易經 base64

hexagram.py

GUA = [63, 0, 17, 34, 23, 58, 2, 16, 55, 59, 7, 56, 61, 47, 4, 8, 25, 38, 3, 48, 41, 37, 32, 1, 57, 39, 33, 30, 18, 45, 28, 14, 60, 15, 40, 5, 53, 43, 20, 10, 35, 49, 31, 62, 24, 6, 26, 22, 29, 46, 9, 36, 52, 11, 13, 44, 54, 27, 50, 19, 51, 12, 21, 42]  # fmt: skip


def bit2gua(bit6: int) -> str:
    return chr(0x4DC0 + GUA.index(bit6 & 0x3F))


def byte_segment(in_byte: bytes) -> bytearray:
    ret: bytearray = []
    rem = 0
    reg = 0
    for byte in in_byte:
        mask = ((1 << (6 - rem)) - 1) << (2 + rem)
        ps = (reg << (6 - rem)) | ((byte & mask) >> (2 + rem))
        nreg = byte & (~mask & 0xFF)
        ret.append(ps)
        reg = nreg
        rem += 2
        if rem >= 6:
            ret.append(reg)
            reg = rem = 0
    if reg != 0x00:
        ret.append(reg << (6 - rem))

    return ret


def main():
    import sys

    data = sys.stdin.buffer.read()
    for gua in map(bit2gua, byte_segment(data)):
        print(gua, end="")


if __name__ == "__main__":
    main()