[perl5.git] / ext / Encode / Encode.pm

package Encode;

$VERSION = 0.01;

require DynaLoader;
require Exporter;

@ISA = qw(Exporter DynaLoader);

@EXPORT_OK =
    qw(
       bytes_to_utf8
       utf8_to_bytes
       chars_to_utf8
       utf8_to_chars
       utf8_to_chars_check
       bytes_to_chars
       chars_to_bytes
       from_to
       is_utf8
       on_utf8
       off_utf8
       utf_to_utf
       encodings
      );

bootstrap Encode ();

=pod

=head1 NAME

Encode - character encodings

=head2 TERMINOLOGY

=over

=item *

I<char>: a character in the range 0..maxint (at least 2**32-1)

=item *

I<byte>: a character in the range 0..255

=back

The marker [INTERNAL] marks Internal Implementation Details, in
general meant only for those who think they know what they are doing,
and such details may change in future releases.

=head2 bytes

=over 4

=item *

        bytes_to_utf8(STRING [, FROM])

The bytes in STRING are recoded in-place into UTF-8.  If no FROM is
specified the bytes are expected to be encoded in US-ASCII or ISO
8859-1 (Latin 1).  Returns the new size of STRING, or C<undef> if
there's a failure.

[INTERNAL] Also the UTF-8 flag of STRING is turned on.

=item *

        utf8_to_bytes(STRING [, TO [, CHECK]])

The UTF-8 in STRING is decoded in-place into bytes.  If no TO encoding
is specified the bytes are expected to be encoded in US-ASCII or ISO
8859-1 (Latin 1).  Returns the new size of STRING, or C<undef> if
there's a failure.

What if there are characters > 255?  What if the UTF-8 in STRING is
malformed?  See L</"Handling Malformed Data">.

[INTERNAL] The UTF-8 flag of STRING is not checked.

=back

=head2 chars

=over 4

=item *

        chars_to_utf8(STRING)

The chars in STRING are encoded in-place into UTF-8.  Returns the new
size of STRING, or C<undef> if there's a failure.

No assumptions are made on the encoding of the chars.  If you want to
assume that the chars are Unicode and to trap illegal Unicode
characters, you must use C<from_to('Unicode', ...)>.

[INTERNAL] Also the UTF-8 flag of STRING is turned on.

=over 4

=item *

        utf8_to_chars(STRING)

The UTF-8 in STRING is decoded in-place into chars.  Returns the new
size of STRING, or C<undef> if there's a failure.

If the UTF-8 in STRING is malformed C<undef> is returned, and also an
optional lexical warning (category utf8) is given.

[INTERNAL] The UTF-8 flag of STRING is not checked.

=item *

        utf8_to_chars_check(STRING [, CHECK])

(Note that special naming of this interface since a two-argument
utf8_to_chars() has different semantics.)

The UTF-8 in STRING is decoded in-place into chars.  Returns the new
size of STRING, or C<undef> if there is a failure.

If the UTF-8 in STRING is malformed?  See L</"Handling Malformed Data">.

[INTERNAL] The UTF-8 flag of STRING is not checked.

=back

=head2 chars With Encoding

=over 4

=item *

        chars_to_utf8(STRING, FROM [, CHECK])

The chars in STRING encoded in FROM are recoded in-place into UTF-8.
Returns the new size of STRING, or C<undef> if there's a failure.

No assumptions are made on the encoding of the chars.  If you want to
assume that the chars are Unicode and to trap illegal Unicode
characters, you must use C<from_to('Unicode', ...)>.

[INTERNAL] Also the UTF-8 flag of STRING is turned on.

=item *

        utf8_to_chars(STRING, TO [, CHECK])

The UTF-8 in STRING is decoded in-place into chars encoded in TO.
Returns the new size of STRING, or C<undef> if there's a failure.

If the UTF-8 in STRING is malformed?  See L</"Handling Malformed Data">.

