StructOvO

A Python library offering a more concise syntax for data packing.

Installation

• From pypi

pip install structovo

Usage

from structovo import *


class PackA(Packet):
    a: PADDING
    b: BYTE = b'A'
    c: CHAR = -1
    d: UCHAR = 1
    e: BOOL = False
    f: SHORT = -2
    g: USHORT = 2
    h: INT = -3
    i: UINT = 3
    j: LONG = -4
    k: ULONG = 4
    l: LONGLONG = -5
    m: ULONGLONG = 5
    n: SIZET = 12
    o: SSIZET = 34
    p: BINARY16 = 3.14
    q: FLOAT = 3.14
    r: DOUBLE = 3.14
    s: FixedString = (b"hello", 10)
    t: LengthPrefixedString = b"world"
    u: UnsignedPointer = 0x0d000721
    v: bytes = b'raw_bytes'


r = PackA.build(endianness=Endianness.NATIVE)
hex_list = [format(byte, '02x') for byte in r]
hex_str = ' '.join(hex_list)
print(hex_str)

And you will get:

00 41 ff 01 00 fe ff 02 00 fd ff ff ff 03 00 00 00 fc ff ff ff 04 00 00 00 fb ff ff ff ff ff ff ff 05 00 00 00 00 00 00 00 0c 00 00 00 00 00 00 00 22 00 00 00 00 00 00 00 48 42 c3 f5 48 40 1f 85 eb 51 b8 1e 09 40 68 65 6c 6c 6f 00 00 00 00 00 05 77 6f 72 6c 64 21 07 00 0d 00 00 00 00 72 61 77 5f 62 79 74 65 73

Advance

Supported Endianness

• Endianness.BIG: Big-endian
• Endianness.LITTLE: Little-endian
• Endianness.NETWORK: Big-endian
• Endianness.NATIVE: Depend on your device (Default)

Custom Data Types

You can define your own data types by simply inheriting the BaseType class:

from typing import Tuple, Type
from structovo import BaseType, Endianness


class MyDataType(BaseType):
    def check_validation(self) -> Tuple[bool, Type]:
        # Implement the validation of whether the self.value is valid.
        return ...

    def encode(self, endianness: Endianness) -> bytes:
        # Implement the operation of converting self.value to bytes.
        return ...    

Like this:

from typing import Tuple, Type
from structovo import BaseType, Endianness


class BYTE(BaseType):
    def check_validation(self) -> Tuple[bool, Type]:
        result = isinstance(self.value, bytes)
        return result, bytes

    def encode(self, endianness: Endianness) -> bytes:
        return self._pack('c', endianness)