/*
Borrowed and stripped of unused bits from the Python 2.5 string library
*/

int stringview_fastsearch(const char* s, int n, const char* p, int m) {
    long mask;
    int skip, count = 0;
    int i, j, mlast, w;

    w = n - m;

    if (w < 0)
        return -1;

    /* look for special cases */
    if (m <= 1) {
        if (m <= 0)
            return -1;
        /* use special case for 1-character strings */
        for (i = 0; i < n; i++)
            if (s[i] == p[0])
                return i;
        return -1;
    }

    mlast = m - 1;

    /* create compressed boyer-moore delta 1 table */
    skip = mlast - 1;
    /* process pattern[:-1] */
    for (mask = i = 0; i < mlast; i++) {
        mask |= (1 << (p[i] & 0x1F));
        if (p[i] == p[mlast])
            skip = mlast - i - 1;
    }
    /* process pattern[-1] outside the loop */
    mask |= (1 << (p[mlast] & 0x1F));

    for (i = 0; i <= w; i++) {
        /* note: using mlast in the skip path slows things down on x86 */
        if (s[i+m-1] == p[m-1]) {
            /* candidate match */
            for (j = 0; j < mlast; j++)
                if (s[i+j] != p[j])
                    break;
            if (j == mlast) return i;

            /* miss: check if next character is part of pattern */
            if (!(mask & (1 << (s[i+m] & 0x1F))))
                i = i + m;
            else
                i = i + skip;
        } else {
            /* skip: check if next character is part of pattern */
            if (!(mask & (1 << (s[i+m] & 0x1F))))
                i = i + m;
        }
    }

    return -1;
}