diff options
Diffstat (limited to 'src/t_zset.c')
| -rw-r--r-- | src/t_zset.c | 985 |
1 files changed, 985 insertions, 0 deletions
diff --git a/src/t_zset.c b/src/t_zset.c new file mode 100644 index 000000000..de32a8eed --- /dev/null +++ b/src/t_zset.c @@ -0,0 +1,985 @@ +#include "redis.h" + +#include <math.h> + +/*----------------------------------------------------------------------------- + * Sorted set API + *----------------------------------------------------------------------------*/ + +/* ZSETs are ordered sets using two data structures to hold the same elements + * in order to get O(log(N)) INSERT and REMOVE operations into a sorted + * data structure. + * + * The elements are added to an hash table mapping Redis objects to scores. + * At the same time the elements are added to a skip list mapping scores + * to Redis objects (so objects are sorted by scores in this "view"). */ + +/* This skiplist implementation is almost a C translation of the original + * algorithm described by William Pugh in "Skip Lists: A Probabilistic + * Alternative to Balanced Trees", modified in three ways: + * a) this implementation allows for repeated values. + * b) the comparison is not just by key (our 'score') but by satellite data. + * c) there is a back pointer, so it's a doubly linked list with the back + * pointers being only at "level 1". This allows to traverse the list + * from tail to head, useful for ZREVRANGE. */ + +zskiplistNode *zslCreateNode(int level, double score, robj *obj) { + zskiplistNode *zn = zmalloc(sizeof(*zn)); + + zn->forward = zmalloc(sizeof(zskiplistNode*) * level); + if (level > 1) + zn->span = zmalloc(sizeof(unsigned int) * (level - 1)); + else + zn->span = NULL; + zn->score = score; + zn->obj = obj; + return zn; +} + +zskiplist *zslCreate(void) { + int j; + zskiplist *zsl; + + zsl = zmalloc(sizeof(*zsl)); + zsl->level = 1; + zsl->length = 0; + zsl->header = zslCreateNode(ZSKIPLIST_MAXLEVEL,0,NULL); + for (j = 0; j < ZSKIPLIST_MAXLEVEL; j++) { + zsl->header->forward[j] = NULL; + + /* span has space for ZSKIPLIST_MAXLEVEL-1 elements */ + if (j < ZSKIPLIST_MAXLEVEL-1) + zsl->header->span[j] = 0; + } + zsl->header->backward = NULL; + zsl->tail = NULL; + return zsl; +} + +void zslFreeNode(zskiplistNode *node) { + decrRefCount(node->obj); + zfree(node->forward); + zfree(node->span); + zfree(node); +} + +void zslFree(zskiplist *zsl) { + zskiplistNode *node = zsl->header->forward[0], *next; + + zfree(zsl->header->forward); + zfree(zsl->header->span); + zfree(zsl->header); + while(node) { + next = node->forward[0]; + zslFreeNode(node); + node = next; + } + zfree(zsl); +} + +int zslRandomLevel(void) { + int level = 1; + while ((random()&0xFFFF) < (ZSKIPLIST_P * 0xFFFF)) + level += 1; + return (level<ZSKIPLIST_MAXLEVEL) ? level : ZSKIPLIST_MAXLEVEL; +} + +void zslInsert(zskiplist *zsl, double score, robj *obj) { + zskiplistNode *update[ZSKIPLIST_MAXLEVEL], *x; + unsigned int rank[ZSKIPLIST_MAXLEVEL]; + int i, level; + + x = zsl->header; + for (i = zsl->level-1; i >= 0; i--) { + /* 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))) { + rank[i] += i > 0 ? x->span[i-1] : 1; + x = x->forward[i]; + } + update[i] = x; + } + /* we assume the key is not already inside, since we allow duplicated + * scores, and the re-insertion of score and redis object should never + * happpen since the caller of zslInsert() should test in the hash table + * if the element is already inside or not. */ + level = zslRandomLevel(); + if (level > zsl->level) { + for (i = zsl->level; i < level; i++) { + rank[i] = 0; + update[i] = zsl->header; + update[i]->span[i-1] = zsl->length; + } + zsl->level = level; + } + x = zslCreateNode(level,score,obj); + for (i = 0; i < level; i++) { + x->forward[i] = update[i]->forward[i]; + update[i]->forward[i] = x; + + /* update span covered by update[i] as x is inserted here */ + 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-1]++; + } + + x->backward = (update[0] == zsl->header) ? NULL : update[0]; + if (x->forward[0]) + x->forward[0]->backward = x; + else + zsl->tail = x; + zsl->length++; +} + +/* Internal function used by zslDelete, zslDeleteByScore and zslDeleteByRank */ +void zslDeleteNode(zskiplist *zsl, zskiplistNode *x, zskiplistNode **update) { + int i; + for (i = 0; i < zsl->level; i++) { + if (update[i]->forward[i] == x) { + if (i > 0) { + update[i]->span[i-1] += x->span[i-1] - 1; + } + update[i]->forward[i] = x->forward[i]; + } else { + /* invariant: i > 0, because update[0]->forward[0] + * is always equal to x */ + update[i]->span[i-1] -= 1; + } + } + if (x->forward[0]) { + x->forward[0]->backward = x->backward; + } else { + zsl->tail = x->backward; + } + while(zsl->level > 1 && zsl->header->forward[zsl->level-1] == NULL) + zsl->level--; + zsl->length--; +} + +/* Delete an element with matching score/object from the skiplist. */ +int zslDelete(zskiplist *zsl, double score, robj *obj) { + zskiplistNode *update[ZSKIPLIST_MAXLEVEL], *x; + 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,obj) < 0))) + x = x->forward[i]; + update[i] = x; + } + /* We may have multiple elements with the same score, what we need + * is to find the element with both the right score and object. */ + x = x->forward[0]; + if (x && score == x->score && equalStringObjects(x->obj,obj)) { + zslDeleteNode(zsl, x, update); + zslFreeNode(x); + return 1; + } else { + return 0; /* not found */ + } + return 0; /* not found */ +} + +/* Delete all the elements with score between min and max from the skiplist. + * Min and mx are inclusive, so a score >= min || score <= max is deleted. + * Note that this function takes the reference to the hash table view of the + * sorted set, in order to remove the elements from the hash table too. */ +unsigned long zslDeleteRangeByScore(zskiplist *zsl, double min, double max, dict *dict) { + zskiplistNode *update[ZSKIPLIST_MAXLEVEL], *x; + unsigned long removed = 0; + int i; + + x = zsl->header; + for (i = zsl->level-1; i >= 0; i--) { + while (x->forward[i] && x->forward[i]->score < min) + x = x->forward[i]; + update[i] = x; + } + /* We may have multiple elements with the same score, what we need + * is to find the element with both the right score and object. */ + x = x->forward[0]; + while (x && x->score <= max) { + zskiplistNode *next = x->forward[0]; + zslDeleteNode(zsl, x, update); + dictDelete(dict,x->obj); + zslFreeNode(x); + removed++; + x = next; + } + return removed; /* not found */ +} + +/* Delete all the elements with rank between start and end from the skiplist. + * Start and end are inclusive. Note that start and end need to be 1-based */ +unsigned long zslDeleteRangeByRank(zskiplist *zsl, unsigned int start, unsigned int end, dict *dict) { + zskiplistNode *update[ZSKIPLIST_MAXLEVEL], *x; + unsigned long traversed = 0, removed = 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)) < start) { + traversed += i > 0 ? x->span[i-1] : 1; + x = x->forward[i]; + } + update[i] = x; + } + + traversed++; + x = x->forward[0]; + while (x && traversed <= end) { + zskiplistNode *next = x->forward[0]; + zslDeleteNode(zsl, x, update); + dictDelete(dict,x->obj); + zslFreeNode(x); + removed++; + traversed++; + x = next; + } + return removed; +} + +/* Find the first node having a score equal or greater than the specified one. + * Returns NULL if there is no match. */ +zskiplistNode *zslFirstWithScore(zskiplist *zsl, double score) { + zskiplistNode *x; + int i; + + x = zsl->header; + for (i = zsl->level-1; i >= 0; i--) { + while (x->forward[i] && x->forward[i]->score < score) + x = x->forward[i]; + } + /* We may have multiple elements with the same score, what we need + * is to find the element with both the right score and object. */ + 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. */ +unsigned long zslistTypeGetRank(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 && equalStringObjects(x->obj,o)) { + return rank; + } + } + return 0; +} + +/* Finds an element by its rank. The rank argument needs to be 1-based. */ +zskiplistNode* zslistTypeGetElementByRank(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; +} + +/*----------------------------------------------------------------------------- + * Sorted set commands + *----------------------------------------------------------------------------*/ + +/* This generic command implements both ZADD and ZINCRBY. + * scoreval is the score if the operation is a ZADD (doincrement == 0) or + * the increment if the operation is a ZINCRBY (doincrement == 1). */ +void zaddGenericCommand(redisClient *c, robj *key, robj *ele, double scoreval, int doincrement) { + robj *zsetobj; + zset *zs; + double *score; + + if (isnan(scoreval)) { + addReplySds(c,sdsnew("-ERR provide score is Not A Number (nan)\r\n")); + return; + } + + zsetobj = lookupKeyWrite(c->db,key); + if (zsetobj == NULL) { + zsetobj = createZsetObject(); + dbAdd(c->db,key,zsetobj); + } else { + if (zsetobj->type != REDIS_ZSET) { + addReply(c,shared.wrongtypeerr); + return; + } + } + zs = zsetobj->ptr; + + /* Ok now since we implement both ZADD and ZINCRBY here the code + * needs to handle the two different conditions. It's all about setting + * '*score', that is, the new score to set, to the right value. */ + score = zmalloc(sizeof(double)); + if (doincrement) { + dictEntry *de; + + /* Read the old score. If the element was not present starts from 0 */ + de = dictFind(zs->dict,ele); + if (de) { + double *oldscore = dictGetEntryVal(de); + *score = *oldscore + scoreval; + } else { + *score = scoreval; + } + if (isnan(*score)) { + addReplySds(c, + sdsnew("-ERR resulting score is Not A Number (nan)\r\n")); + zfree(score); + /* Note that we don't need to check if the zset may be empty and + * should be removed here, as we can only obtain Nan as score if + * there was already an element in the sorted set. */ + return; + } + } else { + *score = scoreval; + } + + /* What follows is a simple remove and re-insert operation that is common + * to both ZADD and ZINCRBY... */ + if (dictAdd(zs->dict,ele,score) == DICT_OK) { + /* case 1: New element */ + incrRefCount(ele); /* added to hash */ + zslInsert(zs->zsl,*score,ele); + incrRefCount(ele); /* added to skiplist */ + server.dirty++; + if (doincrement) + addReplyDouble(c,*score); + else + addReply(c,shared.cone); + } else { + dictEntry *de; + double *oldscore; + + /* case 2: Score update operation */ + de = dictFind(zs->dict,ele); + redisAssert(de != NULL); + oldscore = dictGetEntryVal(de); + if (*score != *oldscore) { + int deleted; + + /* Remove and insert the element in the skip list with new score */ + deleted = zslDelete(zs->zsl,*oldscore,ele); + redisAssert(deleted != 0); + zslInsert(zs->zsl,*score,ele); + incrRefCount(ele); + /* Update the score in the hash table */ + dictReplace(zs->dict,ele,score); + server.dirty++; + } else { + zfree(score); + } + if (doincrement) + addReplyDouble(c,*score); + else + addReply(c,shared.czero); + } +} + +void zaddCommand(redisClient *c) { + double scoreval; + + if (getDoubleFromObjectOrReply(c, c->argv[2], &scoreval, NULL) != REDIS_OK) return; + zaddGenericCommand(c,c->argv[1],c->argv[3],scoreval,0); +} + +void zincrbyCommand(redisClient *c) { + double scoreval; + + if (getDoubleFromObjectOrReply(c, c->argv[2], &scoreval, NULL) != REDIS_OK) return; + zaddGenericCommand(c,c->argv[1],c->argv[3],scoreval,1); +} + +void zremCommand(redisClient *c) { + robj *zsetobj; + zset *zs; + dictEntry *de; + double *oldscore; + int deleted; + + if ((zsetobj = lookupKeyWriteOrReply(c,c->argv[1],shared.czero)) == NULL || + checkType(c,zsetobj,REDIS_ZSET)) return; + + zs = zsetobj->ptr; + de = dictFind(zs->dict,c->argv[2]); + if (de == NULL) { + addReply(c,shared.czero); + return; + } + /* Delete from the skiplist */ + oldscore = dictGetEntryVal(de); + deleted = zslDelete(zs->zsl,*oldscore,c->argv[2]); + redisAssert(deleted != 0); + + /* Delete from the hash table */ + dictDelete(zs->dict,c->argv[2]); + if (htNeedsResize(zs->dict)) dictResize(zs->dict); + if (dictSize(zs->dict) == 0) dbDelete(c->db,c->argv[1]); + server.dirty++; + addReply(c,shared.cone); +} + +void zremrangebyscoreCommand(redisClient *c) { + double min; + double max; + long deleted; + robj *zsetobj; + zset *zs; + + if ((getDoubleFromObjectOrReply(c, c->argv[2], &min, NULL) != REDIS_OK) || + (getDoubleFromObjectOrReply(c, c->argv[3], &max, NULL) != REDIS_OK)) return; + + if ((zsetobj = lookupKeyWriteOrReply(c,c->argv[1],shared.czero)) == NULL || + checkType(c,zsetobj,REDIS_ZSET)) return; + + zs = zsetobj->ptr; + deleted = zslDeleteRangeByScore(zs->zsl,min,max,zs->dict); + if (htNeedsResize(zs->dict)) dictResize(zs->dict); + if (dictSize(zs->dict) == 0) dbDelete(c->db,c->argv[1]); + server.dirty += deleted; + addReplyLongLong(c,deleted); +} + +void zremrangebyrankCommand(redisClient *c) { + long start; + long end; + int llen; + long deleted; + robj *zsetobj; + zset *zs; + + if ((getLongFromObjectOrReply(c, c->argv[2], &start, NULL) != REDIS_OK) || + (getLongFromObjectOrReply(c, c->argv[3], &end, NULL) != REDIS_OK)) return; + + if ((zsetobj = lookupKeyWriteOrReply(c,c->argv[1],shared.czero)) == NULL || + checkType(c,zsetobj,REDIS_ZSET)) return; + zs = zsetobj->ptr; + llen = zs->zsl->length; + + /* convert negative indexes */ + if (start < 0) start = llen+start; + if (end < 0) end = llen+end; + if (start < 0) start = 0; + if (end < 0) end = 0; + + /* indexes sanity checks */ + if (start > end || start >= llen) { + addReply(c,shared.czero); + return; + } + if (end >= llen) end = llen-1; + + /* increment start and end because zsl*Rank functions + * use 1-based rank */ + deleted = zslDeleteRangeByRank(zs->zsl,start+1,end+1,zs->dict); + if (htNeedsResize(zs->dict)) dictResize(zs->dict); + if (dictSize(zs->dict) == 0) dbDelete(c->db,c->argv[1]); + server.dirty += deleted; + addReplyLongLong(c, deleted); +} + +typedef struct { + dict *dict; + double weight; +} zsetopsrc; + +int qsortCompareZsetopsrcByCardinality(const void *s1, const void *s2) { + zsetopsrc *d1 = (void*) s1, *d2 = (void*) s2; + unsigned long size1, size2; + size1 = d1->dict ? dictSize(d1->dict) : 0; + size2 = d2->dict ? dictSize(d2->dict) : 0; + return size1 - size2; +} + +#define REDIS_AGGR_SUM 1 +#define REDIS_AGGR_MIN 2 +#define REDIS_AGGR_MAX 3 +#define zunionInterDictValue(_e) (dictGetEntryVal(_e) == NULL ? 1.0 : *(double*)dictGetEntryVal(_e)) + +inline static void zunionInterAggregate(double *target, double val, int aggregate) { + if (aggregate == REDIS_AGGR_SUM) { + *target = *target + val; + } else if (aggregate == REDIS_AGGR_MIN) { + *target = val < *target ? val : *target; + } else if (aggregate == REDIS_AGGR_MAX) { + *target = val > *target ? val : *target; + } else { + /* safety net */ + redisPanic("Unknown ZUNION/INTER aggregate type"); + } +} + +void zunionInterGenericCommand(redisClient *c, robj *dstkey, int op) { + int i, j, setnum; + int aggregate = REDIS_AGGR_SUM; + zsetopsrc *src; + robj *dstobj; + zset *dstzset; + dictIterator *di; + dictEntry *de; + + /* expect setnum input keys to be given */ + setnum = atoi(c->argv[2]->ptr); + if (setnum < 1) { + addReplySds(c,sdsnew("-ERR at least 1 input key is needed for ZUNIONSTORE/ZINTERSTORE\r\n")); + return; + } + + /* test if the expected number of keys would overflow */ + if (3+setnum > c->argc) { + addReply(c,shared.syntaxerr); + return; + } + + /* read keys to be used for input */ + src = zmalloc(sizeof(zsetopsrc) * setnum); + for (i = 0, j = 3; i < setnum; i++, j++) { + robj *obj = lookupKeyWrite(c->db,c->argv[j]); + if (!obj) { + src[i].dict = NULL; + } else { + if (obj->type == REDIS_ZSET) { + src[i].dict = ((zset*)obj->ptr)->dict; + } else if (obj->type == REDIS_SET) { + src[i].dict = (obj->ptr); + } else { + zfree(src); + addReply(c,shared.wrongtypeerr); + return; + } + } + + /* default all weights to 1 */ + src[i].weight = 1.0; + } + + /* parse optional extra arguments */ + if (j < c->argc) { + int remaining = c->argc - j; + + while (remaining) { + if (remaining >= (setnum + 1) && !strcasecmp(c->argv[j]->ptr,"weights")) { + j++; remaining--; + for (i = 0; i < setnum; i++, j++, remaining--) { + if (getDoubleFromObjectOrReply(c, c->argv[j], &src[i].weight, NULL) != REDIS_OK) + return; + } + } else if (remaining >= 2 && !strcasecmp(c->argv[j]->ptr,"aggregate")) { + j++; remaining--; + if (!strcasecmp(c->argv[j]->ptr,"sum")) { + aggregate = REDIS_AGGR_SUM; + } else if (!strcasecmp(c->argv[j]->ptr,"min")) { + aggregate = REDIS_AGGR_MIN; + } else if (!strcasecmp(c->argv[j]->ptr,"max")) { + aggregate = REDIS_AGGR_MAX; + } else { + zfree(src); + addReply(c,shared.syntaxerr); + return; + } + j++; remaining--; + } else { + zfree(src); + addReply(c,shared.syntaxerr); + return; + } + } + } + + /* sort sets from the smallest to largest, this will improve our + * algorithm's performance */ + qsort(src,setnum,sizeof(zsetopsrc),qsortCompareZsetopsrcByCardinality); + + dstobj = createZsetObject(); + dstzset = dstobj->ptr; + + if (op == REDIS_OP_INTER) { + /* skip going over all entries if the smallest zset is NULL or empty */ + if (src[0].dict && dictSize(src[0].dict) > 0) { + /* precondition: as src[0].dict is non-empty and the zsets are ordered + * from small to large, all src[i > 0].dict are non-empty too */ + di = dictGetIterator(src[0].dict); + while((de = dictNext(di)) != NULL) { + double *score = zmalloc(sizeof(double)), value; + *score = src[0].weight * zunionInterDictValue(de); + + for (j = 1; j < setnum; j++) { + dictEntry *other = dictFind(src[j].dict,dictGetEntryKey(de)); + if (other) { + value = src[j].weight * zunionInterDictValue(other); + zunionInterAggregate(score, value, aggregate); + } else { + break; + } + } + + /* skip entry when not present in every source dict */ + if (j != setnum) { + zfree(score); + } else { + robj *o = dictGetEntryKey(de); + dictAdd(dstzset->dict,o,score); + incrRefCount(o); /* added to dictionary */ + zslInsert(dstzset->zsl,*score,o); + incrRefCount(o); /* added to skiplist */ + } + } + dictReleaseIterator(di); + } + } else if (op == REDIS_OP_UNION) { + for (i = 0; i < setnum; i++) { + if (!src[i].dict) continue; + + di = dictGetIterator(src[i].dict); + while((de = dictNext(di)) != NULL) { + /* skip key when already processed */ + if (dictFind(dstzset->dict,dictGetEntryKey(de)) != NULL) continue; + + double *score = zmalloc(sizeof(double)), value; + *score = src[i].weight * zunionInterDictValue(de); + + /* because the zsets are sorted by size, its only possible + * for sets at larger indices to hold this entry */ + for (j = (i+1); j < setnum; j++) { + dictEntry *other = dictFind(src[j].dict,dictGetEntryKey(de)); + if (other) { + value = src[j].weight * zunionInterDictValue(other); + zunionInterAggregate(score, value, aggregate); + } + } + + robj *o = dictGetEntryKey(de); + dictAdd(dstzset->dict,o,score); + incrRefCount(o); /* added to dictionary */ + zslInsert(dstzset->zsl,*score,o); + incrRefCount(o); /* added to skiplist */ + } + dictReleaseIterator(di); + } + } else { + /* unknown operator */ + redisAssert(op == REDIS_OP_INTER || op == REDIS_OP_UNION); + } + + dbDelete(c->db,dstkey); + if (dstzset->zsl->length) { + dbAdd(c->db,dstkey,dstobj); + addReplyLongLong(c, dstzset->zsl->length); + server.dirty++; + } else { + decrRefCount(dstobj); + addReply(c, shared.czero); + } + zfree(src); +} + +void zunionstoreCommand(redisClient *c) { + zunionInterGenericCommand(c,c->argv[1], REDIS_OP_UNION); +} + +void zinterstoreCommand(redisClient *c) { + zunionInterGenericCommand(c,c->argv[1], REDIS_OP_INTER); +} + +void zrangeGenericCommand(redisClient *c, int reverse) { + robj *o; + long start; + long end; + int withscores = 0; + int llen; + int rangelen, j; + zset *zsetobj; + zskiplist *zsl; + zskiplistNode *ln; + robj *ele; + + if ((getLongFromObjectOrReply(c, c->argv[2], &start, NULL) != REDIS_OK) || + (getLongFromObjectOrReply(c, c->argv[3], &end, NULL) != REDIS_OK)) return; + + if (c->argc == 5 && !strcasecmp(c->argv[4]->ptr,"withscores")) { + withscores = 1; + } else if (c->argc >= 5) { + addReply(c,shared.syntaxerr); + return; + } + + if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.emptymultibulk)) == NULL + || checkType(c,o,REDIS_ZSET)) return; + zsetobj = o->ptr; + zsl = zsetobj->zsl; + llen = zsl->length; + + /* convert negative indexes */ + if (start < 0) start = llen+start; + if (end < 0) end = llen+end; + if (start < 0) start = 0; + if (end < 0) end = 0; + + /* indexes sanity checks */ + if (start > end || start >= llen) { + /* Out of range start or start > end result in empty list */ + addReply(c,shared.emptymultibulk); + return; + } + if (end >= llen) end = llen-1; + rangelen = (end-start)+1; + + /* check if starting point is trivial, before searching + * the element in log(N) time */ + if (reverse) { + ln = start == 0 ? zsl->tail : zslistTypeGetElementByRank(zsl, llen-start); + } else { + ln = start == 0 ? + zsl->header->forward[0] : zslistTypeGetElementByRank(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++) { + ele = ln->obj; + addReplyBulk(c,ele); + if (withscores) + addReplyDouble(c,ln->score); + ln = reverse ? ln->backward : ln->forward[0]; + } +} + +void zrangeCommand(redisClient *c) { + zrangeGenericCommand(c,0); +} + +void zrevrangeCommand(redisClient *c) { + zrangeGenericCommand(c,1); +} + +/* This command implements both ZRANGEBYSCORE and ZCOUNT. + * If justcount is non-zero, just the count is returned. */ +void genericZrangebyscoreCommand(redisClient *c, int justcount) { + robj *o; + double min, max; + int minex = 0, maxex = 0; /* are min or max exclusive? */ + int offset = 0, limit = -1; + int withscores = 0; + int badsyntax = 0; + + /* Parse the min-max interval. If one of the values is prefixed + * by the "(" character, it's considered "open". For instance + * ZRANGEBYSCORE zset (1.5 (2.5 will match min < x < max + * ZRANGEBYSCORE zset 1.5 2.5 will instead match min <= x <= max */ + if (((char*)c->argv[2]->ptr)[0] == '(') { + min = strtod((char*)c->argv[2]->ptr+1,NULL); + minex = 1; + } else { + min = strtod(c->argv[2]->ptr,NULL); + } + if (((char*)c->argv[3]->ptr)[0] == '(') { + max = strtod((char*)c->argv[3]->ptr+1,NULL); + maxex = 1; + } else { + max = strtod(c->argv[3]->ptr,NULL); + } + + /* Parse "WITHSCORES": note that if the command was called with + * the name ZCOUNT then we are sure that c->argc == 4, so we'll never + * enter the following paths to parse WITHSCORES and LIMIT. */ + if (c->argc == 5 || c->argc == 8) { + if (strcasecmp(c->argv[c->argc-1]->ptr,"withscores") == 0) + withscores = 1; + else + badsyntax = 1; + } + if (c->argc != (4 + withscores) && c->argc != (7 + withscores)) + badsyntax = 1; + if (badsyntax) { + addReplySds(c, + sdsnew("-ERR wrong number of arguments for ZRANGEBYSCORE\r\n")); + return; + } + + /* Parse "LIMIT" */ + if (c->argc == (7 + withscores) && strcasecmp(c->argv[4]->ptr,"limit")) { + addReply(c,shared.syntaxerr); + return; + } else if (c->argc == (7 + withscores)) { + offset = atoi(c->argv[5]->ptr); + limit = atoi(c->argv[6]->ptr); + if (offset < 0) offset = 0; + } + + /* Ok, lookup the key and get the range */ + o = lookupKeyRead(c->db,c->argv[1]); + if (o == NULL) { + addReply(c,justcount ? shared.czero : shared.emptymultibulk); + } else { + if (o->type != REDIS_ZSET) { + addReply(c,shared.wrongtypeerr); + } else { + zset *zsetobj = o->ptr; + zskiplist *zsl = zsetobj->zsl; + zskiplistNode *ln; + robj *ele, *lenobj = NULL; + unsigned long rangelen = 0; + + /* Get the first node with the score >= min, or with + * score > min if 'minex' is true. */ + ln = zslFirstWithScore(zsl,min); + while (minex && ln && ln->score == min) ln = ln->forward[0]; + + if (ln == NULL) { + /* No element matching the speciifed interval */ + addReply(c,justcount ? shared.czero : shared.emptymultibulk); + return; + } + + /* We don't know in advance how many matching elements there + * are in the list, so we push this object that will represent + * the multi-bulk length in the output buffer, and will "fix" + * it later */ + if (!justcount) { + lenobj = createObject(REDIS_STRING,NULL); + addReply(c,lenobj); + decrRefCount(lenobj); + } + + while(ln && (maxex ? (ln->score < max) : (ln->score <= max))) { + if (offset) { + offset--; + ln = ln->forward[0]; + continue; + } + if (limit == 0) break; + if (!justcount) { + ele = ln->obj; + addReplyBulk(c,ele); + if (withscores) + addReplyDouble(c,ln->score); + } + ln = ln->forward[0]; + rangelen++; + if (limit > 0) limit--; + } + if (justcount) { + addReplyLongLong(c,(long)rangelen); + } else { + lenobj->ptr = sdscatprintf(sdsempty(),"*%lu\r\n", + withscores ? (rangelen*2) : rangelen); + } + } + } +} + +void zrangebyscoreCommand(redisClient *c) { + genericZrangebyscoreCommand(c,0); +} + +void zcountCommand(redisClient *c) { + genericZrangebyscoreCommand(c,1); +} + +void zcardCommand(redisClient *c) { + robj *o; + zset *zs; + + if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.czero)) == NULL || + checkType(c,o,REDIS_ZSET)) return; + + zs = o->ptr; + addReplyUlong(c,zs->zsl->length); +} + +void zscoreCommand(redisClient *c) { + robj *o; + zset *zs; + dictEntry *de; + + if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.nullbulk)) == NULL || + checkType(c,o,REDIS_ZSET)) return; + + zs = o->ptr; + de = dictFind(zs->dict,c->argv[2]); + if (!de) { + addReply(c,shared.nullbulk); + } else { + double *score = dictGetEntryVal(de); + + addReplyDouble(c,*score); + } +} + +void zrankGenericCommand(redisClient *c, int reverse) { + robj *o; + zset *zs; + zskiplist *zsl; + dictEntry *de; + unsigned long rank; + double *score; + + if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.nullbulk)) == NULL || + checkType(c,o,REDIS_ZSET)) return; + + zs = o->ptr; + zsl = zs->zsl; + de = dictFind(zs->dict,c->argv[2]); + if (!de) { + addReply(c,shared.nullbulk); + return; + } + + score = dictGetEntryVal(de); + rank = zslistTypeGetRank(zsl, *score, c->argv[2]); + if (rank) { + if (reverse) { + addReplyLongLong(c, zsl->length - rank); + } else { + addReplyLongLong(c, rank-1); + } + } else { + addReply(c,shared.nullbulk); + } +} + +void zrankCommand(redisClient *c) { + zrankGenericCommand(c, 0); +} + +void zrevrankCommand(redisClient *c) { + zrankGenericCommand(c, 1); +} |