[redis.git] / src / object.c

#include "redis.h"
#include <pthread.h>

robj *createObject(int type, void *ptr) {
    robj *o;

    if (server.vm_enabled) pthread_mutex_lock(&server.obj_freelist_mutex);
    if (listLength(server.objfreelist)) {
        listNode *head = listFirst(server.objfreelist);
        o = listNodeValue(head);
        listDelNode(server.objfreelist,head);
        if (server.vm_enabled) pthread_mutex_unlock(&server.obj_freelist_mutex);
    } else {
        if (server.vm_enabled) pthread_mutex_unlock(&server.obj_freelist_mutex);
        o = zmalloc(sizeof(*o));
    }
    o->type = type;
    o->encoding = REDIS_ENCODING_RAW;
    o->ptr = ptr;
    o->refcount = 1;
    if (server.vm_enabled) {
        /* Note that this code may run in the context of an I/O thread
         * and accessing server.lruclock in theory is an error
         * (no locks). But in practice this is safe, and even if we read
         * garbage Redis will not fail. */
        o->lru = server.lruclock;
        o->storage = REDIS_VM_MEMORY;
    }
    return o;
}

robj *createStringObject(char *ptr, size_t len) {
    return createObject(REDIS_STRING,sdsnewlen(ptr,len));
}

robj *createStringObjectFromLongLong(long long value) {
    robj *o;
    if (value >= 0 && value < REDIS_SHARED_INTEGERS &&
        pthread_equal(pthread_self(),server.mainthread)) {
        incrRefCount(shared.integers[value]);
        o = shared.integers[value];
    } else {
        if (value >= LONG_MIN && value <= LONG_MAX) {
            o = createObject(REDIS_STRING, NULL);
            o->encoding = REDIS_ENCODING_INT;
            o->ptr = (void*)((long)value);
        } else {
            o = createObject(REDIS_STRING,sdsfromlonglong(value));
        }
    }
    return o;
}

robj *dupStringObject(robj *o) {
    redisAssert(o->encoding == REDIS_ENCODING_RAW);
    return createStringObject(o->ptr,sdslen(o->ptr));
}

robj *createListObject(void) {
    list *l = listCreate();
    robj *o = createObject(REDIS_LIST,l);
    listSetFreeMethod(l,decrRefCount);
    o->encoding = REDIS_ENCODING_LINKEDLIST;
    return o;
}

robj *createZiplistObject(void) {
    unsigned char *zl = ziplistNew();
    robj *o = createObject(REDIS_LIST,zl);
    o->encoding = REDIS_ENCODING_ZIPLIST;
    return o;
}

robj *createSetObject(void) {
    dict *d = dictCreate(&setDictType,NULL);
    return createObject(REDIS_SET,d);
}

robj *createHashObject(void) {
    /* All the Hashes start as zipmaps. Will be automatically converted
     * into hash tables if there are enough elements or big elements
     * inside. */
    unsigned char *zm = zipmapNew();
    robj *o = createObject(REDIS_HASH,zm);
    o->encoding = REDIS_ENCODING_ZIPMAP;
    return o;
}

robj *createZsetObject(void) {
    zset *zs = zmalloc(sizeof(*zs));

    zs->dict = dictCreate(&zsetDictType,NULL);
    zs->zsl = zslCreate();
    return createObject(REDIS_ZSET,zs);
}

void freeStringObject(robj *o) {
    if (o->encoding == REDIS_ENCODING_RAW) {
        sdsfree(o->ptr);
    }
}

void freeListObject(robj *o) {
    switch (o->encoding) {
    case REDIS_ENCODING_LINKEDLIST:
        listRelease((list*) o->ptr);
        break;
    case REDIS_ENCODING_ZIPLIST:
        zfree(o->ptr);
        break;
    default:
        redisPanic("Unknown list encoding type");
    }
}

void freeSetObject(robj *o) {
    dictRelease((dict*) o->ptr);
}

void freeZsetObject(robj *o) {
    zset *zs = o->ptr;

    dictRelease(zs->dict);
    zslFree(zs->zsl);
    zfree(zs);
}

void freeHashObject(robj *o) {
    switch (o->encoding) {
    case REDIS_ENCODING_HT:
        dictRelease((dict*) o->ptr);
        break;
    case REDIS_ENCODING_ZIPMAP:
        zfree(o->ptr);
        break;
    default:
        redisPanic("Unknown hash encoding type");
        break;
    }
}

void incrRefCount(robj *o) {
    o->refcount++;
}

void decrRefCount(void *obj) {
    robj *o = obj;

