Splitting out a frame of bytes

Projects Programming
40

This is one way to do it:

uint32_t makeMask (uint8_t length, uint8_t offset)
{
    uint8_t     i = 0;
    uint32_t mask = 0;

    while (i < length) mask += 1 << i++;
    mask = mask << offset;

    return mask;
}

This is a little idiomatic, that's why i favour the paper & pencil approach to have a clearer understanding of what's going on. Of course what this function does can become a preliminary step in the new getBits(). This new function, then, could take a structure containing the length and the offset (but a simple 2-element uint8_t array would suffice in this case).

Note: I tried this on my PC; it is untested on an arduino.