<?php
/*
Plugin Name: Filter Named Entities
Plugin URI: http://people.w3.org/~dom/2005/04/filter-entities.phi
Description: This plugin fixes the problem with named entities in RSS feeds generated by wordpress (see http://wordpress.org/support/topic.php?id=19421); a patch has been proposed to make this obsolete in the future.
Author: Dominique Hazael-Massieux
Author URI: http://people.w3.org/~dom/
*/


$html_named_entities_mapping = array (
                                 // Obtained with:
                                 // less /usr/share/xml/entities/xhtml/*.ent|grep '^<!ENTITY'|sed -e 's/^<\!ENTITY[ \t]*\([A-Za-z0-9]*\)[ \t]*"&#\([0-9]*\);".*$/"\1"=>\2,/' > /home/dom/data/2005/04/entities-table
"nbsp"=>160,
"iexcl"=>161,
"cent"=>162,
"pound"=>163,
"curren"=>164,
"yen"=>165,
"brvbar"=>166,
"sect"=>167,
"uml"=>168,
"copy"=>169,
"ordf"=>170,
"laquo"=>171,
"not"=>172,
"shy"=>173,
"reg"=>174,
"macr"=>175,
"deg"=>176,
"plusmn"=>177,
"sup2"=>178,
"sup3"=>179,
"acute"=>180,
"micro"=>181,
"para"=>182,
"middot"=>183,
"cedil"=>184,
"sup1"=>185,
"ordm"=>186,
"raquo"=>187,
"frac14"=>188,
"frac12"=>189,
"frac34"=>190,
"iquest"=>191,
"Agrave"=>192,
"Aacute"=>193,
"Acirc"=>194,
"Atilde"=>195,
"Auml"=>196,
"Aring"=>197,
"AElig"=>198,
"Ccedil"=>199,
"Egrave"=>200,
"Eacute"=>201,
"Ecirc"=>202,
"Euml"=>203,
"Igrave"=>204,
"Iacute"=>205,
"Icirc"=>206,
"Iuml"=>207,
"ETH"=>208,
"Ntilde"=>209,
"Ograve"=>210,
"Oacute"=>211,
"Ocirc"=>212,
"Otilde"=>213,
"Ouml"=>214,
"times"=>215,
"Oslash"=>216,
"Ugrave"=>217,
"Uacute"=>218,
"Ucirc"=>219,
"Uuml"=>220,
"Yacute"=>221,
"THORN"=>222,
"szlig"=>223,
"agrave"=>224,
"aacute"=>225,
"acirc"=>226,
"atilde"=>227,
"auml"=>228,
"aring"=>229,
"aelig"=>230,
"ccedil"=>231,
"egrave"=>232,
"eacute"=>233,
"ecirc"=>234,
"euml"=>235,
"igrave"=>236,
"iacute"=>237,
"icirc"=>238,
"iuml"=>239,
"eth"=>240,
"ntilde"=>241,
"ograve"=>242,
"oacute"=>243,
"ocirc"=>244,
"otilde"=>245,
"ouml"=>246,
"divide"=>247,
"oslash"=>248,
"ugrave"=>249,
"uacute"=>250,
"ucirc"=>251,
"uuml"=>252,
"yacute"=>253,
"thorn"=>254,
"yuml"=>255,
"quot"=>34,
"amp"=>38,
"lt"=>60,
"gt"=>62,
"OElig"=>338,
"oelig"=>339,
"Scaron"=>352,
"scaron"=>353,
"Yuml"=>376,
"circ"=>710,
"tilde"=>732,
"ensp"=>8194,
"emsp"=>8195,
"thinsp"=>8201,
"zwnj"=>8204,
"zwj"=>8205,
"lrm"=>8206,
"rlm"=>8207,
"ndash"=>8211,
"mdash"=>8212,
"lsquo"=>8216,
"rsquo"=>8217,
"sbquo"=>8218,
"ldquo"=>8220,
"rdquo"=>8221,
"bdquo"=>8222,
"dagger"=>8224,
"Dagger"=>8225,
"permil"=>8240,
"lsaquo"=>8249,
"rsaquo"=>8250,
