2022q1 第 8 週測驗題

測驗 1

void *memchr_opt(const void *src_void, int c, size_t length)
{
    ...

    if (!TOO_SMALL(length)) {
        
        ...    
        while (length >= LBLOCKSIZE) {
            /* XXXXX: Your implementation should appear here */
            if (!DETECT_CHAR(*asrc, mask)) { 
                /* if not find within sizeof(long) bytes */
                length -= LBLOCKSIZE;
                asrc += 1;
            } else {
                /* the character is within sizeof(long) bytes */
                break;
            }    
        }

        /* If there are fewer than LBLOCKSIZE characters left, then we resort to
         * the bytewise loop.
         */
        src = (unsigned char *) asrc;
    }

    ...
}

測驗 2

• DDD: idx++
• KKK: mask + 1
• RRR: &lfr->ring[tail & mask].idx, __ATOMIC_ACQUIRE
• HHH: head + actual