#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

//This demo gets command line arguments, then uses those arguments to
// open a file and read the first 20 bytes.

int main( int argc, char* argv[] ){

	if( argc < 5 ){
		printf("Error you did it wrong\n");
		return 0;
	}

	char* inFile = argv[1];
	char* outFile = argv[2];
	int run_length = atoi( argv[3] );
	int mode = atoi( argv[4] ); 

	printf("Input file: %s\n", inFile );	
	printf("Output file: %s\n", outFile );	
	printf("Run length: %d\n", run_length );	
	printf("Mode: %d\n", mode );	

	int inFD = open( inFile, O_RDONLY );
	int outFD = open( outFile, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR );

	const int buffer_size = 7;
	char buffer [buffer_size + 1]; //Extra byte for a null terminator

	ssize_t ret_val;
	while( 1 ){
		ret_val = read(inFD, buffer, buffer_size); 
		if( ret_val == -1 ){
			perror("Could not read from file: ");
			//printf("Read error\n");
			break;
		}
		if( ret_val == 0 ){ //End of file
			break;
		}	
		//Null terminate the buffer
		buffer[ret_val] = '\0';
		printf("%s", buffer );
	}

	return 0;
}