Encode::Guess -- Guesses encoding from data
# if you are sure $data won't contain anything bogus
use Encode;
use Encode::Guess qw/euc-jp shiftjis 7bit-jis/;
my $utf8 = decode("Guess", $data);
my $data = encode("Guess", $utf8); # this doesn't work!
# more elaborate way
use Encode::Guess,
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);
# or
$utf8 = decode($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 UTFTo use it more practically, you have to give the names of encodings to check (suspects as follows). The name of suspects can either be canonical names or aliases.
# tries all major Japanese Encodings as well
use Encode::Guess qw/euc-jp shiftjis 7bit-jis/;You can also change the internal suspects list via set_suspects method.
use Encode::Guess;
Encode::Guess->set_suspects(qw/euc-jp shiftjis 7bit-jis/);Or you can use add_suspects method. The difference is that set_suspects flushes the current suspects list while add_suspects adds.
use Encode::Guess;
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/);When you are content with suspects list, you can now
my $utf8 = Encode::decode("Guess", $data);But it will croak if Encode::Guess fails to eliminate all other suspects but the right one or no suspect was good. So you should instead try this;
my $decoder = Encode::Guess->guess($data);On success, $decoder is an object that is documented in 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 would be as follows;
my $decoder = Encode::Guess->guess($data);
die $decoder unless ref($decoder);
my $utf8 = $decoder->decode($data);You can also try 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 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).
use Encode::Guess;
# perhaps ok
my $decoder = guess_encoding($data, 'latin1');
# definitely NOT ok
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 was 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 encodings.
# a very bad idea
my $decoder
= guess_encoding($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
my $decoder =
guess_encoding($data, qw/euc-cn
euc-jp shiftjis 7bit-jis
euc-kr
big5-eten/);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.