配置文件读写案例

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cfg.h

#ifndef _CFG_OP_H_
#define _CFG_OP_H_

#ifdef  __cplusplus
extern "C" {
#endif

//写配置文件
int WriteCfgItem(char *PFilename/*in*/,char *PKey/*in*/,char *PValue/*in*/,char *PValuelen/*in*/);

//读配置文件
int GetCfgItem(char *filename/*in*/,char*key/*in*/,char *value/*in*/,int *PValuelen/*out*/);

//去除空格函数
int trimSpace(char *instr,char *outstr);
int trimspace(char *instr,char *outstr);
#ifdef  __cplusplus
}
#endif

#endif

cfg.c

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

#define MAXLINE 2048

//写配置文件
int WriteCfgItem(char *PFilename/*in*/,char *PKey/*in*/,char *PValue/*in*/,char *PValuelen/*in*/)
{
	int ret = 0;
	FILE* fp;
	int length = 0;
	char *temp = NULL;
	char linebuf[MAXLINE];
	char filebuf[1024*8]={0};	//文件缓冲区 
	int iTag = 0;

	//判断传参是否正确
	if( PFilename==NULL || PKey==NULL || PValue==NULL )
	{
		ret = -1;
		printf("func WriteCfgItem() 参数 error %d.\n",ret);
		return ret;
	}
	//以追加的方式打开文件
	fp = fopen(PFilename,"a+");
	//判断是否打开错误
	if( fp == NULL )
	{
		ret = -2;
		printf("func WriteCfgItem() open error %d.\n",ret);
		return ret;
	}
	//存储文件长度
	fseek(fp,0L,SEEK_END);	//文件指针定位到文件末尾  
    length = ftell(fp);		//返回长度  
    fseek(fp,0L,SEEK_SET);	//文件指针定位到文件开头  
	//判断文件是否大于8K
	if( length > 1024*8 )
	{
		ret = -3;
		printf("func WriteCfgItem() length error %d.\n",ret);
		return ret;
	}
	//扫描全文件，判断key是否已存在，无则追加
	while(!feof(fp))
	{
		memset(linebuf,0,MAXLINE);
		temp = fgets(linebuf,MAXLINE,fp);
		//判空跳出
		if( temp == NULL )
		{
			break;
		}

		//查找关键字
		temp = strstr(linebuf,PKey);
		if( temp != NULL )
		{
			//关键字在本行
			//覆盖本行文件
			sprintf(linebuf,"%s = %s\n",PKey,PValue);
			strcat(filebuf,linebuf);
			iTag = 1;
		}
		else
		{
			//关键字不在本行
			strcat(filebuf,linebuf);//追加本行到filebuf中  
            continue;//继续下轮循环  
		}
	}
	//文件最终处理
	if(iTag == 0)//追加
	{
		ret = fprintf(fp,"%s = %s\n",PKey,PValue);

		if( ret == 0 )
		{
			ret = -4;
			printf("func WriteCfgItem() write error %d.\n",ret);
			return ret;
		}
		else
		{
			fclose(fp);
		}
	}
	else
	{//覆盖旧文件
		if( fp != NULL )
		{
			fclose(fp);
		}
		fp = fopen(PFilename,"w+t");
		if( fp == NULL )
		{
			ret = -5;
			printf("func WriteCfgItem() open error %d.\n",ret);
			return ret;
		}

		ret = fputs(filebuf,fp);
		if ( ret < 0 )  
        {  
            printf("func fputs err \n");  
            return ret;  
        }  
        if (fp!=NULL)  
        {  
            fclose(fp);  
        }  
	}
	return 0;
}

//读配置文件
int GetCfgItem(char *filename/*in*/,char *key/*in*/,char *value/*in*/,int *PValuelen/*out*/)
{
	int ret = 0;
	FILE* fp = NULL;
	char linebuf[MAXLINE];
	char *ptemp = NULL;

