src/object.c

#include "redis.h"
#include <pthread.h>
#include <math.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' || isnan(value)) 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;
            if (errno == ERANGE && (value == LLONG_MIN || value == LLONG_MAX))
                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 or out of range\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
	1	#include "redis.h"
	2	#include <pthread.h>
	3	#include <math.h>
	4
	5	robj createObject(int type, void ptr) {
	6	robj *o;
	7
	8	if (server.vm_enabled) pthread_mutex_lock(&server.obj_freelist_mutex);
	9	if (listLength(server.objfreelist)) {
	10	listNode *head = listFirst(server.objfreelist);
	11	o = listNodeValue(head);
	12	listDelNode(server.objfreelist,head);
	13	if (server.vm_enabled) pthread_mutex_unlock(&server.obj_freelist_mutex);
	14	} else {
	15	if (server.vm_enabled) pthread_mutex_unlock(&server.obj_freelist_mutex);
	16	o = zmalloc(sizeof(*o));
	17	}
	18	o->type = type;
	19	o->encoding = REDIS_ENCODING_RAW;
	20	o->ptr = ptr;
	21	o->refcount = 1;
	22	if (server.vm_enabled) {
	23	/* Note that this code may run in the context of an I/O thread
	24	* and accessing server.lruclock in theory is an error
	25	* (no locks). But in practice this is safe, and even if we read
	26	* garbage Redis will not fail. */
	27	o->lru = server.lruclock;
	28	o->storage = REDIS_VM_MEMORY;
	29	}
	30	return o;
	31	}
	32
	33	robj createStringObject(char ptr, size_t len) {
	34	return createObject(REDIS_STRING,sdsnewlen(ptr,len));
	35	}
	36
	37	robj *createStringObjectFromLongLong(long long value) {
	38	robj *o;
	39	if (value >= 0 && value < REDIS_SHARED_INTEGERS &&
	40	pthread_equal(pthread_self(),server.mainthread)) {
	41	incrRefCount(shared.integers[value]);
	42	o = shared.integers[value];
	43	} else {
	44	if (value >= LONG_MIN && value <= LONG_MAX) {
	45	o = createObject(REDIS_STRING, NULL);
	46	o->encoding = REDIS_ENCODING_INT;
	47	o->ptr = (void*)((long)value);
	48	} else {
	49	o = createObject(REDIS_STRING,sdsfromlonglong(value));
	50	}
	51	}
	52	return o;
	53	}
	54
	55	robj dupStringObject(robj o) {
	56	redisAssert(o->encoding == REDIS_ENCODING_RAW);
	57	return createStringObject(o->ptr,sdslen(o->ptr));
	58	}
	59
	60	robj *createListObject(void) {
	61	list *l = listCreate();
	62	robj *o = createObject(REDIS_LIST,l);
	63	listSetFreeMethod(l,decrRefCount);
	64	o->encoding = REDIS_ENCODING_LINKEDLIST;
	65	return o;
	66	}
	67
	68	robj *createZiplistObject(void) {
	69	unsigned char *zl = ziplistNew();
	70	robj *o = createObject(REDIS_LIST,zl);
	71	o->encoding = REDIS_ENCODING_ZIPLIST;
	72	return o;
	73	}
	74
	75	robj *createSetObject(void) {
	76	dict *d = dictCreate(&setDictType,NULL);
	77	return createObject(REDIS_SET,d);
	78	}
	79
	80	robj *createHashObject(void) {
	81	/* All the Hashes start as zipmaps. Will be automatically converted
	82	* into hash tables if there are enough elements or big elements
	83	* inside. */
	84	unsigned char *zm = zipmapNew();
	85	robj *o = createObject(REDIS_HASH,zm);
	86	o->encoding = REDIS_ENCODING_ZIPMAP;
	87	return o;
	88	}
	89
	90	robj *createZsetObject(void) {
	91	zset zs = zmalloc(sizeof(zs));
	92
	93	zs->dict = dictCreate(&zsetDictType,NULL);
	94	zs->zsl = zslCreate();
	95	return createObject(REDIS_ZSET,zs);
	96	}
	97
	98	void freeStringObject(robj *o) {
	99	if (o->encoding == REDIS_ENCODING_RAW) {
	100	sdsfree(o->ptr);
	101	}
	102	}
	103
	104	void freeListObject(robj *o) {
	105	switch (o->encoding) {
	106	case REDIS_ENCODING_LINKEDLIST:
	107	listRelease((list*) o->ptr);
	108	break;
