请问高手，pak文件有什么办法打开并修改？我尝试用txt记事本打开，但是全是乱码

源程序
#include <stdlib.h>
#include <string.h>
#include <conio.h>
#include <stdio.h>
#include <dos.h>
#include <io.h>
#include <fcntl.h>
#include <commplus.h>

int dbfopen(char *fname, int *fhdl, long *fhdsize,
long *frcsize, long *reccount)
{
unsigned tmp;
char fhead[12];

_dos_open(fname, O_RDWR, fhdl);

_dos_read(*fhdl, fhead, 12, &tmp);
*fhdsize = * (unsigned *)&fhead[8];
*frcsize = * (unsigned *)&fhead[10];
*reccount = * (long *)&fhead[4];
return(0);
}

void wkserv(void)
{ unsigned char mode, port;
unsigned int baudrate;
char buffer[5120];

clrscr();
gotoxy(1, 1);
GetCommMode(&mode, &port, &baudrate);
SetCommMode(_PAK_MODE, port, baudrate);
fServer(port, baudrate, _NOT_SLNT, _IN_CHI, 5120, buffer);
}

void ConverDbToTxt(v