c语言实现配置文件的读写

配置文件的格式如下：

key1 = value1

key2 = value2

　　.

　　.

　　.

名值对以一个=链接，一条记录以换行符分割

头文件：

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

函数原型：

void trim(char *strIn, char *strOut);//去除字符串首位空格

void getValue(char * keyAndValue, char * key, char * value);
//根据key得到value

int writeCFG(const char *filename/*in*/, const char *key/*in*/, const char *value/*in*/);
//写入配置文件

void readCFG(const char *filename/*in*/, const char *key/*in*/, const char **value/*out*/);
//读取配置文件

函数实现：

 void trim(char *strIn, char *strOut){

     char *start, *end, *temp;//定义去除空格后字符串的头尾指针和遍历指针

     temp = strIn;

     while (*temp == ' '){
         ++temp;
     }

     start = temp; //求得头指针

     temp = strIn + strlen(strIn) - ; //得到原字符串最后一个字符的指针(不是'\0')

     while (*temp == ' '){
         --temp;
     }

     end = temp; //求得尾指针

     for(strIn = start; strIn <= end; ){
         *strOut++ = *strIn++;
     }

     *strOut = '\0';
 }

 void getValue(char * keyAndValue, char * key, char * value){

     char *p = keyAndValue;

     p = strstr(keyAndValue, key);
     if(p == NULL){
         //printf("没有key\n");
         return ;
     }

     p += strlen(key);
     trim(p, value);

     p = strstr(value, "=");
     if(p == NULL){
         printf("没有=\n");
         return;
     }
     p+= strlen("=");
     trim(p, value);

     p = strstr(value, "=");
     if(p != NULL){
         printf("多余的=\n");
         return;
     }
     p = value;
     trim(p, value);

 }
 int writeCFG(const char *filename/*in*/, const char *key/*in*/, const char *value/*in*/){

     FILE *pf = NULL;
     char ftemp[flen] = {}, fline[] = {}, *fp;    //文件缓存数组
     long fsize = ;
     int reg = ;
     int exit = ;
     int i = ;

     pf = fopen(filename, "r+");
     if(pf == NULL){
         pf = fopen(filename, "w+");
     }
     //获得文件大小
     fseek(pf, , SEEK_END); // 将文件指针指向末尾
     fsize = ftell(pf);
     if(fsize > flen){
         printf("文件不能超过8k\n");
         reg = -;
         goto end;
     }
     fseek(pf, , SEEK_SET); //将文件指针指向开头

     //一行一行的读，如果存在key则修改value存到缓存数组中
     while(!feof(pf)){
         fgets(fline, , pf);
         if(strstr(fline, key) != NULL && exit == )
             strcpy(fline, "");
         if(strstr(fline, key) != NULL && exit == ){ //判断key是否存在
             exit = ;
             sprintf(fline,"%s = %s\n", key, value);
         }

         printf("fline = %s\n", fline);
         strcat(ftemp, fline);

     }
     if(exit != ){//如果不存在则把key value写入到最后一行
         sprintf(fline,"%s = %s\n", key, value);
         strcat(ftemp, fline);
     }
     if(pf != NULL){
         fclose(pf);
         pf = fopen(filename, "w+");
         fp = (char *)malloc(sizeof(char) * strlen(ftemp) + );
         strcpy(fp, ftemp);
         fp[strlen(fp) - ] = EOF;
         fputs(fp, pf);
         if(fp != NULL){
             free(fp);
             fp = NULL;
         }
         fclose(pf);
     }
     end :
         if(pf != NULL)
             fclose(pf);
     //重新创建一个以filename命名的文件
     return reg;
 }

 void readCFG(const char *filename/*in*/, const char *key/*in*/, const char **value/*out*/){

     FILE *pf = NULL;
     char line[] = {}, vtemp[] = {};

     pf = fopen(filename, "r"); //以只读方式打开

     while(!feof(pf)){
         fgets(line, , pf);
         getValue(line, key, vtemp);
         if(strlen(vtemp) != )
             break;
     }
     if(strlen(vtemp) != ){
         *value = (char *)malloc(sizeof(char) * strlen(vtemp) + );
         strcpy(*value, vtemp);
     }
     else
         *value = NULL;
     if(pf != NULL)
         fclose(pf);
 }

测试：

 #define filename "c:/cfg.ini"
 void menu(){
     printf("===========================\n");
     printf("1 写入配置文件\n");
     printf("2 读取配置文件\n");
     printf("0 退出程序");
     printf("===========================\n");
 }

 int tWrite(){

     char key[] = {}, value[] = {};

     printf("请输入key:");
     scanf("%s", key);
     printf("请输入value:");
     scanf("%s", value);
     printf("\n您输入的是：%s = %s\n", key, value);

     return writeCFG(filename/*in*/,key/*in*/,value/*in*/);
 }

 void tRead(){
     char key[] = {}, *value;

     printf("请输入key:");
     scanf("%s", key);

     readCFG(filename/*in*/,key/*in*/, &value/*out*/);
     if(value == NULL){
         printf("没有key\n");
         return ;
     }
     printf("\nvalue = %s\n", value);

     if(value != NULL){
         free(value);
         value = NULL;
     }

 }
 int main(){

     int choose;

     while(){
         choose = ;
         menu();
         printf("请输入选择:");
         scanf("%d", &choose);
         switch(choose){
             case :
                 if(tWrite() == -)
                     return -;
                 break;
             case :
                 tRead();
                 break;
             case :
                 return ;
             default:
                 return ;
         }
     }
     system("pause");
     return ;
 }

运行结果：