[redis.git] / src / object.c

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

robj *createObject(int type, void *ptr) {
    robj *o = zmalloc(sizeof(*o));
    o->type = type;
    o->encoding = REDIS_ENCODING_RAW;
    o->ptr = ptr;
    o->refcount = 1;

    /* Set the LRU to the current lruclock (minutes resolution).
     * We do this regardless of the fact VM is active as LRU is also
     * used for the maxmemory directive when Redis is used as cache.
     *
     * 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;
    /* The following is only needed if VM is active, but since the conditional
     * is probably more costly than initializing the field it's better to
     * have every field properly initialized anyway. */
    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);
    robj *o = createObject(REDIS_SET,d);
    o->encoding = REDIS_ENCODING_HT;
    return o;
}

robj *createIntsetObject(void) {
    intset *is = intsetNew();
    robj *o = createObject(REDIS_SET,is);
    o->encoding = REDIS_ENCODING_INTSET;
    return o;
}

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) {
    switch (o->encoding) {
    case REDIS_ENCODING_HT:
        dictRelease((dict*) o->ptr);
        break;
    case REDIS_ENCODING_INTSET:
        zfree(o->ptr);
        break;
    default:
        redisPanic("Unknown set encoding type");
    }
}

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. */
        zfree(o);
    }
}

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).
     *
     * Note that we also avoid using shared integers when maxmemory is used
     * because very object needs to have a private LRU field for the LRU
     * algorithm to work well. */
    if (server.maxmemory == 0 && 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) {
            addReplyError(c,(char*)msg);
        } else {
            addReplyError(c,"value is not a double");
        }
        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");
        }
    }

    if (target) *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) {
            addReplyError(c,(char*)msg);
        } else {
            addReplyError(c,"value is not an integer or out of range");
        }
        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) {
            addReplyError(c,(char*)msg);
        } else {
            addReplyError(c,"value is out of range");
        }
        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";
    case REDIS_ENCODING_INTSET: return "intset";
    default: return "unknown";
    }
}

