use Encode
qw(:fallbacks find_encoding);
our $VERSION = do { my @r = (q
$Revision: 2.0 $ =~ /\d+/g); sprintf "%d."."%02d" x
$#r, @r };
our %DEF_SUSPECTS = map { $_ => find_encoding
($_) } qw(ascii utf8);
$Encode::Encoding
{$Canon} =
Suspects
=> { %DEF_SUSPECTS },
use base
qw(Encode::Encoding);
our @EXPORT = qw(guess_encoding);
our $UTF8_BOM = pack("C3", 0xef, 0xbb, 0xbf);
sub import
{ # Exporter not used so we do it on our own
*{"$callpkg\::$item"} = \
&{"$item"};
my $self = ref($class) ?
$class : $Encode::Encoding
{$Canon};
$self->{Suspects
} = { %DEF_SUSPECTS };
my $self = ref($class) ?
$class : $Encode::Encoding
{$Canon};
my $e = find_encoding
($c) or die "Unknown encoding: $c";
$self->{Suspects
}{$e->name} = $e;
DEBUG
and warn "Added: ", $e->name;
my ($obj, $octet, $chk) = @_;
my $guessed = guess
($obj, $octet);
my $utf8 = $guessed->decode($octet, $chk);
guess
($Encode::Encoding
{$Canon}, @_);
my $obj = ref($class) ?
$class : $Encode::Encoding
{$Canon};
return unless defined $octet and length $octet;
if ( Encode
::is_utf8
($octet) ) {
return find_encoding
('utf8') unless $NoUTFAutoGuess;
Encode
::_utf8_off
($octet);
unless ($NoUTFAutoGuess) {
my $BOM = pack('C3', unpack("C3", $octet));
return find_encoding
('utf8')
if (defined $BOM and $BOM eq $UTF8_BOM);
$BOM = unpack('N', $octet);
return find_encoding
('UTF-32')
if (defined $BOM and ($BOM == 0xFeFF or $BOM == 0xFFFe0000));
$BOM = unpack('n', $octet);
return find_encoding
('UTF-16')
if (defined $BOM and ($BOM == 0xFeFF or $BOM == 0xFFFe));
if ($octet =~ /\x00/o){ # if \x00 found, we assume UTF-(16|32)(BE|LE)
if ($octet =~ /\x00\x00/o){ # UTF-32(BE|LE) assumed
for my $char (unpack('N*', $octet)){
$char & 0x0000ffff and $be++;
$char & 0xffff0000 and $le++;
}else{ # UTF-16(BE|LE) assumed
for my $char (unpack('n*', $octet)){
$char & 0x00ff and $be++;
$char & 0xff00 and $le++;
DEBUG
and warn "$utf, be == $be, le == $le";
"Encodings ambiguous between $utf BE and LE ($be, $le)";
$utf .= ($be > $le) ?
'BE' : 'LE';
return find_encoding
($utf);
my %try = %{$obj->{Suspects
}};
my $e = find_encoding
($c) or die "Unknown encoding: $c";
DEBUG
and warn "Added: ", $e->name;
for my $line (split /\r\n?|\n/, $octet){
# cheat 2 -- \e in the string
delete @try{qw
/utf8 ascii/};
ref($try{$k}) eq 'Encode::XS' and delete $try{$k};
# warn join(",", keys %try);
$try{$k}->decode($scratch, FB_QUIET
);
DEBUG
and warn sprintf("%4d:%-24s ok\n", $nline, $k);
warn sprintf("%4d:%-24s not ok; %d bytes left\n",
$nline, $k, bytes
::length($scratch));
%ok or return "No appropriate encodings found!";
if (scalar(keys(%ok)) == 1){
my ($retval) = values(%ok);
return "Encodings too ambiguous: ", join(" or ", keys %try);
Encode::Guess -- Guesses encoding from data
# if you are sure $data won't contain anything bogus
use Encode::Guess qw/euc-jp shiftjis 7bit-jis/;
my $utf8 = decode("Guess", $data);
my $data = encode("Guess", $utf8); # this doesn't work!
my $enc = guess_encoding($data, qw/euc-jp shiftjis 7bit-jis/);
ref($enc) or die "Can't guess: $enc"; # trap error this way
$utf8 = $enc->decode($data);
$utf8 = decode($enc->name, $data)
Encode::Guess enables you to guess in what encoding a given data is
encoded, or at least tries to.
