw) -> None:
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Field.__init__(self, self.__class__.__name__, **kw)
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self._fields = kw.get('set', self.STRUCT)
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if type(self._fields) is not tuple:
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raise ProtocolError('Expected a tuple')
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# LSB first is basically reversed order
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if self.p['order'] in ('little', 'lsb'):
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self._fields = self._fields[::-1]
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# Calculate the overall field length
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if self.len == 0:
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bl_sum = sum([f.bl for f in self._fields])
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self.len = bl_sum // 8
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if bl_sum % 8 > 0:
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self.len += 1
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# Re-define self.get_len() since we always know the length
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self.get_len = lambda vals, data: self.len
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# Pre-calculate offset and mask for each field
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offset = self.len * 8
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for f in self._fields:
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if f.bl > offset:
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raise ProtocolError(f, 'BitFieldSet overflow')
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f.offset = offset - f.bl
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f.mask = 2 ** f.bl - 1
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offset -= f.bl
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def _from_bytes(self, vals: dict, data: bytes) -> None:
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blob = int.from_bytes(data, byteorder='big') # intentionally using 'big' here
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for f in self._fields:
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f.dec_val(vals, blob)
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def _to_bytes(self, vals: dict) -> bytes:
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blob = 0x00
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for f in self._fields: # TODO: use functools.reduce()?
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blob |= f.enc_val(vals)
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return blob.to_bytes(self.len, byteorder='big')
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class BitField:
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''' One field in a BitFieldSet. '''
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# Special fields for BitFieldSet
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offset: int = 0
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mask: int = 0
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class Spare:
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''' Spare filling in a BitFieldSet. '''
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def __init__(self, bl: int) -> None:
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self.name = None
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self.bl = bl
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def enc_val(self, vals: dict) -> int:
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return 0
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def dec_val(self, vals: dict, blob: int) -> None:
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pass # Just ignore it
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def __init__(self, name: str, bl: int, **kw) -> None:
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if bl < 1: # Ensure proper length
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raise ProtocolError('Incorrect bit-field length')
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self.name = name
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self.bl = bl
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# (Optional) fixed value for encoding and decoding
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self.val: Optional[int] = kw.get('val', None)
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def enc_val(self, vals: dict) -> int:
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if self.val is None:
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val = vals[self.name]
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else:
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val = self.val
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return (val & self.mask) << self.offset
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def dec_val(self, vals: dict, blob: int) -> None:
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vals[self.name] = (blob >> self.offset) & self.mask
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if (self.val is not None) and (vals[self.name] != self.val):
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raise DecodeError('Unexpected value %d, expected %d'
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% (vals[self.name], self.val))
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class Envelope:
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''' A group of related fields. '''
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STRUCT: Tuple[Codec, ...] = ()
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def __init__(self, check_len: bool = True):
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# TODO: ensure uniqueue field names in self.STRUCT
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self.c: dict = { }
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self.check_len = check_len
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def __getitem__(self, key: str) -> Any:
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return self.c[key]
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def __setitem__(self, key: str, val: Any) -> None:
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self.c[key] = val
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def __delitem__(self, key: str) -> None:
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del self.c[key]
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def check(self, vals: dict) -> None:
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''' Check the content before encoding and after decoding.
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Raise exceptions (e.g. ValueError) if something is wrong.
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Do not assert for every possible error (e.g. a negative value
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for a Uint field) if an exception will be thrown by the field's
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to_bytes() method anyway. Only additional constraints here.
