1 files changed, 13 insertions, 14 deletions
diff --git a/src/cells/spread_sketch.h b/src/cells/spread_sketch.h
index b1c7a34..ec275ac 100644
--- a/src/cells/spread_sketch.h
+++ b/src/cells/spread_sketch.h
@@ -15,38 +15,37 @@ extern "C"{
 
 struct spread_sketch;
 
+// set time_window_ms to zero, the spread sketch will not slide and decay, in which case, `now` can be any value
 struct spread_sketch *spread_sketch_new(int depth, int width, unsigned char precision, int time_window_ms, struct timeval now);
-
 void spread_sketch_free(struct spread_sketch *ss);
-
-void spread_sketch_reset(struct spread_sketch *ss);
+void spread_sketch_set_exdata_schema(struct spread_sketch *ss, exdata_new_cb new_fn, exdata_free_cb free_fn, exdata_merge_cb merge_fn, exdata_reset_cb reset_fn, exdata_copy_cb copy_fn);
 
 int spread_sketch_add_hash(struct spread_sketch *ss, const char *key, size_t key_length, uint64_t item_hash, void *arg, struct timeval now);
 int spread_sketch_add(struct spread_sketch *ss, const char *key, size_t key_length, const char* item, size_t item_len, void *arg, struct timeval now);
 
-void spread_sketch_set_exdata_schema(struct spread_sketch *ss, exdata_new_cb new_fn, exdata_free_cb free_fn, exdata_merge_cb merge_fn, exdata_reset_cb reset_fn, exdata_copy_cb copy_fn);
-
-// get the number of cells in the heavy keeper
+// get the number of keys stored in spread sketch
 int spread_sketch_get_count(const struct spread_sketch *ss);
-
+// list all the keys in spread sketch. User should free the arrays, but do not free the elements of strings in the array(because they are references to the internal data structure)
+// Example: char **key; size_t *key_len; size_t n_keys; spread_sketch_list_keys(&key, &key_len, &n_keys); free(key); free(key_len);
 void spread_sketch_list_keys(const struct spread_sketch *ss, char ***keys, size_t **key_lens, size_t *n_keys);
+// query the cardinality(or fanout) of a key in spread sketch. 
+// Even thought spread sketch algorithm does not requires keys to exist innately, when querying a key that is not present in the spread sketch, `spread_sketch_get_cardinality` will return -1.
 double spread_sketch_get_cardinality(const struct spread_sketch *ss, const char *key, size_t key_len);
+// query a hyperloglog 's base64 serialization. The serialization format is [1,precision,register...] and then encoded by base64
 char *spread_sketch_get_hll_base64_serialization(const struct spread_sketch *ss, const char *key, size_t key_len);
 void *spread_sketch_get0_exdata(const struct spread_sketch *ss, const char *key, size_t key_len);
 
 void spread_sketch_merge(struct spread_sketch *dest, const struct spread_sketch *src);
-
 struct spread_sketch *spread_sketch_copy(const struct spread_sketch *src);
+void spread_sketch_serialize(const struct spread_sketch *ss, char **blob, size_t *blob_sz);
+struct spread_sketch *spread_sketch_deserialize(const char *blob, size_t blob_sz);
+void spread_sketch_merge_blob(struct spread_sketch *dst, const char *blob, size_t blob_sz);
+void spread_sketch_reset(struct spread_sketch *ss);
 
 void spread_sketch_get_parameter(const struct spread_sketch *ss, int *depth_out, int *width_out, unsigned char *precision_out, int *time_window_ms_out);
-/*
 // spread sketch alway store values more than expected_query_num,expected_query_num is a hint to set spread sketch parameters properly
-*/
 void spread_sketch_get_parameter_recommendation(int expected_super_spreader_number, int *depth_out, int *width_out, unsigned char *precision_out);
-
-
-// for test
-// void spread_sketch_one_point_query(const struct spread_sketch *ss, const char *key, size_t key_len, int *level_out, void **exdata_out);
+size_t spread_sketch_calculate_memory_usage(const struct spread_sketch *ss);
 
 #ifdef __cplusplus
 }