artemis/titles/sao/handlers/helpers.py

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2023-11-09 23:11:58 +00:00
from typing import Tuple
import struct
import logging
BIGINT_OFF = 16
LONG_OFF = 8
INT_OFF = 4
SHORT_OFF = 2
BYTE_OFF = 1
def decode_num(data: bytes, offset: int, size: int) -> int:
try:
return int.from_bytes(data[offset:offset + size], 'big')
except:
logging.getLogger('sao').error(f"Failed to parse {data[offset:offset + size]} as BE number of width {size}")
return 0
def decode_byte(data: bytes, offset: int) -> int:
return decode_num(data, offset, BYTE_OFF)
def decode_short(data: bytes, offset: int) -> int:
return decode_num(data, offset, SHORT_OFF)
def decode_int(data: bytes, offset: int) -> int:
return decode_num(data, offset, INT_OFF)
def decode_long(data: bytes, offset: int) -> int:
return decode_num(data, offset, LONG_OFF)
def decode_bigint(data: bytes, offset: int) -> int:
return decode_num(data, offset, BIGINT_OFF)
def decode_str(data: bytes, offset: int) -> Tuple[str, int]:
try:
str_len = decode_int(data, offset)
num_bytes_decoded = INT_OFF + str_len
str_out = data[offset + INT_OFF:offset + num_bytes_decoded].decode("utf-16-le", errors="replace")
return (str_out, num_bytes_decoded)
except:
logging.getLogger('sao').error(f"Failed to parse {data[offset:]} as string!")
return ("", 0)
def encode_str(s: str) -> bytes:
try:
str_bytes = s.encode("utf-16-le", errors="replace")
str_len_bytes = struct.pack("!I", len(str_bytes))
return str_len_bytes + str_bytes
except:
logging.getLogger('sao').error(f"Failed to encode {s} as bytes!")
return b""