Checksum Types

CRC — Cyclic Redundancy Check

A CRC calculates a crc over the data in its hierarchical level, e.g. the oser.ByteStruct it is located in.

The user can control automatic calculation and checks by setting crc._automatic_calculation to False at runtime.

CRCL8

8-bit crc little endian.

class oser.CRCL8(strict: bool = False, polynomial: int = 213, reflect_input: bool = False, reflect_output: bool = False, initial_value: int = 0, xor_output: int = 0, automatic_calculation: bool = True, format: str = 'hex')

8-bit crc little endian serializer.

Parameters:

  • strict – bool = False: If set to True crc is checked when decoding data. An exception is raised if crcs do not match.

  • polynomial – int = 0xd5: the crc polynomial

  • reflect_input – bool = False: reflect input data

  • reflect_output – bool = False: reflect output data

  • initial_value – int = 0x00: start with initial_value

  • xor_output – int = 0x00: xor output data with xor_output

  • automatic_calculation – bool = True: if set to True crc is automatically calculated when encoding data

  • format – str = “hex” (string): Use “hex” to format values to hexadecimal. Use “bin” to format values to binary. Use None for decimal format.

decode(data: bytes, full_data: bytes = b'', context_data: bytes = b'') → int

Decode a binary string into a byte type and return the number of bytes that were decoded.

Parameters:

  • data (bytes) – the data buffer that is decoded.

  • full_data (bytes) – the binary data string until the part to be decoded. The user normally does not need to supply this.

  • context_data (bytes) – the binary data of the current context. The user normally does not need to supply this.

Returns:

the number of bytes that were decoded.

Return type:

int

encode(full_data: bytes = b'', context_data: bytes = b'') → bytes

Return the encoded byte type as a binary string.

Parameters:

  • full_data (bytes) – the binary data string until the part to be encoded. The user normally does not need to supply this.

  • context_data (bytes) – the binary data of the current context. The user normally does not need to supply this.

get() → int

Return the value.

Returns:

the value.

get_byte_size() → int

Return the length of the byte type in bytes.

Returns:

the length of the byte type in bytes.

Return type:

int

get_size() → int

Return the length of the byte type in bytes.

Returns:

the length of the byte type in bytes.

Return type:

int

introspect(stop_at: ByteStruct | BitStruct | ByteType | BitType | None = None) → str

Return the introspection representation of the object as a string.

Parameters:

stop_at=None (object) – stop introspection at stop_at.

root() → ByteStruct | BitStruct

return root element

set(value: int) → None

Set the value.

Parameters:

value – the new value

set_automatic_calculation(enabled: bool = True) → None

Enable or disable automatic calculation when encode is called.

Parameters:

enabled=True (bool) – the new enabled state.

set_fuzzing_values(values: Generator[Any, None, None] | List[Any] | None) → None

Set fuzzing values.

Parameters:

values (iterable) – the values used for fuzzing.

up() → ByteStruct | BitStruct

Return the parent element.

Usage:

>>> from oser import ByteStruct, UBInt16, CRCL8, to_hex

>>> class Data(ByteStruct):
...         def __init__(self):
...             super(Data, self).__init__()
...
...             self.a = ULInt16(1)
...             self.b = ULInt16(2)
...
...             self.crc = CRCL8(strict=True)
...
>>> instance = Data()
>>> print(instance)
Data():
    a: 1 (ULInt16)
    b: 2 (ULInt16)
    crc: 0 (CRCL8)

>>> print(instance.introspect())
   -    -  Data():
   0 \x01      a: 1 (ULInt16)
   1 \x00
   2 \x02      b: 2 (ULInt16)
   3 \x00
   4 \x00      crc: 0 (CRCL8)

>>> binary = instance.encode()
>>> print(to_hex(binary))
   0|  1|  2|  3|  4
\x01\x00\x02\x00\x53
>>> bytes_decoded = instance.decode(binary)
>>> print(bytes_decoded)
5
>>> print(instance)
Data():
    a: 1 (ULInt16)
    b: 2 (ULInt16)
    crc: 83 (CRCL8)

>>> print(instance.introspect())
   -    -  Data():
   0 \x01      a: 1 (ULInt16)
   1 \x00
   2 \x02      b: 2 (ULInt16)
   3 \x00
   4 \x53      crc: 83 (CRCL8)


>>> bytes_decoded = instance.decode(b"\x01\x00\x02\x00\x53")
>>> print(bytes_decoded)
5
>>> print(instance)
Data():
    a: 1 (ULInt16)
    b: 2 (ULInt16)
    crc: 83 (CRCL8)

>>> print(instance.introspect())
   -    -  Data():
   0 \x01      a: 1 (ULInt16)
   1 \x00
   2 \x02      b: 2 (ULInt16)
   3 \x00
   4 \x53      crc: 83 (CRCL8)


>>> bytes_decoded = instance.decode(b"\x01\x00\x02\x00\x00")  # corrupted crc
oser.ChecksumMismatchException: Data could not be decoded!
Parsing object is:
   -    -  Data():
   0 \x01      a: 1 (ULInt16)
   1 \x00
   2 \x02      b: 2 (ULInt16)
   3 \x00
   4 \x00      crc: 0 (CRCL8)
     ^^^^ Checksum mismatch: expected \x53 but found \x00

CRCB8

8-bit crc big endian.

class oser.CRCB8(strict: bool = False, polynomial: int = 213, reflect_input: bool = False, reflect_output: bool = False, initial_value: int = 0, xor_output: int = 0, automatic_calculation: bool = True, format: str = 'hex')

8-bit crc big endian serializer.