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'''
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def from_bytes(self, data: bytes) -> int:
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self.c.clear() # forget the old content
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return self._from_bytes(self.c, data)
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def to_bytes(self) -> bytes:
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return self._to_bytes(self.c)
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def _from_bytes(self, vals: dict, data: bytes, offset: int = 0) -> int:
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try: # Fields throw exceptions
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for f in self.STRUCT:
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offset += f.from_bytes(vals, data[offset:])
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except Exception as e:
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# Add contextual info
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raise DecodeError(self, f, offset) from e
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if self.check_len and len(data) != offset:
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raise DecodeError(self, 'Unhandled tail octets: %s'
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% data[offset:].hex())
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self.check(vals) # Check the content after decoding (raises exceptions)
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return offset
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def _to_bytes(self, vals: dict) -> bytes:
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def proc(f: Codec):
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try: # Fields throw exceptions
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return f.to_bytes(vals)
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except Exception as e:
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# Add contextual info
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raise EncodeError(self, f) from e
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self.check(vals) # Check the content before encoding (raises exceptions)
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return b''.join([proc(f) for f in self.STRUCT])
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class F(Field):
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''' Field wrapper. '''
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def __init__(self, e: 'Envelope', name: str, **kw) -> None:
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Field.__init__(self, name, **kw)
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self.e = e
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def _from_bytes(self, vals: dict, data: bytes) -> None:
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vals[self.name] = { }
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self.e._from_bytes(vals[self.name], data)
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def _to_bytes(self, vals: dict) -> bytes:
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return self.e._to_bytes(self.get_val(vals))
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def f(self, name: str, **kw) -> Field:
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return self.F(self, name, **kw)
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class Sequence:
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''' A sequence of repeating elements (e.g. TLVs). '''
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# The item of sequence
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ITEM: Optional[Envelope] = None
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def __init__(self, **kw) -> None:
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if (self.ITEM is None) and ('item' not in kw):
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raise ProtocolError('Missing Sequence item')
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self._item = kw.get('item', self.ITEM) # type: Envelope
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self._item.check_len = False
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def from_bytes(self, data: bytes) -> list:
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proc = self._item._from_bytes
