Re^2: help in ruby code to perl

While it probably doesn't matter in this case (since the whole file is being read at once), '<:raw' prevents a buffering layer from being added. You want

open(my $fh, '<:perlio:raw', $qfn);
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open(my $fh, '<', $qfn);
binmode($fh);
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Same goes for '>:raw'.

The usual idiom is

local $/;
my $str = <$FI>;
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rather than

read $FI, my $str, -s $FI;
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A regex (/(.{40} EMF.*)/s) would be a bit simpler than index+pos+substr and more idiomatic. It could be a bit slower, but probably not since it's optimised to look for " EMF" first.

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Re^3: help in ruby code to perl by jwkrahn (Abbot) on Sep 20, 2009 at 17:30 UTC
In my defence `;-)` I was just trying to do a direct translation. If I was going to do it in idiomatic Perl I would have done it differently. `perldoc PerlIO [ SNIP ] :raw The ":raw" layer is defined as being identical to calling " +binmode($fh)" - the stream is made suitable for passing binary data i.e. each byte is pas +sed as-is. The stream will still be buffered.` [download] Also, you should always verify that open worked correctly before trying to use its filehandle. `:-)`	[reply] [d/l] [select]
Re^4: help in ruby code to perl by ikegami (Patriarch) on Sep 20, 2009 at 17:51 UTC
`binmode($fh, ':raw');` is the same thing as `binmode($fh);`, but they're not the same as using `:raw` with `open`. Using `binmode :raw` disables layers that can be disabled. This doesn't disable buffering if the underlying layer does any. Using `open :raw` prevents some layers from being added in the first place, and this has been shown to prevent buffering. `$ perl -le'open $fh, "<", "foo"; print for PerlIO::get_layers($fh)' unix perlio $ perl -le'open $fh, "<", "foo"; binmode $fh; print for PerlIO::get_la +yers($fh)' unix perlio $ perl -le'open $fh, "<", "foo"; binmode $fh, ":raw"; print for PerlIO +::get_layers($fh)' unix perlio $ perl -le'open $fh, "<:raw", "foo"; print for PerlIO::get_layers($fh) +' unix` [download]	[reply] [d/l] [select]
Re^5: help in ruby code to perl by jwkrahn (Abbot) on Sep 20, 2009 at 18:44 UTC
I'm sorry, I can not find anything in the documentation (so far) that says that open and binmode do different things with `:raw`. Could you point me in the right dirrection please? Update: Perhaps you are thinking of this section of PerlIO: `To get an un-buffered stream specify an unbuffered layer (e.g. +":unix") in the open call: open($fh,"<:unix",$path)` [download]	[reply] [d/l] [select]
Re^6: help in ruby code to perl by ikegami (Patriarch) on Sep 20, 2009 at 18:55 UTC