alist: Add a function to empty the list

Sometimes it is useful to empty the list without de-allocating any of
the memory used, e.g. when the list will be re-populated immediately
afterwards.

Add a new function for this.

Signed-off-by: Simon Glass <sjg@chromium.org>

diff --git a/include/alist.h b/include/alist.h
index 0090b9c0eb1cae92c8ddf1a3a9ff4ad748363828..c639e42ab7d92e602d5ab28efebaa2ab2b4117ee 100644 (file)
--- a/include/alist.h
+++ b/include/alist.h
@@ -274,6 +274,13 @@ bool alist_chk_ptr(const struct alist *lst, const void *ptr);
             _pos < alist_end(_lst, typeof(*(_pos))); \
             _pos++)
 
+/**
+ * alist_empty() - Empty an alist
+ *
+ * This removes all entries from the list, without changing the allocated size
+ */
+void alist_empty(struct alist *lst);
+
 /**
  * alist_init() - Set up a new object list
  *

diff --git a/lib/alist.c b/lib/alist.c
index 1a4b4fb9c40c263ec75f77611e74c7fe900aa856..32cd45b0b017539e1269c728afd677877486ef3d 100644 (file)
--- a/lib/alist.c
+++ b/lib/alist.c
@@ -41,6 +41,11 @@ void alist_uninit(struct alist *lst)
        memset(lst, '\0', sizeof(struct alist));
 }
 
+void alist_empty(struct alist *lst)
+{
+       lst->count = 0;
+}
+
 /**
  * alist_expand_to() - Expand a list to the given size
  *

diff --git a/test/lib/alist.c b/test/lib/alist.c
index 1715a22584c280b79d99f10be533a11442dad206..87135bb3a5122e8e83c32a36919e6dbc8ad80a16 100644 (file)
--- a/test/lib/alist.c
+++ b/test/lib/alist.c
@@ -358,6 +358,16 @@ static int lib_test_alist_for_each(struct unit_test_state *uts)
        ptr = lst.data;
        ut_asserteq_ptr(ptr + 3, alist_end(&lst, struct my_struct));
 
+       /* empty the list and try again */
+       alist_empty(&lst);
+       ut_asserteq_ptr(ptr, alist_end(&lst, struct my_struct));
+       ut_assertnull(alist_get(&lst, 0, struct my_struct));
+
+       sum = 0;
+       alist_for_each(ptr, &lst)
+               sum += ptr->val;
+       ut_asserteq(0, sum);
+
        alist_uninit(&lst);
 
        /* Check for memory leaks */
@@ -366,3 +376,35 @@ static int lib_test_alist_for_each(struct unit_test_state *uts)
        return 0;
 }
 LIB_TEST(lib_test_alist_for_each, 0);
+
+/* Test alist_empty()  */
+static int lib_test_alist_empty(struct unit_test_state *uts)
+{
+       struct my_struct data;
+       struct alist lst;
+       ulong start;
+
+       start = ut_check_free();
+
+       ut_assert(alist_init_struct(&lst, struct my_struct));
+       ut_asserteq(0, lst.count);
+       data.val = 1;
+       data.other_val = 0;
+       alist_add(&lst, data);
+       ut_asserteq(1, lst.count);
+       ut_asserteq(4, lst.alloc);
+
+       alist_empty(&lst);
+       ut_asserteq(0, lst.count);
+       ut_asserteq(4, lst.alloc);
+       ut_assertnonnull(lst.data);
+       ut_asserteq(sizeof(data), lst.obj_size);
+
+       alist_uninit(&lst);
+
+       /* Check for memory leaks */
+       ut_assertok(ut_check_delta(start));
+
+       return 0;
+}
+LIB_TEST(lib_test_alist_empty, 0);