#include <iostream>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
using namespace std;



int main (int argc, char * const argv[])
{
	//file directors
	int fd_in;
	int fd_out;
	//file pointers
	char *outfile;
	char *infile;
	//Buffer and count for the reading and writing of the files.
	char buffer[1024];
	int count;

	if(argc != 3)
	{
		cout <<"invalid number of arguments" << endl;
	}

	else {

		//This section initializes the infile and outfile and attempts to open it.

		infile = argv[1];
		outfile = argv[2];

		fd_in = open(infile,O_RDONLY);

		//If the O_RDONLY flag fails this will let the user know.
		if(fd_in < 0)
		{
			cout<<"File did not open correctly."<<endl;
		}

		else {

			//These next two lines of code prime the files so that they can enter the loop and
			//complete the file copy.
			fd_out = open(outfile,O_CREAT | O_WRONLY | O_TRUNC,0666);

			count = read(fd_in, (void*) buffer,sizeof(buffer));

			write(fd_out,(void*)buffer,count);

			while(count >= sizeof(buffer))
			{
				count = read(fd_in, (void*)buffer, sizeof(buffer));
				write(fd_out, (void*)buffer, count);
			}
			//close files
			close(fd_in);
			close(fd_out);

			 }
		}

    return 0;
}



//open file for input
// = open(filename, O_RDONLY);
//int fd_in; file desriptor. Gonna have to hand that integer
//to any other system call that messes with the file.
//if(fd_in<0) means open failed and there is an error
//open file for output: fdout = open(filename, O_CREATE|O_TRUNC)

//opened the files
//copy data
//char buffer[1024]
// count = read(fd_in,buf); or read(fd_in, (void*)buf,sizeof(buf));
//write(fd_out, (void*)buf,count));