	//以只读方式打开文件
	fp = fopen(filename,"r");
	//判断文件是否打开成功
	if(fp == NULL)
	{
		ret = -1;
		printf("func open() error %d.\n",ret);
	}
	//判断是否读完文件
	while(!feof(fp))
	{
		//清空存储区
		memset(linebuf,0,MAXLINE);
		//整行读取文件
		fgets(linebuf,MAXLINE,fp);

		//printf("linebuf = %s\n",linebuf);
		//判断是否存在等号
		ptemp = strchr(linebuf,'=');
		if(ptemp == NULL)
		{
			continue;
		}

		//判断并进行进行挖串操作
		ptemp = strstr(linebuf,key);
		if(ptemp == NULL)
		{
			continue;
		}
		ptemp = ptemp + strlen(key);

		ptemp = strchr(linebuf,'=');

		if(ptemp == NULL)
		{
			continue;
		}
		ptemp = ptemp + 1;

		ret = trimspace(ptemp,value);
		if(ret != 0)
		{
			ret = -2;
			printf("func trimspace error %d.\n",ret);
			return ret;
		}
	}

	if(fp != NULL)
		fclose(fp);

	return ret;
}
//挖串
int trimspace(char *instr,char *outstr)
{
	int ret = 0;
	char *p = NULL;

	p = instr;
	if( p == NULL)
	{
		ret = -1;
		printf("func trimspace error %d.\n",ret);
		return ret;
	}

	while(*(p++) != '\0')
	{
		if(*p != ' ')
		{
			*outstr++ = *p;
		}
	}
	*outstr = '\0';
	return ret;
}
//挖串
int trimSpace(char*inStr,char*out)    
{    
    char *p = inStr;    
    int ret = 0;    
    int i;    
    if (p==NULL)    
    {    
        ret = -1;    
        return;    
    }    
    for (i=0;p[i]!='\0';i++)    
    {    
        if (p[i]!=' ')    
        {    
            *out++ = p[i];    
        }    
    }    
    *out='\0';    
  
    return ret;    
}    

test_cfg.c

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

#define CFGNAME "d:/cfg.ini"

void menu_display()
{
	printf("------------------------------\n");
	printf("1.读文件测试\n");
	printf("2.写文件测试\n");
	printf("0.退出\n");
	printf("------------------------------\n");
	printf("请输入选项:");
}

//写配置文件
int WriteCfg()
{
	char key[1024] = {0};
	char value[1024] = {0};
	int ret = 0;

	printf("\n请键入key:");
	scanf("%s",key);

	printf("\n请键入value:");
	scanf("%s",value);

	ret = WriteCfgItem(CFGNAME/*in*/,key/*in*/,value/*in*/,strlen(value)/*in*/);
	if(ret != 0)
	{
		printf("func WriteCfg() WriteCfgItem error %d!\n",ret);
		return ret;
	}

	printf("你的输入是:%s = %s\n",key,value);

	return 0;
}

//读配置文件
int GetCfg()
{
	//GetCfgItem(char *filename/*in*/,char*key/*in*/,char *value/*in*/,char *PValuelen/*out*/);
	char key[1024] = {0};
	char value[1024] = {0};
	int vlen = 0;
	int ret = 0;

	printf("\n请键入key:");
	scanf("%s",key);

	ret = GetCfgItem(CFGNAME/*in*/,key/*in*/,value/*in*/,&vlen/*in*/);
	if(ret != 0)
	{
		printf("func GetCfgItem() error %d!\n",ret);
		return ret;
	}

	printf("value:%s\n",value);

	return 0;
}

void main()
{
	int choice;
	
	for(;;)
	{
		//显示菜单
		menu_display();
		//输入选项
		scanf("%d",&choice);

		switch(choice)
		{
			case 1:GetCfg();
				break;
			case 2:WriteCfg();
				break;
			case 0:
				exit(0);
			default:
				exit(0);
		}
	}

	system("pause");
}