Merge branch 'zsl-get-rank' of git://github.com/pietern/redis

This commit is contained in:
antirez 2010-03-04 16:43:50 +01:00
commit 947efa8d6e

146
redis.c
View File

@ -4844,7 +4844,8 @@ static zskiplistNode *zslCreateNode(int level, double score, robj *obj) {
zskiplistNode *zn = zmalloc(sizeof(*zn));
zn->forward = zmalloc(sizeof(zskiplistNode*) * level);
zn->span = zmalloc(sizeof(unsigned int) * level);
if (level > 0)
zn->span = zmalloc(sizeof(unsigned int) * (level - 1));
zn->score = score;
zn->obj = obj;
return zn;
@ -4897,19 +4898,19 @@ static int zslRandomLevel(void) {
static void zslInsert(zskiplist *zsl, double score, robj *obj) {
zskiplistNode *update[ZSKIPLIST_MAXLEVEL], *x;
unsigned int span[ZSKIPLIST_MAXLEVEL];
unsigned int rank[ZSKIPLIST_MAXLEVEL];
int i, level;
x = zsl->header;
for (i = zsl->level-1; i >= 0; i--) {
/* store span that is crossed to reach the insert position */
span[i] = i == (zsl->level-1) ? 0 : span[i+1];
/* store rank that is crossed to reach the insert position */
rank[i] = i == (zsl->level-1) ? 0 : rank[i+1];
while (x->forward[i] &&
(x->forward[i]->score < score ||
(x->forward[i]->score == score &&
compareStringObjects(x->forward[i]->obj,obj) < 0))) {
span[i] += x->span[i];
rank[i] += i > 0 ? x->span[i-1] : 1;
x = x->forward[i];
}
update[i] = x;
@ -4921,9 +4922,9 @@ static void zslInsert(zskiplist *zsl, double score, robj *obj) {
level = zslRandomLevel();
if (level > zsl->level) {
for (i = zsl->level; i < level; i++) {
span[i] = 0;
rank[i] = 0;
update[i] = zsl->header;
update[i]->span[i] = zsl->length;
update[i]->span[i-1] = zsl->length;
}
zsl->level = level;
}
@ -4933,13 +4934,15 @@ static void zslInsert(zskiplist *zsl, double score, robj *obj) {
update[i]->forward[i] = x;
/* update span covered by update[i] as x is inserted here */
x->span[i] = update[i]->span[i] - (span[0] - span[i]);
update[i]->span[i] = (span[0] - span[i]) + 1;
if (i > 0) {
x->span[i-1] = update[i]->span[i-1] - (rank[0] - rank[i]);
update[i]->span[i-1] = (rank[0] - rank[i]) + 1;
}
}
/* increment span for untouched levels */
for (i = level; i < zsl->level; i++) {
update[i]->span[i]++;
update[i]->span[i-1]++;
}
x->backward = (update[0] == zsl->header) ? NULL : update[0];
@ -4970,10 +4973,14 @@ static int zslDelete(zskiplist *zsl, double score, robj *obj) {
if (x && score == x->score && compareStringObjects(x->obj,obj) == 0) {
for (i = 0; i < zsl->level; i++) {
if (update[i]->forward[i] == x) {
update[i]->span[i] += x->span[i] - 1;
if (i > 0) {
update[i]->span[i-1] += x->span[i-1] - 1;
}
update[i]->forward[i] = x->forward[i];
} else {
update[i]->span[i] -= 1;
/* invariant: i > 0, because update[0]->forward[0]
* is always equal to x */
update[i]->span[i-1] -= 1;
}
}
if (x->forward[0]) {
@ -5015,10 +5022,14 @@ static unsigned long zslDeleteRange(zskiplist *zsl, double min, double max, dict
for (i = 0; i < zsl->level; i++) {
if (update[i]->forward[i] == x) {
update[i]->span[i] += x->span[i] - 1;
if (i > 0) {
update[i]->span[i-1] += x->span[i-1] - 1;
}
update[i]->forward[i] = x->forward[i];
} else {
update[i]->span[i] -= 1;
/* invariant: i > 0, because update[0]->forward[0]
* is always equal to x */
update[i]->span[i-1] -= 1;
}
}
if (x->forward[0]) {
@ -5054,6 +5065,53 @@ static zskiplistNode *zslFirstWithScore(zskiplist *zsl, double score) {
return x->forward[0];
}
