Free GIL when running check_bytes_arrays_within_dist

[RandomNameUser]

The check_bytes_arrays_within_dist function has the potential to take a long time when searching in a large array. It would be helpful if the lib could free the GIL to let other threads run while that is going on.

Never having written a C Python extension, if I interpret the docs (https://docs.python.org/3/c-api/init.html#c.Py_BEGIN_ALLOW_THREADS) right, all it would take to do that is to add Py_BEGIN_ALLOW_THREADS and Py_END_ALLOW_THREADS macros and remove the in-loop return, i.e. change the loop to:

    int return_value = -1;

    Py_BEGIN_ALLOW_THREADS

    int res;
    uint64_t number_of_elements = big_array_size / small_array_size;
    uint8_t* pBig = big_array;
    for (uint64_t i = 0; i < number_of_elements; i++, pBig += small_array_size) {
        res = (int)ptr__hamming_distance_bytes(pBig, small_array, small_array_size, max_dist);
        if (res == 1)
            return_value = i;
            break;
        }

    Py_END_ALLOW_THREADS

   return Py_BuildValue("i", return_value);

I don't have a good way to test this right now, but it seems trivial enough. I would appreciate if you could give this a try.

Thanks for a greatly useful little library. Stuff like this is why I love Python! ;)

[mrecachinas]

👋 I'll need to think a little about this. It would help if you could give your use case -- e.g., are you planning to use this in a multithreaded application or are you intending for this to be akin to a coroutine, where the program keeps executing until you get a result (i.e., attempt to access the returned variable)? 🤔

[RandomNameUser]

Currently the former. I am running a somewhat lengthy search in a thread parallel to the GUI (Qt) main thread, and things get pretty sluggish while it's running.

Not sure if the coroutine one is more complicated, but for my current use case it's not needed.

Thanks!