Hi, Paul.

PE> PE> Actually, I've changed my mind about that.  I don't think it is
PE> PE> possible to reduce the timing of instructions within that loop,
PE> PE> without causing an overrun.  I was basically moving the testing
PE> PE> before the move, and then special case after the loop, but the
PE> PE> testing I was doing would destroy the register.

PE> PE> HOWEVER, what could be done is if I give you the maximum length
PE> PE> as WELL as just the '\n' terminator, then it could be written
PE> PE> just as fast.

PE> On the assumption that you are only concerned about not overrunning
PE> the buffer, but besides that, you don't mind copying an extra
PE> byte or three.

Yes, I guess for total safety you should specify the routine as copying
up to and including any \n, or the supplied maximum output buffer size,
whichever comes first.

PE> However, on closer reading of the ISO standard, I cannot see

Oh, this is an implementation of an ISO-specified routine? I didn't
realise that.

PE> anything that would allow me to do that.  It says that characters
PE> stop getting read when the newline character is read.  What I
PE> would have LIKED them to have said is "The contents of the
PE> array after the newline character will be indeterminant".  But

True, but if its an ISO standard function you'd have to allow for a user
who knew that his input line would never exceed say 41 bytes, and
provided an output buffer of exactly that size. You'd clobber the
subsequent.

PE> as it stands at the moment, people can instead be sure that their
PE> array will not be clobbered with extra bytes, which means that
PE> they can play silly buggers, and, e.g. do an fgets() and get
PE> a line of BBBBBBBBBBBBBBBBBBBB and then an fgets and get a line
PE> of AAAAAAA, and then clobber the '\n' with a C, knowing that
PE> they will now get a AAAAAACBBBBBBBBBBBB, e.g.

Yeah, users do strange things. :-)

PE> What this means is that two halfword *stores* instead of a single
PE> fullword store is unavoidable in the main loop.

Yes it is, in the *main* loop. You'd modify my Test 10 to do all those
tests before the "mov [di],eax" and handle the special cases of 1, 2 or
3 bytes as special cases after the main loop.

PE> That also means that there is no use in having the length available.

I'd still prefer to have such a routine specified as I suggested above,
but then I'm a programmer who believes in protecting users from
themselves. :-)

It might even have a useful application other than the buffer space
assignment problem - say you want to display the first n characters
of each line of a text file.

Regards, FIM.

 * * Can taglines have sequels?  Hmmm.....
@EOT:

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