try decompress with unknown size, -buflen is guess size

[shuxin]

sorry for trick, maybe there will be a better way

[jd-boyd]

I'm sorry, for the delay in responding, but if you are still interested, I would like to see test(s) added for this.

[shuxin]

lzo have no header like zstd or lz4.
I want to alloc larger buffer and try decompress lzo data without size info.
But you check the new_len and out_len strictly.

I know, it's a trick. Maybe there will be a better solution.

size_guess = len(in)*2
while True:
    if try_decompress(...): # allow a incorrect size.
        break
    size_guess *= 2

[jd-boyd]

It looks to me like your change makes an initial guess of 1 byte output length, which is unlikely to ever be a good guess, especially since there is no resizing if buflen is less than needed. You mention a possible better solution in python, but not as an update to the pull request. I think you can fairly safely guess that a default buflen should be at least as long as the input length. Input length * 2 might be going too far. You could look at what other libraries do.