（Linux平台）配置文件读写demo

很多函数是只有Linux平台有的，自知代码里面还有很多小bug,懒得优化，还望大神们多多指正，简单读写可以直接用，欢迎测试！

#include <stdio.h>#include <stdlib.h>#include <string.h>#include <errno.h>#include <unistd.h>#include <sys/types.h>/***************************************************************************	getKeyPos（）内部调用，用来在获取key值之前，*	筛出key之前的空格**************************************************************************/static int isSpaceBehindKey(FILE *fp,int pos){char m=0;char cb=0;int newPos=0;fseek(fp,pos,SEEK_SET);fread(&cb,1,1,fp);while(cb == ' '){m++;fread(&cb,1,1,fp);}(m>0)?(newPos=ftell(fp)-1):(newPos=pos);fseek(fp,newPos,SEEK_SET);return 0;}/*************************************************************************	getKey（） 、setKey（）都调用此函数获取要操作的属性所在位置************************************************************************/static int getKeyPos(FILE *fp,char *p){char *line = NULL,*token=NULL;char pEdit[100]={'\0'},lineEdit[100]={'\0'};size_t len = 0;strcpy(pEdit,p);strcat(pEdit,"=");int pos=0,jum=0;int ret=isSpaceBehindKey(fp,pos);if(ret<0){printf("isSpaceBehindKey err\n");return -1;}while ((getdelim(&line, &len,'=', fp)) != -1) {//获取‘=’之前的字符串，包括‘=’strncpy(lineEdit,line,strlen(p));strcat(lineEdit,"=");if((strcmp(pEdit,lineEdit))==0){ret = pos;jum=1;break;}getline(&line, &len, fp);pos=ftell(fp);int ret=isSpaceBehindKey(fp,pos);if(ret<0){printf("isSpaceBehindKey err\n");ret = -1;}memset(lineEdit,0,strlen(lineEdit));}if(!jum)ret=-1;//如果没找到，返回-1.free(line);return ret;}/************************************************************************	上层直接调用，获取指定key的属性值，获取到的内容回填到getBuff地址***************************************************************************/int getKey(FILE *fp,char *p,char* getBuff){char Buff[100]={'\0'};char *line = NULL;int i=0;size_t len = 0;int keypos = getKeyPos(fp,p);if(keypos<0){printf("getKeyPos err:%s\n",strerror(errno));return -1;}getline(&line, &len, fp);//截取换行符之前的字符串strcpy(Buff,strtok(line,"\n"));while(Buff[i]==' '){i++;}strcpy(getBuff,&Buff[i]);free(line);return 0;}/**************************************************************	setKey（）内部调用，用来获取删除欲修改行之后的文件大小，*	之后可以调用truncate()改变文件大小到新的大小****************************************************************/static int getfilesize(FILE* fp,int keypos){size_t len=0;char *line=NULL;int filesize=0,pos=0;pos=(int)ftell(fp);//printf("keypos:%d\n",keypos);fseek(fp,keypos,SEEK_SET);if(-1 == (getline(&line, &len, fp))){printf("getline err:\n");return -1;}fseek(fp,0,SEEK_END);printf("file:%d len:%d\n",(int)ftell(fp),(int)strlen(line));filesize = (ftell(fp))-(strlen(line));fseek(fp,pos,SEEK_SET);free(line);return filesize;}/****************************************************************	setKey（）内部调用，用来改变最终文件大小，并将欲修改之属性*	写到文件尾****************************************************************/static int trunfile(int filesize,char *p,char* setBuff,FILE *fp,int flag){char Buff[100]={'\0'};truncate("/data/mrzhang/testfile",filesize);memcpy(Buff,p,strlen(p));strcat(Buff,"=");strcat(Buff,setBuff);(0==flag)?(fprintf(fp,"\n%s",Buff)):(fprintf(fp,"%s",Buff));return 0;}/************************************************************	上层直接调用，设置属性************************************************************/int setKey(FILE *fp,char *p,char* setBuff){size_t len = 0;char *line = NULL;char cb=0,Buff[100]={'\0'};int newpos=0,ret=0,filesize=0,flag=0,markkeypos=0;int keypos = getKeyPos(fp,p);if(keypos<0){//添加新属性memcpy(Buff,p,strlen(p));strcat(Buff,"=");strcat(Buff,setBuff);fprintf(fp,"\n%s",Buff);goto err;}getline(&line, &len, fp);//通过getline（）操作，将文件指针移动到要设置的key所在行的下一行起始处filesize = getfilesize(fp,keypos);if(filesize<0){ret = -1;goto err;}markkeypos = keypos;while(-1 != (getline(&line, &len, fp))){//读取一行到linenewpos = ftell(fp);//记录下次要读取的位置fseek(fp,keypos,SEEK_SET);//指定重置到上次记录的写位置fprintf(fp, "%s", line); //将line内容写文件keypos = ftell(fp);//记录下次要写的位置if(keypos >= filesize){//如果下次要写的位置值大于等于删除欲修改行之后文件的大小，循环将结束break;}fseek(fp,newpos,SEEK_SET);}if(markkeypos>=filesize){fseek(fp,keypos,SEEK_SET);flag=1;}trunfile(filesize,p,setBuff,fp,flag);//退出循环前将要设置的属性写在文件尾err:free(line);return ret;}/*int main(){FILE *fp;char *p="Q";char setBuff[20]="A B";char getBuff[20] = {0};fp = fopen("/data/mrzhang/testfile", "r+");if (fp == NULL)exit(EXIT_FAILURE);//setKey(fp,p,setBuff);printf("----------%d\n",setKey(fp,p,setBuff));printf("----------=%d\n",getKey(fp,p,getBuff));printf("%s=%s\n",p,getBuff);fclose(fp);}*/