	109	case REDIS_ENCODING_ZIPLIST:
	110	zfree(o->ptr);
	111	break;
	112	default:
	113	redisPanic("Unknown list encoding type");
	114	}
	115	}
	116
	117	void freeSetObject(robj *o) {
	118	dictRelease((dict*) o->ptr);
	119	}
	120
	121	void freeZsetObject(robj *o) {
	122	zset *zs = o->ptr;
	123
	124	dictRelease(zs->dict);
	125	zslFree(zs->zsl);
	126	zfree(zs);
	127	}
	128
	129	void freeHashObject(robj *o) {
	130	switch (o->encoding) {
	131	case REDIS_ENCODING_HT:
	132	dictRelease((dict*) o->ptr);
	133	break;
	134	case REDIS_ENCODING_ZIPMAP:
	135	zfree(o->ptr);
	136	break;
	137	default:
	138	redisPanic("Unknown hash encoding type");
	139	break;
	140	}
	141	}
	142
	143	void incrRefCount(robj *o) {
	144	o->refcount++;
	145	}
	146
	147	void decrRefCount(void *obj) {
	148	robj *o = obj;
	149
	150	/* Object is a swapped out value, or in the process of being loaded. */
	151	if (server.vm_enabled &&
	152	(o->storage == REDIS_VM_SWAPPED \|\| o->storage == REDIS_VM_LOADING))
	153	{
	154	vmpointer *vp = obj;
	155	if (o->storage == REDIS_VM_LOADING) vmCancelThreadedIOJob(o);
	156	vmMarkPagesFree(vp->page,vp->usedpages);
	157	server.vm_stats_swapped_objects--;
	158	zfree(vp);
	159	return;
	160	}
	161
	162	if (o->refcount <= 0) redisPanic("decrRefCount against refcount <= 0");
	163	/* Object is in memory, or in the process of being swapped out.
	164	*
	165	* If the object is being swapped out, abort the operation on
	166	* decrRefCount even if the refcount does not drop to 0: the object
	167	* is referenced at least two times, as value of the key AND as
	168	* job->val in the iojob. So if we don't invalidate the iojob, when it is
	169	* done but the relevant key was removed in the meantime, the
	170	* complete jobs handler will not find the key about the job and the
	171	* assert will fail. */
	172	if (server.vm_enabled && o->storage == REDIS_VM_SWAPPING)
	173	vmCancelThreadedIOJob(o);
	174	if (--(o->refcount) == 0) {
	175	switch(o->type) {
	176	case REDIS_STRING: freeStringObject(o); break;
	177	case REDIS_LIST: freeListObject(o); break;
	178	case REDIS_SET: freeSetObject(o); break;
	179	case REDIS_ZSET: freeZsetObject(o); break;
	180	case REDIS_HASH: freeHashObject(o); break;
	181	default: redisPanic("Unknown object type"); break;
	182	}
	183	o->ptr = NULL; /* defensive programming. We'll see NULL in traces. */
	184	if (server.vm_enabled) pthread_mutex_lock(&server.obj_freelist_mutex);
	185	if (listLength(server.objfreelist) > REDIS_OBJFREELIST_MAX \|\|
	186	!listAddNodeHead(server.objfreelist,o))
	187	zfree(o);
	188	if (server.vm_enabled) pthread_mutex_unlock(&server.obj_freelist_mutex);
	189	}
	190	}
	191
	192	int checkType(redisClient c, robj o, int type) {
	193	if (o->type != type) {
	194	addReply(c,shared.wrongtypeerr);
	195	return 1;
	196	}
	197	return 0;
	198	}
	199
	200	/* Try to encode a string object in order to save space */
	201	robj tryObjectEncoding(robj o) {
	202	long value;
	203	sds s = o->ptr;
	204
	205	if (o->encoding != REDIS_ENCODING_RAW)
	206	return o; /* Already encoded */
	207
	208	/* It's not safe to encode shared objects: shared objects can be shared
	209	* everywhere in the "object space" of Redis. Encoded objects can only
	210	* appear as "values" (and not, for instance, as keys) */
	211	if (o->refcount > 1) return o;
	212
	213	/* Currently we try to encode only strings */
	214	redisAssert(o->type == REDIS_STRING);
	215
	216	/* Check if we can represent this string as a long integer */
	217	if (isStringRepresentableAsLong(s,&value) == REDIS_ERR) return o;
	218
	219	/* Ok, this object can be encoded...
