diff --git a/include/ringbuf.h b/include/ringbuf.h
index 580f738..7ca5729 100644
--- a/include/ringbuf.h
+++ b/include/ringbuf.h
@@ -12,7 +12,6 @@
 #define _RINGBUFFER_H_
 
 #include "unicstl_internal.h"
-#include "darray.h"
 
 enum _ringbuf_order
 {
diff --git a/include/segarray.h b/include/segarray.h
new file mode 100644
index 0000000..468f485
--- /dev/null
+++ b/include/segarray.h
@@ -0,0 +1,76 @@
+/**
+ * @file segarray.h
+ * @author wenjf (Orig5826@163.com)
+ * @brief 
+ * @version 0.1
+ * @date 2026-05-15
+ * 
+ * @copyright Copyright (c) 2026
+ * 
+ */
+#ifndef _SEGARRAY_H_
+#define _SEGARRAY_H_
+
+#include "unicstl_internal.h"
+#include "darray.h"
+
+enum _segarray_order
+{
+    SEGARRAY_FORWARD,
+    SEGARRAY_REVERSE,
+};
+
+struct _obj_pos
+{
+    size_t map;
+    size_t seg;
+};
+
+struct _segarray
+{
+    // -------------------- private -------------------- 
+    void *obj;
+
+    size_t _obj_size;
+    size_t _size;
+    size_t _capacity;
+    bool _dynamic;
+
+    darray_t _map;
+
+    struct _obj_pos _head;
+    struct _obj_pos _tail;
+    
+    struct _iterator _iter;
+    void (*_destory)(struct _segarray* self);
+
+    // -------------------- public -------------------- 
+    // kernel
+    bool (*push_back)(struct _segarray* self, const void* obj);
+    bool (*push_front)(struct _segarray* self, const void* obj);
+    bool (*pop_back)(struct _segarray* self, void* obj);
+    bool (*pop_front)(struct _segarray* self, void* obj);
+    bool (*back)(struct _segarray* self, void* obj);
+    bool (*front)(struct _segarray* self, void* obj);
+    
+    // base
+    bool (*resize)(struct _segarray *self, size_t capacity);
+    size_t (*size)(struct _segarray* self);
+    size_t (*capacity)(struct _segarray* self);
+    bool (*empty)(struct _segarray* self);
+    bool (*full)(struct _segarray* self);
+    bool (*clear)(struct _segarray* self);
+
+    // iter
+    iterator_t (*iter)(struct _segarray* self, enum _segarray_order order);
+
+    // -------------------- debug -------------------- 
+    void (*print)(struct _segarray* self);
+    void (*print_obj)(const void* obj);
+};
+typedef struct _segarray* segarray_t;
+
+segarray_t segarray_new(size_t obj_size, size_t capacity);
+void segarray_free(segarray_t* segarray);
+
+#endif
diff --git a/include/unicstl_internal.h b/include/unicstl_internal.h
index 82be680..618cebb 100644
--- a/include/unicstl_internal.h
+++ b/include/unicstl_internal.h
@@ -133,17 +133,6 @@ static inline void obj_copy(void *dst, const void *src, size_t count, size_t obj
     memmove(dst, src, obj_size * count);
 }
 
-static inline size_t index_next(size_t index, size_t capacity)
-{
-    return (index + 1) % capacity;
-}
-
-static inline size_t index_prev(size_t index, size_t capacity)
-{
-    return index == 0 ? (capacity - 1) : index - 1;
-}
-
-
 /**
  * @brief obj compare with obj2
  *
diff --git a/src/ringbuf.c b/src/ringbuf.c
index 3d0082e..73277a8 100644
--- a/src/ringbuf.c
+++ b/src/ringbuf.c
@@ -10,6 +10,16 @@
  */
 #include "ringbuf.h"
 
+static inline size_t index_next(size_t index, size_t capacity)
+{
+    return (index + 1) % capacity;
+}
+
+static inline size_t index_prev(size_t index, size_t capacity)
+{
+    return index == 0 ? (capacity - 1) : index - 1;
+}
+
 static bool ringbuf_push_back(struct _ringbuf *self, const void *obj)
 {
     unicstl_assert(self != NULL);
diff --git a/src/segarray.c b/src/segarray.c
new file mode 100644
index 0000000..bf84fa5
--- /dev/null
+++ b/src/segarray.c
@@ -0,0 +1,392 @@
+/**
+ * @file segarray.c
+ * @author wenjf (Orig5826@163.com)
+ * @brief 
+ * @version 0.1
+ * @date 2026-05-15
+ * 
+ * @copyright Copyright (c) 2026
+ * 
+ */
+#include "segarray.h"
+
+static inline size_t clac_start_index(size_t capacity)
+{
+    return capacity <= 2 ? 0 : (capacity - 1)/ 2;
+}
+
+static inline struct _obj_pos index_next(struct _segarray *self, const struct _obj_pos* cur_pos)
+{
+    struct _obj_pos pos;
+    pos.map = cur_pos->map;
+    pos.seg = cur_pos->seg;
+
+    if(pos.seg + 1 >= self->_capacity)
+    {
+        pos.map++;
+        pos.seg = 0;
