diff --git a/HISTORY b/HISTORY
index 8b0a6db..d9f91bd 100644
--- a/HISTORY
+++ b/HISTORY
@@ -1,5 +1,5 @@
 
-Version 1.44  2020-03-31
+Version 1.44  2020-04-22
   * add test file src/tests/test_pthread_lock.c
   * add uniq_skiplist.[hc]
   * add function split_string_ex
@@ -25,6 +25,7 @@ Version 1.44  2020-03-31
   * add functions getIpAndPort and getPeerIpAndPort 
   * bugfixed: call fast_mblock_destroy in common_blocked_queue_destroy
   * add function fc_get_file_line_count_ex
+  * uniq_skiplist add function find_ge and support bidirection
 
 Version 1.43  2019-12-25
   * replace function call system to getExecResult,
diff --git a/src/hash.c b/src/hash.c
index c4fdacb..2f8d524 100644
--- a/src/hash.c
+++ b/src/hash.c
@@ -1300,7 +1300,7 @@ int calc_hashnr1_ex(const void* key, const int key_len, \
  \
   h = init_value; \
   pEnd = (unsigned char *)key + key_len; \
-  for (p = (unsigned char *)key; p!= pEnd; p++) \
+  for (p = (unsigned char *)key; p != pEnd; p++) \
   { \
     h = 31 * h + *p; \
   } \
diff --git a/src/uniq_skiplist.c b/src/uniq_skiplist.c
index b8f3594..78b4b6a 100644
--- a/src/uniq_skiplist.c
+++ b/src/uniq_skiplist.c
@@ -42,7 +42,7 @@ static void init_best_element_counts()
     }
 }
 
-int uniq_skiplist_init_ex(UniqSkiplistFactory *factory,
+int uniq_skiplist_init_ex2(UniqSkiplistFactory *factory,
         const int max_level_count, skiplist_compare_func compare_func,
         uniq_skiplist_free_func free_func, const int alloc_skiplist_once,
         const int min_alloc_elements_once, const int delay_free_seconds,
diff --git a/src/uniq_skiplist.h b/src/uniq_skiplist.h
index c92a320..83550ad 100644
--- a/src/uniq_skiplist.h
+++ b/src/uniq_skiplist.h
@@ -58,12 +58,19 @@ extern "C" {
 
 #define uniq_skiplist_count(sl) (sl)->element_count
 
+#define uniq_skiplist_init_ex(factory, max_level_count, compare_func, \
+        free_func, alloc_skiplist_once, min_alloc_elements_once, \
+        delay_free_seconds) \
+    uniq_skiplist_init_ex2(factory, max_level_count, compare_func, \
+        free_func, alloc_skiplist_once, min_alloc_elements_once, \
+        delay_free_seconds, false) \
+
 #define uniq_skiplist_init(factory, max_level_count, compare_func, free_func) \
     uniq_skiplist_init_ex(factory, max_level_count,  \
             compare_func, free_func, 64 * 1024, \
-            SKIPLIST_DEFAULT_MIN_ALLOC_ELEMENTS_ONCE, 0, false)
+            SKIPLIST_DEFAULT_MIN_ALLOC_ELEMENTS_ONCE, 0)
 
-int uniq_skiplist_init_ex(UniqSkiplistFactory *factory,
+int uniq_skiplist_init_ex2(UniqSkiplistFactory *factory,
         const int max_level_count, skiplist_compare_func compare_func,
         uniq_skiplist_free_func free_func, const int alloc_skiplist_once,
         const int min_alloc_elements_once, const int delay_free_seconds,
@@ -146,9 +153,16 @@ static inline bool uniq_skiplist_empty(UniqSkiplist *sl)
     return sl->top->links[0] == sl->factory->tail;
 }
 
-#define LEVEL0_DOUBLE_CHAIN_PREV_LINK(node) node->links[node->level_index + 1]
+#define LEVEL0_DOUBLE_CHAIN_NEXT_LINK(node)  node->links[0]
+#define LEVEL0_DOUBLE_CHAIN_PREV_LINK(node)  node->links[node->level_index + 1]
 #define LEVEL0_DOUBLE_CHAIN_TAIL(sl)  LEVEL0_DOUBLE_CHAIN_PREV_LINK(sl->top)
 
+#define UNIQ_SKIPLIST_LEVEL0_PREV_NODE(node)  ((UniqSkiplistNode *) \
+        LEVEL0_DOUBLE_CHAIN_PREV_LINK(node))
+
+#define UNIQ_SKIPLIST_LEVEL0_NEXT_NODE(node)  ((UniqSkiplistNode *) \
+        LEVEL0_DOUBLE_CHAIN_NEXT_LINK(node))
+
 #ifdef __cplusplus
 }
 #endif