/* Given an object returns the min number of seconds the object was never
 * requested, using an approximated LRU algorithm. */
unsigned long estimateObjectIdleTime(robj *o) {
    if (server.lruclock >= o->lru) {
        return (server.lruclock - o->lru) * REDIS_LRU_CLOCK_RESOLUTION;
    } else {
        return ((REDIS_LRU_CLOCK_MAX - o->lru) + server.lruclock) *
                    REDIS_LRU_CLOCK_RESOLUTION;
    }
}
Commit	Line	Data
e2641e09	1	#include "redis.h"
e2641e09	2	#include <pthread.h>
673e1fb7	3	#include <math.h>
e2641e09	4
e2641e09	5	robj createObject(int type, void ptr) {
a9b18e54	6	robj o = zmalloc(sizeof(o));
e2641e09	7	o->type = type;
	8	o->encoding = REDIS_ENCODING_RAW;
	9	o->ptr = ptr;
	10	o->refcount = 1;
a9b18e54	11
ef59a8bc	12	/* Set the LRU to the current lruclock (minutes resolution).
	13	* We do this regardless of the fact VM is active as LRU is also
	14	* used for the maxmemory directive when Redis is used as cache.
	15	*
	16	* Note that this code may run in the context of an I/O thread
	17	* and accessing server.lruclock in theory is an error
	18	* (no locks). But in practice this is safe, and even if we read
	19	* garbage Redis will not fail. */
	20	o->lru = server.lruclock;
	21	/* The following is only needed if VM is active, but since the conditional
	22	* is probably more costly than initializing the field it's better to
	23	* have every field properly initialized anyway. */
	24	o->storage = REDIS_VM_MEMORY;
e2641e09	25	return o;
	26	}
	27
	28	robj createStringObject(char ptr, size_t len) {
	29	return createObject(REDIS_STRING,sdsnewlen(ptr,len));
	30	}
	31
	32	robj *createStringObjectFromLongLong(long long value) {
	33	robj *o;
e002ec68	34	if (value >= 0 && value < REDIS_SHARED_INTEGERS &&
e002ec68	35	pthread_equal(pthread_self(),server.mainthread)) {
e2641e09	36	incrRefCount(shared.integers[value]);
	37	o = shared.integers[value];
	38	} else {
	39	if (value >= LONG_MIN && value <= LONG_MAX) {
	40	o = createObject(REDIS_STRING, NULL);
	41	o->encoding = REDIS_ENCODING_INT;
	42	o->ptr = (void*)((long)value);
	43	} else {
	44	o = createObject(REDIS_STRING,sdsfromlonglong(value));
	45	}
	46	}
	47	return o;
	48	}
	49
	50	robj dupStringObject(robj o) {
	51	redisAssert(o->encoding == REDIS_ENCODING_RAW);
	52	return createStringObject(o->ptr,sdslen(o->ptr));
	53	}
	54
	55	robj *createListObject(void) {
	56	list *l = listCreate();
	57	robj *o = createObject(REDIS_LIST,l);
	58	listSetFreeMethod(l,decrRefCount);
	59	o->encoding = REDIS_ENCODING_LINKEDLIST;
	60	return o;
	61	}
	62
	63	robj *createZiplistObject(void) {
	64	unsigned char *zl = ziplistNew();
	65	robj *o = createObject(REDIS_LIST,zl);
	66	o->encoding = REDIS_ENCODING_ZIPLIST;
	67	return o;
	68	}
	69
	70	robj *createSetObject(void) {
	71	dict *d = dictCreate(&setDictType,NULL);
96ffb2fe PN	72	robj *o = createObject(REDIS_SET,d);
	73	o->encoding = REDIS_ENCODING_HT;
	74	return o;
	75	}
	76
	77	robj *createIntsetObject(void) {
	78	intset *is = intsetNew();
	79	robj *o = createObject(REDIS_SET,is);
	80	o->encoding = REDIS_ENCODING_INTSET;
	81	return o;
e2641e09	82	}
	83
	84	robj *createHashObject(void) {
	85	/* All the Hashes start as zipmaps. Will be automatically converted
	86	* into hash tables if there are enough elements or big elements
	87	* inside. */
	88	unsigned char *zm = zipmapNew();
	89	robj *o = createObject(REDIS_HASH,zm);
	90	o->encoding = REDIS_ENCODING_ZIPMAP;
	91	return o;
	92	}
	93
	94	robj *createZsetObject(void) {
	95	zset zs = zmalloc(sizeof(zs));
	96
	97	zs->dict = dictCreate(&zsetDictType,NULL);
	98	zs->zsl = zslCreate();