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vseq, offset = [], 0
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length = len(data)
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while offset < length:
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vseq.append({ }) # new item of sequence
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offset += proc(vseq[-1], data[offset:])
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return vseq
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def to_bytes(self, vseq: list) -> bytes:
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proc = self._item._to_bytes
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return b''.join([proc(v) for v in vseq])
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class F(Field):
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''' Field wrapper. '''
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def __init__(self, s: 'Sequence', name: str, **kw) -> None:
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Field.__init__(self, name, **kw)
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self.s = s
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def _from_bytes(self, vals: dict, data: bytes) -> None:
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vals[self.name] = self.s.from_bytes(data)
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def _to_bytes(self, vals: dict) -> bytes:
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return self.s.to_bytes(self.get_val(vals))
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def f(self, name: str, **kw) -> Field:
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return self.F(self, name, **kw)
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@ -0,0 +1,592 @@
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#!/usr/bin/env python3
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# -*- coding: utf-8 -*-
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'''
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Unit tests for declarative message codec.
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'''
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# (C) 2021 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
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# Author: Vadim Yanitskiy <vyanitskiy@sysmocom.de>
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#
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# All Rights Reserved
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License along
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# with this program; if not, write to the Free Software Foundation, Inc.,
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# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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import unittest
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import struct
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import codec
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class TestField(codec.Field):
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DEF_PARAMS = { 'key' : 0xde }
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DEF_LEN = 4
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@staticmethod
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def xor(data: bytes, key: int = 0x00):
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return bytes([x ^ key for x in data])
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def _from_bytes(self, vals: dict, data: bytes) -> None:
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vals[self.name] = self.xor(data, self.p['key'])
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def _to_bytes(self, vals: dict) -> bytes:
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return self.xor(self.get_val(vals), self.p['key'])
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class Field(unittest.TestCase):
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MAGIC = b'\xde\xad\xbe\xef'
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def test_to_bytes(self):
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vals = { 'magic' : self.MAGIC, 'other' : 'unrelated' }
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encoded_de = TestField.xor(self.MAGIC, 0xde)
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encoded_88 = TestField.xor(self.MAGIC, 0x88)