	220	*
	221	* Can I use a shared object? Only if the object is inside a given
	222	* range and if this is the main thread, since when VM is enabled we
	223	* have the constraint that I/O thread should only handle non-shared
	224	* objects, in order to avoid race conditions (we don't have per-object
	225	* locking). */
	226	if (value >= 0 && value < REDIS_SHARED_INTEGERS &&
	227	pthread_equal(pthread_self(),server.mainthread)) {
	228	decrRefCount(o);
	229	incrRefCount(shared.integers[value]);
	230	return shared.integers[value];
	231	} else {
	232	o->encoding = REDIS_ENCODING_INT;
	233	sdsfree(o->ptr);
	234	o->ptr = (void*) value;
	235	return o;
	236	}
	237	}
	238
	239	/* Get a decoded version of an encoded object (returned as a new object).
	240	* If the object is already raw-encoded just increment the ref count. */
	241	robj getDecodedObject(robj o) {
	242	robj *dec;
	243
	244	if (o->encoding == REDIS_ENCODING_RAW) {
	245	incrRefCount(o);
	246	return o;
	247	}
	248	if (o->type == REDIS_STRING && o->encoding == REDIS_ENCODING_INT) {
	249	char buf[32];
	250
	251	ll2string(buf,32,(long)o->ptr);
	252	dec = createStringObject(buf,strlen(buf));
	253	return dec;
	254	} else {
	255	redisPanic("Unknown encoding type");
	256	}
	257	}
	258
	259	/* Compare two string objects via strcmp() or alike.
	260	* Note that the objects may be integer-encoded. In such a case we
	261	* use ll2string() to get a string representation of the numbers on the stack
	262	* and compare the strings, it's much faster than calling getDecodedObject().
	263	*
	264	* Important note: if objects are not integer encoded, but binary-safe strings,
	265	* sdscmp() from sds.c will apply memcmp() so this function ca be considered
	266	* binary safe. */
	267	int compareStringObjects(robj a, robj b) {
	268	redisAssert(a->type == REDIS_STRING && b->type == REDIS_STRING);
	269	char bufa[128], bufb[128], astr, bstr;
	270	int bothsds = 1;
	271
	272	if (a == b) return 0;
	273	if (a->encoding != REDIS_ENCODING_RAW) {
	274	ll2string(bufa,sizeof(bufa),(long) a->ptr);
	275	astr = bufa;
	276	bothsds = 0;
	277	} else {
	278	astr = a->ptr;
	279	}
	280	if (b->encoding != REDIS_ENCODING_RAW) {
	281	ll2string(bufb,sizeof(bufb),(long) b->ptr);
	282	bstr = bufb;
	283	bothsds = 0;
	284	} else {
	285	bstr = b->ptr;
	286	}
	287	return bothsds ? sdscmp(astr,bstr) : strcmp(astr,bstr);
	288	}
	289
	290	/* Equal string objects return 1 if the two objects are the same from the
	291	* point of view of a string comparison, otherwise 0 is returned. Note that
	292	* this function is faster then checking for (compareStringObject(a,b) == 0)
	293	* because it can perform some more optimization. */
	294	int equalStringObjects(robj a, robj b) {
	295	if (a->encoding != REDIS_ENCODING_RAW && b->encoding != REDIS_ENCODING_RAW){
	296	return a->ptr == b->ptr;
	297	} else {
	298	return compareStringObjects(a,b) == 0;
	299	}
	300	}
	301
	302	size_t stringObjectLen(robj *o) {
	303	redisAssert(o->type == REDIS_STRING);
	304	if (o->encoding == REDIS_ENCODING_RAW) {
	305	return sdslen(o->ptr);
	306	} else {