    /* Object is a swapped out value, or in the process of being loaded. */
    if (server.vm_enabled &&
        (o->storage == REDIS_VM_SWAPPED || o->storage == REDIS_VM_LOADING))
    {
        vmpointer *vp = obj;
        if (o->storage == REDIS_VM_LOADING) vmCancelThreadedIOJob(o);
        vmMarkPagesFree(vp->page,vp->usedpages);
        server.vm_stats_swapped_objects--;
        zfree(vp);
        return;
    }

    if (o->refcount <= 0) redisPanic("decrRefCount against refcount <= 0");
    /* Object is in memory, or in the process of being swapped out.
     *
     * If the object is being swapped out, abort the operation on
     * decrRefCount even if the refcount does not drop to 0: the object
     * is referenced at least two times, as value of the key AND as
     * job->val in the iojob. So if we don't invalidate the iojob, when it is
     * done but the relevant key was removed in the meantime, the
     * complete jobs handler will not find the key about the job and the
     * assert will fail. */
    if (server.vm_enabled && o->storage == REDIS_VM_SWAPPING)
        vmCancelThreadedIOJob(o);
    if (--(o->refcount) == 0) {
        switch(o->type) {
        case REDIS_STRING: freeStringObject(o); break;
        case REDIS_LIST: freeListObject(o); break;
        case REDIS_SET: freeSetObject(o); break;
        case REDIS_ZSET: freeZsetObject(o); break;
        case REDIS_HASH: freeHashObject(o); break;
        default: redisPanic("Unknown object type"); break;
        }
        o->ptr = NULL; /* defensive programming. We'll see NULL in traces. */
        if (server.vm_enabled) pthread_mutex_lock(&server.obj_freelist_mutex);
        if (listLength(server.objfreelist) > REDIS_OBJFREELIST_MAX ||
            !listAddNodeHead(server.objfreelist,o))
            zfree(o);
        if (server.vm_enabled) pthread_mutex_unlock(&server.obj_freelist_mutex);
    }
}

int checkType(redisClient *c, robj *o, int type) {
    if (o->type != type) {
        addReply(c,shared.wrongtypeerr);
        return 1;
    }
    return 0;
}

/* Try to encode a string object in order to save space */
robj *tryObjectEncoding(robj *o) {
    long value;
    sds s = o->ptr;

    if (o->encoding != REDIS_ENCODING_RAW)
        return o; /* Already encoded */

    /* It's not safe to encode shared objects: shared objects can be shared
     * everywhere in the "object space" of Redis. Encoded objects can only
     * appear as "values" (and not, for instance, as keys) */
     if (o->refcount > 1) return o;

    /* Currently we try to encode only strings */
    redisAssert(o->type == REDIS_STRING);

    /* Check if we can represent this string as a long integer */
    if (isStringRepresentableAsLong(s,&value) == REDIS_ERR) return o;

    /* Ok, this object can be encoded...
     *
     * Can I use a shared object? Only if the object is inside a given
     * range and if this is the main thread, since when VM is enabled we
     * have the constraint that I/O thread should only handle non-shared
     * objects, in order to avoid race conditions (we don't have per-object
     * locking). */
    if (value >= 0 && value < REDIS_SHARED_INTEGERS &&
        pthread_equal(pthread_self(),server.mainthread)) {
        decrRefCount(o);
        incrRefCount(shared.integers[value]);
        return shared.integers[value];
    } else {
        o->encoding = REDIS_ENCODING_INT;
        sdsfree(o->ptr);
        o->ptr = (void*) value;
        return o;
    }
}

/* Get a decoded version of an encoded object (returned as a new object).
 * If the object is already raw-encoded just increment the ref count. */
robj *getDecodedObject(robj *o) {
    robj *dec;

    if (o->encoding == REDIS_ENCODING_RAW) {
        incrRefCount(o);
        return o;
    }
    if (o->type == REDIS_STRING && o->encoding == REDIS_ENCODING_INT) {
        char buf[32];

        ll2string(buf,32,(long)o->ptr);
        dec = createStringObject(buf,strlen(buf));
        return dec;
    } else {
        redisPanic("Unknown encoding type");
    }
}

