#include <stdio.h>
#include "list.h" //list.h這個檔案需要你自己打造，可以拷貝核心原始碼，也可以參考我的博文

struct data_info {
    int data;
    struct list_head list;
};

int  cmp_data(struct list_head *a, struct list_head *b)
{
    struct data_info *pa = list_entry(a, struct data_info, list);
    struct data_info *pb = list_entry(b, struct data_info, list);
    return pa->data - pb->data;
}

void  swap(struct list_head *a, struct list_head *b)
 
//加入一個節點作為快取作用，具有通用性，不管兩個節點是相鄰還是不相鄰。
{
    struct  list_head flag = {NULL, NULL};
    __list_add(&flag, b->prev, b);
    list_del(b);
    __list_add(b, a->prev, a);
    list_del(a);
    __list_add(a, flag.prev, &flag);
    list_del(&flag);
}

void  bubble_sort(struct list_head *head, int  (*compar)(struct list_head *, struct list_head *))
{
    struct list_head *start = NULL; 
    struct list_head *end = NULL;   
     //採用氣泡排序演算法。
    list_for_each_reverse(end, head) //從尾向頭遍歷。
    {   
        list_for_each(start, head) //從頭向尾遍歷。
        {           
            if (start == end)                       
                break;

            if (compar(start, start->next) > 0) 
            {
                swap(start, start->next);                           
                start = start->prev; //start歸位
                if (start == end) 
                    end = end->next; //end歸位            
            }
        }
    }
}

int main(void)
{
    struct data_info s[] =  {{6}, {4}, {7}, {9}, {2}, {8}, {5}, {1}, {3}};

    LIST_HEAD(head);
    int i;
    for (i = 0; i < sizeof s/ sizeof *s; ++i) 
    {
        list_add_tail(&s[i].list, &head);
    } //尾插，構成連結串列

    struct data_info *pdata = NULL;
    list_for_each_entry(pdata, &head, list) 
    {
        printf("%d ", pdata->data);
    }
    printf("\n"); //排序之前

    bubble_sort(&head, cmp_data); //進行排序

    list_for_each_entry(pdata, &head, list) 
    {
        printf("%d ", pdata->data);
    }
    printf("\n"); //排序之後
    return 0;
}