#include <u.h>
#include <libc.h>

extern int (*dec)(uchar *, int, char *, int);
extern int (*enc)(char *, int, uchar *, int);

void
usage(void)
{
	print("usage: %s [-d]\n", argv0);
	exits("usage");
}

void
main(int argc, char **argv)
{
	uchar ibuf[9600];	/* divisible by 4, 5, 6, and 8 */
	uchar obuf[2*sizeof(ibuf)];
	int n, m;
	int dflag = 0;

	ARGBEGIN {
	case 'd':
		dflag++;
		break;
	default:
		usage();
	} ARGEND

	while((n = read(0, ibuf, sizeof ibuf)) > 0) {
		if(dflag)
			m = dec(obuf, sizeof obuf, (char *)ibuf, n);
		else
			m = enc((char *)obuf, sizeof obuf, ibuf, n);
		if(m < 0)
			abort();
		if(write(1, obuf, m) < m)
			sysfatal("write: %r");
	}
	if(n < 0)
		sysfatal("read: %r");

	exits(nil);
}