+    }
+    else
+    {
+        pos.seg++;
+    }
+    return pos;
+}
+
+static inline struct _obj_pos index_prev(struct _segarray *self, const struct _obj_pos* cur_pos)
+{
+    struct _obj_pos pos;
+    pos.map = cur_pos->map;
+    pos.seg = cur_pos->seg;
+
+    if (pos.map == 0 && pos.seg == 0) {
+        return pos;
+    }
+
+    if(pos.seg == 0)
+    {
+        pos.map--;
+        pos.seg = self->_capacity - 1;
+    }
+    else
+    {
+        pos.seg--;
+    }
+    return pos;
+}
+
+static bool segarray_push_back(struct _segarray *self, const void *obj)
+{
+    unicstl_assert(self != NULL);
+    if(self->obj == NULL || obj == NULL)
+    {
+        return false;
+    }
+
+    if (self->full(self))
+    {
+        if(self->_dynamic != true)
+        {
+            return false;
+        }
+        // size_t new_capacity = unicstl_new_capacity(self->capacity(self));
+        // if (self->resize(self, new_capacity) == false)
+        // {
+        //     return false;
+        // }
+    }
+
+
+    self->_size++;
+    return true;
+}
+
+static bool segarray_push_front(struct _segarray *self, const void *obj)
+{
+    unicstl_assert(self != NULL);
+    if(self->obj == NULL || obj == NULL)
+    {
+        return false;
+    }
+
+    if (self->full(self))
+    {
+        if(self->_dynamic != true)
+        {
+            return false;
+        }
+        size_t new_capacity = unicstl_new_capacity(self->capacity(self));
+        if (self->resize(self, new_capacity) == false)
+        {
+            return false;
+        }
+    }
+
+    self->_size++;
+    return true;
+}
+
+static bool segarray_pop_back(struct _segarray *self, void *obj)
+{
+    unicstl_assert(self != NULL);
+    if(self->obj == NULL || self->empty(self))
+    {
+        return false;
+    }
+
+    self->_size--;
+    return true;
+}
+
+static bool segarray_pop_front(struct _segarray *self, void *obj)
+{
+    unicstl_assert(self != NULL);
+    if(self->obj == NULL || self->empty(self))
+    {
+        return false;
+    }
+
+    if (self->empty(self))
+    {
+        return false;
+    }
+
+    self->_size--;
+    return true;
+}
+
+static bool segarray_back(struct _segarray *self, void *obj)
+{
+    unicstl_assert(self != NULL);
+    if(self->obj == NULL || obj == NULL|| self->empty(self))
+    {
+        return false;
+    }
+
+
+    return true;
+}
+
+static bool segarray_front(struct _segarray *self, void *obj)
+{
+    unicstl_assert(self != NULL);
+    if(self->obj == NULL || obj == NULL|| self->empty(self))
+    {
+        return false;
+    }
+
+    
+    return true;
+}
+
+static bool segarray_resize(struct _segarray *self, size_t capacity)
+{
+    unicstl_assert(self != NULL);
+    if (self->_dynamic != true || capacity == 0 || capacity > UNICSTL_CAPACITY_MAX - 1)
+    {
+        return false;
+    }
+
+    return true;
+}
+
+static size_t segarray_size(struct _segarray *self)
+{
+    unicstl_assert(self != NULL);
+    return self->_size;
+}
+
+static size_t segarray_capacity(struct _segarray *self)
+{
+    unicstl_assert(self != NULL);
+    return self->_capacity;
+}
+
+static bool segarray_empty(struct _segarray *self)
+{
+    unicstl_assert(self != NULL);
+    return self->_head.map == self->_tail.map && self->_head.seg == self->_tail.seg;
+}
+
+static bool segarray_full(struct _segarray *self)
+{
+    unicstl_assert(self != NULL);
+    size_t map_cap = self->_map->capacity(self->_map);
+
+    return (self->_head.map == 0 && self->_head.seg == 0) ||
+           ( self->_tail.map == map_cap - 1 && self->_head.seg == self->_capacity - 1);
+}
+
+static bool segarray_clear(struct _segarray *self)
+{
+    unicstl_assert(self != NULL);
+    self->_size = 0;
+    
+    self->_head.map = clac_start_index(self->_map->capacity(self->_map));
+    self->_tail.map = self->_head.map;
+
+    self->_head.seg = clac_start_index(self->capacity(self));
+    self->_tail.seg = self->_head.seg;
+    return true;
+}
+
+static void segarray_destory(struct _segarray *self)
+{
+    unicstl_assert(self != NULL);
+    if (self->obj != NULL && self->_dynamic == true)
