/*
File Test 1:
Read a binary file in arbitrary chunks of bytes.
Modify data:
Add 1 to each byte and write to output file.
Write 1 additional control byte after each chunk.
Write 1 additional byte at eof
*/

#define mywait 1

#include <conio.h>
#include <fcntl.h>
#include <io.h>
#include <stdio.h>
//#include <stdlib.h>
//#include <string.h>
#include <sys/stat.h>
//#include <sys/types.h>
//#include <time.h>

#define chunk 7

void main (void) {

char inbuffer[chunk],outbuffer[chunk];
char infile_name []="data_in.txt";
char outfile_name []="data_out.txt";
char control_char1='$',control_char2='*';

int i,j,i_ok, nbytes;
int fh1, fh2, fl1;
unsigned int uk,bytesread,byteswrite,in_done,out_done,in_todo;
char c;

printf("\nFile Test 1\n\n");

i_ok=0;

/*	open input file	*/
/* ================================================== */
fh1 = _open(infile_name,_O_RDONLY | _O_BINARY  );
if( fh1 == -1 )
	{printf( "Failed to open input file %s\n",infile_name);}
else
   {fl1=_filelength( fh1 ) ;
	printf( "Input file  %s (%d bytes) opened\n",infile_name,fl1);
	i_ok++;
   }

/*	open output file	*/
if (i_ok)	{
	/* ================================================== */
	fh2=_open(outfile_name,_O_RDWR | _O_CREAT | _O_BINARY ,_S_IREAD | _S_IWRITE );
	if( fh2 == -1 )
		{printf( "Failed to open output file %s\n",outfile_name);
		i_ok=0;}
	else
		{printf( "Output file %s opened\n\n",outfile_name );}
}


/*	init task loop	*/
	in_done=0;
	out_done=0;
	nbytes=chunk;

/* task loop	*/
	
while (i_ok) {
	/*	read a chunk	*/
	in_todo=fl1-in_done;
	if(int(in_todo)<nbytes) {nbytes=int(in_todo);}
	/* ================================================== */
	bytesread=_read(fh1,inbuffer,nbytes);
	if (bytesread <= 0) {
		printf("Read error at byte %d...%d\n",in_done,in_done+nbytes);
		i_ok=0;}
	else {
	printf("Read %u bytes: %d...%d of %d\n",bytesread,in_done,in_done+nbytes-1,fl1);
	if (bytesread==0) i_ok=0;}
	
	/*	print input data	*/
	if (i_ok) {
		printf("in: ");
		for (i=0;i<nbytes;i++) {
			j=in_done+i;
			uk=unsigned int(inbuffer[i]);
			c=inbuffer[i];
			/*printf("%4d #%2X %c ",j,uk,c);}*/
			printf("%4d #%2X ",j,uk);}
		printf("\n");
	}
	/*	finish read chunk	*/
	if (i_ok) {
		in_done+=nbytes;
	}
	/*	make output chunk	*/
	if( _eof( fh1 ) ) {nbytes--;}
	if (i_ok) {
		printf("out:");
		for (i=0;i<nbytes;i++) {
			j=out_done+i;
			uk=unsigned int(inbuffer[i])+1;
			outbuffer[i]=uk;
			c=outbuffer[i];
			/*printf("%4d #%2X %c ",j,uk,c);*/
			printf("%4d #%2X ",j,uk);
		}
		j=out_done+i;
		uk=unsigned int(control_char1);
		outbuffer[i]=control_char1;
		/*printf("%4d %2X %c",j,uk,control_char1);*/
		printf("%4d #%2X ",j,uk);
	}
	/*	write to outfile	*/
	/* ================================================== */
	byteswrite = _write( fh2, outbuffer, nbytes+1);
	printf("\nWrite %u bytes\n",byteswrite);
	if (byteswrite==0) {i_ok=0;}

	/*	finish write chunk	*/
	if (i_ok) {out_done+=nbytes+1;}
	/*	end of file ?	*/
	if (int(in_done)>=fl1) {
		outbuffer[0]=control_char2;
		_write( fh2, outbuffer, 1);
		out_done++;
		i_ok=0;}

	/*	wait for user ok	*/
	printf("\nType any key to continue.\n");
	_getch();
}
/*	end of task loop	*/

/*	finish up	*/
	_close( fh1 );
	i = _chsize( fh2, out_done );
	if(i<0) {printf("Error when changing filesize\n");}
	_close( fh2 );

#if mywait
	/*	show console window until key pressed	*/
	printf("\nType any key to exit this program.\n");
	_getch();
#endif

}