	99	return createObject(REDIS_ZSET,zs);
	100	}
	101
	102	void freeStringObject(robj *o) {
	103	if (o->encoding == REDIS_ENCODING_RAW) {
	104	sdsfree(o->ptr);
	105	}
	106	}
	107
	108	void freeListObject(robj *o) {
	109	switch (o->encoding) {
	110	case REDIS_ENCODING_LINKEDLIST:
	111	listRelease((list*) o->ptr);
	112	break;
	113	case REDIS_ENCODING_ZIPLIST:
	114	zfree(o->ptr);
	115	break;
	116	default:
	117	redisPanic("Unknown list encoding type");
	118	}
	119	}
	120
	121	void freeSetObject(robj *o) {
96ffb2fe PN	122	switch (o->encoding) {
	123	case REDIS_ENCODING_HT:
	124	dictRelease((dict*) o->ptr);
	125	break;
	126	case REDIS_ENCODING_INTSET:
	127	zfree(o->ptr);
	128	break;
	129	default:
	130	redisPanic("Unknown set encoding type");
	131	}
e2641e09	132	}
	133
	134	void freeZsetObject(robj *o) {
	135	zset *zs = o->ptr;
	136
	137	dictRelease(zs->dict);
	138	zslFree(zs->zsl);
	139	zfree(zs);
	140	}
	141
	142	void freeHashObject(robj *o) {
	143	switch (o->encoding) {
	144	case REDIS_ENCODING_HT:
	145	dictRelease((dict*) o->ptr);
	146	break;
	147	case REDIS_ENCODING_ZIPMAP:
	148	zfree(o->ptr);
	149	break;
	150	default:
	151	redisPanic("Unknown hash encoding type");
	152	break;
	153	}
	154	}
	155
	156	void incrRefCount(robj *o) {
	157	o->refcount++;
	158	}
	159
	160	void decrRefCount(void *obj) {
	161	robj *o = obj;
	162
	163	/* Object is a swapped out value, or in the process of being loaded. */
	164	if (server.vm_enabled &&
	165	(o->storage == REDIS_VM_SWAPPED \|\| o->storage == REDIS_VM_LOADING))
	166	{
	167	vmpointer *vp = obj;
	168	if (o->storage == REDIS_VM_LOADING) vmCancelThreadedIOJob(o);
	169	vmMarkPagesFree(vp->page,vp->usedpages);
	170	server.vm_stats_swapped_objects--;
	171	zfree(vp);
	172	return;
	173	}
	174
	175	if (o->refcount <= 0) redisPanic("decrRefCount against refcount <= 0");
	176	/* Object is in memory, or in the process of being swapped out.
	177	*
	178	* If the object is being swapped out, abort the operation on
	179	* decrRefCount even if the refcount does not drop to 0: the object
	180	* is referenced at least two times, as value of the key AND as
	181	* job->val in the iojob. So if we don't invalidate the iojob, when it is
	182	* done but the relevant key was removed in the meantime, the
	183	* complete jobs handler will not find the key about the job and the
	184	* assert will fail. */
	185	if (server.vm_enabled && o->storage == REDIS_VM_SWAPPING)
	186	vmCancelThreadedIOJob(o);
	187	if (--(o->refcount) == 0) {
	188	switch(o->type) {
	189	case REDIS_STRING: freeStringObject(o); break;
	190	case REDIS_LIST: freeListObject(o); break;
	191	case REDIS_SET: freeSetObject(o); break;
	192	case REDIS_ZSET: freeZsetObject(o); break;
	193	case REDIS_HASH: freeHashObject(o); break;
	194	default: redisPanic("Unknown object type"); break;
	195	}
2f996f02	196	o->ptr = NULL; /* defensive programming. We'll see NULL in traces. */
a9b18e54	197	zfree(o);
e2641e09	198	}
	199	}
	200
	201	int checkType(redisClient c, robj o, int type) {
	202	if (o->type != type) {
	203	addReply(c,shared.wrongtypeerr);
	204	return 1;
	205	}
	206	return 0;
	207	}
	208
	209	/* Try to encode a string object in order to save space */
	210	robj tryObjectEncoding(robj o) {
	211	long value;
	212	sds s = o->ptr;
	213
	214	if (o->encoding != REDIS_ENCODING_RAW)
	215	return o; /* Already encoded */
	216
	217	/* It's not safe to encode shared objects: shared objects can be shared
	218	* everywhere in the "object space" of Redis. Encoded objects can only
	219	* appear as "values" (and not, for instance, as keys) */
	220	if (o->refcount > 1) return o;
	221
	222	/* Currently we try to encode only strings */
