C读写配置文件

在项目开发中，经常需要读取应用配置文件的初始化参数，用于应用在启动前进行一些初始化配置。比如：Eclipse，参数项包含主题、字体大小、颜色、Jdk安装位置、自动提示等。Eclispe配置的文件格式是以键值对的方式存储的，即：key=value的形式，下面是Eclipse部份设置参数：

/instance/org.eclipse.jdt.ui/useQuickDiffPrefPage=true
/instance/org.eclipse.jdt.ui/content_assist_proposals_foreground=0,0,0
/instance/org.eclipse.egit.core/GitRepositoriesView.GitDirectories=/Users/yangxin/Downloads/kakaolink-android/.git\:/Users/yangxin/Documents/workspace_web/tfyj/.git\:
/instance/org.eclipse.wst.jsdt.ui/fontPropagated=true
/instance/org.eclipse.debug.core/org.eclipse.debug.core.USE_STEP_FILTERS=true
/instance/org.eclipse.jdt.core/org.eclipse.jdt.core.compiler.problem.assertIdentifier=error
/instance/org.eclipse.ui.workbench/org.eclipse.jface.textfont=1|Monaco|14.0|0|COCOA|1|Monaco;
@org.eclipse.jdt.ui=3.8.2.v20130107-165834
/instance/org.eclipse.cdt.ui/spelling_locale_initialized=true

从Eclipse配置文件中可以看出，都是以xxxx=xxxxx，如最后一个配置项，key为/instance/org.eclipse.cdt.ui/spelling_locale_initialized，值为：true。在项目开发当中的也经常采用这种方式，笔者参考了Java的java.util.Properties类，设计了一个C的配置文件读写接口，供大家学习和使用。

1、定义接口头文件（Properties.h）

//
//  Properties.h
//  读写配置文件
//
//  Created by 杨信 on 14-4-24.
//  Copyright (c) 2014年 yangxin. All rights reserved.
//

#ifndef _______Properties_h
#define _______Properties_h

#ifdef _cplusplus
extern "C" {
#endif

// 初始化环境，成功返回0，失败返回非0值
int init(const char *filepath,void **handle);

// 根据KEY获取值，找到返回0，如果未找到返回非0值
int getValue(void *handle, const char *key, char *value);

// 修改key对应的属性值，修改成功返回0，失败返回非0值
int setValue(void *handle, const char *key, const char *value);

// 添加一个属性，添加成功返回0，失败返回非0值
int add(void *handle, const char *key, const char *value);

// 删除一个属性，删除成功返回0，失败返回非0值
int del(void *handle, const char *key);

// 获取属性文件中所有的key，获取成功返回0，失败返回非0值
int getKeys(void *handle, char ***keys, int *keyscount);

// 释放所有key的内存空间，成功返回0，失败返回非0值
int free_keys(char ***keys,int *keyscount);

// 获取属性文件中所有的值，成功返回0，失败返回非0值
int getValues(void *handle, char ***values, int *valuescount);

// 释放所有value的内存空间，成功返回0，失败返回非0值
int free_values(char ***values, int *valuescount);

// 获取属性数量，成功返回0，失败返回非0值
int getCount(void *handle, int *count);

// 释放环境资源，成功返回0，失败返回非0值
int release(void **handle);

#ifdef _cplusplus
}
#endif

#endif

2、实现头文件的接口（Properteis.c）

//
//  Properties.c
//  读写配置文件
//
//  Created by 杨信 on 14-4-24.
//  Copyright (c) 2014年 yangxin. All rights reserved.
//

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "Properties.h"

#define KEY_SIZE        128 // key缓冲区大小
#define VALUE_SIZE      128 // value缓冲区大小

#define LINE_BUF_SIZE   256 // 读取配置文件中每一行的缓冲区大小

typedef struct Properties {
char *key;
char *value;
struct Properties *pNext;
}Properties;

typedef struct PROPS_HANDLE {
Properties *pHead;  // 属性链表头节点
char *filepath;     // 属性文件路径
}PROPS_HANDLE;

static int createPropsNode(Properties **props);         // 创建一个节点
static int trimeSpace(const char *src,char *dest);      // 去空格
static int saveConfig(const char *filepath,Properties *head);   // 将修改或保存后的配置项保存到文件

