add EAPI eina_list_filter(Eina_List *list, Eina_Filter_Cb func)

- eina_list_filter returns a new list
- typedef Eina_Bool (*Eina_Filter_Cb)(const void *data);
- returns EINA_TRUE if satisfies the predicate

src/lib/eina/eina_list.c

@@ -1153,6 +1153,31 @@ eina_list_sort(Eina_List *list, unsigned int limit, Eina_Compare_Cb func)
    return list;
 }
 
+EAPI Eina_List *
+eina_list_filter(Eina_List *list, Eina_Filter_Cb func)
+{
+   const Eina_List *l;
+   Eina_List *lfiltered;
+   void *data;
+
+   if (!list)
+     return NULL;
+
+   EINA_MAGIC_CHECK_LIST(list, NULL);
+
+   if (func == NULL)
+     return eina_list_clone(list);
+
+   lfiltered = NULL;
+   EINA_LIST_FOREACH(list, l, data)
+     {
+        if (func(data) == EINA_TRUE)
+          lfiltered = eina_list_append(lfiltered, data);
+     }
+
+   return lfiltered;
+}
+
 EAPI Eina_List *
 eina_list_shuffle(Eina_List *list, Eina_Random_Cb func)
 {

src/lib/eina/eina_list.h

@@ -939,6 +939,25 @@ EAPI Eina_List            *eina_list_clone(const Eina_List *list) EINA_WARN_UNUS
 EAPI Eina_List            *eina_list_sort(Eina_List *list, unsigned int limit, Eina_Compare_Cb func) EINA_ARG_NONNULL(3) EINA_WARN_UNUSED_RESULT;
 
 
+/**
+ * @brief filter (clone some) the elements in the list in exactly same order.
+ *
+ * @param list The list to filter.
+ * @param func The filter function.
+ * @return The new list.
+ *
+ * This function clone in order the elements in @p list that satisfy the
+ * filter @p func. This filter function @p func must return @c EINA_TRUE if the
+ * element is to be cloned. If @p list is @c NULL, this functon returns @c NULL.
+ * If @p func is @c NULL, this functon calls @see eina_list_clone().
+ * This returns a new list.
+ *
+ * @since 1.8
+ *
+ * @warning @p list must be a pointer to the first element of the list.
+ */
+EAPI Eina_List            *eina_list_filter(Eina_List *list, Eina_Filter_Cb func) EINA_WARN_UNUSED_RESULT;
+
 /**
  * @brief Shuffle list.
  *

src/lib/eina/eina_types.h

@@ -333,6 +333,20 @@ typedef int (*Eina_Compare_Cb)(const void *data1, const void *data2);
  */
 #define EINA_COMPARE_CB(function) ((Eina_Compare_Cb)function)
 
+/**
+ * @typedef Eina_Filter_Cb
+ * Function used in filtering functions.
+ * It returns EINA_TRUE only if @p data satisfies the predicate thus
+ * is not to be filtered.
+ */
+typedef Eina_Bool (*Eina_Filter_Cb)(const void *data);
+
+/**
+ * @def EINA_FILTER_CB
+ * Macro to cast to Eina_Filter_Cb.
+ */
+#define EINA_FILTER_CB(function) ((Eina_Filter_Cb)function)
+
 /**
  * @typedef Eina_Random_Cb
  * Function used in shuffling functions. An integer betwen min and max

src/tests/eina/eina_test_list.c

@@ -496,6 +496,49 @@ START_TEST(eina_test_remove_duplicates)
 }
 END_TEST
 
+static Eina_Bool filter_cb(int *data)
+{
+   return ( (*data < 81) ? EINA_TRUE : EINA_FALSE );
+}
+
+START_TEST(eina_test_filter)
+{
+   int i;
+   int *p;
+   int data[] = { 6, 9, 93, 42, 1, 7, 9, 81, 1664, 1337 };
+   int result[] = { 6, 9, 42, 1, 7, 9, 81 };
+   Eina_List *list = NULL;
+   Eina_List *l = NULL;
+
+   eina_init();
+
+   for (i = 0; i < 10; i++)
+     list = eina_list_append(list, &data[i]);
+
+   l = eina_list_filter(list, NULL);
+      fail_if(eina_list_count(list) != 10);
+      for (i = 0; i < 10; i++)
+        {
+           p = eina_list_nth(l, i);
+           fail_if(*p != data[i]);
+        }
+   l = eina_list_free(l);
+
+   l = eina_list_filter(list, EINA_FILTER_CB(filter_cb));
+      fail_if(eina_list_count(l) != 6);
+      for (i = 0; i < 6; i++)
+        {
+           p = eina_list_nth(l, i);
+           fail_if(*p != result[i]);
+        }
+   l = eina_list_free(l);
+
+   list = eina_list_free(list);
+
+   eina_shutdown();
+}
+END_TEST
+
 void
 eina_test_list(TCase *tc)
 {
@@ -505,4 +548,5 @@ eina_test_list(TCase *tc)
    tcase_add_test(tc, eina_test_list_split);
    tcase_add_test(tc, eina_test_shuffle);
    tcase_add_test(tc, eina_test_remove_duplicates);
+   tcase_add_test(tc, eina_test_filter);
 }