deprecated/buildtools/buildsystemtools/lib/XML/UM.pm
changeset 662 60be34e1b006
parent 655 3f65fd25dfd4
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/deprecated/buildtools/buildsystemtools/lib/XML/UM.pm	Wed Oct 27 16:03:51 2010 +0800
@@ -0,0 +1,466 @@
+#
+# TO DO:
+#
+# - Implement SlowMappers for expat builtin encodings (for which there
+#   are no .enc files), e.g. UTF-16, US-ASCII, ISO-8859-1.
+# - Instead of parsing the .xml file with XML::Encoding, we should use XS.
+#   If this will not be implemented for a while, we could try reading the
+#   .enc file directly, instead of the .xml file.
+#   I started writing XML::UM::EncParser to do this (see EOF), but got stuck.
+#
+
+use strict;
+
+package XML::UM::SlowMapper;
+use Carp;
+use XML::Encoding;
+
+use vars qw{ $ENCDIR %DEFAULT_ASCII_MAPPINGS };
+
+my $UTFCHAR = '[\\x00-\\xBF]|[\\xC0-\\xDF].|[\\xE0-\\xEF]..|[\\xF0-\\xFF]...';
+
+#
+# The directory that contains the .xml files that come with XML::Encoding.
+# Include the terminating '\' or '/' !!
+#
+$ENCDIR = "/home1/enno/perlModules/XML-Encoding-1.01/maps/";
+#$ENCDIR = "c:\\src\\perl\\xml\\XML-Encoding-1.01\\maps\\";
+
+#
+# From xmlparse.h in expat distribution:
+#
+# Expat places certain restrictions on the encodings that are supported
+# using this mechanism.
+#
+# 1. Every ASCII character that can appear in a well-formed XML document,
+# other than the characters
+#
+#  $@\^`{}~
+#
+# must be represented by a single byte, and that byte must be the
+# same byte that represents that character in ASCII.
+#
+# [end of excerpt]
+
+#?? Which 'ASCII characters can appear in a well-formed XML document ??
+
+# All ASCII codes 0 - 127, excl. 36,64,92,94,96,123,125,126 i.e. $@\^`{}~
+%DEFAULT_ASCII_MAPPINGS = map { (chr($_), chr($_)) } (0 .. 35, 37 .. 63, 
+						      65 .. 91, 93, 95, 
+						      97 .. 122, 124, 127);
+
+sub new
+{
+    my ($class, %hash) = @_;
+    my $self = bless \%hash, $class;
+    
+    $self->read_encoding_file;
+
+    $self;
+}
+
+sub dispose
+{
+    my $self = shift;
+    $self->{Factory}->dispose_mapper ($self);
+    delete $self->{Encode};
+}
+
+# Reads the XML file that contains the encoding definition.
+# These files come with XML::Encoding.
+sub read_encoding_file
+{
+#?? This should parse the .enc files (the .xml files are not installed) !!
+
+    my ($self) = @_;
+    my $encoding = $self->{Encoding};
+
+    # There is no .enc (or .xml) file for US-ASCII, but the mapping is simple
+    # so here it goes...
+    if ($encoding eq 'US-ASCII')
+    {
+	$self->{EncMapName} = 'US-ASCII';
+	$self->{Map} = \%DEFAULT_ASCII_MAPPINGS;	# I hope this is right
+	return;
+    }
+
+    my $file = $self->find_encoding_file ($encoding);
+    
+    my %uni = %DEFAULT_ASCII_MAPPINGS;
+    my $prefix = "";
+    my $DIR = "file:$ENCDIR";
+
+    my $enc = new XML::Encoding (Handlers => { 
+					       Init =>
+					       sub {
+						   my $base = shift->base ($DIR);
+					       }
+				 },
+
+				 PushPrefixFcn => 
+				 sub { 
+				     $prefix .= chr (shift); 
+				     undef;
+				 },
+
+				 PopPrefixFcn => 
+				 sub {
+				     chop $prefix;
+				     undef;
+				 },
+
+				 RangeSetFcn => 
+				 sub {
+				     my ($byte, $uni, $len) = @_;
+				     for (my $i = $uni; $len--; $uni++)
+				     {
+					 $uni{XML::UM::unicode_to_utf8($uni)} = $prefix . chr ($byte++);
+				     }
+				     undef;
+				 });
+
+    $self->{EncMapName} = $enc->parsefile ($file);
+
+#print "Parsed Encoding " . $self->{Encoding} . " MapName=" . $self->{EncMapName} . "\n";
+
+    $self->{Map} = \%uni;
+}
+
+sub find_encoding_file
+{
+    my ($self, $enc) = @_;
+
+    return "$ENCDIR\L$enc\E.xml";	 # .xml filename is lower case
+}
+
+# Returns a closure (method) that converts a UTF-8 encoded string to an 
+# encoded byte sequence.