Parameters:

  • strict – bool = False: If set to True crc is checked when decoding data. An exception is raised if crcs do not match.

  • polynomial – int = 0xd5: the crc polynomial

  • reflect_input – bool = False: reflect input data

  • reflect_output – bool = False: reflect output data

  • initial_value – int = 0x00: start with initial_value

  • xor_output – int = 0x00: xor output data with xor_output

  • automatic_calculation – bool = True: if set to True crc is automatically calculated when encoding data

  • format – str = “hex” (string): Use “hex” to format values to hexadecimal. Use “bin” to format values to binary. Use None for decimal format.

decode(data: bytes, full_data: bytes = b'', context_data: bytes = b'') → int

Decode a binary string into a byte type and return the number of bytes that were decoded.

Parameters:

  • data (bytes) – the data buffer that is decoded.

  • full_data (bytes) – the binary data string until the part to be decoded. The user normally does not need to supply this.

  • context_data (bytes) – the binary data of the current context. The user normally does not need to supply this.

encode(full_data: bytes = b'', context_data: bytes = b'') → bytes

Return the encoded binary string.

Parameters:

  • full_data (bytes) – the binary data string until the part to be encoded. The user normally does not need to supply this.

  • context_data (bytes) – the binary data of the current context. The user normally does not need to supply this.

Returns:

the encoded binary string.

Return type:

bytes

get() → int

Return the value.

Returns:

the value.

get_byte_size() → int

Return the length of the byte type in bytes.

Returns:

the length of the byte type in bytes.

Return type:

int

get_size() → int

Return the length of the byte type in bytes.

Returns:

the length of the byte type in bytes.

Return type:

int

introspect(stop_at: ByteStruct | BitStruct | ByteType | BitType | None = None) → str

Return the introspection representation of the object as a string.

Parameters:

stop_at=None (object) – stop introspection at stop_at.

root() → ByteStruct | BitStruct

return root element

set(value: int) → None

Set the value.

Parameters:

value – the new value

set_automatic_calculation(enabled: bool = True) → None

Enable or disable automatic calculation when encode is called.

Parameters:

enabled=True (bool) – the new enabled state.

set_fuzzing_values(values: Generator[Any, None, None] | List[Any] | None) → None

Set fuzzing values.

Parameters:

values (iterable) – the values used for fuzzing.

up() → ByteStruct | BitStruct

Return the parent element.

Usage:

>>> from oser import ByteStruct, UBInt16, CRCB8, to_hex

>>> class Data(ByteStruct):
...         def __init__(self):
...             super(Data, self).__init__()
...
...             self.a = UBInt16(1)
...             self.b = UBInt16(2)
...
...             self.crc = CRCB8(strict=True)
...
>>> instance = Data()
>>> print(instance)
Data():
    a: 1 (UBInt16)
    b: 2 (UBInt16)
    crc: 0 (CRCB8)

>>> print(instance.introspect())
   -    -  Data():
   0 \x00      a: 1 (UBInt16)
   1 \x01
   2 \x00      b: 2 (UBInt16)
   3 \x02
   4 \x00      crc: 0 (CRCB8)

>>> binary = instance.encode()
>>> print(to_hex(binary))
   0|  1|  2|  3|  4
\x00\x01\x00\x02\xFC
>>> bytes_decoded = instance.decode(binary)
>>> print(bytes_decoded)
5
>>> print(instance)
Data():
    a: 1 (UBInt16)
    b: 2 (UBInt16)
    crc: 252 (CRCB8)

>>> print(instance.introspect())
   -    -  Data():
   0 \x00      a: 1 (UBInt16)
   1 \x01
   2 \x00      b: 2 (UBInt16)
   3 \x02
   4 \xfc      crc: 252 (CRCB8)


>>> bytes_decoded = instance.decode(b"\x00\x01\x00\x02\xFC")
>>> print(bytes_decoded)
5
>>> print(instance)
Data():
    a: 1 (UBInt16)
    b: 2 (UBInt16)
    crc: 252 (CRCB8)

>>> print(instance.introspect())
   -    -  Data():
   0 \x00      a: 1 (UBInt16)
   1 \x01
   2 \x00      b: 2 (UBInt16)
   3 \x02
   4 \xfc      crc: 252 (CRCB8)


>>> bytes_decoded = instance.decode(b"\x00\x01\x00\x02\x00")  # corrupted crc
oser.ChecksumMismatchException: Data could not be decoded!
Parsing object is:
   -    -  Data():
   0 \x00      a: 1 (UBInt16)
   1 \x01
   2 \x00      b: 2 (UBInt16)
   3 \x02
   4 \x00      crc: 0 (CRCB8)
     ^^^^ Checksum mismatch: expected \xfc but found \x00

CRCL16

16-bit crc little endian.

class oser.CRCL16(strict: bool = False, polynomial: int = 41003, reflect_input: bool = False, reflect_output: bool = False, initial_value: int = 0, xor_output: int = 0, automatic_calculation: bool = True, format: str = 'hex')

16-bit crc little endian serializer.

Parameters:

  • strict – bool = False: If set to True crc is checked when decoding data. An exception is raised if crcs do not match.

