eina: add eina_inlist_sort (merge sort based on eina_list code).

SVN revision: 58540

legacy/eina/ChangeLog

@@ -41,3 +41,7 @@
 2011-04-06  Gustavo Sverzut Barbieri
 
 	* Add Simple XML parser API.
+
+2011-05-11  Cedric Bail
+
+	* Add eina_inlist_sort.

legacy/eina/src/include/eina_inlist.h

@@ -361,6 +361,53 @@ EAPI Eina_Iterator *eina_inlist_iterator_new(const Eina_Inlist *in_list) EINA_MA
  */
 EAPI Eina_Accessor *eina_inlist_accessor_new(const Eina_Inlist *in_list) EINA_MALLOC EINA_WARN_UNUSED_RESULT;
 
+/**
+ * @brief Sort a list according to the ordering func will return.
+ *
+ * @param list The list handle to sort.
+ * @param func A function pointer that can handle comparing the list data
+ * nodes.
+ * @return the new head of list.
+ *
+ * This function sorts all the elements of @p list. @p func is used to
+ * compare two elements of @p list. If @p list or @p func are @c NULL,
+ * this function returns @c NULL.
+ *
+ * @note @b in-place: this will change the given list, so you should
+ * now point to the new list head that is returned by this function.
+ *
+ * @note worst case is O(n * log2(n)) comparisons (calls to func()),
+ * O(n) comparisons average case. That means that for 1,000,000 list
+ * elements, sort will usually do 1,000,000 comparisons, but may do up
+ * to 20,000,000.
+ *
+ * Example:
+ * @code
+ * typedef struct _Sort_Ex Sort_Ex;
+ * struct _Sort_Ex
+ * {
+ *   INLIST;
+ *   const char *text;
+ * };
+ *
+ * int
+ * sort_cb(const Inlist *l1, const Inlist *l2)
+ * {
+ *    const Sort_Ex *x1;
+ *    const Sort_Ex *x2;
+ *
+ *    x1 = EINA_INLIST_CONTAINER_GET(l1, Sort_Ex);
+ *    x2 = EINA_INLIST_CONTAINER_GET(l2, Sort_Ex);
+ *
+ *    return(strcmp(x1->text, x2->text));
+ * }
+ * extern Eina_Inlist *list;
+ *
+ * list = eina_inlist_sort(list, sort_cb);
+ * @endcode
+ */
+EAPI Eina_Inlist *eina_inlist_sort(Eina_Inlist *head, Eina_Compare_Cb func);
+
 /* This two macros are helpers for the _FOREACH ones, don't use them */
 #define _EINA_INLIST_OFFSET(ref)         ((char *)&(ref)->__in_list - (char *)(ref))
 #define _EINA_INLIST_CONTAINER(ref, ptr) (void *)((char *)(ptr) - \

legacy/eina/src/lib/eina_inlist.c

@@ -42,6 +42,8 @@
  * @cond LOCAL
  */
 
+#define EINA_INLIST_SORT_STACK_SIZE 32
+
 typedef struct _Eina_Iterator_Inlist Eina_Iterator_Inlist;
 typedef struct _Eina_Accessor_Inlist Eina_Accessor_Inlist;
 
@@ -141,6 +143,41 @@ eina_inlist_accessor_free(Eina_Accessor_Inlist *it) {
    free(it);
 }
 
+static Eina_Inlist *
+eina_inlist_sort_merge(Eina_Inlist *a, Eina_Inlist *b, Eina_Compare_Cb func)
+{
+   Eina_Inlist *first, *last;
+
+   if (func(a, b) < 0)
+      a = (last = first = a)->next;
+   else
+      b = (last = first = b)->next;
+
+   while (a && b)
+      if (func(a, b) < 0)
+         a = (last = last->next = a)->next;
+      else
+         b = (last = last->next = b)->next;
+
+   last->next = a ? a : b;
+
+   return first;
+}
+
+static Eina_Inlist *
+eina_inlist_sort_rebuild_prev(Eina_Inlist *list)
+{
+   Eina_Inlist *prev = NULL;
+
+   for (; list; list = list->next)
+     {
+        list->prev = prev;
+        prev = list;
+     }
+
+   return prev;
+}
+
 /**
  * @endcond
  */
@@ -385,6 +422,61 @@ eina_inlist_count(const Eina_Inlist *list)
    return i;
 }
 
+EAPI Eina_Inlist *
+eina_inlist_sort(Eina_Inlist *head, Eina_Compare_Cb func)
+{
+  unsigned int i = 0;
+  unsigned int n = 0;
+  Eina_Inlist *tail = head;
+  Eina_Inlist *unsort = NULL;
+  Eina_Inlist *stack[EINA_INLIST_SORT_STACK_SIZE];
+
+  EINA_SAFETY_ON_NULL_RETURN_VAL(head, NULL);
+  EINA_SAFETY_ON_NULL_RETURN_VAL(func, head);
+
+  while (tail)
+    {
+      unsigned int idx, tmp;
+
+      Eina_Inlist *a = tail;
+      Eina_Inlist *b = tail->next;
+
+      if (!b)
+	{
+	  stack[i++] = a;
+	  break;
+	}
+
+      tail = b->next;
+
+      if (func(a, b) < 0)
+	((stack[i++] = a)->next = b)->next = 0;
+      else
+	((stack[i++] = b)->next = a)->next = 0;
+
+      tmp = n++;
+      for (idx = n ^ tmp; idx &= idx - 1; i--)
+	stack[i - 2] = eina_inlist_sort_merge(stack[i - 2], stack[i - 1], func);
+     }
+
+   while (i-- > 1)
+      stack[i - 1] = eina_inlist_sort_merge(stack[i - 1], stack[i], func);
+
+   head = stack[0];
+   tail = eina_inlist_sort_rebuild_prev(head);
+
+   if (unsort)
+     {
+        tail->next = unsort;
+        unsort->prev = tail;
+     }
+
+   head->last = tail;
+
+   return head;
+
+}
+
 EAPI Eina_Iterator *
 eina_inlist_iterator_new(const Eina_Inlist *list)
 {