static GList *
g_list_sort_real (GList *list,
GFunc compare_func,
gpointer user_data)
{
GList *l1, *l2;
if (!list)
return NULL;
if (!list->next)
return list;
l1 = list;
l2 = list->next;
while ((l2 = l2->next) != NULL)
{
if ((l2 = l2->next) == NULL)
break;
l1 = l1->next;
}
l2 = l1->next;
l1->next = NULL;
return g_list_sort_merge (g_list_sort_real (list, compare_func, user_data),
g_list_sort_real (l2, compare_func, user_data),
compare_func,
user_data);
}
/*将链表按照参数中设定比较方式排序*/
static GList*
g_list_sort_real (GList *list,
GFunc compare_func,
gpointer user_data)
{
GList *l1, *l2;
if (!list)
return NULL;
if (!list->next)
return list;
/*将链表L拆成前后两半，分别由L1与L2所指*/
l1 = list;
l2 = list->next;
while ((l2 = l2->next) != NULL)
{
if ((l2 = l2->next) == NULL)
break;
l1 = l1->next;
}
l2 = l1->next;
l1->next = NULL;
/*递归的方式处理两段子链表，实现整个链表按照参数中的比较方式排序*/
return g_list_sort_merge (g_list_sort_real (list, compare_func, user_data),
g_list_sort_real (l2, compare_func, user_data),
compare_func,
user_data);
}
/**
* GCompareDataFunc:
* @a: a value
* @b: a value to compare with
* @user_data: user data
*
* Specifies the type of a comparison function used to compare two
* values. The function should return a negative integer if the first
* value comes before the second, 0 if they are equal, or a positive
* integer if the first value comes after the second.
*
* Returns: negative value if @a < @b; zero if @a = @b; positive
* value if @a > @b
*/
GList *
g_list_sort_with_data (GList *list,
GCompareDataFunc compare_func,
gpointer user_data)
{
return g_list_sort_real (list, (GFunc) compare_func, user_data);
}
/*将链表按照参数中设定比较方式排序*/
GList *
g_list_sort (GList *list,
GCompareFunc compare_func)
{
return g_list_sort_real (list, (GFunc) compare_func, NULL);
}
