Re: [Flex-help] Handle NULL-NULL in input stream.

[Chris v. <che...@gm...>]

Hmm, I don't see flex skipping consecutive NULLs.  Here's what I got:


% perl -e 'open($fh, "> t.in"); print {$fh} "asdf\0\0\0asdf"; close($fh);'
% cat t.l

%option noyywrap

%%

. {
  printf("'%c' = %i\n", yytext[0], yytext[0]);
}

%%

int main(int argc, char ** argv) {
  yylex();
  return 0;
}

% flex -o t.c t.l
% cc t.c
% ./a.out < t.in
'a' = 97
's' = 115
'd' = 100
'f' = 102
'' = 0
'' = 0
'' = 0
'a' = 97
's' = 115
'd' = 100
'f' = 102

-Chris


On Fri, Dec 12, 2014 at 6:34 AM, Allen Blaylock <Al...@ep...>
wrote:
>
> Is there a way to get the parser to handle more than one consecutive NULL
> in the input stream?
>
> Currently the parser generated by flex recognizes the consecutive NULLs as
> an EOF which I do not want,
> I would like to be able to tell the parser when the end of file is reached
> explicitly through one of my rules calling yyterminate().
>
> For instance say I had a blob of binary data in my input file that may
> contain a sequence of NULL characters.
> Luckily I know the length of the binary data because the preceding token
> contains the following binary length.
> With this information is it possible to tell the parser, move forward by N
> bytes and not scan them?
>
> Allen Blaylock
>
>
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