API函数配置读写文件

cfg_op.h

#pragma once
#ifdef __cplusplus
extern "C" {
#endif
	//获取配置项
	int GetCfgItem(char *pFileName/*in*/, char*pKey/*in*/, char *pValue/*in out*/, int *pValueLen/*out*/);
	//写配置项
	int WriteCfgItem(char*pFileName/*in*/, char *pKey/*in*/, char *pValue/*in*/, int *ValueLen/*in*/);
#ifdef __cplusplus
}
#endif

cfg_op.c

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<string.h>
#include<stdio.h>
#define Maxline 2048
extern "C" {
	int GetCfgItem(char *pFileName, char*pKey, char *pValue, int *pValueLen)
	{
		int ret = 0;
		FILE *fp = NULL;
		char lineBuf[Maxline];
		char *pTmp = NULL, *pEnd = NULL, *pBegin = NULL;
		fp = fopen(pFileName, "r");
		if (fp == NULL) {
			ret = -1;
			return ret;
		}
		while (!feof(fp)) {
			memset(lineBuf, 0, sizeof(lineBuf));
			fgets(lineBuf, Maxline, fp);
			printf("lineBuf:%s ", lineBuf);

			pTmp = strchr(lineBuf, '=');
			if (pTmp == NULL) {	//没有=号
				continue;
			}
			pTmp = strstr(lineBuf, pKey);
			if (pTmp == NULL) {	//判断key是不是在//所在行 是不是有key
				continue;
			}
			pTmp = pTmp + strlen(pKey);	//	mykey1 = myvalue11111111==>"myvalue11111111"
			pTmp = strchr(pTmp, '=');
			if (pTmp == NULL) {	//判断所在行是不是有key
				continue;
			}
			pTmp++;
			printf("pTmp:%s ", pTmp);
			//获取value起点
			while (1) {
				if (*pTmp == ' ') {
					pTmp++;
				}
				else {
					pBegin = pTmp;
					if (*pBegin == '\n') {
						//没有配置value
						printf("配置项:%s 没有配置value \n", pKey);
						goto End;
					}
					break;
				}
			}

			//获取value结束点
			while (1) {
				if (*pTmp == ' ' || *pTmp == '\n') {
					break;
				}
				else {
					pTmp++;
				}
			}
			pEnd = pTmp;
			//赋值
			*pValueLen = pEnd - pBegin;
			memcpy(pValue, pBegin, pEnd - pBegin);
		}
	End:
		if (fp == NULL)
			fclose(fp);
		return ret;
	}
	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() err. param err \n");
			goto End;
		}
		fp = fopen(pFileName, "r+");
		if (fp == NULL) {
			rv = -2;
			printf("fopen() err.\n");
		}
		if (fp == NULL) {
			fp = fopen(pFileName, "w+t");
			if (fp == NULL) {
				rv = -3;
				printf("fopen() err.\n");
				goto End;
			}
		}
		fseek(fp, 0L, SEEK_END);//把文件指针从0位置开始，移动到文件末尾
		//获取文件长度
		length = ftell(fp);
		fseek(fp, 0L, SEEK_SET);
		if (length > 1024 * 8) {
			rv = -3;
			printf("文件超过1024*8,nunsupport");
			goto End;
		}
		while (!feof(fp)) {
			//读每一行
			memset(lineBuf, 0, sizeof(lineBuf));
			pTmp = fgets(lineBuf, Maxline, fp);
			if (pTmp == NULL) {
				break;
			}
			//key关键字是否在本行
			pTmp = strstr(lineBuf, pKey);
			if (pTmp == NULL)//key关键字不在本行，copy到filebuf中
			{
				strcat(filebuf, lineBuf);
				continue;
			}
			else//key关键字在本行中，替换旧的行，再copy到filebuf中
			{
				sprintf(lineBuf, "%s = %s\n", pKey, pValue);
				strcat(filebuf, lineBuf);
				//若存在key
				iTag = 1;
			}
		}
		//若key关键字，不存在 追加
		if (iTag == 0) {
			fprintf(fp, "%s = %s\n", pKey, pValue);
		}
		else {//若key关键字，存在，则重新创建文件
			if (fp != NULL) {
				fclose(fp);
				fp = NULL;//避免野指针
			}
			fp = fopen(pFileName, "w+t");
			if (fp == NULL) {
				rv = -4;
				printf("fopen() err.\n");
				goto End;
			}
			fputs(filebuf, fp);
		}
	End:
		if (fp != NULL) {
			fclose(fp);
		}
		return rv;
	}
}

main.c

#define _CRT_SECURE_NO_WARNINGS
#include"cfg_op.h"
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#define CFGNAME "d:/mycfg.ini"
//读配置项
int GetCfg() {
	int ret = 0;
	char name[1024] = { 0 };
	char value[1024] = { 0 };
	int vlen = 0;
	printf("\n请输入Key:");
	scanf("%s", name);
	ret = GetCfgItem(CFGNAME, name, value, &vlen);
	if (ret != 0) {
		printf("func GetCfgItem err:%d \n", ret);
		return ret;
	}
	printf("value:%s \n");
	return ret;
}
//写配置项
int TWriteCfg() {
	int ret = 0;
	char name[1024] = { 0 };
	char value[1024] = { 0 };
	int vlen = 0;
	printf("\n请输入Key:");
	scanf("%s", name);
	printf("\n请输入Value:");
	scanf("%s", value);
	WriteCfgItem(CFGNAME, name, value, &vlen);
	if (ret != 0) {
		printf("func WriteCfgItem err:%d \n", ret);
		return ret;
	}
	printf("您的输入是：%s = %s \n", name, value);
	return ret;
}

void show_menu() {
	printf("==========================\n");
	printf("1.测试写配置文件\n");
	printf("2.测试读配置文件\n");
	printf("0.退出\n");
	printf("==========================\n");
}
int main() {
	int choice;
	show_menu();
	while (~scanf("%d", &choice)) {
		//显示一个菜单
		switch (choice) {
		case 1:
			TWriteCfg();
			break;
		case 2:
			GetCfg();
			break;
		default:
			exit(0);
		}
		system("pause");
		system("cls");
		show_menu();
	}
	return 0;
}