/* Compare two string objects via strcmp() or alike.
 * Note that the objects may be integer-encoded. In such a case we
 * use ll2string() to get a string representation of the numbers on the stack
 * and compare the strings, it's much faster than calling getDecodedObject().
 *
 * Important note: if objects are not integer encoded, but binary-safe strings,
 * sdscmp() from sds.c will apply memcmp() so this function ca be considered
 * binary safe. */
int compareStringObjects(robj *a, robj *b) {
    redisAssert(a->type == REDIS_STRING && b->type == REDIS_STRING);
    char bufa[128], bufb[128], *astr, *bstr;
    int bothsds = 1;

    if (a == b) return 0;
    if (a->encoding != REDIS_ENCODING_RAW) {
        ll2string(bufa,sizeof(bufa),(long) a->ptr);
        astr = bufa;
        bothsds = 0;
    } else {
        astr = a->ptr;
    }
    if (b->encoding != REDIS_ENCODING_RAW) {
        ll2string(bufb,sizeof(bufb),(long) b->ptr);
        bstr = bufb;
        bothsds = 0;
    } else {
        bstr = b->ptr;
    }
    return bothsds ? sdscmp(astr,bstr) : strcmp(astr,bstr);
}

/* Equal string objects return 1 if the two objects are the same from the
 * point of view of a string comparison, otherwise 0 is returned. Note that
 * this function is faster then checking for (compareStringObject(a,b) == 0)
 * because it can perform some more optimization. */
int equalStringObjects(robj *a, robj *b) {
    if (a->encoding != REDIS_ENCODING_RAW && b->encoding != REDIS_ENCODING_RAW){
        return a->ptr == b->ptr;
    } else {
        return compareStringObjects(a,b) == 0;
    }
}

size_t stringObjectLen(robj *o) {
    redisAssert(o->type == REDIS_STRING);
    if (o->encoding == REDIS_ENCODING_RAW) {
        return sdslen(o->ptr);
    } else {
        char buf[32];

        return ll2string(buf,32,(long)o->ptr);
    }
}

int getDoubleFromObject(robj *o, double *target) {
    double value;
    char *eptr;

    if (o == NULL) {
        value = 0;
    } else {
        redisAssert(o->type == REDIS_STRING);
        if (o->encoding == REDIS_ENCODING_RAW) {
            value = strtod(o->ptr, &eptr);
            if (eptr[0] != '\0') return REDIS_ERR;
        } else if (o->encoding == REDIS_ENCODING_INT) {
            value = (long)o->ptr;
        } else {
            redisPanic("Unknown string encoding");
        }
    }

    *target = value;
    return REDIS_OK;
}

int getDoubleFromObjectOrReply(redisClient *c, robj *o, double *target, const char *msg) {
    double value;
    if (getDoubleFromObject(o, &value) != REDIS_OK) {
        if (msg != NULL) {
            addReplySds(c, sdscatprintf(sdsempty(), "-ERR %s\r\n", msg));
        } else {
            addReplySds(c, sdsnew("-ERR value is not a double\r\n"));
        }
        return REDIS_ERR;
    }

    *target = value;
    return REDIS_OK;
}

int getLongLongFromObject(robj *o, long long *target) {
    long long value;
    char *eptr;

    if (o == NULL) {
        value = 0;
    } else {
        redisAssert(o->type == REDIS_STRING);
        if (o->encoding == REDIS_ENCODING_RAW) {
            value = strtoll(o->ptr, &eptr, 10);
            if (eptr[0] != '\0') return REDIS_ERR;
        } else if (o->encoding == REDIS_ENCODING_INT) {
            value = (long)o->ptr;
        } else {
            redisPanic("Unknown string encoding");
        }
    }

    *target = value;
    return REDIS_OK;
}

int getLongLongFromObjectOrReply(redisClient *c, robj *o, long long *target, const char *msg) {
    long long value;
    if (getLongLongFromObject(o, &value) != REDIS_OK) {
        if (msg != NULL) {
            addReplySds(c, sdscatprintf(sdsempty(), "-ERR %s\r\n", msg));
        } else {
            addReplySds(c, sdsnew("-ERR value is not an integer\r\n"));
        }
        return REDIS_ERR;
    }

