in reply to Re^2: Fastest byteswap (little endian to big endian (eg. 34127856 -> 12345678)
in thread Fastest byteswap (little endian to big endian (eg. 34127856 -> 12345678)

There is in the second method posted by james28909: 

my $data = do {

    local $/ = undef;
    open (my $fh, "<", $input_file) or die "could not open $input_file
+: $!";
    binmode($fh);
    <$fh>;

};

my $reversed_data = pack( "v*", unpack( "n*", $data ) );

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But since it's not copied from one variable to another, it probably makes little difference indeed, I didn't think it through.

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Re^4: Fastest byteswap (little endian to big endian (eg. 34127856 -> 12345678)
by ikegami (Patriarch) on Apr 14, 2015 at 18:19 UTC
    That code does copy —note the assignment operator— but I think COW wouldn't help there either because I think the string would be stolen from the temp rather than copied.
[reply]
      Whoa, why the downvotes? Rephrased in case it was confusing.
[reply]

        No idea about the downvote, but with no comment to go with it, you might as well pretend it's not there. And yes, I do agree that this code probably falls out of COW's scope (that's what I meant by "not copied from one variable to another"), as I said I overlooked that part.

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