  • polynomial – int = 0xa02b: the crc polynomial

  • reflect_input – bool = False: reflect input data

  • reflect_output – bool = False: reflect output data

  • initial_value – int = 0x0000: start with initial_value

  • xor_output – int = 0x0000: xor output data with xor_output

  • automatic_calculation – bool = True: if set to True crc is automatically calculated when encoding data

  • format – str = “hex” (string): Use “hex” to format values to hexadecimal. Use “bin” to format values to binary. Use None for decimal format.

decode(data: bytes, full_data: bytes = b'', context_data: bytes = b'') → int

Decode a binary string into a byte type and return the number of bytes that were decoded.

Parameters:

  • data (bytes) – the data buffer that is decoded.

  • full_data (bytes) – the binary data string until the part to be decoded. The user normally does not need to supply this.

  • context_data (bytes) – the binary data of the current context. The user normally does not need to supply this.

Returns:

the number of bytes that were decoded.

Return type:

int

encode(full_data: bytes = b'', context_data: bytes = b'') → bytes

Return the encoded binary string.

Parameters:

  • full_data (bytes) – the binary data string until the part to be encoded. The user normally does not need to supply this.

  • context_data (bytes) – the binary data of the current context. The user normally does not need to supply this.

Returns:

the encoded binary string.

Return type:

bytes

get() → int

Return the value.

Returns:

the value.

get_byte_size() → int

Return the length of the byte type in bytes.

Returns:

the length of the byte type in bytes.

Return type:

int

get_size() → int

Return the length of the byte type in bytes.

Returns:

the length of the byte type in bytes.

Return type:

int

introspect(stop_at: ByteStruct | BitStruct | ByteType | BitType | None = None) → str

Return the introspection representation of the object as a string.

Parameters:

stop_at=None (object) – stop introspection at stop_at.

root() → ByteStruct | BitStruct

return root element

set(value: int) → None

Set the value.

Parameters:

value – the new value

set_automatic_calculation(enabled: bool = True) → None

Enable or disable automatic calculation when encode is called.

Parameters:

enabled=True (bool) – the new enabled state.

set_fuzzing_values(values: Generator[Any, None, None] | List[Any] | None) → None

Set fuzzing values.

Parameters:

values (iterable) – the values used for fuzzing.

up() → ByteStruct | BitStruct

Return the parent element.

Usage:

>>> from oser import ByteStruct, UBInt16, CRCL16, to_hex

>>> class Data(ByteStruct):
...         def __init__(self):
...             super(Data, self).__init__()
...
...             self.a = ULInt16(1)
...             self.b = ULInt16(2)
...
...             self.crc = CRCL16(strict=True)
...
>>> instance = Data()
>>> print(instance)
Data():
    a: 1 (ULInt16)
    b: 2 (ULInt16)
    crc: 0 (CRCL16)

>>> print(instance.introspect())
   -    -  Data():
   0 \x01      a: 1 (ULInt16)
   1 \x00
   2 \x02      b: 2 (ULInt16)
   3 \x00
   4 \x00      crc: 0 (CRCL16)
   5 \x00

>>> binary = instance.encode()
>>> print(to_hex(binary))
   0|  1|  2|  3|  4|  5
\x01\x00\x02\x00\xFC\xC3
>>> bytes_decoded = instance.decode(binary)
>>> print(bytes_decoded)
6
>>> print(instance)
Data():
    a: 1 (ULInt16)
    b: 2 (ULInt16)
    crc: 50172 (CRCL16)

>>> print(instance.introspect())
   -    -  Data():
   0 \x01      a: 1 (ULInt16)
   1 \x00
   2 \x02      b: 2 (ULInt16)
   3 \x00
   4 \xfc      crc: 50172 (CRCL16)
   5 \xc3


>>> bytes_decoded = instance.decode(b"\x01\x00\x02\x00\xFC\xC3")
>>> print(bytes_decoded)
6
>>> print(instance)
Data():
    a: 1 (ULInt16)
    b: 2 (ULInt16)
    crc: 50172 (CRCL16)

>>> print(instance.introspect())
   -    -  Data():
   0 \x01      a: 1 (ULInt16)
   1 \x00
   2 \x02      b: 2 (ULInt16)
   3 \x00
   4 \xfc      crc: 50172 (CRCL16)
   5 \xc3


>>> bytes_decoded = instance.decode(b"\x01\x00\x02\x00\x00\x00")  # corrupted crc
oser.ChecksumMismatchException: Data could not be decoded!
Parsing object is:
   -    -  Data():
   0 \x01      a: 1 (ULInt16)
   1 \x00
   2 \x02      b: 2 (ULInt16)
   3 \x00
   4 \x00      crc: 0 (CRCL16)
   5 \x00
     ^^^^ Checksum mismatch: expected \xc3fc but found \x0000

CRCB16

16-bit crc big endian.

class oser.CRCB16(strict: bool = False, polynomial: int = 41003, reflect_input: bool = False, reflect_output: bool = False, initial_value: int = 0, xor_output: int = 0, automatic_calculation: bool = True, format: str = 'hex')

16-bit crc big endian serializer.

Parameters:

  • strict – bool = False: If set to True crc is checked when decoding data. An exception is raised if crcs do not match.

  • polynomial – int = 0xa02b: the crc polynomial

  • reflect_input – bool = False: reflect input data

  • reflect_output – bool = False: reflect output data

  • initial_value – int = 0x0000: start with initial_value

  • xor_output – int = 0x0000: xor output data with xor_output

  • automatic_calculation – bool = True: if set to True crc is automatically calculated when encoding data

  • format – str = “hex” (string): Use “hex” to format values to hexadecimal. Use “bin” to format values to binary. Use None for decimal format.

decode(data: bytes, full_data: bytes = b'', context_data: bytes = b'') → int

Decode a binary string into a byte type and return the number of bytes that were decoded.

