/[suikacvs]/markup/html/whatpm/Whatpm/HTML.pm.src
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revision 1.42 by wakaba, Sat Jul 21 06:59:16 2007 UTC revision 1.232 by wakaba, Sun Sep 6 01:30:08 2009 UTC
# Line 1  Line 1 
1  package Whatpm::HTML;  package Whatpm::HTML;
2  use strict;  use strict;
3  our $VERSION=do{my @r=(q$Revision$=~/\d+/g);sprintf "%d."."%02d" x $#r,@r};  our $VERSION=do{my @r=(q$Revision$=~/\d+/g);sprintf "%d."."%02d" x $#r,@r};
4    use Error qw(:try);
5    
6    use Whatpm::HTML::Tokenizer;
7    
8    ## NOTE: This module don't check all HTML5 parse errors; character
9    ## encoding related parse errors are expected to be handled by relevant
10    ## modules.
11    ## Parse errors for control characters that are not allowed in HTML5
12    ## documents, for surrogate code points, and for noncharacter code
13    ## points, as well as U+FFFD substitions for characters whose code points
14    ## is higher than U+10FFFF may be detected by combining the parser with
15    ## the checker implemented by Whatpm::Charset::UnicodeChecker (for its
16    ## usage example, see |t/HTML-tree.t| in the Whatpm package or the
17    ## WebHACC::Language::HTML module in the WebHACC package).
18    
19  ## ISSUE:  ## ISSUE:
20  ## var doc = implementation.createDocument (null, null, null);  ## var doc = implementation.createDocument (null, null, null);
21  ## doc.write ('');  ## doc.write ('');
22  ## alert (doc.compatMode);  ## alert (doc.compatMode);
23    
24  ## ISSUE: HTML5 revision 967 says that the encoding layer MUST NOT  require IO::Handle;
 ## strip BOM and the HTML layer MUST ignore it.  Whether we can do it  
 ## is not yet clear.  
 ## "{U+FEFF}..." in UTF-16BE/UTF-16LE is three or four characters?  
 ## "{U+FEFF}..." in GB18030?  
   
 my $permitted_slash_tag_name = {  
   base => 1,  
   link => 1,  
   meta => 1,  
   hr => 1,  
   br => 1,  
   img=> 1,  
   embed => 1,  
   param => 1,  
   area => 1,  
   col => 1,  
   input => 1,  
 };  
25    
26  my $c1_entity_char = {  ## Namespace URLs
27    0x80 => 0x20AC,  
28    0x81 => 0xFFFD,  my $HTML_NS = q<http://www.w3.org/1999/xhtml>;
29    0x82 => 0x201A,  my $MML_NS = q<http://www.w3.org/1998/Math/MathML>;
30    0x83 => 0x0192,  my $SVG_NS = q<http://www.w3.org/2000/svg>;
31    0x84 => 0x201E,  my $XLINK_NS = q<http://www.w3.org/1999/xlink>;
32    0x85 => 0x2026,  my $XML_NS = q<http://www.w3.org/XML/1998/namespace>;
33    0x86 => 0x2020,  my $XMLNS_NS = q<http://www.w3.org/2000/xmlns/>;
34    0x87 => 0x2021,  
35    0x88 => 0x02C6,  ## Element categories
36    0x89 => 0x2030,  
37    0x8A => 0x0160,  ## Bits 12-15
38    0x8B => 0x2039,  sub SPECIAL_EL () { 0b1_000000000000000 }
39    0x8C => 0x0152,  sub SCOPING_EL () { 0b1_00000000000000 }
40    0x8D => 0xFFFD,  sub FORMATTING_EL () { 0b1_0000000000000 }
41    0x8E => 0x017D,  sub PHRASING_EL () { 0b1_000000000000 }
42    0x8F => 0xFFFD,  
43    0x90 => 0xFFFD,  ## Bits 10-11
44    0x91 => 0x2018,  #sub FOREIGN_EL () { 0b1_00000000000 } # see Whatpm::HTML::Tokenizer
45    0x92 => 0x2019,  sub FOREIGN_FLOW_CONTENT_EL () { 0b1_0000000000 }
46    0x93 => 0x201C,  
47    0x94 => 0x201D,  ## Bits 6-9
48    0x95 => 0x2022,  sub TABLE_SCOPING_EL () { 0b1_000000000 }
49    0x96 => 0x2013,  sub TABLE_ROWS_SCOPING_EL () { 0b1_00000000 }
50    0x97 => 0x2014,  sub TABLE_ROW_SCOPING_EL () { 0b1_0000000 }
51    0x98 => 0x02DC,  sub TABLE_ROWS_EL () { 0b1_000000 }
52    0x99 => 0x2122,  
53    0x9A => 0x0161,  ## Bit 5
54    0x9B => 0x203A,  sub ADDRESS_DIV_P_EL () { 0b1_00000 }
55    0x9C => 0x0153,  
56    0x9D => 0xFFFD,  ## NOTE: Used in </body> and EOF algorithms.
