Re: io:lines() and \0

[Enrico Colombini <erix@...>]

On 18/02/2014 15.04, Roberto Ierusalimschy wrote:
> ANSI C says that about text files:
>
>    Data read in from a text stream will necessarily compare equal to
>    the data that were earlier written out to that stream only if: the
>    data consist only of printing characters and the control characters
>    horizontal tab and new-line; no new-line character is immediately
>    preceded by space characters; and the last character is a new-line
>    character.
>
> So, there is no garanties that a text file with embedded zeros will be
> read correctly, no matter how we implement it.

Another example is the "end-of-text" character (0x04 in Unix, 0x1a in 
Windows) that terminates text files.

> Just for the record: In my machine, the following program,
>
>    local count = 0
>    for l in io.lines() do
>      count = count + #l
>    end
>    print(count)
>
> reading the Bible, takes ~0.07s with the current implementation and
> ~0.14s with this proposal.

I really can't see any advantage in making text file reading worse, just 
to handle the nonstandard case "read a binary file using text file 
functions".
Especially because the nonstandard case can be easily handled in other 
ways, either in C or in pure Lua.

--
  Enrico