#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/ioctl.h>

#define BLIT(fd)	ioctl((fd), _IO('d', 0))
#define DISPLAY(fd, x)	ioctl((fd), _IOW('d', 1, int), (x))

int main(int argc, char *argv[])
{
	int fd;
	caddr_t dmap;
	int i = 0, j = 0;
	char cBuffer[ 4096 ];
	char cLeft = 0, cRight = 0;

	fd = open("/dev/display", O_RDWR);
	if(fd == -1)
		return 1;

	dmap = mmap(0, 2048, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
	if (dmap == (caddr_t) -1)
		return 2;

	if( read( STDIN_FILENO, cBuffer, 4096 ) == -1 )
		return -1;

	// shuffle bits
	for( i = 0; i < 4096; i+=2, ++j )
	{
		cLeft = cBuffer[ i ] >> 6;
		cRight = cBuffer[ i+1 ] >> 6;
		dmap[ j ] = (cRight << 4) | cLeft;
	}

	BLIT(fd);
	DISPLAY(fd, 1);

	if (munmap(dmap, 2048) == -1 || close(fd) == -1)
		return 3;

	return 0;
}