57    0x9E => 0x017E,  ## Bit 4
58    0x9F => 0x0178,  sub ALL_END_TAG_OPTIONAL_EL () { 0b1_0000 }
59  }; # $c1_entity_char  
60    ## NOTE: Used in "generate implied end tags" algorithm.
61  my $special_category = {  ## NOTE: There is a code where a modified version of
62    address => 1, area => 1, base => 1, basefont => 1, bgsound => 1,  ## END_TAG_OPTIONAL_EL is used in "generate implied end tags"
63    blockquote => 1, body => 1, br => 1, center => 1, col => 1, colgroup => 1,  ## implementation (search for the algorithm name).
64    dd => 1, dir => 1, div => 1, dl => 1, dt => 1, embed => 1, fieldset => 1,  ## Bit 3
65    form => 1, frame => 1, frameset => 1, h1 => 1, h2 => 1, h3 => 1,  sub END_TAG_OPTIONAL_EL () { 0b1_000 }
66    h4 => 1, h5 => 1, h6 => 1, head => 1, hr => 1, iframe => 1, image => 1,  
67    img => 1, input => 1, isindex => 1, li => 1, link => 1, listing => 1,  ## Bits 0-2
68    menu => 1, meta => 1, noembed => 1, noframes => 1, noscript => 1,  
69    ol => 1, optgroup => 1, option => 1, p => 1, param => 1, plaintext => 1,  sub MISC_SPECIAL_EL () { SPECIAL_EL | 0b000 }
70    pre => 1, script => 1, select => 1, spacer => 1, style => 1, tbody => 1,  sub FORM_EL () { SPECIAL_EL | 0b001 }
71    textarea => 1, tfoot => 1, thead => 1, title => 1, tr => 1, ul => 1, wbr => 1,  sub FRAMESET_EL () { SPECIAL_EL | 0b010 }
72  };  sub HEADING_EL () { SPECIAL_EL | 0b011 }
73  my $scoping_category = {  sub SELECT_EL () { SPECIAL_EL | 0b100 }
74    button => 1, caption => 1, html => 1, marquee => 1, object => 1,  sub SCRIPT_EL () { SPECIAL_EL | 0b101 }
75    table => 1, td => 1, th => 1,  
76    sub ADDRESS_DIV_EL () { SPECIAL_EL | ADDRESS_DIV_P_EL | 0b001 }
77    sub BODY_EL () { SPECIAL_EL | ALL_END_TAG_OPTIONAL_EL | 0b001 }
78    
79    sub DTDD_EL () {
80      SPECIAL_EL |
81      END_TAG_OPTIONAL_EL |
82      ALL_END_TAG_OPTIONAL_EL |
83      0b010
84    }
85    sub LI_EL () {
86      SPECIAL_EL |
87      END_TAG_OPTIONAL_EL |
88      ALL_END_TAG_OPTIONAL_EL |
89      0b100
90    }
91    sub P_EL () {
92      SPECIAL_EL |
93      ADDRESS_DIV_P_EL |
94      END_TAG_OPTIONAL_EL |
95      ALL_END_TAG_OPTIONAL_EL |
96      0b001
97    }
98    
99    sub TABLE_ROW_EL () {
100      SPECIAL_EL |
101      TABLE_ROWS_EL |
102      TABLE_ROW_SCOPING_EL |
103      ALL_END_TAG_OPTIONAL_EL |
104      0b001
105    }
106    sub TABLE_ROW_GROUP_EL () {
107      SPECIAL_EL |
108      TABLE_ROWS_EL |
109      TABLE_ROWS_SCOPING_EL |
110      ALL_END_TAG_OPTIONAL_EL |
111      0b001
112    }
113    
114    sub MISC_SCOPING_EL () { SCOPING_EL | 0b000 }
115    sub BUTTON_EL () { SCOPING_EL | 0b001 }
116    sub CAPTION_EL () { SCOPING_EL | 0b010 }
117    sub HTML_EL () {
