> So it doesn't allow you to differentiate between a character that was broken by the read, and an actually malformed input file.

providing a call back helps identifying the malformed bytes 

  DB<131> dd $rr
"\x84\xC3\x96\xC3\x9C.\r\n\r\n"

  DB<132> $start=0

  DB<133> $rru = Encode::decode('utf8',$rr, sub{ my $broken = shift; $
+start++; "" });

  DB<134> dd $rru
"\xD6\xDC.\r\n\r\n"

  DB<135> p $start
1
  DB<136>

[download]

> I don't use the debugger often, so reading its output doesn't come naturally to me ;-)

as commented

furthermore debugger commands 

 DB<79> h p
p expr        Same as "print {DB::OUT} expr" in current package.

  DB<80> h x
x expr        Evals expression in list context, dumps the result.

[download]

update

one way to identify how many malformed bytes are at the start and to be sure the rest is well. 

  DB<159> $start=0

  DB<160> $rru = Encode::decode('utf8',$rr,sub{ $start++; return "" })
+;

  DB<161> $sub= substr $rr,$start

  DB<162> $rru2 = Encode::decode('utf8',$sub ,Encode::FB_CROAK);

  DB<163> p $rru2 eq $rru
1
  DB<164>

[download]

Cheers Rolf
(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery FootballPerl is like chess, only without the dice

In reply to Re^4: Processing an encoded file backwards (updated) by LanX
in thread Processing an encoded file backwards by LanX

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