    *target = value;
    return REDIS_OK;
}

int getLongFromObjectOrReply(redisClient *c, robj *o, long *target, const char *msg) {
    long long value;

    if (getLongLongFromObjectOrReply(c, o, &value, msg) != REDIS_OK) return REDIS_ERR;
    if (value < LONG_MIN || value > LONG_MAX) {
        if (msg != NULL) {
            addReplySds(c, sdscatprintf(sdsempty(), "-ERR %s\r\n", msg));
        } else {
            addReplySds(c, sdsnew("-ERR value is out of range\r\n"));
        }
        return REDIS_ERR;
    }

    *target = value;
    return REDIS_OK;
}

char *strEncoding(int encoding) {
    switch(encoding) {
    case REDIS_ENCODING_RAW: return "raw";
    case REDIS_ENCODING_INT: return "int";
    case REDIS_ENCODING_HT: return "hashtable";
    case REDIS_ENCODING_ZIPMAP: return "zipmap";
    case REDIS_ENCODING_LINKEDLIST: return "linkedlist";
    case REDIS_ENCODING_ZIPLIST: return "ziplist";
    default: return "unknown";
    }
}
Commit	Line	Data
e2641e09	1	#include "redis.h"
	2	#include <pthread.h>
	3
	4	robj createObject(int type, void ptr) {
	5	robj *o;
	6
	7	if (server.vm_enabled) pthread_mutex_lock(&server.obj_freelist_mutex);
	8	if (listLength(server.objfreelist)) {
	9	listNode *head = listFirst(server.objfreelist);
	10	o = listNodeValue(head);
	11	listDelNode(server.objfreelist,head);
	12	if (server.vm_enabled) pthread_mutex_unlock(&server.obj_freelist_mutex);
	13	} else {
2cffe299	14	if (server.vm_enabled) pthread_mutex_unlock(&server.obj_freelist_mutex);
e2641e09	15	o = zmalloc(sizeof(*o));
	16	}
	17	o->type = type;
	18	o->encoding = REDIS_ENCODING_RAW;
	19	o->ptr = ptr;
	20	o->refcount = 1;
	21	if (server.vm_enabled) {
	22	/* Note that this code may run in the context of an I/O thread
	23	* and accessing server.lruclock in theory is an error
	24	* (no locks). But in practice this is safe, and even if we read
	25	* garbage Redis will not fail. */
	26	o->lru = server.lruclock;
	27	o->storage = REDIS_VM_MEMORY;
	28	}
	29	return o;
	30	}
	31
	32	robj createStringObject(char ptr, size_t len) {
	33	return createObject(REDIS_STRING,sdsnewlen(ptr,len));
	34	}
	35
	36	robj *createStringObjectFromLongLong(long long value) {
	37	robj *o;
e002ec68	38	if (value >= 0 && value < REDIS_SHARED_INTEGERS &&
e002ec68	39	pthread_equal(pthread_self(),server.mainthread)) {
e2641e09	40	incrRefCount(shared.integers[value]);
	41	o = shared.integers[value];
	42	} else {
	43	if (value >= LONG_MIN && value <= LONG_MAX) {
	44	o = createObject(REDIS_STRING, NULL);
	45	o->encoding = REDIS_ENCODING_INT;
	46	o->ptr = (void*)((long)value);
	47	} else {
	48	o = createObject(REDIS_STRING,sdsfromlonglong(value));
	49	}
	50	}
	51	return o;
	52	}
	53
	54	robj dupStringObject(robj o) {
	55	redisAssert(o->encoding == REDIS_ENCODING_RAW);
	56	return createStringObject(o->ptr,sdslen(o->ptr));
	57	}
	58
	59	robj *createListObject(void) {
	60	list *l = listCreate();
	61	robj *o = createObject(REDIS_LIST,l);
	62	listSetFreeMethod(l,decrRefCount);
	63	o->encoding = REDIS_ENCODING_LINKEDLIST;
	64	return o;
	65	}
	66
	67	robj *createZiplistObject(void) {
	68	unsigned char *zl = ziplistNew();
	69	robj *o = createObject(REDIS_LIST,zl);
	70	o->encoding = REDIS_ENCODING_ZIPLIST;
	71	return o;
	72	}
	73
	74	robj *createSetObject(void) {
	75	dict *d = dictCreate(&setDictType,NULL);
	76	return createObject(REDIS_SET,d);
	77	}
	78
	79	robj *createHashObject(void) {
