Finding consecutive bit string of 1 or 0

Question

How to find the length of the longest consecutive bit string(either 1 or 0)?

00000000 11110000 00000000 00000000 -> If it is 0 then length will be 20

11111

Answer 1

To use the table idea, you need something like

static struct {
    int lead;  /* leading 0 bits */
    int max;   /* maximum 0 bits */
    int trail; /* trailing 0 bits */
} table[256] = { ....data.... };

int mostConsecutiveBits(unsigned char *str, int length, bool count_ones) {
    int max = 0; /* max seen so far */
    int trail = 0; /* trailing 0s from previous bytes */
    while (length-- > 0) {
        int byte = *str++;
        if (count_ones)
            byte ^= 0xff;
        if (table[byte].max > max)
            max = table[byte].max;
        if (trail + table[byte].lead > max)
            max = trail + table[byte].lead;
        if (byte)
            trail = table[byte].trail;
        else
            trail += 8;
    }
    return max;
}

initializing the table is straight-forward, but depends on your bit- and byte-ordering (little endian or big endian).