[INTERNAL] The UTF-8 flag of STRING is not checked.

=item *

	bytes_to_chars(STRING, FROM [, CHECK])

The bytes in STRING encoded in FROM are recoded in-place into chars.
Returns the new size of STRING in bytes, or C<undef> if there's a
failure.

If the mapping is impossible?  See L</"Handling Malformed Data">.

=item *

	chars_to_bytes(STRING, TO [, CHECK])

The chars in STRING are recoded in-place to bytes encoded in TO.
Returns the new size of STRING in bytes, or C<undef> if there's a
failure.

If the mapping is impossible?  See L</"Handling Malformed Data">.

=item *

        from_to(STRING, FROM, TO [, CHECK])

The chars in STRING encoded in FROM are recoded in-place into TO.
Returns the new size of STRING, or C<undef> if there's a failure.

If mapping between the encodings is impossible?
See L</"Handling Malformed Data">.

[INTERNAL] If TO is UTF-8, also the UTF-8 flag of STRING is turned on.

=back

=head2 Testing For UTF-8

=over 4

=item *

        is_utf8(STRING [, CHECK])

[INTERNAL] Test whether the UTF-8 flag is turned on in the STRING.
If CHECK is true, also checks the data in STRING for being
well-formed UTF-8.  Returns true if successful, false otherwise.

=back

=head2 Toggling UTF-8-ness

=over 4

=item *

        on_utf8(STRING)

[INTERNAL] Turn on the UTF-8 flag in STRING.  The data in STRING is
B<not> checked for being well-formed UTF-8.  Do not use unless you
B<know> that the STRING is well-formed UTF-8.  Returns the previous
state of the UTF-8 flag (so please don't test the return value as
I<not> success or failure), or C<undef> if STRING is not a string.

=item *

        off_utf8(STRING)

[INTERNAL] Turn off the UTF-8 flag in STRING.  Do not use frivolously.
Returns the previous state of the UTF-8 flag (so please don't test the
return value as I<not> success or failure), or C<undef> if STRING is
not a string.

=back

=head2 UTF-16 and UTF-32 Encodings

=over 4

=item *

        utf_to_utf(STRING, FROM, TO [, CHECK])

The data in STRING is converted from Unicode Transfer Encoding FROM to
Unicode Transfer Encoding TO.  Both FROM and TO may be any of the
following tags (case-insensitive, with or without 'utf' or 'utf-' prefix):

        tag             meaning

        '7'             UTF-7
        '8'             UTF-8
        '16be'          UTF-16 big-endian
        '16le'          UTF-16 little-endian
        '16'            UTF-16 native-endian
        '32be'          UTF-32 big-endian
        '32le'          UTF-32 little-endian
        '32'            UTF-32 native-endian

UTF-16 is also known as UCS-2, 16 bit or 2-byte chunks, and UTF-32 as
UCS-4, 32-bit or 4-byte chunks.  Returns the new size of STRING, or
C<undef> is there's a failure.

If FROM is UTF-8 and the UTF-8 in STRING is malformed?  See
L</"Handling Malformed Data">.

[INTERNAL] Even if CHECK is true and FROM is UTF-8, the UTF-8 flag of
STRING is not checked.  If TO is UTF-8, also the UTF-8 flag of STRING is
turned on.  Identical FROM and TO are fine.

=back

=head2 Handling Malformed Data

If CHECK is not set, C<undef> is returned.  If the data is supposed to
be UTF-8, an optional lexical warning (category utf8) is given.  If
CHECK is true but not a code reference, dies.  If CHECK is a code
reference, it is called with the arguments

	(MALFORMED_STRING, STRING_FROM_SO_FAR, STRING_TO_SO_FAR)

Two return values are expected from the call: the string to be used in
the result string in place of the malformed section, and the length of
the malformed section in bytes.