	307	char buf[32];
	308
	309	return ll2string(buf,32,(long)o->ptr);
	310	}
	311	}
	312
	313	int getDoubleFromObject(robj o, double target) {
	314	double value;
	315	char *eptr;
	316
	317	if (o == NULL) {
	318	value = 0;
	319	} else {
	320	redisAssert(o->type == REDIS_STRING);
	321	if (o->encoding == REDIS_ENCODING_RAW) {
	322	value = strtod(o->ptr, &eptr);
	323	if (eptr[0] != '\0' \|\| isnan(value)) return REDIS_ERR;
	324	} else if (o->encoding == REDIS_ENCODING_INT) {
	325	value = (long)o->ptr;
	326	} else {
	327	redisPanic("Unknown string encoding");
	328	}
	329	}
	330
	331	*target = value;
	332	return REDIS_OK;
	333	}
	334
	335	int getDoubleFromObjectOrReply(redisClient c, robj o, double target, const char msg) {
	336	double value;
	337	if (getDoubleFromObject(o, &value) != REDIS_OK) {
	338	if (msg != NULL) {
	339	addReplySds(c, sdscatprintf(sdsempty(), "-ERR %s\r\n", msg));
	340	} else {
	341	addReplySds(c, sdsnew("-ERR value is not a double\r\n"));
	342	}
	343	return REDIS_ERR;
	344	}
	345
	346	*target = value;
	347	return REDIS_OK;
	348	}
	349
	350	int getLongLongFromObject(robj o, long long target) {
	351	long long value;
	352	char *eptr;
	353
	354	if (o == NULL) {
	355	value = 0;
	356	} else {
	357	redisAssert(o->type == REDIS_STRING);
	358	if (o->encoding == REDIS_ENCODING_RAW) {
	359	value = strtoll(o->ptr, &eptr, 10);
	360	if (eptr[0] != '\0') return REDIS_ERR;
	361	if (errno == ERANGE && (value == LLONG_MIN \|\| value == LLONG_MAX))
	362	return REDIS_ERR;
	363	} else if (o->encoding == REDIS_ENCODING_INT) {
	364	value = (long)o->ptr;
	365	} else {
	366	redisPanic("Unknown string encoding");
	367	}
	368	}
	369
	370	*target = value;
	371	return REDIS_OK;
	372	}
	373
	374	int getLongLongFromObjectOrReply(redisClient c, robj o, long long target, const char msg) {
	375	long long value;
	376	if (getLongLongFromObject(o, &value) != REDIS_OK) {
	377	if (msg != NULL) {
	378	addReplySds(c, sdscatprintf(sdsempty(), "-ERR %s\r\n", msg));
	379	} else {
	380	addReplySds(c, sdsnew("-ERR value is not an integer or out of range\r\n"));
	381	}
	382	return REDIS_ERR;
	383	}
	384
	385	*target = value;
	386	return REDIS_OK;
	387	}
	388
	389	int getLongFromObjectOrReply(redisClient c, robj o, long target, const char msg) {
	390	long long value;
	391
	392	if (getLongLongFromObjectOrReply(c, o, &value, msg) != REDIS_OK) return REDIS_ERR;
	393	if (value < LONG_MIN \|\| value > LONG_MAX) {
	394	if (msg != NULL) {
	395	addReplySds(c, sdscatprintf(sdsempty(), "-ERR %s\r\n", msg));
	396	} else {
	397	addReplySds(c, sdsnew("-ERR value is out of range\r\n"));
	398	}
	399	return REDIS_ERR;
	400	}
	401
	402	*target = value;
	403	return REDIS_OK;
	404	}
	405
	406	char *strEncoding(int encoding) {
	407	switch(encoding) {
	408	case REDIS_ENCODING_RAW: return "raw";
	409	case REDIS_ENCODING_INT: return "int";
	410	case REDIS_ENCODING_HT: return "hashtable";
	411	case REDIS_ENCODING_ZIPMAP: return "zipmap";
	412	case REDIS_ENCODING_LINKEDLIST: return "linkedlist";
	413	case REDIS_ENCODING_ZIPLIST: return "ziplist";
	414	default: return "unknown";
	415	}
	416	}