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) - 1; //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] = {0}, fline[1024] = {0}, *fp;    //文件缓存数组
    long fsize = 0;
    int reg = 0;
    int exit = 0;
    int i = 0;

    pf = fopen(filename, "r+");
    if(pf == NULL){
        pf = fopen(filename, "w+");
    }
    //获得文件大小
    fseek(pf, 0, 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 = -1;
        goto end;
    }
    fseek(pf, 0, 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, 1024, pf);
        if(strstr(fline, key) != NULL && exit == 1)
            strcpy(fline, "");
        if(strstr(fline, key) != NULL && exit == 0){ //判断key是否存在
            exit = 1;
            sprintf(fline,"%s = %s\n", key, value);
        }
        
        printf("fline = %s\n", fline);
        strcat(ftemp, fline);
        
    }
    if(exit != 1){//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) + 1);
        strcpy(fp, ftemp);
        fp[strlen(fp) - 1] = 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[1024] = {0}, vtemp[1024] = {0};

    pf = fopen(filename, "r"); //以只读方式打开
    
    while(!feof(pf)){
        fgets(line, 1024, pf);
        getValue(line, key, vtemp);
        if(strlen(vtemp) != 0)
            break;
    }
    if(strlen(vtemp) != 0){
        *value = (char *)malloc(sizeof(char) * strlen(vtemp) + 1);
        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[1024] = {0}, value[1024] = {0};

    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[1024] = {0}, *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(1){
        choose = 0;
        menu();
        printf("请输入选择:");
        scanf("%d", &choose);
        switch(choose){
            case 1:
                if(tWrite() == -1)
                    return -1;
                break;
            case 2:
                tRead();
                break;
            case 0:
                return 0;
            default: 
                return 0;
        }
    }
    system("pause");
    return 0;
}

运行结果：