=cut

sub bytes_to_utf8 {
    &_bytes_to_utf8;
}

sub utf8_to_bytes {
    &_utf8_to_bytes;
}

sub chars_to_utf8 {
    &C_to_utf8;
}

sub utf8_to_chars {
    &_utf8_to_chars;
}

sub utf8_to_chars_check {
    &_utf8_to_chars_check;
}

sub bytes_to_chars {
    &_bytes_to_chars;
}

sub chars_to_bytes {
    &_chars_to_bytes;
}

sub is_utf8 {
    &_is_utf8;
}

sub on_utf8 {
    &_on_utf8;
}

sub off_utf8 {
    &_off_utf8;
}

sub utf_to_utf {
    &_utf_to_utf;
}

use Carp;

sub from_to
{
 my ($string,$from,$to,$check) = @_;
 my $f = __PACKAGE__->getEncoding($from);
 croak("Unknown encoding '$from'") unless $f;
 my $t = __PACKAGE__->getEncoding($to);
 croak("Unknown encoding '$to'") unless $t;
 my $uni = $f->toUnicode($string,$check);
 return undef if ($check && length($string));
 $string = $t->fromUnicode($uni,$check);
 return undef if ($check && length($uni));
 return length($_[0] = $string);
}

sub encodings
{
 my ($class) = @_;
 my ($dir) = __FILE__ =~ /^(.*)\.pm$/;
 my @names = ('Unicode');
 if (opendir(my $dh,$dir))
  {
   while (defined(my $name = readdir($dh)))
    {
     push(@names,$1) if ($name =~ /^(.*)\.enc$/);
    }
   closedir($dh);
  }
 else
  {
   die "Cannot open $dir:$!";
  }
 return @names;
}

my %encoding = ( Unicode => 'Encode::Unicode' );

sub getEncoding
{
 my ($class,$name) = @_;
 unless (exists $encoding{$name})
  {
   my $file;
   foreach my $dir (@INC)
    {
     last if -f ($file = "$dir/Encode/$name.enc");
    }
   if (open(my $fh,$file))
    {
     my $type;
     while (1)
      {
       my $line = <$fh>;
       $type = substr($line,0,1);
       last unless $type eq '#';
      }
     $class .= ('::'.(($type eq 'E') ? 'Escape' : 'Table'));
     $encoding{$name} = $class->read($fh,$name,$type);
    }
  }
 return $encoding{$name};
}

package Encode::Unicode;

# Dummy package that provides the encode interface

sub name { 'Unicode' }

sub toUnicode   { $_[1] }

sub fromUnicode { $_[1] }

package Encode::Table;

sub read
{
 my ($class,$fh,$name,$type) = @_;
 my $rep = $class->can("rep_$type");
 my ($def,$sym,$pages) = split(/\s+/,scalar(<$fh>));
 my @touni;
 my %fmuni;
 my $count = 0;
 $def = hex($def);
 $def = pack(&$rep($def),$def);
 while ($pages--)
  {
   my $page = hex(<$fh>);
   my @page;
   my $ch = $page * 256;
   for (my $i = 0; $i < 16; $i++)
    {
     my $line = <$fh>;
     for (my $j = 0; $j < 16; $j++)
      {
       my $val = hex(substr($line,0,4,''));
       if ($val || !$ch)
        {
         my $uch = chr($val);
         push(@page,$uch);
         $fmuni{$uch} = pack(&$rep($ch),$ch);
         $count++;
        }
       else
        {
         push(@page,undef);
        }
       $ch++;
      }
    }
   $touni[$page] = \@page;
  }

 return bless {Name  => $name,
               Rep   => $rep,
               ToUni => \@touni,
               FmUni => \%fmuni,
               Def   => $def,
               Num   => $count,
              },$class;
}

sub name { shift->{'Name'} }

sub rep_S { 'C' }

sub rep_D { 'S' }

sub rep_M { ($_[0] > 255) ? 'S' : 'C' }

sub representation
{
 my ($obj,$ch) = @_;
 $ch = 0 unless @_ > 1;
 $obj-{'Rep'}->($ch);
}