// 初始化环境，成功返回0，失败返回非0值
int init(const char *filepath,void **handle)
{
int ret = 0;
FILE *fp = NULL;
Properties *pHead = NULL,*pCurrent = NULL, *pMalloc = NULL;
PROPS_HANDLE *ph = NULL;
char line[LINE_BUF_SIZE];               // 存放读取每一行的缓冲区
char keybuff[KEY_SIZE] = { 0 };         // 存放key的缓冲区
char valuebuff[VALUE_SIZE] = { 0 };     // 存放value的缓冲区
char *pLine = NULL;                     // 每行缓冲区数据的指针

if(filepath == NULL || handle == NULL)
{
ret = -1;
printf("fun init error:%d from (filepath == NULL || handler == NULL)\n",ret);
return ret;
}

ph = (PROPS_HANDLE *)malloc(sizeof(PROPS_HANDLE));
if (ph == NULL) {
ret = -2;
printf("fun init malloc handle error:%d",ret);
return ret;
}
memset(ph, 0, sizeof(PROPS_HANDLE));

// 打开文件
fp = fopen(filepath, "r");
if (!fp) {
ret = -3;
printf("fun init open file error:%d from %s\n",ret,filepath);
return ret;
}

// 创建头节点
ret = createPropsNode(&pHead);
if (ret != 0) {
fclose(fp);  // 关闭文件
printf("fun init create head node error:%d\n",ret);
return ret;
}
memset(pHead, 0, sizeof(Properties));

// 保存链表头节点和文件路径到handle中
ph->pHead = pHead;
ph->filepath = (char *)malloc(strlen(filepath) + 1);
strcpy(ph->filepath, filepath);

pCurrent = pHead;

// 读取配置文件中的所有数据
while (!feof(fp)) {
if(fgets(line, LINE_BUF_SIZE, fp) == NULL)
{
break;
}

// 找等号
if ((pLine = strstr(line, "=")) == NULL) {   // 没有等号，继续读取下一行
continue;
}

// 循环创建节点
ret = createPropsNode(&pMalloc);
if (ret != 0) {
fclose(fp);  // 关闭文件
release((void **)&ph);  // 创建节点失败，释放所有资源
printf("create new node error:%d\n",ret);
return ret;
}

// 设置Key
memcpy(keybuff, line, pLine-line);
trimeSpace(keybuff, pMalloc->key);    // 将keybuff去空格后放到pMallock.key中

// 设置Value
pLine += 1;
trimeSpace(pLine, valuebuff);
strcpy(pMalloc->value, valuebuff);

// 将新节点入链表
pMalloc->pNext = NULL;
pCurrent->pNext = pMalloc;
pCurrent = pMalloc; // 当前节点下移

// 重置key,value
memset(keybuff, 0, KEY_SIZE);
memset(valuebuff, 0, VALUE_SIZE);
}

// 设置环境句柄给调用者
*handle = ph;

// 关闭文件
fclose(fp);

return ret;
}

// 获取属性数量，成功返回0，失败返回非0值
int getCount(void *handle, int *count)
{
int ret = 0,cn = 0;
PROPS_HANDLE *ph = NULL;
Properties *pCurrent = NULL;
if (handle == NULL || count == NULL) {
ret = -1;
printf("fun getCount error:%d from (handle == NULL || count == NULL)\n",ret);
return ret;
}
ph = (PROPS_HANDLE *)handle;
pCurrent = ph->pHead->pNext;
while (pCurrent != NULL) {
cn++;
pCurrent = pCurrent->pNext;
}

*count = cn;

return ret;
}

// 根据KEY获取值，找到返回0，如果未找到返回非0值
int getValue(void *handle, const char *key, char *value)
{
int ret = 0;
PROPS_HANDLE *ph = NULL;
Properties *pCurrent = NULL;
if (handle == NULL || key == NULL || value == NULL) {
ret = -1;
printf("getValue error:%d from (handle == NULL || key == NULL || value == NULL)\n",ret);
return ret;
}

ph = (PROPS_HANDLE *)handle;
pCurrent = ph->pHead->pNext;
while (pCurrent != NULL) {
if (strcmp(pCurrent->key,key) == 0) {
break;
}
pCurrent = pCurrent->pNext;
}

if (pCurrent == NULL) {
ret = -2;
printf("fun getValue warning: not found the key:%s\n",key);
return ret;
}

strcpy(value, pCurrent->value);

return ret;
}

// 修改key对应的属性值，修改成功返回0，失败返回非0值
int setValue(void *handle, const char *key, const char *value)
{
int ret = 0;
PROPS_HANDLE *ph = NULL;
Properties *pCurrent = NULL;
if (handle == NULL || key == NULL || value == NULL) {
ret = -1;
printf("fun setValue error:%d from (handle == NULL || key == NULL || value == NULL)\n",ret);
return ret;
}