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with self.subTest('default length=4, default key=0xde'):
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field = TestField('magic')
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self.assertEqual(field.to_bytes(vals), encoded_de)
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with self.subTest('different length=2, default key=0xde'):
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field = TestField('magic', len=2)
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vals['magic'] = vals['magic'][:2]
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self.assertEqual(field.to_bytes(vals), encoded_de[:2])
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with self.subTest('EncodeError due to length mismatch'):
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field = TestField('magic', len=8)
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with self.assertRaises(codec.EncodeError):
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field.to_bytes(vals)
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def test_from_bytes(self):
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encoded_de = TestField.xor(self.MAGIC, 0xde) + b'\xff' * 60
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encoded_88 = TestField.xor(self.MAGIC, 0x88) + b'\xff' * 60
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vals = { 'magic' : 'overrien', 'other' : 'unchanged' }
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with self.subTest('default length=4, default key=0xde'):
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field = TestField('magic')
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offset = field.from_bytes(vals, encoded_de)
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self.assertEqual(vals['other'], 'unchanged')
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self.assertEqual(vals['magic'], self.MAGIC)
|
||||
self.assertEqual(offset, len(self.MAGIC))
|
||||
|
||||
with self.subTest('default length=4, different key=0x88'):
|
||||
field = TestField('magic', key=0x88)
|
||||
offset = field.from_bytes(vals, encoded_88)
|
||||
self.assertEqual(vals['other'], 'unchanged')
|
||||
self.assertEqual(vals['magic'], self.MAGIC)
|
||||
self.assertEqual(offset, len(self.MAGIC))
|
||||
|
||||
with self.subTest('different length=2, default key=0xde'):
|
||||
field = TestField('magic', len=2)
|
||||
offset = field.from_bytes(vals, encoded_de)
|
||||
self.assertEqual(vals['other'], 'unchanged')
|
||||
self.assertEqual(vals['magic'], self.MAGIC[:2])
|
||||
self.assertEqual(offset, 2)
|
||||
|
||||
with self.subTest('full length, different key=0x88'):
|
||||
field = TestField('magic', len=0, key=0x88)
|
||||
offset = field.from_bytes(vals, encoded_88)
|
||||
self.assertEqual(vals['other'], 'unchanged')
|
||||
self.assertEqual(vals['magic'], self.MAGIC + b'\x77' * 60)
|
||||
self.assertEqual(offset, len(encoded_88))
|
||||
|
||||
with self.subTest('DecodeError due to short read'):
|
||||
field = TestField('magic', len=4)
|
||||
with self.assertRaises(codec.DecodeError):
|
||||
field.from_bytes(vals, b'\x00')
|
||||
|
||||
def test_get_pres(self):
|
||||
vals = { 'magic' : self.MAGIC }
|
||||
|
||||
with self.subTest('to_bytes() for a non-existing field'):
|
||||
field = TestField('not-there')
|
||||
with self.assertRaises(KeyError):
|
||||
field.to_bytes(vals)
|
||||
|
||||
with self.subTest('to_bytes() for a field with get_pres()'):
|
||||
field = TestField('magic', key=0x00)
|
||||
field.get_pres = lambda v: not v['omit']
|
||||
|
||||
data = field.to_bytes({ **vals, 'omit' : False })
|
||||
self.assertEqual(data, self.MAGIC)
|
||||
|
||||
data = field.to_bytes({ **vals, 'omit' : True })
|
||||
self.assertEqual(data, b'')
|
||||
|
||||
with self.subTest('from_bytes() for a field with get_pres()'):
|
||||
field = TestField('magic', key=0x00)
|
||||
field.get_pres = lambda v: not v['omit']
|
||||
|
||||
vals = { 'omit' : False }
|
||||
offset = field.from_bytes(vals, self.MAGIC)
|
||||
self.assertEqual(vals['magic'], self.MAGIC)
|
||||
self.assertEqual(offset, len(self.MAGIC))
|
||||
|
||||
vals = { 'omit' : True }
|
||||
offset = field.from_bytes(vals, self.MAGIC)
|
||||
self.assertFalse('magic' in vals)
|
||||
self.assertEqual(offset, 0)
|
||||
|
||||
def test_get_len(self):
|
||||
vals = { 'len' : 32, 'unrelated' : 'foo' }
