char *bmMatch(char *text, int len, char *pattern, int patlen,
              int *skip, int *next)
{
    int i, j;

    i = patlen - 1;
    while (i < len) {
        j = patlen - 1;
        while (j >= 0 && text[i] == pattern[j]) {
            i--;
            j--;
        }
        if (j < 0) return text + i + 1;
        if (skip[text[i] & 0x00ff] >= next[j])
            i += skip[text[i] & 0x00ff];
        else i += next[j];
    }
    return NULL;
}

int bmSkip(int *skip, int slen, char *pattern, int patlen)
{
    int j;

    if (slen < 256) return -1;
    for (j = 0; j < 256; j++) skip[j] = patlen;
    for (j = 0; j < patlen - 1; j++)
        skip[pattern[j] & 0x00ff] = patlen-1-j;
    return 0;
}

int bmNext(int *next, int nlen, char *pattern, int patlen)
{
    int  j, k, s;
    int  *g;

    if (nlen < patlen) return -1;
    if ((g = (int *)malloc(sizeof(int)*patlen)) == NULL) return -1;
    for (j = 0; j < patlen; j++) next[j] = 2*patlen - 1 - j;
    j = patlen;
    for (k = patlen - 1; k >= 0; k--) {
        g[k] = j;
        while (j != patlen && pattern[j] != pattern[k]) {
            next[j] = (next[j] <= patlen-1-k) ? next[j] : patlen-1-k;
            j = g[j];
        }
        j--;
    }
    s = j;
    for (j = 0; j < patlen; j++) {
        next[j] = (next[j] <= s+patlen-j) ? next[j] : s+patlen-j;
        if (j >= s) s = g[s];
    }
    free(g);
    return 0;
}