+sub get_encode
+{
+    my ($self, %hash) = @_;
+    my $MAP = $self->{Map};
+    my $ENCODE_UNMAPPED = $hash{EncodeUnmapped} || \&XML::UM::encode_unmapped_dec;
+
+    my $code = "sub {\n    my \$str = shift;\n    \$str =~ s/";
+
+    $code .= "($UTFCHAR)/\n";
+    $code .= "defined \$MAP->{\$1} ? \$MAP->{\$1} : ";
+    $code .= "\&\$ENCODE_UNMAPPED(\$1) /egs;\n";
+
+    $code .= "\$str }\n";
+#    print $code;
+
+    my $func = eval $code;
+    croak "could not eval generated code=[$code]: $@" if $@;
+
+    $func;
+}
+
+#
+# Optimized version for when the encoding is UTF-8.
+# (In that case no conversion takes place.)
+#
+package XML::UM::SlowMapper::UTF8;
+use vars qw{ @ISA };
+@ISA = qw{ XML::UM::SlowMapper };
+
+sub read_encoding_file
+{
+    # ignore it
+}
+
+sub get_encode
+{
+    \&dont_convert;
+}
+
+sub dont_convert	# static
+{
+    shift		# return argument unchanged
+}
+
+package XML::UM::SlowMapperFactory;
+
+sub new
+{
+    my ($class, %hash) = @_;
+    bless \%hash, $class;
+}
+
+sub get_encode
+{
+    my ($self, %options) = @_;
+    my $encoding = $options{Encoding};
+
+    my $mapper = $self->get_mapper ($encoding);
+    return $mapper->get_encode (%options);
+}
+
+sub get_mapper
+{
+    my ($self, $encoding) = @_;
+    $self->{Mapper}->{$encoding} ||= 
+	($encoding eq "UTF-8" ?
+	 new XML::UM::SlowMapper::UTF8 (Encoding => $encoding, 
+					Factory => $self) :
+	 new XML::UM::SlowMapper (Encoding => $encoding, 
+				  Factory => $self));
+}
+
+#
+# Prepare for garbage collection (remove circular refs)
+#
+sub dispose_encoding
+{
+    my ($self, $encoding) = @_;
+    my $mapper = $self->{Mapper}->{$encoding};
+    return unless defined $mapper;
+
+    delete $mapper->{Factory};
+    delete $self->{Mapper}->{$encoding};
+}
+
+package XML::UM;
+use Carp;
+
+use vars qw{ $FACTORY %XML_MAPPING_CRITERIA };
+$FACTORY = XML::UM::SlowMapperFactory->new;
+
+sub get_encode		# static
+{
+    $FACTORY->get_encode (@_);
+}
+
+sub dispose_encoding	# static
+{
+    $FACTORY->dispose_encoding (@_);
+}
+
+# Convert UTF-8 byte sequence to Unicode index; then to '&#xNN;' string
+sub encode_unmapped_hex	# static
+{
+    my $n = utf8_to_unicode (shift);
+    sprintf ("&#x%X;", $n);
+}
+
+sub encode_unmapped_dec	# static
+{
+    my $n = utf8_to_unicode (shift);
+    "&#$n;"
+}
+
+# Converts a UTF-8 byte sequence that represents one character,
+# to its Unicode index.
