decrease encode time

The functions encode and decode are now capable of processing larger
buffers with less conditional logic. Input and output functions need to
follow suit to make better use of this next. Encode without line
wrapping already makes use of these improvements, because input and
output are now entirely handled by <stdio.h> functions.

input.h

@@ -3,9 +3,6 @@
 
 #include <stdio.h>
 
-int
-getocts(FILE *fp, unsigned char *o);
-
 int
 getsxts(FILE *fp, unsigned char *s);