D. J. Bernstein
Internet mail
8-bit text messages
An 8-bit text message means a sequence of lines.
Each line is a string of zero or more 8-bit bytes.
A message is safe if none of its bytes are \012.
How are 8-bit messages stored under current operating systems?
Under DOS and Windows, a message is normally stored on disk as
firstline\015\012secondline\015\012...\015\012lastline.
Under UNIX, a message is normally stored on disk as
firstline\012secondline\012...\012lastline.
In practice, it is very common for the last line to be empty.
A partial line means a nonempty last line.
Beware that some text-processing utilities ignore partial lines.
Why are safe messages a useful concept?
The DOS and UNIX message encodings are reversible for safe messages.
Any string of 8-bit bytes can be interpreted as a safe message
in the UNIX encoding.