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""" Base45 Data Encoding as described in draft-faltstrom-base45-02 """

from typing import Union

BASE45_CHARSET = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ $%*+-./:" BASE45_DICT = {v: i for i, v in enumerate(BASE45_CHARSET)}

def b45encode(buf: bytes) -> bytes: """Convert bytes to base45-encoded string""" res = "" buflen = len(buf) for i in range(0, buflen & ~1, 2): x = (buf[i] << 8) + buf[i + 1] e, x = divmod(x, 45 * 45) d, c = divmod(x, 45) res += BASE45_CHARSET[c] + BASE45_CHARSET[d] + BASE45_CHARSET[e] if buflen & 1: d, c = divmod(buf[-1], 45) res += BASE45_CHARSET[c] + BASE45_CHARSET[d] return res.encode()

def b45decode(s: Union[bytes, str]) -> bytes: """Decode base45-encoded string to bytes""" try: if isinstance(s, str): buf = [BASE45_DICT[c] for c in s.rstrip("\n")] elif isinstance(s, bytes): buf = [BASE45_DICT[c] for c in s.decode()] else: raise TypeError("Type must be 'str' or 'bytes'")

    buflen = len(buf)
    if buflen % 3 == 1:
        raise ValueError("Invalid base45 string")

    res = []
    for i in range(0, buflen, 3):
        if buflen - i >= 3:
            x = buf[i] + buf[i + 1] * 45 + buf[i + 2] * 45 * 45
            if x > 0xFFFF:
                raise ValueError
            res.extend(divmod(x, 256))
        else:
            x = buf[i] + buf[i + 1] * 45
            if x > 0xFF:
                raise ValueError
            res.append(x)
    return bytes(res)
except (ValueError, KeyError, AttributeError):
    raise ValueError("Invalid base45 string")