|
||||
|
||||
field = TestField('magic', key=0x00)
|
||||
field.get_len = lambda v, _: v['len']
|
||||
|
||||
with self.subTest('not enough octets in the buffer: 16 < 32'):
|
||||
with self.assertRaises(codec.DecodeError):
|
||||
field.from_bytes(vals, b'\xff' * 16)
|
||||
|
||||
with self.subTest('more than enough octets in the buffer'):
|
||||
offset = field.from_bytes(vals, b'\xff' * 64)
|
||||
self.assertEqual(vals['magic'], b'\xff' * 32)
|
||||
self.assertEqual(offset, 32)
|
||||
|
||||
with self.subTest('length field does not exist'):
|
||||
with self.assertRaises(KeyError):
|
||||
field.from_bytes({ }, b'\xff' * 64)
|
||||
|
||||
def test_get_val(self):
|
||||
field = TestField('magic', key=0x00, len=0)
|
||||
field.get_val = lambda v: v.get('val', self.MAGIC)
|
||||
|
||||
with self.subTest('value is present in the dict'):
|
||||
data = field.to_bytes({ 'val' : b'\xd0\xde' })
|
||||
self.assertEqual(data, b'\xd0\xde')
|
||||
|
||||
with self.subTest('value is not present in the dict'):
|
||||
data = field.to_bytes({ })
|
||||
self.assertEqual(data, self.MAGIC)
|
||||
|
||||
class Buf(unittest.TestCase):
|
||||
MAGIC = b'\xde\xad' * 4
|
||||
|
||||
def test_to_bytes(self):
|
||||
vals = { 'buf' : self.MAGIC }
|
||||
|
||||
with self.subTest('with no length constraints'):
|
||||
field = codec.Buf('buf') # default: len=0
|
||||
self.assertEqual(field.to_bytes(vals), self.MAGIC)
|
||||
|
||||
with self.subTest('with length constraints'):
|
||||
field = codec.Buf('buf', len=len(self.MAGIC))
|
||||
self.assertEqual(field.to_bytes(vals), self.MAGIC)
|
||||
|
||||
with self.subTest('EncodeError due to length mismatch'):
|
||||
field = codec.Buf('buf', len=4)
|
||||
with self.assertRaises(codec.EncodeError):
|
||||
field.to_bytes(vals)
|
||||
|
||||
def test_from_bytes(self):
|
||||
vals = { }
|
||||
|
||||
with self.subTest('with no length constraints'):
|
||||
field = codec.Buf('buf') # default: len=0
|
||||
offset = field.from_bytes(vals, self.MAGIC)
|
||||
self.assertEqual(vals['buf'], self.MAGIC)
|
||||
self.assertEqual(offset, len(self.MAGIC))
|
||||
|
||||
with self.subTest('with length constraints'):
|
||||
field = codec.Buf('buf', len=2)
|
||||
offset = field.from_bytes(vals, self.MAGIC)
|
||||
self.assertEqual(vals['buf'], self.MAGIC[:2])
|
||||
self.assertEqual(offset, len(self.MAGIC[:2]))
|
||||
|
||||
with self.subTest('DecodeError due to not enough bytes'):
|
||||
field = codec.Buf('buf', len=64)
|
||||
with self.assertRaises(codec.DecodeError):
|
||||
field.from_bytes(vals, self.MAGIC)
|
||||
|
||||
class Spare(unittest.TestCase):
|
||||
# Fixed length with custom filler
|
||||
SAA = codec.Spare('pad', len=4, filler=b'\xaa')
|
||||
# Auto-calculated length with custom filler
|
||||
SFF = codec.Spare('pad', filler=b'\xff')
|
||||
SFF.get_len = lambda v, _: v['len']
|
||||
# Fixed length with default filler
|
||||
S00 = codec.Spare('pad', len=2)
|
||||
|
||||
def test_to_bytes(self):
|
||||
self.assertEqual(self.SFF.to_bytes({ 'len' : 8 }), b'\xff' * 8)
|
||||
self.assertEqual(self.SAA.to_bytes({ }), b'\xaa' * 4)
|
||||
self.assertEqual(self.S00.to_bytes({ }), b'\x00' * 2)
|
||||
|
||||
def test_from_bytes(self):
|
||||
with self.assertRaises(codec.DecodeError):
|
||||
self.S00.from_bytes({ }, b'\x00') # Short read
|
||||
self.assertEqual(self.SFF.from_bytes({ 'len' : 8 }, b'\xff' * 8), 8)
|
||||
self.assertEqual(self.SAA.from_bytes({ }, b'\xaa' * 64), 4)
|
||||
self.assertEqual(self.S00.from_bytes({ }, b'\x00' * 64), 2)
|
||||
|
||||
class Uint(unittest.TestCase):
|
||||
def _test_uint(self, field, fmt, vals):
|
||||
for i in vals:
|
||||
with self.subTest('to_bytes()'):
|
||||
val = field.to_bytes({ field.name : i })
|
||||
self.assertEqual(val, struct.pack(fmt, i))
|
||||
|
||||
with self.subTest('from_bytes()'):
|
||||
data, parsed = struct.pack(fmt, i), { }
|
||||
offset = field.from_bytes(parsed, data)
|
||||
self.assertEqual(offset, len(data))
|
||||
self.assertEqual(parsed[field.name], i)
|
||||
|
||||
def test_uint8(self):
|
||||
self._test_uint(codec.Uint('foo'), 'B', range(2 ** 8))
|
||||
|
||||
def test_int8(self):
|
||||
self._test_uint(codec.Int('foo'), 'b', range(-128, 128))
|
||||
|
||||
def test_uint16(self):
|
||||
vals = (0, 65, 128, 255, 512, 1023, 2 ** 16 - 1)
|
||||
self._test_uint(codec.Uint16BE('foo'), '>H', vals)
|
||||
self._test_uint(codec.Uint16LE('foo'), '<H', vals)
|
||||
|
||||