+sub utf8_to_unicode	 # static
+{
+    my $str = shift;
+    my $len = length ($str);
+
+    if ($len == 1)
+    {
+	return ord ($str);
+    }
+    if ($len == 2)
+    {
+	my @n = unpack "C2", $str;
+	return (($n[0] & 0x3f) << 6) + ($n[1] & 0x3f);
+    }
+    elsif ($len == 3)
+    {
+	my @n = unpack "C3", $str;
+	return (($n[0] & 0x1f) << 12) + (($n[1] & 0x3f) << 6) + 
+		($n[2] & 0x3f);
+    }
+    elsif ($len == 4)
+    {
+	my @n = unpack "C4", $str;
+	return (($n[0] & 0x0f) << 18) + (($n[1] & 0x3f) << 12) + 
+		(($n[2] & 0x3f) << 6) + ($n[3] & 0x3f);
+    }
+    else
+    {
+	croak "bad UTF8 sequence [$str] hex=" . hb($str);
+    }
+}
+
+# Converts a Unicode character index to the byte sequence
+# that represents that character in UTF-8.
+sub unicode_to_utf8	# static
+{
+    my $n = shift;
+    if ($n < 0x80)
+    {
+	return chr ($n);
+    }
+    elsif ($n < 0x800)
+    {
+	return pack ("CC", (($n >> 6) | 0xc0), (($n & 0x3f) | 0x80));
+    }
+    elsif ($n < 0x10000)
+    {
+	return pack ("CCC", (($n >> 12) | 0xe0), ((($n >> 6) & 0x3f) | 0x80),
+		     (($n & 0x3f) | 0x80));
+    }
+    elsif ($n < 0x110000)
+    {
+	return pack ("CCCC", (($n >> 18) | 0xf0), ((($n >> 12) & 0x3f) | 0x80),
+		     ((($n >> 6) & 0x3f) | 0x80), (($n & 0x3f) | 0x80));
+    }
+    croak "number [$n] is too large for Unicode in \&unicode_to_utf8";
+}
+
+#?? The following package is unfinished. 
+#?? It should parse the .enc file and create an array that maps
+#?? Unicode-index to encoded-str. I got stuck...
+
+# package XML::UM::EncParser;
+#
+# sub new
+# {
+#     my ($class, %hash) = @_;
+#     my $self = bless \%hash, $class;
+#     $self;
+# }
+#
+# sub parse
+# {
+#     my ($self, $filename) = @_;
+#     open (FILE, $filename) || die "can't open .enc file $filename";
+#     binmode (FILE);
+#
+#     my $buf;
+#     read (FILE, $buf, 4 + 40 + 2 + 2 + 1024);
+#    
+#     my ($magic, $name, $pfsize, $bmsize, @map) = unpack ("NA40nnN256", $buf);
+#     printf "magic=%04x name=$name pfsize=$pfsize bmsize=$bmsize\n", $magic;
+#    
+#     if ($magic != 0xFEEBFACE)
+#     {
+# 	close FILE;
+# 	die sprintf ("bad magic number [0x%08X] in $filename, expected 0xFEEBFACE", $magic);
+#     }
+#
+#     for (my $i = 0; $i < 256; $i++)
+#     {
+# 	printf "[%d]=%d ", $i, $map[$i];
+# 	print "\n" if ($i % 8 == 7);
+#     }
+#
+#     for (my $i = 0; $i < $pfsize; $i++)
+#     {
+# 	print "----- PrefixMap $i ----\n";
+# 	read (FILE, $buf, 2 + 2 + 32 + 32);
+# 	my ($min, $len, $bmap_start, @ispfx) = unpack ("CCnC64", $buf);
+# 	my (@ischar) = splice @ispfx, 32, 32, ();
+# #?? could use b256 instead of C32 for bitvector a la vec()
+#
+# 	print "ispfx=@ispfx\n";
+# 	print "ischar=@ischar\n";
+# 	$len = 256 if $len == 0;
+#
+# 	print " min=$min len=$len bmap_start=$bmap_start\n";
+#     }
+#
+#     close FILE;
+# }
+
+1; # package return code
+
+__END__
+
+=head1 NAME
+
+XML::UM - Convert UTF-8 strings to any encoding supported by XML::Encoding
+
+=head1 SYNOPSIS
+
+ use XML::UM;
+
+ # Set directory with .xml files that comes with XML::Encoding distribution
+ # Always include the trailing slash!
