+unsigned char *zzlInsert(unsigned char *zl, robj *ele, double score);
+double zzlGetScore(unsigned char *sptr);
+void zzlNext(unsigned char *zl, unsigned char **eptr, unsigned char **sptr);
+void zzlPrev(unsigned char *zl, unsigned char **eptr, unsigned char **sptr);
+unsigned int zsetLength(robj *zobj);
+void zsetConvert(robj *zobj, int encoding);