/wp-includes/formatting.php

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<?php
/**
 * Main Wordpress Formatting API.
 *
 * Handles many functions for formatting output.
 *
 * @package WordPress
 **/

/**
 * Replaces common plain text characters into formatted entities
 *
 * As an example,
 * <code>
 * 'cause today's effort makes it worth tomorrow's "holiday"...
 * </code>
 * Becomes:
 * <code>
 * &#8217;cause today&#8217;s effort makes it worth tomorrow&#8217;s &#8220;holiday&#8221;&#8230;
 * </code>
 * Code within certain html blocks are skipped.
 *
 * @since 0.71
 * @uses $wp_cockneyreplace Array of formatted entities for certain common phrases
 *
 * @param string $text The text to be formatted
 * @return string The string replaced with html entities
 */
function wptexturize($text) {
	global $wp_cockneyreplace;
	$next = true;
	$has_pre_parent = false;
	$output = '';
	$curl = '';
	$textarr = preg_split('/(<.*>|\[.*\])/Us', $text, -1, PREG_SPLIT_DELIM_CAPTURE);
	$stop = count($textarr);

	// if a plugin has provided an autocorrect array, use it
	if ( isset($wp_cockneyreplace) ) {
		$cockney = array_keys($wp_cockneyreplace);
		$cockneyreplace = array_values($wp_cockneyreplace);
	} else {
		$cockney = array("'tain't","'twere","'twas","'tis","'twill","'til","'bout","'nuff","'round","'cause");
		$cockneyreplace = array("&#8217;tain&#8217;t","&#8217;twere","&#8217;twas","&#8217;tis","&#8217;twill","&#8217;til","&#8217;bout","&#8217;nuff","&#8217;round","&#8217;cause");
	}

	$static_characters = array_merge(array('---', ' -- ', '--', 'xn&#8211;', '...', '``', '\'s', '\'\'', ' (tm)'), $cockney);
	$static_replacements = array_merge(array('&#8212;', ' &#8212; ', '&#8211;', 'xn--', '&#8230;', '&#8220;', '&#8217;s', '&#8221;', ' &#8482;'), $cockneyreplace);

	$dynamic_characters = array('/\'(\d\d(?:&#8217;|\')?s)/', '/(\s|\A|")\'/', '/(\d+)"/', '/(\d+)\'/', '/(\S)\'([^\'\s])/', '/(\s|\A)"(?!\s)/', '/"(\s|\S|\Z)/', '/\'([\s.]|\Z)/', '/(\d+)x(\d+)/');
	$dynamic_replacements = array('&#8217;$1','$1&#8216;', '$1&#8243;', '$1&#8242;', '$1&#8217;$2', '$1&#8220;$2', '&#8221;$1', '&#8217;$1', '$1&#215;$2');

	for ( $i = 0; $i < $stop; $i++ ) {
		$curl = $textarr[$i];

		if ( !empty($curl) && '<' != $curl{0} && '[' != $curl{0} && $next && !$has_pre_parent) { // If it's not a tag
			// static strings
			$curl = str_replace($static_characters, $static_replacements, $curl);
			// regular expressions
			$curl = preg_replace($dynamic_characters, $dynamic_replacements, $curl);
		} elseif (strpos($curl, '<code') !== false || strpos($curl, '<kbd') !== false || strpos($curl, '<style') !== false || strpos($curl, '<script') !== false) {
			$next = false;
		} elseif (strpos($curl, '<pre') !== false) {
			$has_pre_parent = true;
		} elseif (strpos($curl, '</pre>') !== false) {
			$has_pre_parent = false;
		} else {
			$next = true;
		}

		$curl = preg_replace('/&([^#])(?![a-zA-Z1-4]{1,8};)/', '&#038;$1', $curl);
		$output .= $curl;
	}

	return $output;
}

/**
 * Accepts matches array from preg_replace_callback in wpautop() or a string.
 *
 * Ensures that the contents of a <<pre>>...<</pre>> HTML block are not
 * converted into paragraphs or line-breaks.
 *
 * @since 1.2.0
 *
 * @param array|string $matches The array or string
 * @return string The pre block without paragraph/line-break conversion.
 */
function clean_pre($matches) {
	if ( is_array($matches) )
		$text = $matches[1] . $matches[2] . "</pre>";
	else
		$text = $matches;