/* Find the rank for an element by both score and key.
* Returns 0 when the element cannot be found, rank otherwise.
* Note that the rank is 1-based due to the span of zsl->header to the
* first element. */
static unsigned long zslGetRank(zskiplist *zsl, double score, robj *o) {
zskiplistNode *x;
unsigned long rank = 0;
int i;
x = zsl->header;
for (i = zsl->level-1; i >= 0; i--) {
while (x->forward[i] &&
(x->forward[i]->score < score ||
(x->forward[i]->score == score &&
compareStringObjects(x->forward[i]->obj,o) <= 0))) {
rank += i > 0 ? x->span[i-1] : 1;
x = x->forward[i];
}
/* x might be equal to zsl->header, so test if obj is non-NULL */
if (x->obj && compareStringObjects(x->obj,o) == 0) {
return rank;
}
}
return 0;
}
/* Finds an element by its rank. The rank argument needs to be 1-based. */
zskiplistNode* zslGetElementByRank(zskiplist *zsl, unsigned long rank) {
zskiplistNode *x;
unsigned long traversed = 0;
int i;
x = zsl->header;
for (i = zsl->level-1; i >= 0; i--) {
while (x->forward[i] && (traversed + (i > 0 ? x->span[i-1] : 1)) <= rank) {
traversed += i > 0 ? x->span[i-1] : 1;
x = x->forward[i];
}
if (traversed == rank) {
return x;
}
}
return NULL;
}
/* The actual Z-commands implementations */
/* This generic command implements both ZADD and ZINCRBY.
@ -5253,17 +5311,15 @@ static void zrangeGenericCommand(redisClient *c, int reverse) {
if (end >= llen) end = llen-1;
rangelen = (end-start)+1;
/* Return the result in form of a multi-bulk reply */
/* check if starting point is trivial, before searching
* the element in log(N) time */
if (reverse) {
ln = zsl->tail;
while (start--)
ln = ln->backward;
ln = start == 0 ? zsl->tail : zslGetElementByRank(zsl, llen - start);
} else {
ln = zsl->header->forward[0];
while (start--)
ln = ln->forward[0];
ln = start == 0 ? zsl->header->forward[0] : zslGetElementByRank(zsl, start + 1);
}
/* Return the result in form of a multi-bulk reply */
addReplySds(c,sdscatprintf(sdsempty(),"*%d\r\n",
withscores ? (rangelen*2) : rangelen));
for (j = 0; j < rangelen; j++) {
@ -5467,42 +5523,26 @@ static void zrankCommand(redisClient *c) {
}
if (o->type != REDIS_ZSET) {
addReply(c,shared.wrongtypeerr);
return;
}
} else {
zset *zs = o->ptr;
zskiplist *zsl = zs->zsl;
dictEntry *de;
unsigned long rank;
zset *zs = o->ptr;
zskiplist *zsl = zs->zsl;
dictEntry *de = dictFind(zs->dict,c->argv[2]);
if (!de) {
addReply(c,shared.nullbulk);
return;
}
double *score = dictGetEntryVal(de);
zskiplistNode *x;
unsigned int rank = 0;
int i;
x = zsl->header;
for (i = zsl->level-1; i >= 0; i--) {
while (x->forward[i] &&
(x->forward[i]->score < *score ||
(x->forward[i]->score == *score &&
compareStringObjects(x->forward[i]->obj,c->argv[2]) <= 0))) {
rank += x->span[i];
x = x->forward[i];
}
/* x might be equal to zsl->header, so test if obj is non-NULL */
if (x->obj && compareStringObjects(x->obj,c->argv[2]) == 0) {
/* the pointer from zsl->header to the first element also spans one,
* which makes the rank 1-based */
addReplyLong(c, rank-1);
de = dictFind(zs->dict,c->argv[2]);
if (!de) {
addReply(c,shared.nullbulk);
return;
}
}
addReply(c,shared.nullbulk);
double *score = dictGetEntryVal(de);
rank = zslGetRank(zsl, *score, c->argv[2]);
if (rank) {
addReplyLong(c, rank-1);
} else {
addReply(c,shared.nullbulk);
}
}
}
/* ========================= Non type-specific commands ==================== */