C语言实现读写配置文件项目

C语言实现配置文件的查找key的value，根据key修改value.

实现环境：windows 7 vs2010

配置文件cfg.ini：

oracle=orcl
sql=mysql

程序实现根据key ：oracle 来获取value ：orcl

程序实现根据key ：oracle 来修改value ：orcl 为abc

cf_op.h 头文件

#define LineMaxLen 2048
#define KeyMaxLen 128
#define MaxFileLength 1024*10

#ifndef CF_OP_H
#define CF_OP_H

#ifdef __cplusplus
extern "C" {
#endif

int GetCfItem(const char *pFileName /*in*/, char *pKey /*in*/, char * pValue/*in out*/, int * pValueLen /*out*/);
int SetCfItem(const char *pFileName /*in*/, char *pKey /*in*/, char *pValue/*in*/);

#ifdef  __cplusplus
}
#endif

#endif

cf_op.c 文件

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include"cf_op.h"
/* 该函数作用是判断linebuf中是否存在 pKey 这里使用的完全匹配
stu=123
student=124
这里都有stu，substr函数功能就是排除这种情况的
*/
static char *substr(char *linebuf,char *pKey)
{
	char *pTmp = NULL, *pRv = NULL;
	int lenKey = 0,len = 0;
	if (linebuf==NULL || pKey==NULL)
	{
		printf("func parameter err: (str==NULL || substr==NULL)");
		return pRv;
	}
	pRv = strstr(linebuf, pKey);
	if(pRv == NULL)
	{
		return pRv;
	}
	pTmp = pRv;
	lenKey = strlen(pKey);
	while(*pTmp != '\0' && *pTmp != ' '&& *pTmp != '=' && *pTmp != '\n')
	{
		len++;
		pTmp++;
		if(len>lenKey)
		{
			break;
		}
	}
	if (lenKey != len)
	{
		return NULL;
	}

	return pRv;
}
//实现流程
//打开文件
//按照行的方式 循环读文件
//解析每一行，若匹配key关键字，在进行value值的提取
//提取value值需要 去除前后空格 
int GetCfItem(const char *pFileName, char *pKey, char * pValue, int * pValueLen )
{
	int rv = 0;
	FILE *fp = NULL;
	char linebuf[LineMaxLen];
	char *pTmp = NULL, *pBegin = NULL, *pEnd = NULL;

	if (pFileName==NULL||pKey==NULL||pValue==NULL||pValueLen==NULL)
	{
		rv = -1;
		printf("func GetCfItem paramter err!");
		goto End;
	}
	fp = fopen(pFileName,"r");//以只读方式打开文件
	if (fp==NULL)
	{
		rv = -2;
		printf("fopen file err %d (fp==NULL)",rv);
		goto End;
	}

	while(!feof(fp))
	{
		memset(linebuf,0,LineMaxLen);
		pTmp = fgets(linebuf, LineMaxLen, fp);// 按行读取
		if (pTmp==NULL)
		{
			break;
		}

		pTmp = substr(linebuf, pKey);//判断key是否在该行
		if (pTmp==NULL)
		{
			continue;
		}
		pTmp = strchr(linebuf, '=');// 判断该行可有'='
		if (pTmp==NULL)
		{
			continue;
		}
		pTmp=pTmp+1;// 从等号后面开始
	
		while (1)//获取value 起点
		{
			if(*pTmp==' ')
			{
				pTmp++;
			}
			else
			{
				pBegin = pTmp;
				if(*pBegin == '\n'||*pBegin=='\0')
				{
					rv = -3;
					printf("The key %s don't have value",pKey);
				}
				break;
			}
		}