"euro"=>8364,
"fnof"=>402,
"Alpha"=>913,
"Beta"=>914,
"Gamma"=>915,
"Delta"=>916,
"Epsilon"=>917,
"Zeta"=>918,
"Eta"=>919,
"Theta"=>920,
"Iota"=>921,
"Kappa"=>922,
"Lambda"=>923,
"Mu"=>924,
"Nu"=>925,
"Xi"=>926,
"Omicron"=>927,
"Pi"=>928,
"Rho"=>929,
"Sigma"=>931,
"Tau"=>932,
"Upsilon"=>933,
"Phi"=>934,
"Chi"=>935,
"Psi"=>936,
"Omega"=>937,
"alpha"=>945,
"beta"=>946,
"gamma"=>947,
"delta"=>948,
"epsilon"=>949,
"zeta"=>950,
"eta"=>951,
"theta"=>952,
"iota"=>953,
"kappa"=>954,
"lambda"=>955,
"mu"=>956,
"nu"=>957,
"xi"=>958,
"omicron"=>959,
"pi"=>960,
"rho"=>961,
"sigmaf"=>962,
"sigma"=>963,
"tau"=>964,
"upsilon"=>965,
"phi"=>966,
"chi"=>967,
"psi"=>968,
"omega"=>969,
"thetasym"=>977,
"upsih"=>978,
"piv"=>982,
"bull"=>8226,
"hellip"=>8230,
"prime"=>8242,
"Prime"=>8243,
"oline"=>8254,
"frasl"=>8260,
"weierp"=>8472,
"image"=>8465,
"real"=>8476,
"trade"=>8482,
"alefsym"=>8501,
"larr"=>8592,
"uarr"=>8593,
"rarr"=>8594,
"darr"=>8595,
"harr"=>8596,
"crarr"=>8629,
"lArr"=>8656,
"uArr"=>8657,
"rArr"=>8658,
"dArr"=>8659,
"hArr"=>8660,
"forall"=>8704,
"part"=>8706,
"exist"=>8707,
"empty"=>8709,
"nabla"=>8711,
"isin"=>8712,
"notin"=>8713,
"ni"=>8715,
"prod"=>8719,
"sum"=>8721,
"minus"=>8722,
"lowast"=>8727,
"radic"=>8730,
"prop"=>8733,
"infin"=>8734,
"ang"=>8736,
"and"=>8743,
"or"=>8744,
"cap"=>8745,
"cup"=>8746,
"int"=>8747,
"there4"=>8756,
"sim"=>8764,
"cong"=>8773,
"asymp"=>8776,
"ne"=>8800,
"equiv"=>8801,
"le"=>8804,
"ge"=>8805,
"sub"=>8834,
"sup"=>8835,
"nsub"=>8836,
"sube"=>8838,
"supe"=>8839,
"oplus"=>8853,
"otimes"=>8855,
"perp"=>8869,
"sdot"=>8901,
"lceil"=>8968,
"rceil"=>8969,
"lfloor"=>8970,
"rfloor"=>8971,
"lang"=>9001,
"rang"=>9002,
"loz"=>9674,
"spades"=>9824,
"clubs"=>9827,
"hearts"=>9829,
"diams"=>9830,
);

// A simple call as 
// return html_entity_decode($content,ENT_NOQUOTES,get_settings('blog_charset'));
// would have been enough if it were not for bug in PHP 4.x
// http://bugs.php.net/bug.php?id=25670
// also get_html_translation_table(HTML_ENTITIES); does not have all the entities!
function filter_named_entities($content) {
  global $html_named_entities_mapping;
  foreach($html_named_entities_mapping as $name => $value) {
    $content=str_replace('&'.$name.';','&#'.$value.';',$content);
  }  
  return $content;
  
}

// Now we filter the title and the content used in RSS feeds
add_filter('the_title_rss', 'filter_named_entities');
add_filter('the_content', 'filter_named_entities');
add_filter('the_excerpt_rss', 'filter_named_entities');


?>