in reply to Re^35: Interleaving bytes in a string quickly
in thread Interleaving bytes in a string quickly

That makes no sense at all. It breaks everything: 

pp \$a;;
[Malformed UTF-8 character (fatal) at C:/Perl64/lib/Data/Dump.pm line 
+458, <STDIN> line 13.

print unpack 'H*', $a;;
Malformed UTF-8 character (byte 0xfe) in unpack at (eval 21) line 1, <
+STDIN> line 14.
Malformed UTF-8 character (unexpected continuation byte 0x84, with no 
+preceding start byte) in unpack
Malformed UTF-8 character (unexpected continuation byte 0x80, with no 
+preceding start byte) in unpack
Malformed UTF-8 character (unexpected continuation byte 0x80, with no 
+preceding start byte) in unpack
Malformed UTF-8 character (unexpected continuation byte 0x80, with no 
+preceding start byte) in unpack
Malformed UTF-8 character (unexpected continuation byte 0x80, with no 
+preceding start byte) in unpack
Malformed UTF-8 character (unexpected continuation byte 0x80, with no 
+preceding start byte) in unpack
4100000000000000

[download]

And perl already has a perfectly good mechanism for packing integers into strings.

It also means that you now have a mechanism that will allow you to construct a string of packed integers that Perl has no way of unambiguously deconstructing.

I look forward to seeing that deperecated & removed sometime soon.

And it has no bearing upon the original desicussion because SvPVbytes() wouldn't know what to do with it either.

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.
"I'd rather go naked than blow up my ass"

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Re^37: Interleaving bytes in a string quickly
by ikegami (Patriarch) on Mar 01, 2010 at 18:56 UTC

    unpack 'H' requires bytes. Well, pretty much all of unpack does. That's the point. Just like interleave does.

    Note that it properly handles both string formats: 

    $ perl -wle'$x="\x80"; for (1..2) { print unpack "H*", $x; utf8::upgra
+de($x); }'
80
80

    [download]

    It also means that you now have a mechanism that will allow you to construct a string of packed integers that Perl has no way of unambiguously deconstructing.

    I don't understand this at all.

[reply]
[d/l]
[select]
      It also means that you now have a mechanism that will allow you to construct a string of packed integers that Perl has no way of unambiguously deconstructing.

      I don't understand this at all.

      This is what I mean: 

      $a = ''; $a .= chr 1<<$_ for 0..63;;

Dump $a;;
SV = PVMG(0x37b528) at 0x3058a0
  REFCNT = 1
  FLAGS = (SMG,POK,pPOK,UTF8)
  IV = 0
  NV = 0
  PV = 0x3cb90f8 "\1\2\4\10\20 @\302\200\304\200\310\200\320\200\340\2
+40\200\341\200\200\342\200\200\344
...
\200"\0Malformed UTF-8 character (byte 0xfe) in subroutine entry 
Malformed UTF-8 character (byte 0xfe) in subroutine entry 
Malformed UTF-8 character (byte 0xfe) in subroutine entry 
Malformed UTF-8 character (byte 0xfe) in subroutine entry 
Malformed UTF-8 character (byte 0xfe) in subroutine entry 
Malformed UTF-8 character (byte 0xff) in subroutine entry 
Malformed UTF-8 character (byte 0xff) in subroutine entry 
Malformed UTF-8 character (byte 0xff) in subroutine entry 
Malformed UTF-8 character (byte 0xff) in subroutine entry 
Malformed UTF-8 character (byte 0xff) in subroutine entry 
Malformed UTF-8 character (byte 0xff) in subroutine entry 
Malformed UTF-8 character (byte 0xff) in subroutine entry 
Malformed UTF-8 character (byte 0xff) in subroutine entry 
Malformed UTF-8 character (byte 0xff) in subroutine entry 
Malformed UTF-8 character (byte 0xff) in subroutine entry 
Malformed UTF-8 character (byte 0xff) in subroutine entry 
Malformed UTF-8 character (byte 0xff) in subroutine entry 
Malformed UTF-8 character (byte 0xff) in subroutine entry 
Malformed UTF-8 character (byte 0xff) in subroutine entry 
Malformed UTF-8 character (byte 0xff) in subroutine entry 
Malformed UTF-8 character (byte 0xff) in subroutine entry 
Malformed UTF-8 character (byte 0xff) in subroutine entry 
Malformed UTF-8 character (byte 0xff) in subroutine entry 
Malformed UTF-8 character (byte 0xff) in subroutine entry 
Malformed UTF-8 character (byte 0xff) in subroutine entry 
Malformed UTF-8 character (byte 0xff) in subroutine entry 
Malformed UTF-8 character (byte 0xff) in subroutine entry 
Malformed UTF-8 character (byte 0xff) in subroutine entry 
Malformed UTF-8 character (byte 0xff) in subroutine entry 
Malformed UTF-8 character (byte 0xff) in subroutine entry 
Malformed UTF-8 character (byte 0xff) in subroutine entry 
Malformed UTF-8 character (byte 0xff) in subroutine entry 
Malformed UTF-8 character (byte 0xff) in subroutine entry 
 [UTF8 "\x{1}\x{2}\x{4}\x{8}\x{10} 
     @\x{80}\x{100}\x{200}\x{400}\x{800}
     \x{1000}\x{2000}\x{4000}\x{8000}
     \x{10000}\x{20000}\x{40000}
  CUR = 504
  LEN = 512
  MAGIC = 0x3c856c8
    MG_VIRTUAL = &PL_vtbl_utf8
    MG_TYPE = PERL_MAGIC_utf8(w)
    MG_LEN = -1

print join '-', map ord( chop $a ), 1 .. 64;;
0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-
+0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0

      [download]

      And: 

      $a = ''; $a .= chr 1<<$_ for 0..63;;

print length $a;;
64

$a = reverse $a;;
Malformed UTF-8 character (byte 0xfe) in reverse at (eval 47)

print length $a;;
75

      [download]

      If Perl can't handle it, it's a bug, not a feature. And not something I would concern myself with trying to handle.

      Yet another, just another red herring.

      Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
      "Science is about questioning the status quo. Questioning authority".
      In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]
[d/l]
[select]

        If Perl can't handle it, it's a bug, not a feature.

        You can't have a bug in a feature without having a feature.

[reply]

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