+ $XML::UM::ENCDIR = '/home1/enno/perlModules/XML-Encoding-1.01/maps/';
+
+ # Create the encoding routine
+ my $encode = XML::UM::get_encode (
+	Encoding => 'ISO-8859-2',
+	EncodeUnmapped => \&XML::UM::encode_unmapped_dec);
+
+ # Convert a string from UTF-8 to the specified Encoding
+ my $encoded_str = $encode->($utf8_str);
+
+ # Remove circular references for garbage collection
+ XML::UM::dispose_encoding ('ISO-8859-2');
+
+=head1 DESCRIPTION
+
+This module provides methods to convert UTF-8 strings to any XML encoding
+that L<XML::Encoding> supports. It creates mapping routines from the .xml
+files that can be found in the maps/ directory in the L<XML::Encoding>
+distribution. Note that the XML::Encoding distribution does install the 
+.enc files in your perl directory, but not the.xml files they were created
+from. That's why you have to specify $ENCDIR as in the SYNOPSIS.
+
+This implementation uses the XML::Encoding class to parse the .xml
+file and creates a hash that maps UTF-8 characters (each consisting of up
+to 4 bytes) to their equivalent byte sequence in the specified encoding. 
+Note that large mappings may consume a lot of memory! 
+
+Future implementations may parse the .enc files directly, or
+do the conversions entirely in XS (i.e. C code.)
+
+=head1 get_encode (Encoding => STRING, EncodeUnmapped => SUB)
+
+The central entry point to this module is the XML::UM::get_encode() method. 
+It forwards the call to the global $XML::UM::FACTORY, which is defined as
+an instance of XML::UM::SlowMapperFactory by default. Override this variable
+to plug in your own mapper factory.
+
+The XML::UM::SlowMapperFactory creates an instance of XML::UM::SlowMapper
+(and caches it for subsequent use) that reads in the .xml encoding file and
+creates a hash that maps UTF-8 characters to encoded characters.
+
+The get_encode() method of XML::UM::SlowMapper is called, finally, which
+generates an anonimous subroutine that uses the hash to convert 
+multi-character UTF-8 blocks to the proper encoding.
+
+=head1 dispose_encoding ($encoding_name)
+
+Call this to free the memory used by the SlowMapper for a specific encoding.
+Note that in order to free the big conversion hash, the user should no longer
+have references to the subroutines generated by get_encode().
+
+The parameters to the get_encode() method (defined as name/value pairs) are:
+
+=over 4
+
+=item * Encoding
+
+The name of the desired encoding, e.g. 'ISO-8859-2'
+
+=item * EncodeUnmapped (Default: \&XML::UM::encode_unmapped_dec)
+
+Defines how Unicode characters not found in the mapping file (of the 
+specified encoding) are printed. 
+By default, they are converted to decimal entity references, like '&#123;'
+
+Use \&XML::UM::encode_unmapped_hex for hexadecimal constants, like '&#xAB;'
+
+=back
+
+=head1 CAVEATS
+
+I'm not exactly sure about which Unicode characters in the range (0 .. 127) 
+should be mapped to themselves. See comments in XML/UM.pm near
+%DEFAULT_ASCII_MAPPINGS.
+
+The encodings that expat supports by default are currently not supported, 
+(e.g. UTF-16, ISO-8859-1),
+because there are no .enc files available for these encodings.
+This module needs some more work. If you have the time, please help!
+
+=head1 AUTHOR
+
+Send bug reports, hints, tips, suggestions to Enno Derksen at
+<F<enno@att.com>>. 
+
+=cut