sub toUnicode
{
 my ($obj,$str,$chk) = @_;
 my $rep   = $obj->{'Rep'};
 my $touni = $obj->{'ToUni'};
 my $uni   = '';
 while (length($str))
  {
   my $ch = ord(substr($str,0,1,''));
   my $x;
   if (&$rep($ch) eq 'C')
    {
     $x = $touni->[0][$ch];
    }
   else
    {
     $x = $touni->[$ch][ord(substr($str,0,1,''))];
    }
   unless (defined $x)
    {
     last if $chk;
     # What do we do here ?
     $x = '';
    }
   $uni .= $x;
  }
 $_[1] = $str if $chk;
 return $uni;
}

sub fromUnicode
{
 my ($obj,$uni,$chk) = @_;
 my $fmuni = $obj->{'FmUni'};
 my $str   = '';
 my $def   = $obj->{'Def'};
 while (length($uni))
  {
   my $ch = substr($uni,0,1,'');
   my $x  = $fmuni->{$ch};
   unless (defined $x)
    {
     last if ($chk);
     $x = $def;
    }
   $str .= $x;
  }
 $_[1] = $uni if $chk;
 return $str;
}

package Encode::Escape;
use Carp;

sub read
{
 my ($class,$fh,$name) = @_;
 my %self = (Name => $name, Num => 0);
 while (<$fh>)
  {
   my ($key,$val) = /^(\S+)\s+(.*)$/;
   $val =~ s/^\{(.*?)\}/$1/g;
   $val =~ s/\\x([0-9a-f]{2})/chr(hex($1))/ge;
   $self{$key} = $val;
  }
 return bless \%self,$class;
}

sub name { shift->{'Name'} }

sub toUnicode
{
 croak("Not implemented yet");
}

sub fromUnicode
{
 croak("Not implemented yet");
}

1;

