读写配置文件

#include"readConfig.h"
#define CFGNAME "./test.txt"

void mymenu()
{
    printf("=========================\n");
    printf("1 Test Write Config file\n");
    printf("2 Test Read Config file\n");
    printf("0 exit\n");
    printf("=========================\n");
}

int TGetCfg()
{
    int ret = 0;
    char name[1024] = {0};
    char value[1024] = {0};
    int vlen = 0;

    printf("\nplease input key: ");
    scanf("%s,",name);

    ret = GetCfgItem(CFGNAME, name, value, &vlen);
    if (0 != ret)
    {
        printf("func WriteCfgItem err:%d \n",ret);
        return ret;
    }

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

int TWriteCfg()
{
    int ret = 0;
    char name[1024] = {0};
    char value[1024] = {0};

    printf("\nplease input key: ");
    scanf("%s",name);

    printf("\nplease input value: ");
    scanf("%s", value);

    ret = WriteCfgItem(CFGNAME, name, value, strlen(value));
    if (0 != ret)
    {
        printf("func WriteCfgItem err : %d \n", ret);
        return ret;
    }

    printf("your input name is %s , value is %s\n", name, value);
    return ret;
}


int main()
{
    int choice;

    for(;;)
    {
        mymenu();
        scanf("%d",&choice);

        switch(choice)
        {
            case 1:
                TWriteCfg();
                break;
            case 2:
                TGetCfg();
                break;
            case 0:
                exit(0);
            default:
                exit(0);
        }
    }

    printf("end......");
    return 0;

}

/*
readConfig.h
*/
#ifndef _READCONFIG_H__
#define _READCONFIG_H__

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

#define MaxLine 2048

#ifdef __cplusplus
extern "C"{
#endif

int GetCfgItem(char *pFileName, char *pKey, char *pValue, int *pValueLen);

//函数声明只是声明传入参数类型，参数名称可以和实现时不一样
int WriteCfgItem(char *pFileName, char *pItemName, char *pItemValue, int itemValueLen);

#ifdef __cplusplus
}

#endif

#endif

/*
readConfig.c
*/
#include "readConfig.h"

//获取配置项
int GetCfgItem(char *pFileName, char *pKey, char *pValue, int *pValueLen)
{
    int ret = 0;
    FILE *fp = NULL;
    char *pTmp = NULL, *pEnd = NULL, *pBegin = NULL;

    char lineBuf[MaxLine];

    fp = fopen(pFileName, "r");
    if (fp == NULL)
    {
        //-1 means the file is not exist
        ret = -1;
        return ret;
    }

    while (!feof(fp))
    {
        memset(lineBuf, 0 ,sizeof(lineBuf));
        fgets(lineBuf, MaxLine, fp);
        
        pTmp = strchr(lineBuf, ‘=‘);    //没有 = 号行跳过
        if (pTmp == NULL)
        {
            continue;
        }
        
        pTmp = strstr(lineBuf, pKey);    //判断该行是否有pKey
        if (pTmp == NULL)
        {
            continue;
        }
        pTmp = pTmp + strlen(pKey);    // wang = qing  ==> "= qing"
        
        pTmp = strchr(pTmp, ‘=‘);    //判断pKey后面是否有=
        if (pTmp == NULL)
        {
            continue;
        }
        
        pTmp = pTmp + 1;    //有等号把指针移到 = 号后一位

        //获取value的起点 去除空格，遇到第一个非空格符号位置赋予pBegin
        while(1)
        {
            if (*pTmp == ‘ ‘)
            {
                pTmp++;
            }
            else
            {
                pBegin = pTmp;
                if (*pBegin == ‘\n‘)
                {
                    //-2 means the value is empty
                    fclose(fp);
                    ret = -2;
                    return ret;
                }
                break;
            }
        }
        
        //获取value终点
        //遇到换行符或空格符终止(value值中不能有换行符空格符)
        while(1)
        {
            if ((*pTmp == ‘ ‘) || (*pTmp == ‘\n‘))
            {
                break;
            }
            else
            {
                pTmp++;
            }
        }
        pEnd = pTmp;
        
        *pValueLen = pEnd - pBegin;
        memcpy(pValue, pBegin, pEnd-pBegin);
    }
    if (fp != NULL)
    {
        fclose(fp);
    }
    return 0;
}

/*
写配置文件
循环写每一行，检查key配置项是否存在，若存在，则修改对应value值
若不存在，则在文件末尾添加 “key = value”
*/
int WriteCfgItem(char *pFileName, char *pKey, char *pValue, int ValueLen)
{
    int rv = 0, iTag = 0, length = 0;
    FILE *fp = NULL;
    char lineBuf[MaxLine];
    char *pTmp = NULL, *pBegin = NULL, *pEnd = NULL;
    char filebuf[1024*8] = {0};

    if (pFileName == NULL || pKey == NULL || pValue == NULL)
    {
        rv = -1;
        printf("setCfgItem() error. param error \n");
        return rv;
    }

    fp = fopen(pFileName, "r+");
    if (fp == NULL)
    {
        printf("The file %s is not exist, now create it.\n", pFileName);

        fp = fopen(pFileName, "w+t");
        if (fp == NULL)
        {
            rv = -2;
            printf("create new file %s error. \n",pFileName);
            return rv;
        }
    }
    
    fseek(fp, 0L, SEEK_END);    //把文件指针从文件开头移动到文件结尾
    length = ftell(fp);        //获取文件长度
    if (length > 1024 *8)
    {
        rv = -3;
        printf("the size of file is too big, and no support\n");
        fclose(fp);
        return rv;
    }

    fseek(fp, 0L, SEEK_SET);

    while (!feof(fp))
    {
        memset(lineBuf, 0, sizeof(lineBuf));
        pTmp = fgets(lineBuf, MaxLine, fp);
        if (pTmp == NULL)
        {
            break;
        }

        /*检查pKey是否在本行
        不在copy到filebuf中
        在先修改，copy到filebuf中（替换）
        读完整个文件
        */
        pTmp = strstr(lineBuf, pKey);
        if (pTmp == NULL)
        {
            strcat(filebuf, lineBuf);
            continue;
        }
        else
        {
            sprintf(lineBuf,"%s = %s\n", pKey, pValue);
            //将linebuf内容追加复制到filebuf中            
            strcat(filebuf, lineBuf);
            iTag = 1;
        }
    }

    //关键字不存在，追加
    if (iTag == 0)
    {
        fprintf(fp, "%s = %s\n", pKey, pValue);
    }
    else    //若关键字存在，则重新创建文件 先关闭源文件，再重新从头写入该文件中
    {
        if (fp != NULL)
        {
            fclose(fp);
            fp = NULL;
        }

        fp = fopen(pFileName, "w+t");
        if (fp == NULL)
        {
            rv = -4;
            printf("fopen() err. \n");
            if (fp != NULL)
            {
                fclose(fp);
                return rv;
            }
        }
        fputs(filebuf, fp);
    }

    if (fp != NULL)
    {
        fclose(fp);
    }
    return rv;
}