		while (1)//获取valude结束点
		{
			if(*pTmp==' '||*pTmp=='\n'||*pTmp=='\0')
			{
				break;
			}
			else
			{
				pTmp++;
			}
		}
		pEnd = pTmp;
		*pValueLen = pEnd-pBegin;
		memcpy(pValue,pBegin,*pValueLen);//拷贝
		*(pValue+*pValueLen)='\0';
		break;
	}
	if(pBegin==NULL) // 没有找到key
	{
		printf("can't find the key:%s \n",pKey);
		rv = -4;
	}
End:
	if (fp!=NULL)
	{
		fclose(fp);
	}
	return rv;
}
//实现流程
//循环读每一行，检查key配置项是否存在 若存在修改对应value值
//若不存在，在文件末尾 添加 "key = value"
//难点：如何修改文件流中的值
int SetCfItem(const char *pFileName, char *pKey, char *pValue)
{
	int rv = 0;
	int length = 0,iFlag = 0;
	FILE *fp = NULL;
	char filebuf[MaxFileLength];
	char linebuf[LineMaxLen];
	char *pTmp = NULL;

	memset(filebuf, 0, MaxFileLength);

	if (pFileName==NULL||pKey==NULL||pValue==NULL)
	{
		rv = -1;
		printf("func WriteCfItem paramter err!");
		goto End;
	}
	fp = fopen(pFileName,"r+");
	if (fp==NULL)
	{
		rv = -2;
		printf("fopen file err:%d",rv);
		goto End;
	}
	fseek(fp, 0L, SEEK_END); 
	//获取文件长度;
	length = ftell(fp);
	fseek(fp, 0L, SEEK_SET);
	if (length>MaxFileLength)
	{
		rv = -3;
		printf("file too long unspport:%d",rv);
		goto End;
	}
	while (!feof(fp))
	{
		//读每一行
		memset(linebuf, 0, sizeof(linebuf));
		pTmp = fgets(linebuf, LineMaxLen, fp);
		if(pTmp==NULL)
		{
			break;
		}

		pTmp = substr(linebuf, pKey);
		if(pTmp==NULL)
		{
			strcat(filebuf, linebuf);
			continue;
		}
		else
		{
			sprintf(linebuf,"%s=%s\n", pKey, pValue);
			strcat(filebuf, linebuf);
			iFlag = 1;//若存在key
		}
	}
	//若不存在 追加
	if (iFlag == 0)
	{
		fprintf(fp,"\n%s=%s", pKey, pValue);
	}
	else//若存在
	{
		if (fp!=NULL)
		{
			fclose(fp);
		}
		fp = fopen(pFileName,"w+");
		if (fp==NULL)
		{
			rv = -4;
			printf("fopen file err:%d",rv);
			goto End;
		}
		fputs(filebuf, fp);//写回文件
	}
	
End:
	if (fp!=NULL)
	{
		fclose(fp);
	}
	return rv;
}

测试主函数test_main.c：

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


void Test_SetCfItem()
{
	int rv = 0;
	char *pFileName="cfg.ini";
	char key[KeyMaxLen];
	char value[KeyMaxLen];

	memset(key, 0, sizeof(key));
	memset(value, 0, sizeof(value));
	printf("\n please input the key:",key);
	scanf("%s",key);
	printf("\n please input the value:",value);
	scanf("%s",value);
	rv = SetCfItem(pFileName,key,value);
	if (rv!=0)
	{
		printf("set the key value err! \n");
		return;
	}
	printf("set the key value success! \n");
}


void Test_GetCfItem()
{
	char *pFileName="cfg.ini";
	char key[KeyMaxLen];
	char value[KeyMaxLen];
	int len = 0, rv = 0;

	memset(key, 0, sizeof(key));
	memset(value, 0, sizeof(value));

	printf("\n please input the key:",key);
	scanf("%s",key);
	rv = GetCfItem(pFileName,key,value,&len);
	if(rv!=0)
	{
		printf("Get the key value err!");
		return;
	}
	printf("\n %s=%s",key,value);
}

void main_menu()
{
	printf("\n1 Test GetCfItem(测试读取配置文件)	");
	printf("\n2 Test SetCfItem(测试设置配置文件)	");
	printf("\n0 exit(0)        (程序退出)	    ");
	printf("\nplease enter your choice:[1/2/0]: ");
}
void main()
{
	int choice;

	while (1)
	{
	  main_menu();
	  scanf("%d",&choice);
	  switch(choice)
	  {
	  case 0:
		exit(0);
	  case 1:
		Test_GetCfItem(); break;
	  case 2:
		Test_SetCfItem(); break;
	  default:
		exit(0);
	  }
	 
	}
	system("pause");
}

测试结果：