__END__
Commit	Line	Data
2c674647 JH	1	package Encode;
	2
	3	$VERSION = 0.01;
	4
	5	require DynaLoader;
	6	require Exporter;
	7
	8	@ISA = qw(Exporter DynaLoader);
	9
	10	@EXPORT_OK =
	11	qw(
	12	bytes_to_utf8
	13	utf8_to_bytes
	14	chars_to_utf8
	15	utf8_to_chars
	16	utf8_to_chars_check
	17	bytes_to_chars
	18	chars_to_bytes
	19	from_to
	20	is_utf8
	21	on_utf8
	22	off_utf8
	23	utf_to_utf
656753f8	24	encodings
2c674647 JH	25	);
	26
	27	bootstrap Encode ();
	28
	29	=pod
	30
	31	=head1 NAME
	32
	33	Encode - character encodings
	34
	35	=head2 TERMINOLOGY
	36
	37	=over
	38
	39	=item *
	40
	41	I<char>: a character in the range 0..maxint (at least 2**32-1)
	42
	43	=item *
	44
	45	I<byte>: a character in the range 0..255
	46
	47	=back
	48
	49	The marker [INTERNAL] marks Internal Implementation Details, in
	50	general meant only for those who think they know what they are doing,
	51	and such details may change in future releases.
	52
	53	=head2 bytes
	54
	55	=over 4
	56
	57	=item *
	58
	59	bytes_to_utf8(STRING [, FROM])
	60
	61	The bytes in STRING are recoded in-place into UTF-8. If no FROM is
	62	specified the bytes are expected to be encoded in US-ASCII or ISO
	63	8859-1 (Latin 1). Returns the new size of STRING, or C<undef> if
	64	there's a failure.
	65
656753f8	66	[INTERNAL] Also the UTF-8 flag of STRING is turned on.
2c674647 JH	67
	68	=item *
	69
	70	utf8_to_bytes(STRING [, TO [, CHECK]])
	71
	72	The UTF-8 in STRING is decoded in-place into bytes. If no TO encoding
	73	is specified the bytes are expected to be encoded in US-ASCII or ISO
	74	8859-1 (Latin 1). Returns the new size of STRING, or C<undef> if
	75	there's a failure.
	76
	77	What if there are characters > 255? What if the UTF-8 in STRING is
	78	malformed? See L</"Handling Malformed Data">.
	79
	80	[INTERNAL] The UTF-8 flag of STRING is not checked.
	81
	82	=back
	83
	84	=head2 chars
	85
	86	=over 4
	87
	88	=item *
	89
	90	chars_to_utf8(STRING)
	91
	92	The chars in STRING are encoded in-place into UTF-8. Returns the new
	93	size of STRING, or C<undef> if there's a failure.
	94
	95	No assumptions are made on the encoding of the chars. If you want to
	96	assume that the chars are Unicode and to trap illegal Unicode
	97	characters, you must use C<from_to('Unicode', ...)>.
	98
	99	[INTERNAL] Also the UTF-8 flag of STRING is turned on.
	100
	101	=over 4
	102
	103	=item *
	104
	105	utf8_to_chars(STRING)
	106
	107	The UTF-8 in STRING is decoded in-place into chars. Returns the new
656753f8	108	size of STRING, or C<undef> if there's a failure.
2c674647 JH	109
	110	If the UTF-8 in STRING is malformed C<undef> is returned, and also an
	111	optional lexical warning (category utf8) is given.
	112
	113	[INTERNAL] The UTF-8 flag of STRING is not checked.
	114
	115	=item *
	116
	117	utf8_to_chars_check(STRING [, CHECK])
	118
	119	(Note that special naming of this interface since a two-argument
	120	utf8_to_chars() has different semantics.)
	121
	122	The UTF-8 in STRING is decoded in-place into chars. Returns the new
	123	size of STRING, or C<undef> if there is a failure.
	124
	125	If the UTF-8 in STRING is malformed? See L</"Handling Malformed Data">.
	126
	127	[INTERNAL] The UTF-8 flag of STRING is not checked.
	128
	129	=back
	130
	131	=head2 chars With Encoding
	132
	133	=over 4
	134
	135	=item *
	136