// 获得环境句柄
ph = (PROPS_HANDLE *)handle;

// 从环境句柄中获取头节点
pCurrent = ph->pHead->pNext;
while (pCurrent != NULL) {
if (strcmp(pCurrent->key, key) == 0) {  // 找到
break;
}
pCurrent = pCurrent->pNext;
}

if (pCurrent == NULL) { // 未找到key
ret = -2;
printf("fun setValue warning: not found the key:%s\n",key);
return ret;
}

// 修改key的value
strcpy(pCurrent->value, value);
if (strchr(value, '\n') == NULL) {  // 加一个换行符
strcat(pCurrent->value, "\n");
}

// 将修改的配置项写入到文件
ret = saveConfig(ph->filepath, ph->pHead);

return ret;
}

// 添加一个属性，添加成功返回0，失败返回非0值
int add(void *handle, const char *key, const char *value)
{
int ret = 0;
PROPS_HANDLE *ph = NULL;
Properties *pCurrent = NULL;
if (handle == NULL || key == NULL || value == NULL) {
ret = -1;
printf("fun add error:%d from (handle == NULL || key == NULL || value == NULL)\n",ret);
return ret;
}

ph = (PROPS_HANDLE *)handle;

//-----------如果key存在链表中，则直接修改，否则添加到链表中-----------//
pCurrent = ph->pHead;
while (pCurrent->pNext != NULL) {
if (strcmp(pCurrent->pNext->key,key) == 0) {
break;
}
pCurrent = pCurrent->pNext;
}

if (pCurrent->pNext != NULL) {
return setValue(handle, key, value);
}

//-----------key不存在，创建一个新的配置项，添加到链表中-----------//
Properties *pMalloc;
ret = createPropsNode(&pMalloc);
if (ret != 0) {
printf("fun add error:%d from malloc new node.",ret);
return ret;
}

strcpy(pMalloc->key, key);
if (strchr(pCurrent->value,'\n') == NULL) {
strcat(pCurrent->value, "\n");
}
strcpy(pMalloc->value, value);
if (strchr(value, '\n') == NULL) {  // 加一个换行符
strcat(pMalloc->value, "\n");
}
pCurrent->pNext = pMalloc;  // 新配置项入链表

// 将新配置项写入到文件
ret = saveConfig(ph->filepath, ph->pHead);

return ret;
}

// 删除一个属性，删除成功返回0，失败返回非0值
int del(void *handle, const char *key)
{
int ret = 0;
PROPS_HANDLE *ph = NULL;
Properties *pCurrent = NULL, *pPrev = NULL;
if (handle == NULL || key == NULL) {
ret = -1;
printf("fun del error:%d from (handle == NULL || key == NULL)\n",ret);
return ret;
}

ph = (PROPS_HANDLE *)handle;
pPrev = ph->pHead;
pCurrent = ph->pHead->pNext;

while (pCurrent != NULL) {
if (strcmp(pCurrent->key, key) == 0) {
break;
}
pPrev = pCurrent;           // 上一个节点下移
pCurrent = pCurrent->pNext; // 当前节点下移
}

if (pCurrent == NULL) { // 没有找到
ret = -2;
printf("fun del warning:not found the key:%s\n",key);
return  ret;
}

pPrev->pNext = pCurrent->pNext; // 从链表中删除
free(pCurrent); // 释放内存
pCurrent = NULL;

// 保存到文件
ret = saveConfig(ph->filepath, ph->pHead);

return ret;
}

// 获取属性文件中所有的key，获取成功返回0，失败返回非0值
int getKeys(void *handle, char ***keys, int *keyscount)
{
int ret = 0, count = 0, index = 0;
PROPS_HANDLE *ph = NULL;
Properties *pCurrent = NULL;
char **pKeys = NULL;
if (handle == NULL || keys == NULL || keyscount == NULL) {
ret = -1;
printf("fun getKeys error:%d from (handle == NULL || keys == NULL || keyscount == NULL) \n",ret);
return ret;
}

