fix ZRANK (realize that rank is 1-based due to the skip list header)

[redis.git] / redis.c

diff --git a/redis.c b/redis.c
index f750ca681e09cf0360b470f1917403e40e6242f2..6ad439b0c73fa179f227bdef1f6e05cb83f067c5 100644 (file)
--- a/redis.c
+++ b/redis.c
@@ -456,7 +456,7 @@ typedef struct _redisSortOperation {
 typedef struct zskiplistNode {
     struct zskiplistNode **forward;
     struct zskiplistNode *backward;
-    unsigned long *span;
+    unsigned int *span;
     double score;
     robj *obj;
 } zskiplistNode;
@@ -659,6 +659,7 @@ static void discardCommand(redisClient *c);
 static void blpopCommand(redisClient *c);
 static void brpopCommand(redisClient *c);
 static void appendCommand(redisClient *c);
+static void substrCommand(redisClient *c);
 static void zrankCommand(redisClient *c);
 
 /*================================= Globals ================================= */
@@ -670,6 +671,7 @@ static struct redisCommand cmdTable[] = {
     {"set",setCommand,3,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,0,0,0},
     {"setnx",setnxCommand,3,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,0,0,0},
     {"append",appendCommand,3,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,1,1,1},
+    {"substr",substrCommand,4,REDIS_CMD_INLINE,1,1,1},
     {"del",delCommand,-2,REDIS_CMD_INLINE,0,0,0},
     {"exists",existsCommand,2,REDIS_CMD_INLINE,1,1,1},
     {"incr",incrCommand,2,REDIS_CMD_INLINE|REDIS_CMD_DENYOOM,1,1,1},
@@ -3764,6 +3766,45 @@ static void appendCommand(redisClient *c) {
     addReplySds(c,sdscatprintf(sdsempty(),":%lu\r\n",(unsigned long)totlen));
 }
 
+static void substrCommand(redisClient *c) {
+    robj *o;
+    long start = atoi(c->argv[2]->ptr);
+    long end = atoi(c->argv[3]->ptr);
+
+    o = lookupKeyRead(c->db,c->argv[1]);
+    if (o == NULL) {
+        addReply(c,shared.nullbulk);
+    } else {
+        if (o->type != REDIS_STRING) {
+            addReply(c,shared.wrongtypeerr);
+        } else {
+            size_t rangelen, strlen = sdslen(o->ptr);
+            sds range;
+
+            /* convert negative indexes */
+            if (start < 0) start = strlen+start;
+            if (end < 0) end = strlen+end;
+            if (start < 0) start = 0;
+            if (end < 0) end = 0;
+
+            /* indexes sanity checks */
+            if (start > end || (size_t)start >= strlen) {
+                /* Out of range start or start > end result in null reply */
+                addReply(c,shared.nullbulk);
+                return;
+            }
+            if ((size_t)end >= strlen) end = strlen-1;
+            rangelen = (end-start)+1;
+
+            /* Return the result */
+            addReplySds(c,sdscatprintf(sdsempty(),"$%lu\r\n",rangelen));
+            range = sdsnewlen((char*)o->ptr+start,rangelen);
+            addReplySds(c,range);
+            addReply(c,shared.crlf);
+        }
+    }
+}
+
 /* ========================= Type agnostic commands ========================= */
 
 static void delCommand(redisClient *c) {
@@ -4798,7 +4839,7 @@ 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 long) * level);
+    zn->span = zmalloc(sizeof(unsigned int) * level);
     zn->score = score;
     zn->obj = obj;
     return zn;
@@ -4851,7 +4892,7 @@ static int zslRandomLevel(void) {
 
 static void zslInsert(zskiplist *zsl, double score, robj *obj) {
     zskiplistNode *update[ZSKIPLIST_MAXLEVEL], *x;
-    unsigned long span[ZSKIPLIST_MAXLEVEL];
+    unsigned int span[ZSKIPLIST_MAXLEVEL];
     int i, level;
 
     x = zsl->header;
@@ -5434,7 +5475,7 @@ static void zrankCommand(redisClient *c) {
 
     double *score = dictGetEntryVal(de);
     zskiplistNode *x;
-    unsigned long rank = 0;
+    unsigned int rank = 0;
     int i;
 
     x = zsl->header;
@@ -5442,13 +5483,16 @@ static void zrankCommand(redisClient *c) {
         while (x->forward[i] &&
             (x->forward[i]->score < *score ||
                 (x->forward[i]->score == *score &&
-                compareStringObjects(x->forward[i]->obj,c->argv[2]) < 0))) {
+                compareStringObjects(x->forward[i]->obj,c->argv[2]) <= 0))) {
             rank += x->span[i];
             x = x->forward[i];
         }
 
-        if (x->forward[i] && compareStringObjects(x->forward[i]->obj,c->argv[2]) == 0) {
-            addReplyLong(c, rank);
+        /* 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);
             return;
         }
     }