	223	redisAssert(o->type == REDIS_STRING);
	224
	225	/* Check if we can represent this string as a long integer */
	226	if (isStringRepresentableAsLong(s,&value) == REDIS_ERR) return o;
	227
0e5441d8	228	/* Ok, this object can be encoded...
	229	*
	230	* Can I use a shared object? Only if the object is inside a given
cdbea20a	231	* range and if this is the main thread, since when VM is enabled we
0e5441d8	232	* have the constraint that I/O thread should only handle non-shared
0e5441d8	233	* objects, in order to avoid race conditions (we don't have per-object
13a49af4	234	* locking).
	235	*
	236	* Note that we also avoid using shared integers when maxmemory is used
	237	* because very object needs to have a private LRU field for the LRU
	238	* algorithm to work well. */
	239	if (server.maxmemory == 0 && value >= 0 && value < REDIS_SHARED_INTEGERS &&
0e5441d8	240	pthread_equal(pthread_self(),server.mainthread)) {
e2641e09	241	decrRefCount(o);
	242	incrRefCount(shared.integers[value]);
	243	return shared.integers[value];
	244	} else {
	245	o->encoding = REDIS_ENCODING_INT;
	246	sdsfree(o->ptr);
	247	o->ptr = (void*) value;
	248	return o;
	249	}
	250	}
	251
	252	/* Get a decoded version of an encoded object (returned as a new object).
	253	* If the object is already raw-encoded just increment the ref count. */
	254	robj getDecodedObject(robj o) {
	255	robj *dec;
	256
	257	if (o->encoding == REDIS_ENCODING_RAW) {
	258	incrRefCount(o);
	259	return o;
	260	}
	261	if (o->type == REDIS_STRING && o->encoding == REDIS_ENCODING_INT) {
	262	char buf[32];
	263
	264	ll2string(buf,32,(long)o->ptr);
	265	dec = createStringObject(buf,strlen(buf));
	266	return dec;
	267	} else {
	268	redisPanic("Unknown encoding type");
	269	}
	270	}
	271
	272	/* Compare two string objects via strcmp() or alike.
	273	* Note that the objects may be integer-encoded. In such a case we
	274	* use ll2string() to get a string representation of the numbers on the stack
	275	* and compare the strings, it's much faster than calling getDecodedObject().
	276	*
	277	* Important note: if objects are not integer encoded, but binary-safe strings,
	278	* sdscmp() from sds.c will apply memcmp() so this function ca be considered
	279	* binary safe. */
	280	int compareStringObjects(robj a, robj b) {
	281	redisAssert(a->type == REDIS_STRING && b->type == REDIS_STRING);
	282	char bufa[128], bufb[128], astr, bstr;
	283	int bothsds = 1;
	284
	285	if (a == b) return 0;
	286	if (a->encoding != REDIS_ENCODING_RAW) {
	287	ll2string(bufa,sizeof(bufa),(long) a->ptr);
	288	astr = bufa;
	289	bothsds = 0;
	290	} else {
	291	astr = a->ptr;
	292	}
	293	if (b->encoding != REDIS_ENCODING_RAW) {
	294	ll2string(bufb,sizeof(bufb),(long) b->ptr);
	295	bstr = bufb;
	296	bothsds = 0;
	297	} else {
	298	bstr = b->ptr;
	299	}
	300	return bothsds ? sdscmp(astr,bstr) : strcmp(astr,bstr);
	301	}
	302
	303	/* Equal string objects return 1 if the two objects are the same from the
	304	* point of view of a string comparison, otherwise 0 is returned. Note that
305	* this function is faster then checking for (compareStringObject(a,b) == 0)
306	* because it can perform some more optimization. */
307	int equalStringObjects(robj a, robj b) {
308	if (a->encoding != REDIS_ENCODING_RAW && b->encoding != REDIS_ENCODING_RAW){
309	return a->ptr == b->ptr;
310	} else {
311	return compareStringObjects(a,b) == 0;
312	}
313	}
314
315	size_t stringObjectLen(robj *o) {
316	redisAssert(o->type == REDIS_STRING);
317	if (o->encoding == REDIS_ENCODING_RAW) {
318	return sdslen(o->ptr);
319	} else {
320	char buf[32];
321