def test_int16(self):
|
||||
vals = (-32767, -16384, 0, 16384, 32767)
|
||||
self._test_uint(codec.Int16BE('foo'), '>h', vals)
|
||||
self._test_uint(codec.Int16LE('foo'), '<h', vals)
|
||||
|
||||
def test_uint32(self):
|
||||
vals = (0, 33, 255, 1024, 1337, 4099, 2 ** 32 - 1)
|
||||
self._test_uint(codec.Uint32BE('foo'), '>I', vals)
|
||||
self._test_uint(codec.Uint32LE('foo'), '<I', vals)
|
||||
|
||||
def test_int32(self):
|
||||
vals = (-2147483647, 0, 2147483647)
|
||||
self._test_uint(codec.Int32BE('foo'), '>i', vals)
|
||||
self._test_uint(codec.Int32LE('foo'), '<i', vals)
|
||||
|
||||
def test_offset_mult(self):
|
||||
with self.subTest('encode / decode with offset=5'):
|
||||
field = codec.Uint('foo', offset=5)
|
||||
|
||||
self.assertEqual(field.to_bytes({ 'foo' : 10 }), b'\x05')
|
||||
self.assertEqual(field.to_bytes({ 'foo' : 5 }), b'\x00')
|
||||
|
||||
vals = { 'foo' : 'overriden' }
|
||||
field.from_bytes(vals, b'\xff')
|
||||
self.assertEqual(vals['foo'], 260)
|
||||
field.from_bytes(vals, b'\x00')
|
||||
self.assertEqual(vals['foo'], 5)
|
||||
|
||||
with self.subTest('encode / decode with mult=2'):
|
||||
field = codec.Uint('foo', mult=2)
|
||||
|
||||
self.assertEqual(field.to_bytes({ 'foo' : 0 }), b'\x00')
|
||||
self.assertEqual(field.to_bytes({ 'foo' : 3 }), b'\x01')
|
||||
self.assertEqual(field.to_bytes({ 'foo' : 32 }), b'\x10')
|
||||
self.assertEqual(field.to_bytes({ 'foo' : 64 }), b'\x20')
|
||||
|
||||
vals = { 'foo' : 'overriden' }
|
||||
field.from_bytes(vals, b'\x00')
|
||||
self.assertEqual(vals['foo'], 0 * 2)
|
||||
field.from_bytes(vals, b'\x0f')
|
||||
self.assertEqual(vals['foo'], 15 * 2)
|
||||
field.from_bytes(vals, b'\xff')
|
||||
self.assertEqual(vals['foo'], 255 * 2)
|
||||
|
||||
class BitFieldSet(unittest.TestCase):
|
||||
S16 = codec.BitFieldSet(set=(
|
||||
codec.BitField('f4a', bl=4),
|
||||
codec.BitField('f8', bl=8),
|
||||
codec.BitField('f4b', bl=4),
|
||||
))
|
||||
|
||||
S8M = codec.BitFieldSet(order='msb', set=(
|
||||
codec.BitField('f4', bl=4),
|
||||
codec.BitField('f1', bl=1),
|
||||
codec.BitField('f3', bl=3),
|
||||
))
|
||||
|
||||
S8L = codec.BitFieldSet(order='lsb', set=(
|
||||
codec.BitField('f4', bl=4),
|
||||
codec.BitField('f1', bl=1),
|
||||
codec.BitField('f3', bl=3),
|
||||
))
|
||||
|
||||
S8V = codec.BitFieldSet(set=(
|
||||
codec.BitField('f4', bl=4, val=2),
|
||||
codec.BitField('f1', bl=1, val=0),
|
||||
codec.BitField('f3', bl=3),
|
||||
))
|
||||
|
||||
S8P = codec.BitFieldSet(set=(
|
||||
codec.BitField.Spare(bl=4),
|
||||
codec.BitField('f4', bl=4),
|
||||
))
|
||||
|
||||
@staticmethod
|
||||
def from_bytes(s: codec.BitFieldSet, data: bytes) -> dict:
|
||||
vals = { }
|
||||
s.from_bytes(vals, data)
|
||||
return vals
|
||||
|
||||
def test_len_auto(self):
|
||||
with self.subTest('1 + 2 = 3 bits => 1 octet (with padding)'):
|
||||
s = codec.BitFieldSet(set=(
|
||||
codec.BitField('f1', bl=1),
|
||||
codec.BitField('f2', bl=2),
|
||||
))
|
||||
self.assertEqual(s.len, 1)
|
||||
|
||||
with self.subTest('4 + 2 + 2 = 8 bits => 1 octet'):
|
||||
s = codec.BitFieldSet(set=(
|
||||
codec.BitField('f4', bl=4),
|
||||
codec.BitField('f2a', bl=2),
|
||||
codec.BitField('f2b', bl=2),
|
||||
))
|
||||
self.assertEqual(s.len, 1)
|
||||
|
||||
with self.subTest('12 + 4 + 2 = 18 bits => 3 octets (with padding)'):
|
||||
s = codec.BitFieldSet(set=(
|
||||
codec.BitField('f12', bl=12),
|
||||
codec.BitField('f4', bl=4),
|
||||
codec.BitField('f2', bl=2),
|
||||
))
|
||||
self.assertEqual(s.len, 3)
|
||||
|
||||
def test_overflow(self):
|
||||
with self.assertRaises(codec.ProtocolError):
|
||||
s = codec.BitFieldSet(len=1, set=(
|
||||
codec.BitField('f6', bl=6),
|
||||
codec.BitField('f4', bl=4),
|
||||
))
|
||||
|
||||
def test_offset_mask(self):
|
||||
calc = lambda s: [(f.name, f.offset, f.mask) for f in s._fields]
|
||||
|
||||
with self.subTest('16 bit total (MSB): f4a + f8 + f4b'):
|
||||
om = [('f4a', 8 + 4, 0x0f), ('f8', 4, 0xff), ('f4b', 0, 0x0f)]
|
||||
self.assertEqual(len(self.S16._fields), 3)
|
||||
self.assertEqual(calc(self.S16), om)
|
||||
|
||||
with self.subTest('8 bit total (MSB): f4 + f1 + f3'):
|
||||
om = [('f4', 1 + 3, 0x0f), ('f1', 3, 0x01), ('f3', 0, 0x07)]
|
||||
self.assertEqual(len(self.S8M._fields), 3)
|
||||
self.assertEqual(calc(self.S8M), om)
|
||||
|
||||
with self.subTest('8 bit total (LSB): f4 + f1 + f3'):
|
||||