118      SCOPING_EL |
119      TABLE_SCOPING_EL |
120      TABLE_ROWS_SCOPING_EL |
121      TABLE_ROW_SCOPING_EL |
122      ALL_END_TAG_OPTIONAL_EL |
123      0b001
124    }
125    sub TABLE_EL () {
126      SCOPING_EL |
127      TABLE_ROWS_EL |
128      TABLE_SCOPING_EL |
129      0b001
130    }
131    sub TABLE_CELL_EL () {
132      SCOPING_EL |
133      TABLE_ROW_SCOPING_EL |
134      ALL_END_TAG_OPTIONAL_EL |
135      0b001
136    }
137    
138    sub MISC_FORMATTING_EL () { FORMATTING_EL | 0b000 }
139    sub A_EL () { FORMATTING_EL | 0b001 }
140    sub NOBR_EL () { FORMATTING_EL | 0b010 }
141    
142    sub RUBY_EL () { PHRASING_EL | 0b001 }
143    
144    ## ISSUE: ALL_END_TAG_OPTIONAL_EL?
145    sub OPTGROUP_EL () { PHRASING_EL | END_TAG_OPTIONAL_EL | 0b001 }
146    sub OPTION_EL () { PHRASING_EL | END_TAG_OPTIONAL_EL | 0b010 }
147    sub RUBY_COMPONENT_EL () { PHRASING_EL | END_TAG_OPTIONAL_EL | 0b100 }
148    
149    sub MML_AXML_EL () { PHRASING_EL | FOREIGN_EL | 0b001 }
150    
151    my $el_category = {
152      a => A_EL,
153      address => ADDRESS_DIV_EL,
154      applet => MISC_SCOPING_EL,
155      area => MISC_SPECIAL_EL,
156      article => MISC_SPECIAL_EL,
157      aside => MISC_SPECIAL_EL,
158      b => FORMATTING_EL,
159      base => MISC_SPECIAL_EL,
160      basefont => MISC_SPECIAL_EL,
161      bgsound => MISC_SPECIAL_EL,
162      big => FORMATTING_EL,
163      blockquote => MISC_SPECIAL_EL,
164      body => BODY_EL,
165      br => MISC_SPECIAL_EL,
166      button => BUTTON_EL,
167      caption => CAPTION_EL,
168      center => MISC_SPECIAL_EL,
169      col => MISC_SPECIAL_EL,
170      colgroup => MISC_SPECIAL_EL,
171      command => MISC_SPECIAL_EL,
172      datagrid => MISC_SPECIAL_EL,
173      dd => DTDD_EL,
174      details => MISC_SPECIAL_EL,
175      dialog => MISC_SPECIAL_EL,
176      dir => MISC_SPECIAL_EL,
177      div => ADDRESS_DIV_EL,
178      dl => MISC_SPECIAL_EL,
179      dt => DTDD_EL,
180      em => FORMATTING_EL,
181      embed => MISC_SPECIAL_EL,
182      fieldset => MISC_SPECIAL_EL,
183      figure => MISC_SPECIAL_EL,
184      font => FORMATTING_EL,
185      footer => MISC_SPECIAL_EL,
186      form => FORM_EL,
187      frame => MISC_SPECIAL_EL,
188      frameset => FRAMESET_EL,
189      h1 => HEADING_EL,
190      h2 => HEADING_EL,
191      h3 => HEADING_EL,
192      h4 => HEADING_EL,
193      h5 => HEADING_EL,
194      h6 => HEADING_EL,
195      head => MISC_SPECIAL_EL,
196      header => MISC_SPECIAL_EL,
197      hr => MISC_SPECIAL_EL,
198      html => HTML_EL,
199      i => FORMATTING_EL,
200      iframe => MISC_SPECIAL_EL,
201      img => MISC_SPECIAL_EL,
202      #image => MISC_SPECIAL_EL, ## NOTE: Commented out in the spec.