322	return ll2string(buf,32,(long)o->ptr);
323	}
324	}
325
326	int getDoubleFromObject(robj o, double target) {
327	double value;
328	char *eptr;
329
330	if (o == NULL) {
331	value = 0;
332	} else {
333	redisAssert(o->type == REDIS_STRING);
334	if (o->encoding == REDIS_ENCODING_RAW) {
335	value = strtod(o->ptr, &eptr);
673e1fb7	336	if (eptr[0] != '\0' \|\| isnan(value)) return REDIS_ERR;
e2641e09	337	} else if (o->encoding == REDIS_ENCODING_INT) {
	338	value = (long)o->ptr;
	339	} else {
	340	redisPanic("Unknown string encoding");
	341	}
	342	}
	343
	344	*target = value;
	345	return REDIS_OK;
	346	}
	347
	348	int getDoubleFromObjectOrReply(redisClient c, robj o, double target, const char msg) {
	349	double value;
	350	if (getDoubleFromObject(o, &value) != REDIS_OK) {
	351	if (msg != NULL) {
3ab20376	352	addReplyError(c,(char*)msg);
e2641e09	353	} else {
3ab20376	354	addReplyError(c,"value is not a double");
e2641e09	355	}
	356	return REDIS_ERR;
	357	}
	358
	359	*target = value;
	360	return REDIS_OK;
	361	}
	362
	363	int getLongLongFromObject(robj o, long long target) {
	364	long long value;
	365	char *eptr;
	366
	367	if (o == NULL) {
	368	value = 0;
	369	} else {
	370	redisAssert(o->type == REDIS_STRING);
	371	if (o->encoding == REDIS_ENCODING_RAW) {
	372	value = strtoll(o->ptr, &eptr, 10);
	373	if (eptr[0] != '\0') return REDIS_ERR;
c91abdcd	374	if (errno == ERANGE && (value == LLONG_MIN \|\| value == LLONG_MAX))
c91abdcd	375	return REDIS_ERR;
e2641e09	376	} else if (o->encoding == REDIS_ENCODING_INT) {
	377	value = (long)o->ptr;
	378	} else {
	379	redisPanic("Unknown string encoding");
	380	}
	381	}
	382
96ffb2fe	383	if (target) *target = value;
e2641e09	384	return REDIS_OK;
	385	}
	386
	387	int getLongLongFromObjectOrReply(redisClient c, robj o, long long target, const char msg) {
	388	long long value;
	389	if (getLongLongFromObject(o, &value) != REDIS_OK) {
	390	if (msg != NULL) {
3ab20376	391	addReplyError(c,(char*)msg);
e2641e09	392	} else {
3ab20376	393	addReplyError(c,"value is not an integer or out of range");
e2641e09	394	}
	395	return REDIS_ERR;
	396	}
	397
	398	*target = value;
	399	return REDIS_OK;
	400	}
	401
	402	int getLongFromObjectOrReply(redisClient c, robj o, long target, const char msg) {
	403	long long value;
	404
	405	if (getLongLongFromObjectOrReply(c, o, &value, msg) != REDIS_OK) return REDIS_ERR;
	406	if (value < LONG_MIN \|\| value > LONG_MAX) {
	407	if (msg != NULL) {
3ab20376	408	addReplyError(c,(char*)msg);
e2641e09	409	} else {
3ab20376	410	addReplyError(c,"value is out of range");
e2641e09	411	}
	412	return REDIS_ERR;
	413	}
	414
	415	*target = value;
	416	return REDIS_OK;
	417	}
	418
	419	char *strEncoding(int encoding) {
	420	switch(encoding) {
	421	case REDIS_ENCODING_RAW: return "raw";
	422	case REDIS_ENCODING_INT: return "int";
	423	case REDIS_ENCODING_HT: return "hashtable";
	424	case REDIS_ENCODING_ZIPMAP: return "zipmap";
	425	case REDIS_ENCODING_LINKEDLIST: return "linkedlist";
	426	case REDIS_ENCODING_ZIPLIST: return "ziplist";
96ffb2fe	427	case REDIS_ENCODING_INTSET: return "intset";
e2641e09	428	default: return "unknown";
	429	}
	430	}
ef59a8bc	431
	432	/* Given an object returns the min number of seconds the object was never
	433	* requested, using an approximated LRU algorithm. */
	434	unsigned long estimateObjectIdleTime(robj *o) {
	435	if (server.lruclock >= o->lru) {
165346ca	436	return (server.lruclock - o->lru) * REDIS_LRU_CLOCK_RESOLUTION;
ef59a8bc	437	} else {
165346ca	438	return ((REDIS_LRU_CLOCK_MAX - o->lru) + server.lruclock) *
165346ca	439	REDIS_LRU_CLOCK_RESOLUTION;
ef59a8bc	440	}
ef59a8bc	441	}