	80	/* All the Hashes start as zipmaps. Will be automatically converted
	81	* into hash tables if there are enough elements or big elements
	82	* inside. */
	83	unsigned char *zm = zipmapNew();
	84	robj *o = createObject(REDIS_HASH,zm);
	85	o->encoding = REDIS_ENCODING_ZIPMAP;
	86	return o;
	87	}
	88
	89	robj *createZsetObject(void) {
	90	zset zs = zmalloc(sizeof(zs));
	91
	92	zs->dict = dictCreate(&zsetDictType,NULL);
	93	zs->zsl = zslCreate();
	94	return createObject(REDIS_ZSET,zs);
	95	}
	96
	97	void freeStringObject(robj *o) {
	98	if (o->encoding == REDIS_ENCODING_RAW) {
	99	sdsfree(o->ptr);
	100	}
	101	}
	102
	103	void freeListObject(robj *o) {
104	switch (o->encoding) {
105	case REDIS_ENCODING_LINKEDLIST:
106	listRelease((list*) o->ptr);
107	break;
108	case REDIS_ENCODING_ZIPLIST:
109	zfree(o->ptr);
110	break;
111	default:
112	redisPanic("Unknown list encoding type");
113	}
114	}
115
116	void freeSetObject(robj *o) {
117	dictRelease((dict*) o->ptr);
118	}
119
120	void freeZsetObject(robj *o) {
121	zset *zs = o->ptr;
122
123	dictRelease(zs->dict);
124	zslFree(zs->zsl);
125	zfree(zs);
126	}
127
128	void freeHashObject(robj *o) {
129	switch (o->encoding) {
130	case REDIS_ENCODING_HT:
131	dictRelease((dict*) o->ptr);
132	break;
133	case REDIS_ENCODING_ZIPMAP:
134	zfree(o->ptr);
135	break;
136	default:
137	redisPanic("Unknown hash encoding type");
138	break;
139	}
140	}
141
142	void incrRefCount(robj *o) {
143	o->refcount++;
144	}
145
146	void decrRefCount(void *obj) {
147	robj *o = obj;
148
149	/* Object is a swapped out value, or in the process of being loaded. */
150	if (server.vm_enabled &&
151	(o->storage == REDIS_VM_SWAPPED \|\| o->storage == REDIS_VM_LOADING))
152	{
153	vmpointer *vp = obj;
154	if (o->storage == REDIS_VM_LOADING) vmCancelThreadedIOJob(o);
155	vmMarkPagesFree(vp->page,vp->usedpages);
156	server.vm_stats_swapped_objects--;
157	zfree(vp);
158	return;
159	}
160
161	if (o->refcount <= 0) redisPanic("decrRefCount against refcount <= 0");
162	/* Object is in memory, or in the process of being swapped out.
163	*
164	* If the object is being swapped out, abort the operation on
165	* decrRefCount even if the refcount does not drop to 0: the object
166	* is referenced at least two times, as value of the key AND as
167	* job->val in the iojob. So if we don't invalidate the iojob, when it is
168	* done but the relevant key was removed in the meantime, the
169	* complete jobs handler will not find the key about the job and the
170	* assert will fail. */
171	if (server.vm_enabled && o->storage == REDIS_VM_SWAPPING)
172	vmCancelThreadedIOJob(o);
173	if (--(o->refcount) == 0) {
174	switch(o->type) {
175	case REDIS_STRING: freeStringObject(o); break;
176	case REDIS_LIST: freeListObject(o); break;
177	case REDIS_SET: freeSetObject(o); break;
178	case REDIS_ZSET: freeZsetObject(o); break;
179	case REDIS_HASH: freeHashObject(o); break;
180	default: redisPanic("Unknown object type"); break;
181	}
2f996f02	182	o->ptr = NULL; /* defensive programming. We'll see NULL in traces. */
e2641e09	183	if (server.vm_enabled) pthread_mutex_lock(&server.obj_freelist_mutex);
	184	if (listLength(server.objfreelist) > REDIS_OBJFREELIST_MAX \|\|
	185	!listAddNodeHead(server.objfreelist,o))
	186	zfree(o);
	187	if (server.vm_enabled) pthread_mutex_unlock(&server.obj_freelist_mutex);
	188	}
	189	}
	190
	191	int checkType(redisClient c, robj o, int type) {
	192	if (o->type != type) {
