幂次定律在Redis中的应用

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/* Returns a random level for the new skiplist node we are going to create.

 * The return value of this function is between 1 and ZSKIPLIST_MAXLEVEL

 * (both inclusive), with a powerlaw-alike distribution where higher

 * levels are less likely to be returned. */

int zslRandomLevel(void) {

    int level = 1;

    while ((random()&0xFFFF) < (ZSKIPLIST_P * 0xFFFF))

        level += 1;

    return (level<ZSKIPLIST_MAXLEVEL) ? level : ZSKIPLIST_MAXLEVEL;

}