+    {
+        free(self->obj);
+        self->obj = NULL;
+    }
+}
+
+static void segarray_print(struct _segarray *self)
+{
+    unicstl_assert(self != NULL);
+
+    for (size_t i = 0; i < self->size(self); i++)
+    {
+        self->print_obj(obj_at(self->obj, self->_obj_size, i));
+    }
+}
+
+bool segarray_iter_hasnext(struct _iterator *iter)
+{
+    unicstl_assert(iter != NULL);
+    unicstl_assert(iter->_container != NULL);
+
+    segarray_t self = (segarray_t)iter->_container;
+
+    if (iter->_order == SEGARRAY_FORWARD)
+    {
+
+    }
+    else
+    {
+
+    }
+    return true;
+}
+
+const void *segarray_iter_next(struct _iterator *iter)
+{
+    unicstl_assert(iter != NULL);
+    unicstl_assert(iter->_container != NULL);
+
+    segarray_t self = (segarray_t)iter->_container;
+
+    size_t index = iter->_index;
+    if (iter->_order == SEGARRAY_FORWARD)
+    {
+        //iter->_index = index_next(index, self->_capacity);
+    }
+    else
+    {
+        //iter->_index = index_prev(index, self->_capacity);
+    }
+
+    return obj_at(self->obj, index, self->_obj_size);
+}
+
+iterator_t segarray_iter(struct _segarray *self, enum _segarray_order order)
+{
+    unicstl_assert(self != NULL);
+    iterator_t iter = &self->_iter;
+
+    iter->_container = self;
+    iter->_index = 0;
+    iter->_order = order;
+
+    //..
+
+    iter->hasnext = segarray_iter_hasnext;
+    iter->next = segarray_iter_next;
+    return iter;
+}
+
+/**
+ * @brief
+ *
+ * @param self
+ * @param obj_size
+ * @param capacity
+ * @param mem_pool !!! mem_pool_size = capacity * obj_size
+ * @return true
+ * @return false
+ */
+bool segarray_init(struct _segarray *self, size_t obj_size, size_t capacity, void *mem_pool)
+{
+    unicstl_assert(self != NULL);
+    unicstl_assert(obj_size > 0);
+
+    // -------------------- private --------------------
+    self->_obj_size = obj_size;
+    self->_size = 0;
+    self->_capacity = capacity + 1;
+
+    if (mem_pool != NULL)
+    {
+        self->obj = (char *)mem_pool;
+        self->_dynamic = false;
+    }
+    else
+    {
+        self->_dynamic = true;
+
+        self->_map = darray_new(sizeof(darray_t), 8);
+        if(self->_map == NULL)
+        {
+            return false;
+        }
+
+        darray_t seg = darray_new(obj_size, capacity);
+        if(seg == NULL)
+        {
+            darray_free(&self->_map);
+            return false;
+        }
+
+        self->_head.map = clac_start_index(self->_map->capacity(self->_map));
+        self->_tail.map = self->_head.map;
+
+        self->_head.seg = clac_start_index(self->_capacity);
+        self->_tail.seg = self->_head.seg;
+    }
+
+    self->_destory = segarray_destory;
+
+    // -------------------- public --------------------
+    // kernel
+    self->push_back = segarray_push_back;
+    self->push_front = segarray_push_front;
+    self->pop_back = segarray_pop_back;
+    self->pop_front = segarray_pop_front;
+    self->back = segarray_back;
+    self->front = segarray_front;
+
+    // base
+    self->resize = segarray_resize;
+    self->size = segarray_size;
+    self->capacity = segarray_capacity;
+    self->empty = segarray_empty;
+    self->full = segarray_full;
+    self->clear = segarray_clear;
+
+    // iter
+    self->iter = segarray_iter;
+
+    // -------------------- default --------------------
+    self->print_obj = default_print_obj;
+
+    // -------------------- debug --------------------
+    self->print = segarray_print;
+
+    return true;
+}
+
+segarray_t segarray_new(size_t obj_size, size_t capacity)
+{
+    struct _segarray *segarray = NULL;
+    segarray = (struct _segarray *)unicstl_malloc(sizeof(struct _segarray));
+    if (segarray == NULL)
+    {
+        return NULL;
+    }
+
+    if (segarray_init(segarray, obj_size, capacity, NULL) != true)
+    {
+        free(segarray);
+        return NULL;
+    }
+    return segarray;
+}
+
+void segarray_free(segarray_t *segarray)
+{
+    if (*segarray != NULL)
+    {
+        (*segarray)->_destory(*segarray);
+        free(*segarray);
+    }
+    *segarray = NULL;
+}