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update LRANGE to use basic iteration code to support dual encoding

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This commit is contained in:
Pieter Noordhuis 2010-05-30 02:15:34 +02:00
parent 697bd5673f
commit a6dd455b09
1 changed files with 79 additions and 10 deletions
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89
redis.c
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@ -4836,6 +4836,77 @@ static unsigned long lLength(robj *subject) {
}
}
/* Structure to hold set iteration abstraction. */
typedef struct {
robj *subject;
unsigned char encoding;
unsigned char *zi;
listNode *ln;
} lIterator;
/* Initialize an iterator at the specified index. */
static lIterator *lInitIterator(robj *subject, int index) {
lIterator *li = zmalloc(sizeof(lIterator));
li->subject = subject;
li->encoding = subject->encoding;
if (li->encoding == REDIS_ENCODING_ZIPLIST) {
li->zi = ziplistIndex(subject->ptr,index);
} else if (li->encoding == REDIS_ENCODING_LIST) {
li->ln = listIndex(subject->ptr,index);
} else {
redisPanic("Unknown list encoding");
}
return li;
}
/* Clean up the iterator. */
static void lReleaseIterator(lIterator *li) {
zfree(li);
}
/* Return entry or NULL at the current position of the iterator. */
static robj *lGet(lIterator *li) {
robj *value = NULL;
if (li->encoding == REDIS_ENCODING_ZIPLIST) {
char *v;
unsigned int vlen;
long long vval;
redisAssert(li->zi != NULL);
if (ziplistGet(li->zi,&v,&vlen,&vval)) {
if (v) {
value = createStringObject(v,vlen);
} else {
value = createStringObjectFromLongLong(vval);
}
}
} else if (li->encoding == REDIS_ENCODING_LIST) {
redisAssert(li->ln != NULL);
value = listNodeValue(li->ln);
incrRefCount(value);
} else {
redisPanic("Unknown list encoding");
}
return value;
}
/* Move to the next or previous entry in the list. */
static void lMove(lIterator *li, int where) {
if (li->encoding == REDIS_ENCODING_ZIPLIST) {
redisAssert(li->zi != NULL);
if (where == REDIS_HEAD)
li->zi = ziplistPrev(li->zi);
else
li->zi = ziplistNext(li->zi);
} else if (li->encoding == REDIS_ENCODING_LIST) {
redisAssert(li->ln != NULL);
if (where == REDIS_HEAD)
li->ln = li->ln->prev;
else
li->ln = li->ln->next;
} else {
redisPanic("Unknown list encoding");
}
}
static void pushGenericCommand(redisClient *c, int where) {
robj *lobj = lookupKeyWrite(c->db,c->argv[1]);
@ -4968,19 +5039,15 @@ static void rpopCommand(redisClient *c) {
}
static void lrangeCommand(redisClient *c) {
robj *o;
robj *o, *value;
int start = atoi(c->argv[2]->ptr);
int end = atoi(c->argv[3]->ptr);
int llen;
int rangelen, j;
list *list;
listNode *ln;
robj *ele;
if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.emptymultibulk)) == NULL
|| checkType(c,o,REDIS_LIST)) return;
list = o->ptr;
llen = listLength(list);
llen = lLength(o);
/* convert negative indexes */
if (start < 0) start = llen+start;
@ -4998,13 +5065,15 @@ static void lrangeCommand(redisClient *c) {
rangelen = (end-start)+1;
/* Return the result in form of a multi-bulk reply */
ln = listIndex(list, start);
addReplySds(c,sdscatprintf(sdsempty(),"*%d\r\n",rangelen));
lIterator *li = lInitIterator(o,start);
for (j = 0; j < rangelen; j++) {
ele = listNodeValue(ln);
addReplyBulk(c,ele);
ln = ln->next;
value = lGet(li);
redisAssert(value != NULL);
addReplyBulk(c,value);
lMove(li,REDIS_TAIL);
}
lReleaseIterator(li);
}
static void ltrimCommand(redisClient *c) {