// 获取配置项数量
ret = getCount(handle, &count);
if (ret != 0) {
printf("fun getKeys error:%d from getCount \n",ret);
return ret;
}

ph = (PROPS_HANDLE *)handle;
pCurrent = ph->pHead->pNext;

// 根据链表长度，申请内存空间
pKeys = (char **)malloc(sizeof(char *) * count);
if (pKeys == NULL) {
ret = -2;
printf("fun getKeys error:%d from malloc keys\n",ret);
return ret;
}

pCurrent = ph->pHead->pNext;
while (pCurrent != NULL) {
pKeys[index] = pCurrent->key;
pCurrent = pCurrent->pNext;
index++;
}

*keys = pKeys;
*keyscount = count;

return ret;
}

// 释放所有key的内存空间，成功返回0，失败返回非0值
int free_keys(char ***keys,int *keyscount)
{
int ret = 0;
if (keys == NULL || keyscount == NULL) {
ret = -1;
printf("fun free_keys error:%d from (keys == NULL || keyscount == NULL) \n",ret);
return ret;
}

free(*keys);
*keys = NULL;
*keyscount = 0;

return ret;
}

// 获取属性文件中所有的值，成功返回0，失败返回非0值
int getValues(void *handle, char ***values, int *valuescount)
{
int ret = 0, count = 0, index = 0;
PROPS_HANDLE *ph = NULL;
Properties *pCurrent = NULL;
char **pValues = NULL;
if (handle == NULL || values == NULL || valuescount == NULL) {
ret = -1;
printf("fun getValues error:%d from (handle == NULL || values == NULL || valuescount == NULL)\n",ret);
return ret;
}

// 获取配置项数量
ret = getCount(handle, &count);
if (ret != 0) {
printf("fun getValues error:%d from getCount \n",ret);
return ret;
}

// 申请内存空间，存放所有的value
pValues = (char **)malloc(sizeof(char *) * count);
if (pValues == NULL) {
ret = -2;
printf("fun getValues error:%d from malloc values\n",ret);
return ret;
}

ph = (PROPS_HANDLE *)handle;
pCurrent = ph->pHead->pNext;
while (pCurrent != NULL) {
pValues[index] = pCurrent->value;
pCurrent = pCurrent->pNext;
index++;
}

*values = pValues;
*valuescount = count;

return ret;
}

// 释放所有value的内存空间，成功返回0，失败返回非0值
int free_values(char ***values, int *valuescount)
{
int ret = 0;
if (values == NULL || valuescount == NULL) {
ret = -1;
printf("fun free_values error:%d from (values == NULL || valuescount == NULL) \n",ret);
return ret;
}

free(*values);
*values = NULL;
*valuescount = 0;

return ret;
}

// 释放环境资源，成功返回0，失败返回非0值
int release(void **handle)
{
int ret = 0;
PROPS_HANDLE *ph = NULL;
if(handle == NULL)
{
ret = -1;
printf("release error:%d from (handler == NULL)\n",ret);
return ret;
}

ph = (PROPS_HANDLE *)*handle;

// 释放链表内存资源
Properties *pCurr = ph->pHead;
Properties *pTemp = NULL;

while (pCurr != NULL) {
if (pCurr->key != NULL) {
free(pCurr->key);
pCurr->key = NULL;
}

if (pCurr->value != NULL) {
free(pCurr->value);
pCurr->value = NULL;
}

pTemp = pCurr->pNext;

free(pCurr);

pCurr = pTemp;
}

// 释放存放配置文件路径分配的内存空间
if(ph->filepath != NULL)
{
free(ph->filepath);
ph->filepath = NULL;
}

