c语言双向链表的实现

1. dlist.h

#ifndef _DLIST_H
#define _DLIST_H


typedef struct _dlist_node
{
    struct _dlist_node *p_next; /* 指向下一个结点的指针 */
    struct _dlist_node *p_prev; /* 指向上一个结点的指针 */
}dlist_node_t;

typedef dlist_node_t dlist_head_t;
typedef int (*dlist_node_process_t)(void *p_arg, dlist_node_t *p_node);

int dlist_init(dlist_head_t *p_head);
int dlist_add(dlist_head_t *p_head, dlist_node_t *p_pos, dlist_node_t *p_node);
int dlist_add_tail(dlist_head_t *p_head, dlist_node_t *p_node);
int dlist_add_head(dlist_head_t *p_head, dlist_node_t *p_node);
int dlist_del(dlist_head_t *p_head, dlist_node_t *p_node);

dlist_node_t *dlist_prev_get(dlist_head_t *p_head, dlist_node_t *p_pos);
dlist_node_t *dlist_next_get(dlist_head_t *p_head, dlist_node_t *p_pos);
dlist_node_t *dlist_tail_get(dlist_head_t *p_head);
dlist_node_t *dlist_begin_get(dlist_head_t *p_head);
dlist_node_t *dlist_end_get (dlist_head_t *p_head);
int dlist_foreach(dlist_head_t *p_head,
                dlist_node_process_t pfn_node_process,
                void *p_arg);

#endif

2. dlist.c

#include "dlist.h"
#include <stdlib.h>

int dlist_init(dlist_head_t *p_head)
{
    if (p_head == NULL)
    {
        return -1;
    }
    p_head->p_next = p_head;
    p_head->p_prev = p_head;
    return 0;
}

int dlist_add(dlist_head_t *p_head, dlist_node_t *p_pos, dlist_node_t *p_node)
{
    if ((p_head == NULL) || (p_pos == NULL) || (p_node == NULL))
    {
        return -1;
    }
    p_node->p_prev = p_pos;
    p_node->p_next = p_pos->p_next;
    p_pos->p_next->p_prev = p_node;
    p_pos->p_next = p_node;
    return 0;
}

int dlist_add_tail(dlist_head_t *p_head, dlist_node_t *p_node)
{
    return dlist_add(p_head, p_head->p_prev, p_node);
}

int dlist_add_head(dlist_head_t *p_head, dlist_node_t *p_node)
{
    return dlist_add(p_head, p_head, p_node);    
}

int dlist_del(dlist_head_t *p_head, dlist_node_t *p_node)
{
    if ((p_head == NULL) || (p_node == NULL) || (p_node == p_head))
    {
        return -1;
    }
    p_node->p_prev->p_next = p_node->p_next;
    p_node->p_next->p_prev = p_node->p_prev;
    p_node->p_next = NULL;
    p_node->p_prev = NULL;
    return 0;
}

dlist_node_t *dlist_prev_get(dlist_head_t *p_head, dlist_node_t *p_pos)
{
    if (p_pos != NULL)
    {
        return p_pos->p_prev;
    }
    return NULL;    
}

dlist_node_t *dlist_next_get(dlist_head_t *p_head, dlist_node_t *p_pos)
{
    if (p_pos != NULL)
    {
        return p_pos->p_next;
    }
    return NULL;   
}

dlist_node_t *dlist_tail_get(dlist_head_t *p_head)
{
    if (p_head != NULL) 
    {
        return p_head->p_prev;
    }
    return NULL;
}

dlist_node_t *dlist_begin_get(dlist_head_t *p_head)
{
    if (p_head != NULL)
    {
        return p_head->p_next;
    }
    return NULL;
}

dlist_node_t *dlist_end_get (dlist_head_t *p_head)
{
    return p_head;
    /*
    if (p_head != NULL) 
    {
        return p_head->p_prev;
    }
    return NULL;
    */
}

int dlist_foreach(dlist_head_t *p_head,
                  dlist_node_process_t pfn_node_process,
                  void *p_arg)
{
    dlist_node_t *p_tmp, *p_end;
    int ret;

    if ((p_head == NULL) || (pfn_node_process == NULL)) 
    {
        return -1;
    }

    p_tmp = dlist_begin_get(p_head);
    p_end = dlist_end_get(p_head);

    while (p_tmp != p_end) 
    {
        ret = pfn_node_process(p_arg, p_tmp);
        if (ret < 0) 
        {
            return ret;
        }
        p_tmp = dlist_next_get(p_head, p_tmp);
    }
//    pfn_node_process(p_arg, p_tmp);
    return 0;
}

3. demo

#include <stdio.h>
#include "dlist.h"

typedef struct _dlist_int 
{
    dlist_node_t node; /* 包含链表结点 */
    int data; /* int类型数据 */
}dlist_int_t;

int list_node_process(void *p_arg, dlist_node_t *p_node)
{
    printf("%d ", ((dlist_int_t *)p_node)->data);
    return 0;
}

int main(void)
{
    dlist_head_t head; /* 定义链表头结点 */
    dlist_int_t node1, node2, node3;
    dlist_init(&head);

    node1.data = 1;
    dlist_add(&head, &head, &(node1.node));
    node2.data = 2;
    dlist_add(&head, &(node1.node), &(node2.node));
    node3.data = 3;
    dlist_add(&head, &(node2.node), &(node3.node));
    printf("Before delete node.
");
    dlist_foreach(&head, list_node_process, NULL);
    dlist_del(&head, &(node2.node));
    printf("
After delet node.
");
    dlist_foreach(&head, list_node_process, NULL); /* 遍历链表，用户参数为NULL */
    return 0;
}