C语言实现一个简单的单向链表list

C语言实现一个简单的单向链表list

cheungmine

用C语言实现一个简单实用的单向链表list，具有一定的实际意义。尤其我们不想使用STL里面的list<...>类的时候。我实现的这个list，结点存储任何调用者分配的任意类型的数据（void*）。这个list适用于一些简单的场合，消耗极少的资源。

头文件：

/*
* list.h
* Generic sequential linked list node structure -- can hold any type data.
* cheungmine
* Sep. 22, 2007. All rights reserved.
*/
#ifndef LIST_H_INCLUDED
#define LIST_H_INCLUDED

#include "unistd.h"

typedef struct _listnode_t
{
struct _listnode_t *next;
union{
void* data;
struct _list_t *list;
const char *str;
long key;
};
}listnode_t;

typedef struct _list_t
{
size_t size; /* count of nodes */
listnode_t *head;
listnode_t *tail;
}list_t, *list_p;

/* A prototype of callbacked function called by list_destroy(), NULL for no use. */
typedef void(*pfcb_list_node_free)(listnode_t* node);

/* An example of free node data function implemented by callee:
void my_list_node_free(listnode_t *node)
{
free(node->data);
}
*/

/* Appends a node to a list */
extern void
list_append_node(list_t *in_list, listnode_t *in_node);

/* Removes the first node from a list and returns it */
extern listnode_t*
list_remove_head(list_t *in_list);

/* Removes all nodes but for list itself */
extern void
list_remove_all(list_t *in_list, pfcb_list_node_free pfunc /* NULL for no use or a key node */);

/* Returns a copy of a list_t from heap */
extern list_t*
list_copy(list_t in_list);

/* Concatenates two lists into first list. NOT freeing the second */
extern void
list_concat(list_t *first, list_t *second);

/* Allocates a new listnode_t from heap. NO memory allocated for input node_data */
extern listnode_t*
list_node_create(void* node_data);

/* Allocates a new listnode_t with a key node type */
extern listnode_t*
list_key_create(long node_key);

/* Allocates a empty list_t from heap */
extern list_t*
list_create();

/* Frees in_list's all nodes and destroys in_list from heap.
* the callee is responsible for freeing node data.
* the node freed-function(pfunc) is called by list_destroy.
*/
extern void
list_destroy(list_t *in_list, pfcb_list_node_free pfunc /* NULL for no use or a key node */);

/* Gets count of nodes in the list */
extern size_t
list_size(const list_t* in_list);

/* Gets node by index 0-based. 0 is head */
extern listnode_t*
list_node_at(const list_t* in_list, int index);

#endif /* LIST_H_INCLUDED */

实现文件：

/*
* list.c
* Generic linked list implementation.
* cheungmine
* Sep. 22, 2007. All rights reserved.
*/

#include "list.h"

/* Appends a node to a list */
void
list_append_node(list_t *in_list, listnode_t *node)
{
node->next = NULL;

if (in_list->head)
{
in_list->tail->next = node;
in_list->tail = node;
}
else
in_list->head = in_list->tail = node;

in_list->size++;
}

/* Removes the first node from a list and returns it */
listnode_t*
list_remove_head(list_t *in_list)
{
listnode_t *node = NULL;
if (in_list->head)
{
node = in_list->head;
in_list->head = in_list->head->next;
if (in_list->head == NULL)
in_list->tail = NULL;
node->next = NULL;

in_list->size--;
}
assert(in_list->size >= 0);
return node;
}

/* Removes all nodes but for list itself */
void
list_remove_all(list_t *in_list, pfcb_list_node_free pf)
{
listnode_t *node;
while((node = list_remove_head(in_list))){
if (pf) (*pf)(node);
free(node);
}
assert (in_list->size==0);
}

/* Returns a copy of a list_t from heap */
list_t*
list_copy(list_t list)
{
list_t *newlist = (list_t*)malloc (sizeof(list_t));
*newlist = list;
return newlist;
}

/* Concatenates two lists into first list */
void
list_concat(list_t *first, list_t *second)
{
if (first->head)
{
if (second->head)
{
first->tail->next = second->head;
first->tail = second->tail;
}
}
else
*first = *second;
second->head = second->tail = NULL;

first->size += second->size;
}

/* Allocates a new listnode_t from heap */
listnode_t*
list_node_create(void* data)
{
listnode_t *node = (listnode_t*)malloc (sizeof(listnode_t));
node->next = NULL;
node->data = data;
return node;
}

listnode_t*
list_key_create(long key)
{
listnode_t *node = (listnode_t*)malloc (sizeof(listnode_t));
node->next = NULL;
node->key = key;
return node;
}

/* Allocates a empty list_t from heap */
list_t*
list_create()
{
list_t *list = (list_t*)malloc (sizeof(list_t));
list->size = 0;
list->head = list->tail = NULL;
return list;
}

/* Frees a empty list_t from heap */
void
list_destroy(list_t *in_list, pfcb_list_node_free pf)
{
list_remove_all(in_list, pf);
free(in_list);
}

/* Gets count of nodes in the list */
size_t
list_size(const list_t* in_list)
{
return in_list->size;
}

/* Gets node by index 0-based. 0 is head */
listnode_t*
list_node_at(const list_t* in_list, int index)
{
int i=0;
listnode_t *node = in_list->head;

assert(index >=0 && index < (int)in_list->size);

while (i < index)
{
node = node->next;
i++;
}

return node;
}

公共头文件：

/* unistd.h
2008-09-15 Last created by cheungmine.
All rights reserved by cheungmine.
*/
#ifndef UNISTD_H__
#define UNISTD_H__

/* Standard C header files included */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>

/*============================================================================*/

typedef unsigned char uchar, byte, BYTE;

typedef unsigned short uint16, word_t, ushort;

typedef unsigned __int32 uint, uint32, dword_t, size_t;

typedef unsigned long ulong;

typedef __int16 int16;
typedef __int32 int32;
typedef __int64 int64, longlong;

typedef long lresult;

typedef unsigned __int64 uint64, qword_t, ulonglong;

#ifndef BOOL
typedef int BOOL;
#define TRUE 1
#define FALSE 0
#endif

#ifndef RESULT
#define RESULT lresult
#define _SUCCESS 0
#define _ERROR -1
#endif

#ifndef IN
#define IN
#endif

#ifndef OUT
#define OUT
#endif

#ifndef INOUT
#define INOUT
#endif

#ifndef OPTIONAL
#define OPTIONAL
#endif

#define SIZE_BYTE 1
#define SIZE_ACHAR 1
#define SIZE_WCHAR 2
#define SIZE_SHORT 2
#define SIZE_INT 4
#define SIZE_LONG 4
#define SIZE_FLT 4
#define SIZE_DBL 8
#define SIZE_WORD 2
#define SIZE_DWORD 4
#define SIZE_QWORD 8
#define SIZE_LINT 8
#define SIZE_INT64 8
#define SIZE_UUID 16

/*============================================================================*/
#endif /*UNISTD_H__*/

好了。是不是很简单啊。适合初学者学习，适合喜欢简单就是生活的人！