[list]1.Modify rt_slist_foreach to rt_slist_for_each_entry. 2.Add rt_sllist_isempty. 3.Make code cleanup

1.Modify rt_slist_foreach to rt_slist_for_each_entry. 2.Add rt_sllist_isempty. 3.Make code cleanup

include/rtservice.h

@@ -23,6 +23,8 @@
  * 2006-09-07     Bernard      move the kservice APIs to rtthread.h
  * 2007-06-27     Bernard      fix the rt_list_remove bug
  * 2012-03-22     Bernard      rename kservice.h to rtservice.h
+ * 2017-11-15     JasonJia     Modify rt_slist_foreach to rt_slist_for_each_entry.
+ *                             Make code cleanup.
  */
 
 #ifndef __RT_SERVICE_H__
@@ -38,6 +40,14 @@ extern "C" {
 
 /*@{*/
 
+/**
+ * rt_container_of - return the member address of ptr, if the type of ptr is the
+ * struct type.
+ */
+#define rt_container_of(ptr, type, member) \
+    ((type *)((char *)(ptr) - (unsigned long)(&((type *)0)->member)))
+
+
 /**
  * @brief initialize a list object
  */
@@ -128,7 +138,7 @@ rt_inline unsigned int rt_list_len(const rt_list_t *l)
  * @param member the name of list in structure
  */
 #define rt_list_entry(node, type, member) \
-    ((type *)((char *)(node) - (unsigned long)(&((type *)0)->member)))
+    rt_container_of(node, type, member)
 
 /**
  * rt_list_for_each_entry  -   iterate over list of given type
@@ -195,18 +205,6 @@ rt_inline void rt_slist_insert(rt_slist_t *l, rt_slist_t *n)
     l->next = n;
 }
 
-rt_inline rt_slist_t *rt_slist_remove(rt_slist_t *l, rt_slist_t *n)
-{
-    /* remove slist head */
-    struct rt_slist_node *node = l;
-    while (node->next && node->next != n) node = node->next;
-
-    /* remove node */
-    if (node->next != (rt_slist_t *)0) node->next = node->next->next;
-
-    return l;
-}
-
 rt_inline unsigned int rt_slist_len(const rt_slist_t *l)
 {
     unsigned int len = 0;
@@ -220,6 +218,23 @@ rt_inline unsigned int rt_slist_len(const rt_slist_t *l)
     return len;
 }
 
+rt_inline rt_slist_t *rt_slist_remove(rt_slist_t *l, rt_slist_t *n)
+{
+    /* remove slist head */
+    struct rt_slist_node *node = l;
+    while (node->next && node->next != n) node = node->next;
+
+    /* remove node */
+    if (node->next != (rt_slist_t *)0) node->next = node->next->next;
+
+    return l;
+}
+
+rt_inline int rt_slist_isempty(rt_slist_t *l)
+{
+    return l->next == RT_NULL;
+}
+
 /**
  * @brief get the struct for this single list node
  * @param node the entry point
@@ -227,22 +242,29 @@ rt_inline unsigned int rt_slist_len(const rt_slist_t *l)
  * @param member the name of list in structure
  */
 #define rt_slist_entry(node, type, member) \
-    ((type *)((char*)(node)-(unsigned long)(&((type *)0)->member)))
+    rt_container_of(node, type, member)
 
 /**
  * rt_slist_for_each_entry  -   iterate over single list of given type
- * @node:   the type * to use as a loop cursor.
- * @list:   the head for your single list.
+ * @pos:    the type * to use as a loop cursor.
+ * @head:   the head for your single list.
+ * @member: the name of the list_struct within the struct.
  */
-#define rt_slist_foreach(node, list)  \
-    for ((node) = (list)->next; (node) != RT_NULL; (node) = (node)->next)
+#define rt_slist_fore_each_entry(pos, head, member) \
+    for (pos = rt_slist_entry((head)->next, typeof(*pos), member); \
+         &pos->member != (RT_NULL); \
+         pos = rt_slist_entry(pos->member.next, typeof(*pos), member))
 
 /**
- * rt_container_of - return the member address of ptr, if the type of ptr is the 
- * struct type.
+ * rt_slist_first_entry - get the first element from a slist
+ * @ptr:    the slist head to take the element from.
+ * @type:   the type of the struct this is embedded in.
+ * @member: the name of the slist_struct within the struct.
+ *
+ * Note, that slist is expected to be not empty.
  */
-#define rt_container_of(ptr, type, member) \
-    ((type *)((char *)(ptr) - (unsigned long)(&((type *)0)->member)))
+#define rt_slist_first_entry(ptr, type, member) \
+    rt_slist_entry((ptr)->next, type, member)
 
 /*@}*/