2進に変換

末尾にdのついた10進数文字列、末尾にhのついた16進数文字列、末尾にbのついた2進数文字列をbitの並びに変換するテスト

def any2bin(valstr: str, is_signed: bool, bitlen: int):
    """ 2進数に変換する """
    final_char = valstr[-1]
    valstr = valstr[:-1]
    ret = ''
    if final_char == 'b':
        if len(valstr) == bitlen:
            ret = valstr
        else:
            raise Exception     # 桁数不一致
    elif final_char == 'd':
        ret = dec2bin(valstr, is_signed, bitlen)
    elif final_char == 'h':
        ret = hex2bin(valstr, is_signed, bitlen)
    else:
        raise Exception

    return ret


def dec2bin(valstr: str, is_signed: bool, bitlen: int):
    """十進数を二進数のbitが並んだ文字列に変換する"""
    val = int(valstr)
    if _range_check(val, is_signed, bitlen):
        if is_signed and val < 0:
            all_one = int('1' * bitlen, base=2)     # 1111...1b (bitlen個の1)
            ret = f'{~(all_one ^ val): b}'
        else:
            ret = f'{val:b}'.zfill(bitlen)
    else:
        raise Exception  # out of range

    return ret


def hex2bin(valstr: str, is_signed: bool, bitlen: int):
    """16進数を二進数のbitが並んだ文字列に変換する"""
    # unsignedとしてbit変換
    val = int(valstr, base=16)
    maxval = (2 ** bitlen) - 1
    if val > maxval:
        raise Exception  # out of range

    ret = f'{val:b}'.zfill(bitlen)

    return ret


def _range_check(decval: int, is_signed: bool, bitlen: int):
    """範囲をチェックする"""
    ret = True
    if is_signed:
        min_val = -1 * (2 ** (bitlen-1))
        max_val = (2 ** (bitlen - 1)) - 1
    else:
        min_val = 0
        max_val = (2 ** bitlen) - 1

    if decval > max_val:
        ret = False
    if decval < min_val:
        ret = False

    return ret