om = [('f3', 1 + 4, 0x07), ('f1', 4, 0x01), ('f4', 0, 0x0f)]
|
||||
self.assertEqual(len(self.S8L._fields), 3)
|
||||
self.assertEqual(calc(self.S8L), om)
|
||||
|
||||
with self.subTest('8 bit total (LSB): s4 + f4'):
|
||||
om = [(None, 4, 0x0f), ('f4', 0, 0x0f)]
|
||||
self.assertEqual(len(self.S8P._fields), 2)
|
||||
self.assertEqual(calc(self.S8P), om)
|
||||
|
||||
def test_to_bytes(self):
|
||||
with self.subTest('16 bit total (MSB): f4a + f8 + f4b'):
|
||||
vals = { 'f4a' : 0x0f, 'f8' : 0xff, 'f4b' : 0x0f }
|
||||
self.assertEqual(self.S16.to_bytes(vals), b'\xff\xff')
|
||||
vals = { 'f4a' : 0x00, 'f8' : 0x00, 'f4b' : 0x00 }
|
||||
self.assertEqual(self.S16.to_bytes(vals), b'\x00\x00')
|
||||
vals = { 'f4a' : 0x0f, 'f8' : 0x00, 'f4b' : 0x0f }
|
||||
self.assertEqual(self.S16.to_bytes(vals), b'\xf0\x0f')
|
||||
vals = { 'f4a' : 0x00, 'f8' : 0xff, 'f4b' : 0x00 }
|
||||
self.assertEqual(self.S16.to_bytes(vals), b'\x0f\xf0')
|
||||
|
||||
with self.subTest('8 bit total (MSB): f4 + f1 + f3'):
|
||||
vals = { 'f4' : 0x0f, 'f1' : 0x01, 'f3' : 0x07 }
|
||||
self.assertEqual(self.S8M.to_bytes(vals), b'\xff')
|
||||
vals = { 'f4' : 0x00, 'f1' : 0x00, 'f3' : 0x00 }
|
||||
self.assertEqual(self.S8M.to_bytes(vals), b'\x00')
|
||||
vals = { 'f4' : 0x0f, 'f1' : 0x00, 'f3' : 0x00 }
|
||||
self.assertEqual(self.S8M.to_bytes(vals), b'\xf0')
|
||||
|
||||
with self.subTest('8 bit total (LSB): f4 + f1 + f3'):
|
||||
vals = { 'f4' : 0x0f, 'f1' : 0x01, 'f3' : 0x07 }
|
||||
self.assertEqual(self.S8L.to_bytes(vals), b'\xff')
|
||||
vals = { 'f4' : 0x00, 'f1' : 0x00, 'f3' : 0x00 }
|
||||
self.assertEqual(self.S8L.to_bytes(vals), b'\x00')
|
||||
vals = { 'f4' : 0x0f, 'f1' : 0x00, 'f3' : 0x00 }
|
||||
self.assertEqual(self.S8L.to_bytes(vals), b'\x0f')
|
||||
|
||||
def test_from_bytes(self):
|
||||
pad = b'\xff' * 64
|
||||
|
||||
with self.subTest('16 bit total (MSB): f4a + f8 + f4b'):
|
||||
vals = { 'f4a' : 0x0f, 'f8' : 0xff, 'f4b' : 0x0f }
|
||||
self.assertEqual(self.from_bytes(self.S16, b'\xff\xff' + pad), vals)
|
||||
vals = { 'f4a' : 0x00, 'f8' : 0x00, 'f4b' : 0x00 }
|
||||
self.assertEqual(self.from_bytes(self.S16, b'\x00\x00' + pad), vals)
|
||||
vals = { 'f4a' : 0x0f, 'f8' : 0x00, 'f4b' : 0x0f }
|
||||
self.assertEqual(self.from_bytes(self.S16, b'\xf0\x0f' + pad), vals)
|
||||
vals = { 'f4a' : 0x00, 'f8' : 0xff, 'f4b' : 0x00 }
|
||||
self.assertEqual(self.from_bytes(self.S16, b'\x0f\xf0' + pad), vals)
|
||||
|
||||
with self.subTest('8 bit total (MSB): f4 + f1 + f3'):
|
||||
vals = { 'f4' : 0x0f, 'f1' : 0x01, 'f3' : 0x07 }
|
||||
self.assertEqual(self.from_bytes(self.S8M, b'\xff' + pad), vals)
|
||||
vals = { 'f4' : 0x00, 'f1' : 0x00, 'f3' : 0x00 }
|
||||
self.assertEqual(self.from_bytes(self.S8M, b'\x00' + pad), vals)
|
||||
vals = { 'f4' : 0x0f, 'f1' : 0x00, 'f3' : 0x00 }
|
||||
self.assertEqual(self.from_bytes(self.S8M, b'\xf0' + pad), vals)
|
||||
|
||||
with self.subTest('8 bit total (LSB): f4 + f1 + f3'):
|
||||
vals = { 'f4' : 0x0f, 'f1' : 0x01, 'f3' : 0x07 }
|
||||
self.assertEqual(self.from_bytes(self.S8L, b'\xff' + pad), vals)
|
||||
vals = { 'f4' : 0x00, 'f1' : 0x00, 'f3' : 0x00 }
|
||||
self.assertEqual(self.from_bytes(self.S8L, b'\x00' + pad), vals)
|
||||
vals = { 'f4' : 0x0f, 'f1' : 0x00, 'f3' : 0x00 }
|
||||
self.assertEqual(self.from_bytes(self.S8L, b'\x0f' + pad), vals)
|
||||
|
||||
def test_to_bytes_val(self):
|
||||
with self.subTest('fixed values in absence of user-supplied values'):
|
||||
vals = { 'f3' : 0x00 } # | { 'f4' : 2, 'f1' : 0 }
|
||||
self.assertEqual(self.S8V.to_bytes(vals), b'\x20')
|
||||
|
||||
with self.subTest('fixed values take precedence'):
|
||||
vals = { 'f4' : 1, 'f1' : 1, 'f3' : 0 }
|
||||
self.assertEqual(self.S8V.to_bytes(vals), b'\x20')
|
||||
|
||||
def test_from_bytes_val(self):
|
||||
with self.assertRaises(codec.DecodeError):
|
||||
self.S8V.from_bytes({ }, b'\xf0') # 'f4': 15 vs 2
|
||||
|
||||
with self.assertRaises(codec.DecodeError):
|
||||
self.S8V.from_bytes({ }, b'\x08') # 'f1': 1 vs 0
|
||||
|
||||
# Field 'f3' takes any value, no exceptions shall be raised
|
||||
for i in range(8):
|
||||
data, vals = bytes([0x20 + i]), { 'f4' : 2, 'f1' : 0, 'f3' : i }
|
||||
self.assertEqual(self.from_bytes(self.S8V, data), vals)
|
||||
|
||||
def test_to_bytes_spare(self):
|
||||
self.assertEqual(self.S8P.to_bytes({ 'f4' : 0x00 }), b'\x00')
|
||||
self.assertEqual(self.S8P.to_bytes({ 'f4' : 0x0f }), b'\x0f')
|
||||