Parameters:

  • data (bytes) – the data buffer that is decoded.

  • full_data (bytes) – the binary data string until the part to be decoded. The user normally does not need to supply this.

  • context_data (bytes) – the binary data of the current context. The user normally does not need to supply this.

Returns:

the number of bytes that were decoded.

Return type:

int

encode(full_data: bytes = b'', context_data: bytes = b'') → bytes

Return the encoded binary string.

Parameters:

  • full_data (bytes) – the binary data string until the part to be encoded. The user normally does not need to supply this.

  • context_data (bytes) – the binary data of the current context. The user normally does not need to supply this.

Returns:

the encoded binary string.

Return type:

bytes

get() → int

Return the value.

Returns:

the value.

get_byte_size() → int

Return the length of the byte type in bytes.

Returns:

the length of the byte type in bytes.

Return type:

int

get_size() → int

Return the length of the byte type in bytes.

Returns:

the length of the byte type in bytes.

Return type:

int

introspect(stop_at: ByteStruct | BitStruct | ByteType | BitType | None = None) → str

Return the introspection representation of the object as a string.

Parameters:

stop_at=None (object) – stop introspection at stop_at.

root() → ByteStruct | BitStruct

return root element

set(value: int) → None

Set the value.

Parameters:

value – the new value

set_automatic_calculation(enabled: bool = True) → None

Enable or disable automatic calculation when encode is called.

Parameters:

enabled=True (bool) – the new enabled state.

set_fuzzing_values(values: Generator[Any, None, None] | List[Any] | None) → None

Set fuzzing values.

Parameters:

values (iterable) – the values used for fuzzing.

up() → ByteStruct | BitStruct

Return the parent element.

Usage:

>>> from oser import ByteStruct, UBInt16, CRCB16, to_hex

>>> class Data(ByteStruct):
...         def __init__(self):
...             super(Data, self).__init__()
...
...             self.a = UBInt16(1)
...             self.b = UBInt16(2)
...
...             self.crc = CRCB16(strict=True)
...
>>> instance = Data()
>>> print(instance)
Data():
    a: 1 (UBInt16)
    b: 2 (UBInt16)
    crc: 0 (CRCB16)

>>> print(instance.introspect())
   -    -  Data():
   0 \x00      a: 1 (UBInt16)
   1 \x01
   2 \x00      b: 2 (UBInt16)
   3 \x02
   4 \x00      crc: 0 (CRCB16)
   5 \x00

>>> binary = instance.encode()
>>> print(to_hex(binary))
   0|  1|  2|  3|  4|  5
\x00\x01\x00\x02\xF8\x51
>>> bytes_decoded = instance.decode(binary)
>>> print(bytes_decoded)
6
>>> print(instance)
Data():
    a: 1 (UBInt16)
    b: 2 (UBInt16)
    crc: 63569 (CRCB16)

>>> print(instance.introspect())
   -    -  Data():
   0 \x00      a: 1 (UBInt16)
   1 \x01
   2 \x00      b: 2 (UBInt16)
   3 \x02
   4 \xf8      crc: 63569 (CRCB16)
   5 \x51


>>> bytes_decoded = instance.decode(b"\x00\x01\x00\x02\xF8\x51")
>>> print(bytes_decoded)
6
>>> print(instance)
Data():
    a: 1 (UBInt16)
    b: 2 (UBInt16)
    crc: 63569 (CRCB16)

>>> print(instance.introspect())
   -    -  Data():
   0 \x00      a: 1 (UBInt16)
   1 \x01
   2 \x00      b: 2 (UBInt16)
   3 \x02
   4 \xf8      crc: 63569 (CRCB16)
   5 \x51


>>> bytes_decoded = instance.decode(b"\x00\x01\x00\x02\x00\x00")  # corrupted crc
oser.ChecksumMismatchException: Data could not be decoded!
Parsing object is:
   -    -  Data():
   0 \x00      a: 1 (UBInt16)
   1 \x01
   2 \x00      b: 2 (UBInt16)
   3 \x02
   4 \x00      crc: 0 (CRCB16)
   5 \x00
     ^^^^ Checksum mismatch: expected \xf851 but found \x0000

CRCL32

32-bit crc little endian.

class oser.CRCL32(strict: bool = False, polynomial: int = 517762881, reflect_input: bool = False, reflect_output: bool = False, initial_value: int = 0, xor_output: int = 0, automatic_calculation: bool = True, format: str = 'hex')

32-bit crc little endian serializer.

Parameters:

  • strict – bool = False: If set to True crc is checked when decoding data. An exception is raised if crcs do not match.

  • polynomial – int = 0x1edc6f41: the crc polynomial

  • reflect_input – bool = False: reflect input data

  • reflect_output – bool = False: reflect output data

  • initial_value – int = 0x00000000: start with initial_value

  • xor_output – int = 0x00000000: xor output data with xor_output

  • automatic_calculation – bool = True: if set to True crc is automatically calculated when encoding data

  • format – str = “hex” (string): Use “hex” to format values to hexadecimal. Use “bin” to format values to binary. Use None for decimal format.

decode(data: bytes, full_data: bytes = b'', context_data: bytes = b'') → int

Decode a binary string into a byte type and return the number of bytes that were decoded.