	193	addReply(c,shared.wrongtypeerr);
	194	return 1;
	195	}
	196	return 0;
	197	}
	198
	199	/* Try to encode a string object in order to save space */
	200	robj tryObjectEncoding(robj o) {
	201	long value;
	202	sds s = o->ptr;
	203
	204	if (o->encoding != REDIS_ENCODING_RAW)
	205	return o; /* Already encoded */
	206
	207	/* It's not safe to encode shared objects: shared objects can be shared
	208	* everywhere in the "object space" of Redis. Encoded objects can only
	209	* appear as "values" (and not, for instance, as keys) */
	210	if (o->refcount > 1) return o;
	211
	212	/* Currently we try to encode only strings */
	213	redisAssert(o->type == REDIS_STRING);
	214
	215	/* Check if we can represent this string as a long integer */
	216	if (isStringRepresentableAsLong(s,&value) == REDIS_ERR) return o;
	217
0e5441d8	218	/* Ok, this object can be encoded...
	219	*
	220	* Can I use a shared object? Only if the object is inside a given
cdbea20a	221	* range and if this is the main thread, since when VM is enabled we
0e5441d8	222	* have the constraint that I/O thread should only handle non-shared
	223	* objects, in order to avoid race conditions (we don't have per-object
	224	* locking). */
	225	if (value >= 0 && value < REDIS_SHARED_INTEGERS &&
	226	pthread_equal(pthread_self(),server.mainthread)) {
e2641e09	227	decrRefCount(o);
	228	incrRefCount(shared.integers[value]);
	229	return shared.integers[value];
	230	} else {
	231	o->encoding = REDIS_ENCODING_INT;
	232	sdsfree(o->ptr);
	233	o->ptr = (void*) value;
	234	return o;
	235	}
	236	}
	237
	238	/* Get a decoded version of an encoded object (returned as a new object).
	239	* If the object is already raw-encoded just increment the ref count. */
	240	robj getDecodedObject(robj o) {
	241	robj *dec;
	242
	243	if (o->encoding == REDIS_ENCODING_RAW) {
	244	incrRefCount(o);
	245	return o;
	246	}
	247	if (o->type == REDIS_STRING && o->encoding == REDIS_ENCODING_INT) {
	248	char buf[32];
	249
	250	ll2string(buf,32,(long)o->ptr);
	251	dec = createStringObject(buf,strlen(buf));
	252	return dec;
	253	} else {
	254	redisPanic("Unknown encoding type");
	255	}
	256	}
	257
	258	/* Compare two string objects via strcmp() or alike.
	259	* Note that the objects may be integer-encoded. In such a case we
	260	* use ll2string() to get a string representation of the numbers on the stack
	261	* and compare the strings, it's much faster than calling getDecodedObject().
	262	*
	263	* Important note: if objects are not integer encoded, but binary-safe strings,
	264	* sdscmp() from sds.c will apply memcmp() so this function ca be considered
	265	* binary safe. */
	266	int compareStringObjects(robj a, robj b) {
	267	redisAssert(a->type == REDIS_STRING && b->type == REDIS_STRING);
	268	char bufa[128], bufb[128], astr, bstr;
	269	int bothsds = 1;
	270
	271	if (a == b) return 0;
	272	if (a->encoding != REDIS_ENCODING_RAW) {
	273	ll2string(bufa,sizeof(bufa),(long) a->ptr);
	274	astr = bufa;
	275	bothsds = 0;
	276	} else {
	277	astr = a->ptr;
	278	}
	279	if (b->encoding != REDIS_ENCODING_RAW) {
	280	ll2string(bufb,sizeof(bufb),(long) b->ptr);
	281	bstr = bufb;
	282	bothsds = 0;
	283	} else {
	284	bstr = b->ptr;
	285	}
	286	return bothsds ? sdscmp(astr,bstr) : strcmp(astr,bstr);
	287	}
	288
	289	/* Equal string objects return 1 if the two objects are the same from the
	290	* point of view of a string comparison, otherwise 0 is returned. Note that