203      input => MISC_SPECIAL_EL,
204      isindex => MISC_SPECIAL_EL,
205      ## XXX keygen? (Whether a void element is in Special or not does not
206      ## affect to the processing, however.)
207      li => LI_EL,
208      link => MISC_SPECIAL_EL,
209      listing => MISC_SPECIAL_EL,
210      marquee => MISC_SCOPING_EL,
211      menu => MISC_SPECIAL_EL,
212      meta => MISC_SPECIAL_EL,
213      nav => MISC_SPECIAL_EL,
214      nobr => NOBR_EL,
215      noembed => MISC_SPECIAL_EL,
216      noframes => MISC_SPECIAL_EL,
217      noscript => MISC_SPECIAL_EL,
218      object => MISC_SCOPING_EL,
219      ol => MISC_SPECIAL_EL,
220      optgroup => OPTGROUP_EL,
221      option => OPTION_EL,
222      p => P_EL,
223      param => MISC_SPECIAL_EL,
224      plaintext => MISC_SPECIAL_EL,
225      pre => MISC_SPECIAL_EL,
226      rp => RUBY_COMPONENT_EL,
227      rt => RUBY_COMPONENT_EL,
228      ruby => RUBY_EL,
229      s => FORMATTING_EL,
230      script => MISC_SPECIAL_EL,
231      select => SELECT_EL,
232      section => MISC_SPECIAL_EL,
233      small => FORMATTING_EL,
234      spacer => MISC_SPECIAL_EL,
235      strike => FORMATTING_EL,
236      strong => FORMATTING_EL,
237      style => MISC_SPECIAL_EL,
238      table => TABLE_EL,
239      tbody => TABLE_ROW_GROUP_EL,
240      td => TABLE_CELL_EL,
241      textarea => MISC_SPECIAL_EL,
242      tfoot => TABLE_ROW_GROUP_EL,
243      th => TABLE_CELL_EL,
244      thead => TABLE_ROW_GROUP_EL,
245      title => MISC_SPECIAL_EL,
246      tr => TABLE_ROW_EL,
247      tt => FORMATTING_EL,
248      u => FORMATTING_EL,
249      ul => MISC_SPECIAL_EL,
250      wbr => MISC_SPECIAL_EL,
251  };  };
252  my $formatting_category = {  
253    a => 1, b => 1, big => 1, em => 1, font => 1, i => 1, nobr => 1,  my $el_category_f = {
254    s => 1, small => 1, strile => 1, strong => 1, tt => 1, u => 1,    $MML_NS => {
255        'annotation-xml' => MML_AXML_EL,
256        mi => FOREIGN_EL | FOREIGN_FLOW_CONTENT_EL,
257        mo => FOREIGN_EL | FOREIGN_FLOW_CONTENT_EL,
258        mn => FOREIGN_EL | FOREIGN_FLOW_CONTENT_EL,
259        ms => FOREIGN_EL | FOREIGN_FLOW_CONTENT_EL,
260        mtext => FOREIGN_EL | FOREIGN_FLOW_CONTENT_EL,
261      },
262      $SVG_NS => {
263        foreignObject => SCOPING_EL | FOREIGN_EL | FOREIGN_FLOW_CONTENT_EL,
264        desc => FOREIGN_EL | FOREIGN_FLOW_CONTENT_EL,
265        title => FOREIGN_EL | FOREIGN_FLOW_CONTENT_EL,
266      },
267      ## NOTE: In addition, FOREIGN_EL is set to non-HTML elements.