Parameters:

  • data (bytes) – the data buffer that is decoded.

  • full_data (bytes) – the binary data string until the part to be decoded. The user normally does not need to supply this.

  • context_data (bytes) – the binary data of the current context. The user normally does not need to supply this.

Returns:

the number of bytes that were decoded.

Return type:

int

encode(full_data: bytes = b'', context_data: bytes = b'') → bytes

Return the encoded binary string.

Parameters:

  • full_data (bytes) – the binary data string until the part to be encoded. The user normally does not need to supply this.

  • context_data (bytes) – the binary data of the current context. The user normally does not need to supply this.

Returns:

the encoded binary string.

Return type:

bytes

get() → int

Return the value.

Returns:

the value.

get_byte_size() → int

Return the length of the byte type in bytes.

Returns:

the length of the byte type in bytes.

Return type:

int

get_size() → int

Return the length of the byte type in bytes.

Returns:

the length of the byte type in bytes.

Return type:

int

introspect(stop_at: ByteStruct | BitStruct | ByteType | BitType | None = None) → str

Return the introspection representation of the object as a string.

Parameters:

stop_at=None (object) – stop introspection at stop_at.

root() → ByteStruct | BitStruct

return root element

set(value: int) → None

Set the value.

Parameters:

value – the new value

set_automatic_calculation(enabled: bool = True) → None

Enable or disable automatic calculation when encode is called.

Parameters:

enabled=True (bool) – the new enabled state.

set_fuzzing_values(values: Generator[Any, None, None] | List[Any] | None) → None

Set fuzzing values.

Parameters:

values (iterable) – the values used for fuzzing.

up() → ByteStruct | BitStruct

Return the parent element.

Usage:

>>> from oser import ByteStruct, UBInt16, CRCL32, to_hex

>>> class Data(ByteStruct):
...         def __init__(self):
...             super(Data, self).__init__()
...
...             self.a = ULInt16(1)
...             self.b = ULInt16(2)
...
...             self.crc = CRCL32(strict=True)
...
>>> instance = Data()
>>> print(instance)
Data():
    a: 1 (ULInt16)
    b: 2 (ULInt16)
    crc: 0 (CRCL32)

>>> print(instance.introspect())
   -    -  Data():
   0 \x01      a: 1 (ULInt16)
   1 \x00
   2 \x02      b: 2 (ULInt16)
   3 \x00
   4 \x00      crc: 0 (CRCL32)
   5 \x00
   6 \x00
   7 \x00

>>> binary = instance.encode()
>>> print(to_hex(binary))
   0|  1|  2|  3|  4|  5|  6|  7
\x01\x00\x02\x00\xB5\xED\xF0\xDC
>>> bytes_decoded = instance.decode(binary)
>>> print(bytes_decoded)
8
>>> print(instance)
Data():
    a: 1 (ULInt16)
    b: 2 (ULInt16)
    crc: 3706777013 (CRCL32)

>>> print(instance.introspect())
   -    -  Data():
   0 \x01      a: 1 (ULInt16)
   1 \x00
   2 \x02      b: 2 (ULInt16)
   3 \x00
   4 \xb5      crc: 3706777013 (CRCL32)
   5 \xed
   6 \xf0
   7 \xdc


>>> bytes_decoded = instance.decode(b"\x01\x00\x02\x00\xB5\xED\xF0\xDC")
>>> print(bytes_decoded)
8
>>> print(instance)
Data():
    a: 1 (ULInt16)
    b: 2 (ULInt16)
    crc: 3706777013 (CRCL32)

>>> print(instance.introspect())
   -    -  Data():
   0 \x01      a: 1 (ULInt16)
   1 \x00
   2 \x02      b: 2 (ULInt16)
   3 \x00
   4 \xb5      crc: 3706777013 (CRCL32)
   5 \xed
   6 \xf0
   7 \xdc


>>> bytes_decoded = instance.decode(b"\x01\x00\x02\x00\x00\x00\x00\x00")  # corrupted crc
oser.ChecksumMismatchException: Data could not be decoded!
Parsing object is:
   -    -  Data():
   0 \x01      a: 1 (ULInt16)
   1 \x00
   2 \x02      b: 2 (ULInt16)
   3 \x00
   4 \x00      crc: 0 (CRCL32)
   5 \x00
   6 \x00
   7 \x00
     ^^^^ Checksum mismatch: expected \xdcf0edb5 but found \x00000000

CRCB32

32-bit crc big endian.

class oser.CRCB32(strict: bool = False, polynomial: int = 517762881, reflect_input: bool = False, reflect_output: bool = False, initial_value: int = 0, xor_output: int = 0, automatic_calculation: bool = True, format: str = 'hex')

32-bit crc big endian serializer.

Parameters:

  • strict – bool = False: If set to True crc is checked when decoding data. An exception is raised if crcs do not match.

  • polynomial – int = 0x1edc6f41: the crc polynomial

  • reflect_input – bool = False: reflect input data

  • reflect_output – bool = False: reflect output data

  • initial_value – int = 0x00000000: start with initial_value

  • xor_output – int = 0x00000000: xor output data with xor_output

  • automatic_calculation – bool = True: if set to True crc is automatically calculated when encoding data

  • format – str = “hex” (string): Use “hex” to format values to hexadecimal. Use “bin” to format values to binary. Use None for decimal format.

decode(data: bytes, full_data: bytes = b'', context_data: bytes = b'') → int

Decode a binary string into a byte type and return the number of bytes that were decoded.

