static ngx_inline uint32_t
ngx_crc32_short(u_char *p, size_t len)
{
    u_char    c;
    uint32_t  crc;

    crc = 0xffffffff;

    while (len--) {
        c = *p++;
        crc = ngx_crc32_table_short[(crc ^ (c & 0xf)) & 0xf] ^ (crc >> 4);
        crc = ngx_crc32_table_short[(crc ^ (c >> 4)) & 0xf] ^ (crc >> 4);
    }

    return crc ^ 0xffffffff;
}