By default, it checks only ascii, utf8 and UTF-16/32 with BOM.
use Encode::Guess; # ascii/utf8/BOMed UTF
To use it more practically, you have to give the names of encodings to
check (I<suspects> as follows). The name of suspects can either be
canonical names or aliases.
CAVEAT: Unlike UTF-(16|32), BOM in utf8 is NOT AUTOMATICALLY STRIPPED.
# tries all major Japanese Encodings as well
use Encode::Guess qw/euc-jp shiftjis 7bit-jis/;
If the C<$Encode::Guess::NoUTFAutoGuess> variable is set to a true
value, no heuristics will be applied to UTF8/16/32, and the result
will be limited to the suspects and C<ascii>.
=item Encode::Guess->set_suspects
You can also change the internal suspects list via C<set_suspects>
Encode::Guess->set_suspects(qw/euc-jp shiftjis 7bit-jis/);
=item Encode::Guess->add_suspects
Or you can use C<add_suspects> method. The difference is that
C<set_suspects> flushes the current suspects list while
Encode::Guess->add_suspects(qw/euc-jp shiftjis 7bit-jis/);
# now the suspects are euc-jp,shiftjis,7bit-jis, AND
# euc-kr,euc-cn, and big5-eten
Encode::Guess->add_suspects(qw/euc-kr euc-cn big5-eten/);
=item Encode::decode("Guess" ...)
When you are content with suspects list, you can now
my $utf8 = Encode::decode("Guess", $data);
=item Encode::Guess->guess($data)
Two or more suspects remain
So you should instead try this;
my $decoder = Encode::Guess->guess($data);
On success, $decoder is an object that is documented in
L<Encode::Encoding>. So you can now do this;
my $utf8 = $decoder->decode($data);
On failure, $decoder now contains an error message so the whole thing
my $decoder = Encode::Guess->guess($data);
die $decoder unless ref($decoder);
my $utf8 = $decoder->decode($data);
=item guess_encoding($data, [, I<list of suspects>])
You can also try C<guess_encoding> function which is exported by
default. It takes $data to check and it also takes the list of
suspects by option. The optional suspect list is I<not reflected> to
the internal suspects list.
my $decoder = guess_encoding($data, qw/euc-jp euc-kr euc-cn/);
die $decoder unless ref($decoder);
my $utf8 = $decoder->decode($data);
# check only ascii and utf8
my $decoder = guess_encoding($data);
Because of the algorithm used, ISO-8859 series and other single-byte
encodings do not work well unless either one of ISO-8859 is the only
one suspect (besides ascii and utf8).
my $decoder = guess_encoding($data, 'latin1');
my $decoder = guess_encoding($data, qw/latin1 greek/);
The reason is that Encode::Guess guesses encoding by trial and error.
It first splits $data into lines and tries to decode the line for each
suspect. It keeps it going until all but one encoding is eliminated
out of suspects list. ISO-8859 series is just too successful for most
cases (because it fills almost all code points in \x00-\xff).
Do not mix national standard encodings and the corresponding vendor
= guess_encoding($data, qw/shiftjis MacJapanese cp932/);
The reason is that vendor encoding is usually a superset of national
standard so it becomes too ambiguous for most cases.
On the other hand, mixing various national standard encodings
automagically works unless $data is too short to allow for guessing.
# This is ok if $data is long enough
guess_encoding($data, qw/euc-cn
DO NOT PUT TOO MANY SUSPECTS! Don't you try something like this!
my $decoder = guess_encoding($data,
Encode->encodings(":all"));
It is, after all, just a guess. You should alway be explicit when it
comes to encodings. But there are some, especially Japanese,
environment that guess-coding is a must. Use this module with care.
Encode::Guess does not work on EBCDIC platforms.
L<Encode>, L<Encode::Encoding>