Parameters:

  • data (bytes) – the data buffer that is decoded.

  • full_data (bytes) – the binary data string until the part to be decoded. The user normally does not need to supply this.

  • context_data (bytes) – the binary data of the current context. The user normally does not need to supply this.

Returns:

the number of bytes that were decoded.

Return type:

int

encode(full_data: bytes = b'', context_data: bytes = b'') → bytes

Return the encoded binary string.

Parameters:

  • full_data (bytes) – the binary data string until the part to be encoded. The user normally does not need to supply this.

  • context_data (bytes) – the binary data of the current context. The user normally does not need to supply this.

Returns:

the encoded binary string.

Return type:

bytes

get() → int

Return the value.

Returns:

the value.

get_byte_size() → int

Return the length of the byte type in bytes.

Returns:

the length of the byte type in bytes.

Return type:

int

get_size() → int

Return the length of the byte type in bytes.

Returns:

the length of the byte type in bytes.

Return type:

int

introspect(stop_at: ByteStruct | BitStruct | ByteType | BitType | None = None) → str

Return the introspection representation of the object as a string.

Parameters:

stop_at=None (object) – stop introspection at stop_at.

root() → ByteStruct | BitStruct

return root element

set(value: int) → None

Set the value.

Parameters:

value – the new value

set_automatic_calculation(enabled: bool = True) → None

Enable or disable automatic calculation when encode is called.

Parameters:

enabled=True (bool) – the new enabled state.

set_fuzzing_values(values: Generator[Any, None, None] | List[Any] | None) → None

Set fuzzing values.

Parameters:

values (iterable) – the values used for fuzzing.

up() → ByteStruct | BitStruct

Return the parent element.

Usage:

>>> from oser import ByteStruct, UBInt16, CRCB32, to_hex

>>> class Data(ByteStruct):
...         def __init__(self):
...             super(Data, self).__init__()
...
...             self.a = UBInt16(1)
...             self.b = UBInt16(2)
...
...             self.crc = CRCB32(strict=True)
...
>>> instance = Data()
>>> print(instance)
Data():
    a: 1 (UBInt16)
    b: 2 (UBInt16)
    crc: 0 (CRCB32)

>>> print(instance.introspect())
   -    -  Data():
   0 \x00      a: 1 (UBInt16)
   1 \x01
   2 \x00      b: 2 (UBInt16)
   3 \x02
   4 \x00      crc: 0 (CRCB32)
   5 \x00
   6 \x00
   7 \x00

>>> binary = instance.encode()
>>> print(to_hex(binary))
   0|  1|  2|  3|  4|  5|  6|  7
\x00\x01\x00\x02\xFF\x56\x3A\x53
>>> bytes_decoded = instance.decode(binary)
>>> print(bytes_decoded)
8
>>> print(instance)
Data():
    a: 1 (UBInt16)
    b: 2 (UBInt16)
    crc: 4283841107 (CRCB32)

>>> print(instance.introspect())
   -    -  Data():
   0 \x00      a: 1 (UBInt16)
   1 \x01
   2 \x00      b: 2 (UBInt16)
   3 \x02
   4 \xff      crc: 4283841107 (CRCB32)
   5 \x56
   6 \x3a
   7 \x53


>>> bytes_decoded = instance.decode(b"\x00\x01\x00\x02\xFF\x56\x3A\x53")
>>> print(bytes_decoded)
8
>>> print(instance)
Data():
    a: 1 (UBInt16)
    b: 2 (UBInt16)
    crc: 4283841107 (CRCB32)

>>> print(instance.introspect())
   -    -  Data():
   0 \x00      a: 1 (UBInt16)
   1 \x01
   2 \x00      b: 2 (UBInt16)
   3 \x02
   4 \xff      crc: 4283841107 (CRCB32)
   5 \x56
   6 \x3a
   7 \x53


>>> bytes_decoded = instance.decode(b"\x00\x01\x00\x02\x00\x00\x00\x00")  # corrupted crc
oser.ChecksumMismatchException: Data could not be decoded!
Parsing object is:
   -    -  Data():
   0 \x00      a: 1 (UBInt16)
   1 \x01
   2 \x00      b: 2 (UBInt16)
   3 \x02
   4 \x00      crc: 0 (CRCB32)
   5 \x00
   6 \x00
   7 \x00
     ^^^^ Checksum mismatch: expected \xff563a53 but found \x00000000

CRCL64

64-bit crc little endian.

class oser.CRCL64(strict: bool = False, polynomial: int = 4823603603198064275, reflect_input: bool = False, reflect_output: bool = False, initial_value: int = 0, xor_output: int = 0, automatic_calculation: bool = True, format: str = 'hex')

64-bit crc little endian serializer.

Parameters:

  • strict – bool = False: If set to True crc is checked when decoding data. An exception is raised if crcs do not match.

  • polynomial – int = 0x42f0e1eba9ea3693: the crc polynomial

  • reflect_input – bool = False: reflect input data

  • reflect_output – bool = False: reflect output data

  • initial_value – int = 0x0000000000000000: start with initial_value

  • xor_output – int = 0x0000000000000000: xor output data with xor_output

  • automatic_calculation – bool = True: if set to True crc is automatically calculated when encoding data

  • format – str = “hex” (string): Use “hex” to format values to hexadecimal. Use “bin” to format values to binary. Use None for decimal format.

decode(data: bytes, full_data: bytes = b'', context_data: bytes = b'') → int

Decode a binary string into a byte type and return the number of bytes that were decoded.