	137	chars_to_utf8(STRING, FROM [, CHECK])
	138
	139	The chars in STRING encoded in FROM are recoded in-place into UTF-8.
	140	Returns the new size of STRING, or C<undef> if there's a failure.
	141
	142	No assumptions are made on the encoding of the chars. If you want to
	143	assume that the chars are Unicode and to trap illegal Unicode
	144	characters, you must use C<from_to('Unicode', ...)>.
	145
	146	[INTERNAL] Also the UTF-8 flag of STRING is turned on.
	147
	148	=item *
	149
	150	utf8_to_chars(STRING, TO [, CHECK])
	151
	152	The UTF-8 in STRING is decoded in-place into chars encoded in TO.
	153	Returns the new size of STRING, or C<undef> if there's a failure.
	154
	155	If the UTF-8 in STRING is malformed? See L</"Handling Malformed Data">.
	156
	157	[INTERNAL] The UTF-8 flag of STRING is not checked.
	158
	159	=item *
	160
	161	bytes_to_chars(STRING, FROM [, CHECK])
	162
	163	The bytes in STRING encoded in FROM are recoded in-place into chars.
	164	Returns the new size of STRING in bytes, or C<undef> if there's a
	165	failure.
	166
	167	If the mapping is impossible? See L</"Handling Malformed Data">.
	168
	169	=item *
	170
	171	chars_to_bytes(STRING, TO [, CHECK])
	172
173	The chars in STRING are recoded in-place to bytes encoded in TO.
174	Returns the new size of STRING in bytes, or C<undef> if there's a
175	failure.
176
177	If the mapping is impossible? See L</"Handling Malformed Data">.
178
179	=item *
180
181	from_to(STRING, FROM, TO [, CHECK])
182
183	The chars in STRING encoded in FROM are recoded in-place into TO.
184	Returns the new size of STRING, or C<undef> if there's a failure.
185
186	If mapping between the encodings is impossible?
187	See L</"Handling Malformed Data">.
188
189	[INTERNAL] If TO is UTF-8, also the UTF-8 flag of STRING is turned on.
190
191	=back
192
193	=head2 Testing For UTF-8
194
195	=over 4
196
197	=item *
198
199	is_utf8(STRING [, CHECK])
200
201	[INTERNAL] Test whether the UTF-8 flag is turned on in the STRING.
202	If CHECK is true, also checks the data in STRING for being
203	well-formed UTF-8. Returns true if successful, false otherwise.
204
205	=back
206
207	=head2 Toggling UTF-8-ness
208
209	=over 4
210
211	=item *
212
213	on_utf8(STRING)
214
215	[INTERNAL] Turn on the UTF-8 flag in STRING. The data in STRING is
216	B<not> checked for being well-formed UTF-8. Do not use unless you
217	B<know> that the STRING is well-formed UTF-8. Returns the previous
218	state of the UTF-8 flag (so please don't test the return value as
219	I<not> success or failure), or C<undef> if STRING is not a string.
220
221	=item *
222
223	off_utf8(STRING)
224
225	[INTERNAL] Turn off the UTF-8 flag in STRING. Do not use frivolously.
226	Returns the previous state of the UTF-8 flag (so please don't test the
227	return value as I<not> success or failure), or C<undef> if STRING is
228	not a string.
229
230	=back
231
232	=head2 UTF-16 and UTF-32 Encodings
233
234	=over 4
235
236	=item *
237
238	utf_to_utf(STRING, FROM, TO [, CHECK])
239
240	The data in STRING is converted from Unicode Transfer Encoding FROM to
241	Unicode Transfer Encoding TO. Both FROM and TO may be any of the
242	following tags (case-insensitive, with or without 'utf' or 'utf-' prefix):
243
244	tag meaning
245
246	'7' UTF-7
247	'8' UTF-8
248	'16be' UTF-16 big-endian
