void zzlPrev(unsigned char *zl, unsigned char **eptr, unsigned char **sptr) {
    unsigned char *_eptr, *_sptr;
    serverAssert(*eptr != NULL && *sptr != NULL);

    _sptr = ziplistPrev(zl,*eptr);
    if (_sptr != NULL) {
        _eptr = ziplistPrev(zl,_sptr);
        serverAssert(_eptr != NULL);
    } else {
        /* No previous entry. */
        _eptr = NULL;
    }

    *eptr = _eptr;
    *sptr = _sptr;
}
void zzlPrev(unsigned char *zl, unsigned char **eptr, unsigned char **sptr) {
    unsigned char *_eptr, *_sptr;
    serverAssert(*eptr != NULL && *sptr != NULL);

    _sptr = ziplistPrev(zl,*eptr);
    if (_sptr != NULL) {
        _eptr = ziplistPrev(zl,_sptr);
        serverAssert(_eptr != NULL);
    } else {
         
        _eptr = NULL;
    }

    *eptr = _eptr;
    *sptr = _sptr;
}