Parameters:

  • data (bytes) – the data buffer that is decoded.

  • full_data (bytes) – the binary data string until the part to be decoded. The user normally does not need to supply this.

  • context_data (bytes) – the binary data of the current context. The user normally does not need to supply this.

Returns:

the number of bytes that were decoded.

Return type:

int

encode(full_data: bytes = b'', context_data: bytes = b'') → bytes

Return the encoded binary string.

Parameters:

  • full_data (bytes) – the binary data string until the part to be encoded. The user normally does not need to supply this.

  • context_data (bytes) – the binary data of the current context. The user normally does not need to supply this.

Returns:

the encoded binary string.

Return type:

bytes

get() → int

Return the value.

Returns:

the value.

get_byte_size() → int

Return the length of the byte type in bytes.

Returns:

the length of the byte type in bytes.

Return type:

int

get_size() → int

Return the length of the byte type in bytes.

Returns:

the length of the byte type in bytes.

Return type:

int

introspect(stop_at: ByteStruct | BitStruct | ByteType | BitType | None = None) → str

Return the introspection representation of the object as a string.

Parameters:

stop_at=None (object) – stop introspection at stop_at.

root() → ByteStruct | BitStruct

return root element

set(value: int) → None

Set the value.

Parameters:

value – the new value

set_automatic_calculation(enabled: bool = True) → None

Enable or disable automatic calculation when encode is called.

Parameters:

enabled=True (bool) – the new enabled state.

set_fuzzing_values(values: Generator[Any, None, None] | List[Any] | None) → None

Set fuzzing values.

Parameters:

values (iterable) – the values used for fuzzing.

up() → ByteStruct | BitStruct

Return the parent element.

Usage:

>>> from oser import ByteStruct, UBInt16, CRCL64, to_hex

>>> class Data(ByteStruct):
...         def __init__(self):
...             super(Data, self).__init__()
...
...             self.a = ULInt16(1)
...             self.b = ULInt16(2)
...
...             self.crc = CRCL64(strict=True)
...
>>> instance = Data()
>>> print(instance)
Data():
    a: 1 (ULInt16)
    b: 2 (ULInt16)
    crc: 0 (CRCL64)

>>> print(instance.introspect())
   -    -  Data():
   0 \x01      a: 1 (ULInt16)
   1 \x00
   2 \x02      b: 2 (ULInt16)
   3 \x00
   4 \x00      crc: 0 (CRCL64)
   5 \x00
   6 \x00
   7 \x00
   8 \x00
   9 \x00
  10 \x00
  11 \x00

>>> binary = instance.encode()
>>> print(to_hex(binary))
   0|  1|  2|  3|  4|  5|  6|  7|  8|  9| 10| 11
\x01\x00\x02\x00\xEA\x1F\x12\x02\xC4\xF9\x66\xF9
>>> bytes_decoded = instance.decode(binary)
>>> print(bytes_decoded)
12
>>> print(instance)
Data():
    a: 1 (ULInt16)
    b: 2 (ULInt16)
    crc: 17971325983312191466 (CRCL64)

>>> print(instance.introspect())
   -    -  Data():
   0 \x01      a: 1 (ULInt16)
   1 \x00
   2 \x02      b: 2 (ULInt16)
   3 \x00
   4 \xea      crc: 17971325983312191466 (CRCL64)
   5 \x1f
   6 \x12
   7 \x02
   8 \xc4
   9 \xf9
  10 \x66
  11 \xf9


>>> bytes_decoded = instance.decode(b"\x01\x00\x02\x00\xEA\x1F\x12\x02\xC4\xF9\x66\xF9")
>>> print(bytes_decoded)
12
>>> print(instance)
Data():
    a: 1 (ULInt16)
    b: 2 (ULInt16)
    crc: 17971325983312191466 (CRCL64)

>>> print(instance.introspect())
   -    -  Data():
   0 \x01      a: 1 (ULInt16)
   1 \x00
   2 \x02      b: 2 (ULInt16)
   3 \x00
   4 \xea      crc: 17971325983312191466 (CRCL64)
   5 \x1f
   6 \x12
   7 \x02
   8 \xc4
   9 \xf9
  10 \x66
  11 \xf9


>>> bytes_decoded = instance.decode(b"\x01\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00")  # corrupted crc
oser.ChecksumMismatchException: Data could not be decoded!
Parsing object is:
   -    -  Data():
   0 \x01      a: 1 (ULInt16)
   1 \x00
   2 \x02      b: 2 (ULInt16)
   3 \x00
   4 \x00      crc: 0 (CRCL64)
   5 \x00
   6 \x00
   7 \x00
   8 \x00
   9 \x00
  10 \x00
  11 \x00
     ^^^^ Checksum mismatch: expected \xf966f9c402121fea but found \x0000000000000000

CRCB64

64-bit crc big endian.

class oser.CRCB64(strict: bool = False, polynomial: int = 4823603603198064275, reflect_input: bool = False, reflect_output: bool = False, initial_value: int = 0, xor_output: int = 0, automatic_calculation: bool = True, format: str = 'hex')

64-bit crc big endian serializer.

Parameters:

  • strict – bool = False: If set to True crc is checked when decoding data. An exception is raised if crcs do not match.