249	'16le' UTF-16 little-endian
250	'16' UTF-16 native-endian
251	'32be' UTF-32 big-endian
252	'32le' UTF-32 little-endian
253	'32' UTF-32 native-endian
254
255	UTF-16 is also known as UCS-2, 16 bit or 2-byte chunks, and UTF-32 as
256	UCS-4, 32-bit or 4-byte chunks. Returns the new size of STRING, or
257	C<undef> is there's a failure.
258
259	If FROM is UTF-8 and the UTF-8 in STRING is malformed? See
260	L</"Handling Malformed Data">.
261
262	[INTERNAL] Even if CHECK is true and FROM is UTF-8, the UTF-8 flag of
263	STRING is not checked. If TO is UTF-8, also the UTF-8 flag of STRING is
264	turned on. Identical FROM and TO are fine.
265
266	=back
267
268	=head2 Handling Malformed Data
269
270	If CHECK is not set, C<undef> is returned. If the data is supposed to
271	be UTF-8, an optional lexical warning (category utf8) is given. If
272	CHECK is true but not a code reference, dies. If CHECK is a code
273	reference, it is called with the arguments
274
275	(MALFORMED_STRING, STRING_FROM_SO_FAR, STRING_TO_SO_FAR)
276
277	Two return values are expected from the call: the string to be used in
278	the result string in place of the malformed section, and the length of
279	the malformed section in bytes.
280
281	=cut
282
283	sub bytes_to_utf8 {
284	&_bytes_to_utf8;
285	}
286
287	sub utf8_to_bytes {
288	&_utf8_to_bytes;
289	}
290
291	sub chars_to_utf8 {
292	&C_to_utf8;
293	}
294
295	sub utf8_to_chars {
296	&_utf8_to_chars;
297	}
298
299	sub utf8_to_chars_check {
300	&_utf8_to_chars_check;
301	}
302
303	sub bytes_to_chars {
304	&_bytes_to_chars;
305	}
306
307	sub chars_to_bytes {
308	&_chars_to_bytes;
309	}
310
2c674647 JH	311	sub is_utf8 {
	312	&_is_utf8;
	313	}
	314
	315	sub on_utf8 {
	316	&_on_utf8;
	317	}
	318
	319	sub off_utf8 {
	320	&_off_utf8;
	321	}
	322
	323	sub utf_to_utf {
	324	&_utf_to_utf;
	325	}
	326
bf230f3d NIS	327	use Carp;
bf230f3d NIS	328
656753f8 NIS	329	sub from_to
	330	{
	331	my ($string,$from,$to,$check) = @_;
	332	my $f = __PACKAGE__->getEncoding($from);
bf230f3d	333	croak("Unknown encoding '$from'") unless $f;
656753f8	334	my $t = __PACKAGE__->getEncoding($to);
bf230f3d	335	croak("Unknown encoding '$to'") unless $t;
656753f8	336	my $uni = $f->toUnicode($string,$check);
bf230f3d	337	return undef if ($check && length($string));
656753f8	338	$string = $t->fromUnicode($uni,$check);
bf230f3d	339	return undef if ($check && length($uni));
656753f8 NIS	340	return length($_[0] = $string);
	341	}
	342
	343	sub encodings
	344	{
	345	my ($class) = @_;
	346	my ($dir) = __FILE__ =~ /^(.*)\.pm$/;
	347	my @names = ('Unicode');
	348	if (opendir(my $dh,$dir))
	349	{
	350	while (defined(my $name = readdir($dh)))
	351	{
	352	push(@names,$1) if ($name =~ /^(.*)\.enc$/);
	353	}
	354	closedir($dh);
	355	}
	356	else
	357	{
	358	die "Cannot open $dir:$!";
	359	}
	360	return @names;
	361	}
	362
	363	my %encoding = ( Unicode => 'Encode::Unicode' );
	364
	365	sub getEncoding
	366	{
	367	my ($class,$name) = @_;
	368	unless (exists $encoding{$name})
	369	{
bf230f3d NIS	370	my $file;
	371	foreach my $dir (@INC)
	372	{
	373	last if -f ($file = "$dir/Encode/$name.enc");
	374	}
656753f8 NIS	375	if (open(my $fh,$file))
	376	{
	377	my $type;
	378	while (1)
	379	{
	380	my $line = <$fh>;
	381	$type = substr($line,0,1);
	382	last unless $type eq '#';
	383	}