268  };  };
 # $phrasing_category: all other elements  
269    
270  sub parse_string ($$$;$) {  my $svg_attr_name = {
271    my $self = shift->new;    attributename => 'attributeName',
272    my $s = \$_[0];    attributetype => 'attributeType',
273    $self->{document} = $_[1];    basefrequency => 'baseFrequency',
274      baseprofile => 'baseProfile',
275      calcmode => 'calcMode',
276      clippathunits => 'clipPathUnits',
277      contentscripttype => 'contentScriptType',
278      contentstyletype => 'contentStyleType',
279      diffuseconstant => 'diffuseConstant',
280      edgemode => 'edgeMode',
281      externalresourcesrequired => 'externalResourcesRequired',
282      filterres => 'filterRes',
283      filterunits => 'filterUnits',
284      glyphref => 'glyphRef',
285      gradienttransform => 'gradientTransform',
286      gradientunits => 'gradientUnits',
287      kernelmatrix => 'kernelMatrix',
288      kernelunitlength => 'kernelUnitLength',
289      keypoints => 'keyPoints',
290      keysplines => 'keySplines',
291      keytimes => 'keyTimes',
292      lengthadjust => 'lengthAdjust',
293      limitingconeangle => 'limitingConeAngle',
294      markerheight => 'markerHeight',
295      markerunits => 'markerUnits',
296      markerwidth => 'markerWidth',
297      maskcontentunits => 'maskContentUnits',
298      maskunits => 'maskUnits',
299      numoctaves => 'numOctaves',
300      pathlength => 'pathLength',
301      patterncontentunits => 'patternContentUnits',
302      patterntransform => 'patternTransform',
303      patternunits => 'patternUnits',
304      pointsatx => 'pointsAtX',
305      pointsaty => 'pointsAtY',
306      pointsatz => 'pointsAtZ',
307      preservealpha => 'preserveAlpha',
308      preserveaspectratio => 'preserveAspectRatio',
309      primitiveunits => 'primitiveUnits',
310      refx => 'refX',
311      refy => 'refY',
312      repeatcount => 'repeatCount',
313      repeatdur => 'repeatDur',
314      requiredextensions => 'requiredExtensions',
315      requiredfeatures => 'requiredFeatures',
316      specularconstant => 'specularConstant',
317      specularexponent => 'specularExponent',
318      spreadmethod => 'spreadMethod',
319      startoffset => 'startOffset',
320      stddeviation => 'stdDeviation',
321      stitchtiles => 'stitchTiles',
322      surfacescale => 'surfaceScale',
323      systemlanguage => 'systemLanguage',
324      tablevalues => 'tableValues',
325      targetx => 'targetX',
326      targety => 'targetY',
327      textlength => 'textLength',
328      viewbox => 'viewBox',
329      viewtarget => 'viewTarget',
330      xchannelselector => 'xChannelSelector',
331      ychannelselector => 'yChannelSelector',
332      zoomandpan => 'zoomAndPan',
333    };
334    
335    ## NOTE: |set_inner_html| copies most of this method's code  my $foreign_attr_xname = {
336      'xlink:actuate' => [$XLINK_NS, ['xlink', 'actuate']],
337      'xlink:arcrole' => [$XLINK_NS, ['xlink', 'arcrole']],
338      'xlink:href' => [$XLINK_NS, ['xlink', 'href']],
339      'xlink:role' => [$XLINK_NS, ['xlink', 'role']],
340      'xlink:show' => [$XLINK_NS, ['xlink', 'show']],
341      'xlink:title' => [$XLINK_NS, ['xlink', 'title']],
342      'xlink:type' => [$XLINK_NS, ['xlink', 'type']],
343      'xml:base' => [$XML_NS, ['xml', 'base']],
344      'xml:lang' => [$XML_NS, ['xml', 'lang']],
345      'xml:space' => [$XML_NS, ['xml', 'space']],
346      'xmlns' => [$XMLNS_NS, [undef, 'xmlns']],
347      'xmlns:xlink' => [$XMLNS_NS, ['xmlns', 'xlink']],
348    };
349    
350    my $i = 0;  ## ISSUE: xmlns:xlink="non-xlink-ns" is not an error.
   my $line = 1;  
   my $column = 0;  
   $self->{set_next_input_character} = sub {  
     my $self = shift;  
351    
352      pop @{$self->{prev_input_character}};  ## TODO: Invoke the reset algorithm when a resettable element is
353      unshift @{$self->{prev_input_character}}, $self->{next_input_character};  ## created (cf. HTML5 revision 2259).