  • polynomial – int = 0x42f0e1eba9ea3693: the crc polynomial

  • reflect_input – bool = False: reflect input data

  • reflect_output – bool = False: reflect output data

  • initial_value – int = 0x0000000000000000: start with initial_value

  • xor_output – int = 0x0000000000000000: xor output data with xor_output

  • automatic_calculation – bool = True: if set to True crc is automatically calculated when encoding data

  • format – str = “hex” (string): Use “hex” to format values to hexadecimal. Use “bin” to format values to binary. Use None for decimal format.

decode(data: bytes, full_data: bytes = b'', context_data: bytes = b'') → int

Decode a binary string into a byte type and return the number of bytes that were decoded.

Parameters:

  • data (bytes) – the data buffer that is decoded.

  • full_data (bytes) – the binary data string until the part to be decoded. The user normally does not need to supply this.

  • context_data (bytes) – the binary data of the current context. The user normally does not need to supply this.

Returns:

the number of bytes that were decoded.

Return type:

int

encode(full_data: bytes = b'', context_data: bytes = b'') → bytes

Return the encoded binary string.

Parameters:

  • full_data (bytes) – the binary data string until the part to be encoded. The user normally does not need to supply this.

  • context_data (bytes) – the binary data of the current context. The user normally does not need to supply this.

Returns:

the encoded binary string.

Return type:

bytes

get() → int

Return the value.

Returns:

the value.

get_byte_size() → int

Return the length of the byte type in bytes.

Returns:

the length of the byte type in bytes.

Return type:

int

get_size() → int

Return the length of the byte type in bytes.

Returns:

the length of the byte type in bytes.

Return type:

int

introspect(stop_at: ByteStruct | BitStruct | ByteType | BitType | None = None) → str

Return the introspection representation of the object as a string.

Parameters:

stop_at=None (object) – stop introspection at stop_at.

root() → ByteStruct | BitStruct

return root element

set(value: int) → None

Set the value.

Parameters:

value – the new value

set_automatic_calculation(enabled: bool = True) → None

Enable or disable automatic calculation when encode is called.

Parameters:

enabled=True (bool) – the new enabled state.

set_fuzzing_values(values: Generator[Any, None, None] | List[Any] | None) → None

Set fuzzing values.

Parameters:

values (iterable) – the values used for fuzzing.

up() → ByteStruct | BitStruct

Return the parent element.

Usage:

>>> from oser import ByteStruct, UBInt16, CRCB64, to_hex

>>> class Data(ByteStruct):
...         def __init__(self):
...             super(Data, self).__init__()
...
...             self.a = UBInt16(1)
...             self.b = UBInt16(2)
...
...             self.crc = CRCB64(strict=True)
...
>>> instance = Data()
>>> print(instance)
Data():
    a: 1 (UBInt16)
    b: 2 (UBInt16)
    crc: 0 (CRCB64)

>>> print(instance.introspect())
   -    -  Data():
   0 \x00      a: 1 (UBInt16)
   1 \x01
   2 \x00      b: 2 (UBInt16)
   3 \x02
   4 \x00      crc: 0 (CRCB64)
   5 \x00
   6 \x00
   7 \x00
   8 \x00
   9 \x00
  10 \x00
  11 \x00

>>> binary = instance.encode()
>>> print(to_hex(binary))
   0|  1|  2|  3|  4|  5|  6|  7|  8|  9| 10| 11
\x00\x01\x00\x02\xA6\x0F\x34\x48\x69\x03\x75\xE1
>>> bytes_decoded = instance.decode(binary)
>>> print(bytes_decoded)
12
>>> print(instance)
Data():
    a: 1 (UBInt16)
    b: 2 (UBInt16)
    crc: 11965840220550821345 (CRCB64)

>>> print(instance.introspect())
   -    -  Data():
   0 \x00      a: 1 (UBInt16)
   1 \x01
   2 \x00      b: 2 (UBInt16)
   3 \x02
   4 \xa6      crc: 11965840220550821345 (CRCB64)
   5 \x0f
   6 \x34
   7 \x48
   8 \x69
   9 \x03
  10 \x75
  11 \xe1


>>> bytes_decoded = instance.decode(b"\x00\x01\x00\x02\xA6\x0F\x34\x48\x69\x03\x75\xE1")
>>> print(bytes_decoded)
12
>>> print(instance)
Data():
    a: 1 (UBInt16)
    b: 2 (UBInt16)
    crc: 11965840220550821345 (CRCB64)

>>> print(instance.introspect())
   -    -  Data():
   0 \x00      a: 1 (UBInt16)
   1 \x01
   2 \x00      b: 2 (UBInt16)
   3 \x02
   4 \xa6      crc: 11965840220550821345 (CRCB64)
   5 \x0f
   6 \x34
   7 \x48
   8 \x69
   9 \x03
  10 \x75
  11 \xe1


>>> bytes_decoded = instance.decode(b"\x00\x01\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00")  # corrupted crc
oser.ChecksumMismatchException: Data could not be decoded!
Parsing object is:
   -    -  Data():
   0 \x00      a: 1 (UBInt16)
   1 \x01
   2 \x00      b: 2 (UBInt16)
   3 \x02
   4 \x00      crc: 0 (CRCB64)
   5 \x00
   6 \x00
   7 \x00
   8 \x00
   9 \x00
  10 \x00
  11 \x00
     ^^^^ Checksum mismatch: expected \xa60f3448690375e1 but found \x0000000000000000