	384	$class .= ('::'.(($type eq 'E') ? 'Escape' : 'Table'));
	385	$encoding{$name} = $class->read($fh,$name,$type);
	386	}
	387	}
bf230f3d	388	return $encoding{$name};
656753f8 NIS	389	}
	390
	391	package Encode::Unicode;
	392
	393	# Dummy package that provides the encode interface
	394
	395	sub name { 'Unicode' }
	396
	397	sub toUnicode { $_[1] }
	398
	399	sub fromUnicode { $_[1] }
	400
	401	package Encode::Table;
	402
	403	sub read
	404	{
	405	my ($class,$fh,$name,$type) = @_;
	406	my $rep = $class->can("rep_$type");
	407	my ($def,$sym,$pages) = split(/\s+/,scalar(<$fh>));
	408	my @touni;
	409	my %fmuni;
	410	my $count = 0;
	411	$def = hex($def);
	412	$def = pack(&$rep($def),$def);
	413	while ($pages--)
	414	{
	415	my $page = hex(<$fh>);
	416	my @page;
	417	my $ch = $page * 256;
	418	for (my $i = 0; $i < 16; $i++)
	419	{
	420	my $line = <$fh>;
	421	for (my $j = 0; $j < 16; $j++)
	422	{
	423	my $val = hex(substr($line,0,4,''));
	424	if ($val \|\| !$ch)
	425	{
	426	my $uch = chr($val);
	427	push(@page,$uch);
	428	$fmuni{$uch} = pack(&$rep($ch),$ch);
	429	$count++;
	430	}
	431	else
	432	{
	433	push(@page,undef);
	434	}
	435	$ch++;
	436	}
	437	}
	438	$touni[$page] = \@page;
	439	}
	440
	441	return bless {Name => $name,
	442	Rep => $rep,
	443	ToUni => \@touni,
	444	FmUni => \%fmuni,
	445	Def => $def,
	446	Num => $count,
	447	},$class;
	448	}
	449
	450	sub name { shift->{'Name'} }
	451
	452	sub rep_S { 'C' }
453
454	sub rep_D { 'S' }
455
456	sub rep_M { ($_[0] > 255) ? 'S' : 'C' }
457
458	sub representation
459	{
460	my ($obj,$ch) = @_;
461	$ch = 0 unless @_ > 1;
462	$obj-{'Rep'}->($ch);
463	}
464
465	sub toUnicode
466	{
bf230f3d	467	my ($obj,$str,$chk) = @_;
656753f8 NIS	468	my $rep = $obj->{'Rep'};
	469	my $touni = $obj->{'ToUni'};
	470	my $uni = '';
	471	while (length($str))
	472	{
	473	my $ch = ord(substr($str,0,1,''));
bf230f3d	474	my $x;
656753f8 NIS	475	if (&$rep($ch) eq 'C')
656753f8 NIS	476	{
bf230f3d	477	$x = $touni->[0][$ch];
656753f8 NIS	478	}
	479	else
	480	{
bf230f3d	481	$x = $touni->[$ch][ord(substr($str,0,1,''))];
656753f8	482	}
bf230f3d NIS	483	unless (defined $x)
	484	{
	485	last if $chk;
	486	# What do we do here ?
	487	$x = '';
	488	}
	489	$uni .= $x;
656753f8	490	}
bf230f3d	491	$_[1] = $str if $chk;
656753f8 NIS	492	return $uni;
	493	}
	494
	495	sub fromUnicode
	496	{
bf230f3d	497	my ($obj,$uni,$chk) = @_;
656753f8 NIS	498	my $fmuni = $obj->{'FmUni'};
	499	my $str = '';
	500	my $def = $obj->{'Def'};
	501	while (length($uni))
	502	{
	503	my $ch = substr($uni,0,1,'');
	504	my $x = $fmuni->{$ch};
bf230f3d NIS	505	unless (defined $x)
	506	{
	507	last if ($chk);
	508	$x = $def;
	509	}
	510	$str .= $x;
656753f8	511	}
bf230f3d	512	$_[1] = $uni if $chk;
656753f8 NIS	513	return $str;
	514	}
	515
	516	package Encode::Escape;
	517	use Carp;
	518
	519	sub read
	520	{
	521	my ($class,$fh,$name) = @_;
	522	my %self = (Name => $name, Num => 0);
	523	while (<$fh>)
	524	{
	525	my ($key,$val) = /^(\S+)\s+(.*)$/;
	526	$val =~ s/^\{(.*?)\}/$1/g;
	527	$val =~ s/\\x([0-9a-f]{2})/chr(hex($1))/ge;
	528	$self{$key} = $val;
	529	}
	530	return bless \%self,$class;
	531	}
	532
	533	sub name { shift->{'Name'} }
	534
	535	sub toUnicode
	536	{
	537	croak("Not implemented yet");
	538	}
	539
	540	sub fromUnicode
	541	{
	542	croak("Not implemented yet");
	543	}
	544
	545	1;
	546
	547	__END__