354    
355      $self->{next_input_character} = -1 and return if $i >= length $$s;  sub parse_byte_string ($$$$;$) {
356      $self->{next_input_character} = ord substr $$s, $i++, 1;    my $self = shift;
357      $column++;    my $charset_name = shift;
358          open my $input, '<', ref $_[0] ? $_[0] : \($_[0]);
359      if ($self->{next_input_character} == 0x000A) { # LF    return $self->parse_byte_stream ($charset_name, $input, @_[1..$#_]);
360        $line++;  } # parse_byte_string
361        $column = 0;  
362      } elsif ($self->{next_input_character} == 0x000D) { # CR  sub parse_byte_stream ($$$$;$$) {
363        $i++ if substr ($$s, $i, 1) eq "\x0A";    # my ($self, $charset_name, $byte_stream, $doc, $onerror, $get_wrapper) = @_;
364        $self->{next_input_character} = 0x000A; # LF # MUST    my $self = ref $_[0] ? shift : shift->new;
365        $line++;    my $charset_name = shift;
366        $column = 0;    my $byte_stream = $_[0];
     } elsif ($self->{next_input_character} > 0x10FFFF) {  
       $self->{next_input_character} = 0xFFFD; # REPLACEMENT CHARACTER # MUST  
     } elsif ($self->{next_input_character} == 0x0000) { # NULL  
       !!!parse-error (type => 'NULL');  
       $self->{next_input_character} = 0xFFFD; # REPLACEMENT CHARACTER # MUST  
     }  
   };  
   $self->{prev_input_character} = [-1, -1, -1];  
   $self->{next_input_character} = -1;  
367    
368    my $onerror = $_[2] || sub {    my $onerror = $_[2] || sub {
369      my (%opt) = @_;      my (%opt) = @_;
370      warn "Parse error ($opt{type}) at line $opt{line} column $opt{column}\n";      warn "Parse error ($opt{type})\n";
   };  
   $self->{parse_error} = sub {  
     $onerror->(@_, line => $line, column => $column);  
371    };    };
372      $self->{parse_error} = $onerror; # updated later by parse_char_string
373    
374    $self->_initialize_tokenizer;    my $get_wrapper = $_[3] || sub ($) {
375    $self->_initialize_tree_constructor;      return $_[0]; # $_[0] = byte stream handle, returned = arg to char handle
   $self->_construct_tree;  
   $self->_terminate_tree_constructor;  
   
   return $self->{document};  
 } # parse_string  
   
 sub new ($) {  
   my $class = shift;  
   my $self = bless {}, $class;  
   $self->{set_next_input_character} = sub {  
     $self->{next_input_character} = -1;  
   };  
   $self->{parse_error} = sub {  
     #  
376    };    };
   return $self;  
 } # new  
377    
378  sub CM_ENTITY () { 0b001 } # & markup in data    ## HTML5 encoding sniffing algorithm
379  sub CM_LIMITED_MARKUP () { 0b010 } # < markup in data (limited)    require Message::Charset::Info;
380  sub CM_FULL_MARKUP () { 0b100 } # < markup in data (any)    my $charset;
381      my $buffer;
382  sub PLAINTEXT_CONTENT_MODEL () { 0 }    my ($char_stream, $e_status);
383  sub CDATA_CONTENT_MODEL () { CM_LIMITED_MARKUP }  
384  sub RCDATA_CONTENT_MODEL () { CM_ENTITY | CM_LIMITED_MARKUP }    SNIFFING: {
385  sub PCDATA_CONTENT_MODEL () { CM_ENTITY | CM_FULL_MARKUP }      ## NOTE: By setting |allow_fallback| option true when the
386        ## |get_decode_handle| method is invoked, we ignore what the HTML5
387        ## spec requires, i.e. unsupported encoding should be ignored.
388          ## TODO: We should not do this unless the parser is invoked
389          ## in the conformance checking mode, in which this behavior
390          ## would be useful.
391    
392  ## Implementations MUST act as if state machine in the spec      ## Step 1
393        if (defined $charset_name) {
394          $charset = Message::Charset::Info->get_by_html_name ($charset_name);
395              ## TODO: Is this ok?  Transfer protocol's parameter should be
396              ## interpreted in its semantics?