// 释放环境句柄本身
free(ph);
*handle = NULL;    // 避免野指针

return ret;
}

// 去空格
static int trimeSpace(const char *src,char *dest)
{
int ret = 0;
if (src == NULL || dest == NULL) {
ret = -1;
printf("trimeSpace error:%d from (src == NULL || dest == NULL)\n",ret);
return ret;
}

const char *psrc = src;
unsigned long i = 0,j = strlen(psrc) - 1,len;
while (psrc[i] == ' ')
{
i++;
}

while (psrc[j] == ' ') {
j--;
}

len = j - i + 1;

memcpy(dest,psrc+i,len);
*(dest+len) = '\0';

return ret;
}

// 创建一个节点
static int createPropsNode(Properties **props)
{
int ret = 0;
Properties *p = NULL;
if (props == NULL) {
ret = -100;
printf("createProps error:%d from (props == NULL)\n",ret);
return ret;
}

p = (Properties *)malloc(sizeof(Properties));
if (p == NULL) {
ret = -200;
printf("createProps malloc %ld bytes error:%d\n",sizeof(Properties),ret);
return ret;
}
p->key = (char *)malloc(KEY_SIZE);
p->value = (char *)malloc(VALUE_SIZE);
p->pNext = NULL;

*props = p;

return ret;
}

// 保存到文件
static int saveConfig(const char *filepath,Properties *head)
{
int ret = 0,writeLen = 0;
FILE *fp = NULL;
Properties *pCurrent = NULL;
if (filepath == NULL || head == NULL) {
ret = -100;
printf("fun saveConfig error:%d from (filepath == NULL || head == NULL)\n",ret);
return ret;
}

fp = fopen(filepath,"w");
if (fp == NULL) {
ret = -200;
printf("fun saveConfig:open file error:%d from %s\n",ret,filepath);
return ret;
}

pCurrent = head->pNext;
while (pCurrent != NULL) {
writeLen = fprintf(fp, "%s=%s",pCurrent->key,pCurrent->value);    // 返回写入的字节数，出现错误返回一个负值
if (writeLen < 0) {  //TODO 如果写入失败，如何将写入的数据回退？？？
ret = -300;
printf("fun saveConfig err:%d from (%s=%s)\n",ret,pCurrent->key,pCurrent->value);
break;
}
pCurrent = pCurrent->pNext;
}

fclose(fp); // 关闭文件

return ret;
}

3、测试代码（需要在项目根目录创建props.txt）

//
//  main.c
//  读写配置文件
//
//  Created by 杨信 on 14-4-24.
//  Copyright (c) 2014年 yangxin. All rights reserved.
//

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "Properties.h"

int main(int argc, const char * argv[])
{
int ret;
void *handle;
const char *filepath = "/Users/yangxin/Desktop/props.txt";
// 初始化
ret = init(filepath, &handle);
if (ret != 0) {
printf("env init error:%d\n",ret);
return 0;
}

char valuebuf[128];
// 测试获取配置项
ret = getValue(handle, "host", valuebuf);
if (ret == 0) {
printf("value=%s\n",valuebuf);
}
else {
printf("获取值host的值失败\n");
}

// 测试修改配置项
ret = setValue(handle, "version", "1.2.3");
if (ret == 0) {
printf("修改成功!\n");
}
else{
printf("修改失败\n");
}

// 测试添加配置项
ret = add(handle, "pool_connection_countxx", "2000");
if (ret == 0) {
printf("添加成功!\n");
}
else{
printf("添加失败\n");
}

// 测试删除配置项
ret = del(handle, "connectionMax");
if (ret == 0) {
printf("删除成功!\n");
}
else{
printf("删除失败\n");
}

// 测试获取所有配置项的key
char **keys = NULL;
int keyscount;
ret = getKeys(handle, &keys, &keyscount);
if (ret == 0) {
printf("一共有%d个Key\n",keyscount);
for (int i =0; i<keyscount; i++) {
printf("%s\n",keys[i]);
}
}
// 释放内存
ret = free_keys(&keys, &keyscount);
if (ret == 0) {
printf("keys释放内存成功!\n");
}

// 测试获取所有配置项的value
char **values = NULL;
int valuescount;
ret = getValues(handle, &values, &valuescount);
if (ret == 0) {
printf("一共有%d个Value\n",valuescount);
for (int i = 0; i < valuescount; i++) {
printf("%s",values[i]);
}
}
// 释放内存
ret = free_values(&values, &valuescount);
if (ret == 0) {
printf("values释放内存成功!\n");
}

// 释放资源
ret = release(&handle);
if (ret != 0) {
printf("env release error:%d\n",ret);
}

return 0;
}

测试配置文件：

username=root
password=root123456
host=192.168.1.100
port=9090
connectionMax=200
version=1.0

测试结果：



源码下载地址：git@github.com:xyang0917/RWAppProperites.git