Re: Fastest byteswap (little endian to big endian (eg. 34127856 -> 12345678)

Before v5.20 the copy on write feature of string was not activated by default. This means that you may win a little time by avoiding to copy the strings in multiple scalars: print $output pack("v*", unpack("n*", scalar <$fh>));

Comment on Re: Fastest byteswap (little endian to big endian (eg. 34127856 -> 12345678) Download Code

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Re^2: Fastest byteswap (little endian to big endian (eg. 34127856 -> 12345678) by ikegami (Patriarch) on Apr 14, 2015 at 12:48 UTC
What copying? No string is copied in that code. COW would not help.	[reply]
Re^3: Fastest byteswap (little endian to big endian (eg. 34127856 -> 12345678) by Eily (Monsignor) on Apr 14, 2015 at 14:38 UTC
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 ) );` [download] But since it's not copied from one variable to another, it probably makes little difference indeed, I didn't think it through.	[reply] [d/l]
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]
Re^5: Fastest byteswap (little endian to big endian (eg. 34127856 -> 12345678) by ikegami (Patriarch) on Apr 14, 2015 at 18:42 UTC
Re^6: Fastest byteswap (little endian to big endian (eg. 34127856 -> 12345678) by Eily (Monsignor) on Apr 15, 2015 at 08:06 UTC
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