397    
398          ($char_stream, $e_status) = $charset->get_decode_handle
399              ($byte_stream, allow_error_reporting => 1,
400               allow_fallback => 1);
401          if ($char_stream) {
402            $self->{confident} = 1;
403            last SNIFFING;
404          } else {
405            !!!parse-error (type => 'charset:not supported',
406                            layer => 'encode',
407                            line => 1, column => 1,
408                            value => $charset_name,
409                            level => $self->{level}->{uncertain});
410          }
411        }
412    
413  sub _initialize_tokenizer ($) {      ## Step 2
414    my $self = shift;      my $byte_buffer = '';
415    $self->{state} = 'data'; # MUST      for (1..1024) {
416    $self->{content_model} = PCDATA_CONTENT_MODEL; # be        my $char = $byte_stream->getc;
417    undef $self->{current_token}; # start tag, end tag, comment, or DOCTYPE        last unless defined $char;
418    undef $self->{current_attribute};        $byte_buffer .= $char;
419    undef $self->{last_emitted_start_tag_name};      } ## TODO: timeout
   undef $self->{last_attribute_value_state};  
   $self->{char} = [];  
   # $self->{next_input_character}  
   !!!next-input-character;  
   $self->{token} = [];  
   # $self->{escape}  
 } # _initialize_tokenizer  
   
 ## A token has:  
 ##   ->{type} eq 'DOCTYPE', 'start tag', 'end tag', 'comment',  
 ##       'character', or 'end-of-file'  
 ##   ->{name} (DOCTYPE, start tag (tag name), end tag (tag name))  
 ##   ->{public_identifier} (DOCTYPE)  
 ##   ->{system_identifier} (DOCTYPE)  
 ##   ->{correct} == 1 or 0 (DOCTYPE)  
 ##   ->{attributes} isa HASH (start tag, end tag)  
 ##   ->{data} (comment, character)  
   
 ## Emitted token MUST immediately be handled by the tree construction state.  
   
 ## Before each step, UA MAY check to see if either one of the scripts in  
 ## "list of scripts that will execute as soon as possible" or the first  
 ## script in the "list of scripts that will execute asynchronously",  
 ## has completed loading.  If one has, then it MUST be executed  
 ## and removed from the list.  
420    
421  sub _get_next_token ($) {      ## Step 3
422    my $self = shift;      if ($byte_buffer =~ /^\xFE\xFF/) {
423    if (@{$self->{token}}) {        $charset = Message::Charset::Info->get_by_html_name ('utf-16be');
424      return shift @{$self->{token}};        ($char_stream, $e_status) = $charset->get_decode_handle
425    }            ($byte_stream, allow_error_reporting => 1,
426               allow_fallback => 1, byte_buffer => \$byte_buffer);
427          $self->{confident} = 1;
428          last SNIFFING;
429        } elsif ($byte_buffer =~ /^\xFF\xFE/) {
430          $charset = Message::Charset::Info->get_by_html_name ('utf-16le');
431          ($char_stream, $e_status) = $charset->get_decode_handle
432              ($byte_stream, allow_error_reporting => 1,
433               allow_fallback => 1, byte_buffer => \$byte_buffer);
434          $self->{confident} = 1;
435          last SNIFFING;
436        } elsif ($byte_buffer =~ /^\xEF\xBB\xBF/) {
437          $charset = Message::Charset::Info->get_by_html_name ('utf-8');
438          ($char_stream, $e_status) = $charset->get_decode_handle
439              ($byte_stream, allow_error_reporting => 1,
440               allow_fallback => 1, byte_buffer => \$byte_buffer);
441          $self->{confident} = 1;
442          last SNIFFING;
443        }
444    
445    A: {      ## Step 4
446      if ($self->{state} eq 'data') {      ## TODO: <meta charset>
       if ($self->{next_input_character} == 0x0026) { # &  
         if ($self->{content_model} & CM_ENTITY) { # PCDATA | RCDATA  
           $self->{state} = 'entity data';  
           !!!next-input-character;  
           redo A;  
         } else {  
           #  
         }  
       } elsif ($self->{next_input_character} == 0x002D) { # -  
         if ($self->{content_model} & CM_LIMITED_MARKUP) { # RCDATA | CDATA  
           unless ($self->{escape}) {  
             if ($self->{prev_input_character}->[0] == 0x002D and # -