291	* this function is faster then checking for (compareStringObject(a,b) == 0)
292	* because it can perform some more optimization. */
293	int equalStringObjects(robj a, robj b) {
294	if (a->encoding != REDIS_ENCODING_RAW && b->encoding != REDIS_ENCODING_RAW){
295	return a->ptr == b->ptr;
296	} else {
297	return compareStringObjects(a,b) == 0;
298	}
299	}
300
301	size_t stringObjectLen(robj *o) {
302	redisAssert(o->type == REDIS_STRING);
303	if (o->encoding == REDIS_ENCODING_RAW) {
304	return sdslen(o->ptr);
305	} else {
306	char buf[32];
307
308	return ll2string(buf,32,(long)o->ptr);
309	}
310	}
311
312	int getDoubleFromObject(robj o, double target) {
313	double value;
314	char *eptr;
315
316	if (o == NULL) {
317	value = 0;
318	} else {
319	redisAssert(o->type == REDIS_STRING);
320	if (o->encoding == REDIS_ENCODING_RAW) {
321	value = strtod(o->ptr, &eptr);
322	if (eptr[0] != '\0') return REDIS_ERR;
323	} else if (o->encoding == REDIS_ENCODING_INT) {
324	value = (long)o->ptr;
325	} else {
326	redisPanic("Unknown string encoding");
327	}
328	}
329
330	*target = value;
331	return REDIS_OK;
332	}
333
334	int getDoubleFromObjectOrReply(redisClient c, robj o, double target, const char msg) {
335	double value;
336	if (getDoubleFromObject(o, &value) != REDIS_OK) {
337	if (msg != NULL) {
338	addReplySds(c, sdscatprintf(sdsempty(), "-ERR %s\r\n", msg));
339	} else {
340	addReplySds(c, sdsnew("-ERR value is not a double\r\n"));
341	}
342	return REDIS_ERR;
343	}
344
345	*target = value;
346	return REDIS_OK;
347	}
348
349	int getLongLongFromObject(robj o, long long target) {
350	long long value;
351	char *eptr;
352
353	if (o == NULL) {
354	value = 0;
355	} else {
356	redisAssert(o->type == REDIS_STRING);
357	if (o->encoding == REDIS_ENCODING_RAW) {
358	value = strtoll(o->ptr, &eptr, 10);
359	if (eptr[0] != '\0') return REDIS_ERR;
360	} else if (o->encoding == REDIS_ENCODING_INT) {
361	value = (long)o->ptr;
362	} else {
363	redisPanic("Unknown string encoding");
364	}
365	}
366
367	*target = value;
368	return REDIS_OK;
369	}
370
371	int getLongLongFromObjectOrReply(redisClient c, robj o, long long target, const char msg) {
372	long long value;
373	if (getLongLongFromObject(o, &value) != REDIS_OK) {
374	if (msg != NULL) {
375	addReplySds(c, sdscatprintf(sdsempty(), "-ERR %s\r\n", msg));
376	} else {
377	addReplySds(c, sdsnew("-ERR value is not an integer\r\n"));
378	}
379	return REDIS_ERR;
380	}
381
382	*target = value;
383	return REDIS_OK;
384	}
385
386	int getLongFromObjectOrReply(redisClient c, robj o, long target, const char msg) {
387	long long value;
388
389	if (getLongLongFromObjectOrReply(c, o, &value, msg) != REDIS_OK) return REDIS_ERR;
390	if (value < LONG_MIN \|\| value > LONG_MAX) {
391	if (msg != NULL) {
392	addReplySds(c, sdscatprintf(sdsempty(), "-ERR %s\r\n", msg));
393	} else {
394	addReplySds(c, sdsnew("-ERR value is out of range\r\n"));
395	}
396	return REDIS_ERR;
397	}
398
399	*target = value;
400	return REDIS_OK;
401	}
402
403	char *strEncoding(int encoding) {
404	switch(encoding) {
405	case REDIS_ENCODING_RAW: return "raw";
406	case REDIS_ENCODING_INT: return "int";
407	case REDIS_ENCODING_HT: return "hashtable";
408	case REDIS_ENCODING_ZIPMAP: return "zipmap";
409	case REDIS_ENCODING_LINKEDLIST: return "linkedlist";
410	case REDIS_ENCODING_ZIPLIST: return "ziplist";
411	default: return "unknown";
412	}
413	}