self.assertEqual(self.S8P.to_bytes({ 'f4' : 0xff }), b'\x0f')
|
||||
|
||||
def test_from_bytes_spare(self):
|
||||
self.assertEqual(self.from_bytes(self.S8P, b'\x00'), { 'f4' : 0x00 })
|
||||
self.assertEqual(self.from_bytes(self.S8P, b'\x0f'), { 'f4' : 0x0f })
|
||||
self.assertEqual(self.from_bytes(self.S8P, b'\xff'), { 'f4' : 0x0f })
|
||||
|
||||
class TestPDU(codec.Envelope):
|
||||
STRUCT = (
|
||||
codec.BitFieldSet(len=2, set=(
|
||||
codec.BitField('ver', bl=4),
|
||||
codec.BitField('flag', bl=1),
|
||||
)),
|
||||
codec.Uint16BE('len'),
|
||||
codec.Buf('data'),
|
||||
codec.Buf('tail', len=2),
|
||||
)
|
||||
|
||||
def __init__(self, *args, **kw):
|
||||
codec.Envelope.__init__(self, *args, **kw)
|
||||
self.STRUCT[-3].get_val = lambda v: len(v['data'])
|
||||
self.STRUCT[-2].get_len = lambda v, _: v['len']
|
||||
self.STRUCT[-1].get_pres = lambda v: bool(v['flag'])
|
||||
|
||||
def check(self, vals: dict) -> None:
|
||||
if not vals['ver'] in (0, 1, 2):
|
||||
raise ValueError('Unknown version %d' % vals['ver'])
|
||||
|
||||
class Envelope(unittest.TestCase):
|
||||
def test_rest_octets(self):
|
||||
pdu = TestPDU(check_len=False)
|
||||
pdu.from_bytes(b'\x00' * 64)
|
||||
|
||||
with self.assertRaises(codec.DecodeError):
|
||||
pdu = TestPDU(check_len=True)
|
||||
pdu.from_bytes(b'\x00' * 64) # 'len' : 0
|
||||
|
||||
def test_field_raises(self):
|
||||
pdu = TestPDU()
|
||||
with self.assertRaises(codec.EncodeError):
|
||||
pdu.c = { 'ver' : 0, 'flag' : 1, 'data' : b'\xff' * 16 }
|
||||
pdu.to_bytes() # KeyError: 'tail' not found
|
||||
|
||||
def test_to_bytes(self):
|
||||
pdu = TestPDU()
|
||||
|
||||
# No content in the new instances
|
||||
self.assertEqual(pdu.c, { })
|
||||
|
||||
pdu.c = { 'ver' : 0, 'flag' : 1, 'data' : b'', 'tail' : b'\xde\xbe' }
|
||||
self.assertEqual(pdu.to_bytes(), b'\x08\x00\x00\x00' + b'\xde\xbe')
|
||||
|
||||
pdu.c = { 'ver' : 1, 'flag' : 0, 'data' : b'\xff' * 15 }
|
||||
self.assertEqual(pdu.to_bytes(), b'\x10\x00\x00\x0f' + b'\xff' * 15)
|
||||
|
||||
pdu.c = { 'ver' : 2, 'flag' : 1, 'data' : b'\xf0', 'tail' : b'\xbe\xed' }
|
||||
self.assertEqual(pdu.to_bytes(), b'\x28\x00\x00\x01\xf0\xbe\xed')
|
||||
|
||||
def test_from_bytes(self):
|
||||
pdu = TestPDU()
|
||||
|
||||
# No content in the new instances
|
||||
self.assertEqual(pdu.c, { })
|
||||
|
||||
c = { 'ver' : 0, 'flag' : 1, 'len' : 0, 'data' : b'', 'tail' : b'\xde\xbe' }
|
||||
pdu.from_bytes(b'\x08\x00\x00\x00' + b'\xde\xbe')
|
||||
self.assertEqual(pdu.c, c)
|
||||
|
||||
c = { 'ver' : 1, 'flag' : 0, 'len' : 15, 'data' : b'\xff' * 15 }
|
||||
pdu.from_bytes(b'\x10\x00\x00\x0f' + b'\xff' * 15)
|
||||
self.assertEqual(pdu.c, c)
|
||||
|
||||
c = { 'ver' : 2, 'flag' : 1, 'len' : 1, 'data' : b'\xf0', 'tail' : b'\xbe\xed' }
|
||||
pdu.from_bytes(b'\x28\x00\x00\x01\xf0\xbe\xed')
|
||||
self.assertEqual(pdu.c, c)
|
||||
|
||||
def test_to_bytes_check(self):
|
||||
pdu = TestPDU()
|
||||
|
||||
pdu.c = { 'ver' : 8, 'flag' : 1, 'data' : b'', 'tail' : b'\xde\xbe' }
|
||||
with self.assertRaises(ValueError):
|
||||
pdu.to_bytes()
|
||||
|
||||
def test_from_bytes_check(self):
|
||||
pdu = TestPDU()
|
||||
|
||||
with self.assertRaises(ValueError):
|
||||
pdu.from_bytes(b'\xf0\x00\x00\x00')
|
||||
|
||||
class Sequence(unittest.TestCase):
|
||||
class TLV(codec.Envelope):
|
||||
STRUCT = (
|
||||
codec.Uint('T'),
|
||||
codec.Uint('L'),
|
||||
codec.Buf('V'),
|
||||
)
|
||||
|
||||
def __init__(self, *args, **kw) -> None:
|
||||
codec.Envelope.__init__(self, *args, **kw)
|
||||
self.STRUCT[-2].get_val = lambda v: len(v['V'])
|
||||
self.STRUCT[-1].get_len = lambda v, _: v['L']
|
||||
|
||||
# Sequence of TLVs
|
||||
SEQ = codec.Sequence(item=TLV())
|
||||
|
||||
Vseq, Bseq = [
|
||||
{ 'T' : 0xde, 'L' : 4, 'V' : b'\xde\xad\xbe\xef' },
|
||||
{ 'T' : 0xbe, 'L' : 2, 'V' : b'\xbe\xef' },
|
||||
{ 'T' : 0xbe, 'L' : 2, 'V' : b'\xef\xbe' },
|
||||
{ 'T' : 0x00, 'L' : 0, 'V' : b'' },
|
||||
], b''.join([
|
||||
b'\xde\x04\xde\xad\xbe\xef',
|
||||
b'\xbe\x02\xbe\xef',
|
||||
b'\xbe\x02\xef\xbe',
|
||||
b'\x00\x00',
|
||||
])
|
||||
|
||||
def test_to_bytes(self):
|
||||
res = self.SEQ.to_bytes(self.Vseq)
|
||||
self.assertEqual(res, self.Bseq)
|
||||
|
||||
def test_from_bytes(self):
|
||||
res = self.SEQ.from_bytes(self.Bseq)
|
||||
self.assertEqual(res, self.Vseq)
|
||||
|
||||
if __name__ == '__main__':
|
||||
unittest.main()
|
Loading…
Reference in New Issue