	$text = str_replace('<br />', '', $text);
	$text = str_replace('<p>', "\n", $text);
	$text = str_replace('</p>', '', $text);

	return $text;
}

/**
 * Replaces double line-breaks with paragraph elements.
 *
 * A group of regex replaces used to identify text formatted with newlines and
 * replace double line-breaks with HTML paragraph tags. The remaining
 * line-breaks after conversion become <<br />> tags, unless $br is set to '0'
 * or 'false'.
 *
 * @since 0.71
 *
 * @param string $pee The text which has to be formatted.
 * @param int|bool $br Optional. If set, this will convert all remaining line-breaks after paragraphing. Default true.
 * @return string Text which has been converted into correct paragraph tags.
 */
function wpautop($pee, $br = 1) {
	$pee = $pee . "\n"; // just to make things a little easier, pad the end
	$pee = preg_replace('|<br />\s*<br />|', "\n\n", $pee);
	// Space things out a little
	$allblocks = '(?:table|thead|tfoot|caption|colgroup|tbody|tr|td|th|div|dl|dd|dt|ul|ol|li|pre|select|form|map|area|blockquote|address|math|style|input|p|h[1-6]|hr)';
	$pee = preg_replace('!(<' . $allblocks . '[^>]*>)!', "\n$1", $pee);
	$pee = preg_replace('!(</' . $allblocks . '>)!', "$1\n\n", $pee);
	$pee = str_replace(array("\r\n", "\r"), "\n", $pee); // cross-platform newlines
	if ( strpos($pee, '<object') !== false ) {
		$pee = preg_replace('|\s*<param([^>]*)>\s*|', "<param$1>", $pee); // no pee inside object/embed
		$pee = preg_replace('|\s*</embed>\s*|', '</embed>', $pee);
	}
	$pee = preg_replace("/\n\n+/", "\n\n", $pee); // take care of duplicates
	// make paragraphs, including one at the end
	$pees = preg_split('/\n\s*\n/', $pee, -1, PREG_SPLIT_NO_EMPTY);
	$pee = '';
	foreach ( $pees as $tinkle )
		$pee .= '<p>' . trim($tinkle, "\n") . "</p>\n";
	$pee = preg_replace('|<p>\s*</p>|', '', $pee); // under certain strange conditions it could create a P of entirely whitespace
	$pee = preg_replace('!<p>([^<]+)</(div|address|form)>!', "<p>$1</p></$2>", $pee);
	$pee = preg_replace('!<p>\s*(</?' . $allblocks . '[^>]*>)\s*</p>!', "$1", $pee); // don't pee all over a tag
	$pee = preg_replace("|<p>(<li.+?)</p>|", "$1", $pee); // problem with nested lists
	$pee = preg_replace('|<p><blockquote([^>]*)>|i', "<blockquote$1><p>", $pee);
	$pee = str_replace('</blockquote></p>', '</p></blockquote>', $pee);
	$pee = preg_replace('!<p>\s*(</?' . $allblocks . '[^>]*>)!', "$1", $pee);
	$pee = preg_replace('!(</?' . $allblocks . '[^>]*>)\s*</p>!', "$1", $pee);
	if ($br) {
		$pee = preg_replace_callback('/<(script|style).*?<\/\\1>/s', create_function('$matches', 'return str_replace("\n", "<WPPreserveNewline />", $matches[0]);'), $pee);
		$pee = preg_replace('|(?<!<br />)\s*\n|', "<br />\n", $pee); // optionally make line breaks
		$pee = str_replace('<WPPreserveNewline />', "\n", $pee);
	}
	$pee = preg_replace('!(</?' . $allblocks . '[^>]*>)\s*<br />!', "$1", $pee);
	$pee = preg_replace('!<br />(\s*</?(?:p|li|div|dl|dd|dt|th|pre|td|ul|ol)[^>]*>)!', '$1', $pee);
	if (strpos($pee, '<pre') !== false)
		$pee = preg_replace_callback('!(<pre[^>]*>)(.*?)</pre>!is', 'clean_pre', $pee );
	$pee = preg_replace( "|\n</p>$|", '</p>', $pee );
	$pee = preg_replace('/<p>\s*?(' . get_shortcode_regex() . ')\s*<\/p>/s', '$1', $pee); // don't auto-p wrap shortcodes that stand alone

	return $pee;
}

/**
 * Checks to see if a string is utf8 encoded.
 *
 * @author bmorel at ssi dot fr
 *
 * @since 1.2.1
 *
 * @param string $Str The string to be checked
 * @return bool True if $Str fits a UTF-8 model, false otherwise.
 */
function seems_utf8($Str) { # by bmorel at ssi dot fr
	$length = strlen($Str);
	for ($i=0; $i < $length; $i++) {
		if (ord($Str[$i]) < 0x80) continue; # 0bbbbbbb
		elseif ((ord($Str[$i]) & 0xE0) == 0xC0) $n=1; # 110bbbbb
		elseif ((ord($Str[$i]) & 0xF0) == 0xE0) $n=2; # 1110bbbb
		elseif ((ord($Str[$i]) & 0xF8) == 0xF0) $n=3; # 11110bbb
		elseif ((ord($Str[$i]) & 0xFC) == 0xF8) $n=4; # 111110bb
		elseif ((ord($Str[$i]) & 0xFE) == 0xFC) $n=5; # 1111110b
		else return false; # Does not match any model
		for ($j=0; $j<$n; $j++) { # n bytes matching 10bbbbbb follow ?
			if ((++$i == $length) || ((ord($Str[$i]) & 0xC0) != 0x80))
			return false;
		}
	}
	return true;
}

/**
 * Converts a number of special characters into their HTML entities.
 *
 * Specifically deals with: &, <, >, ", and '.
 *
 * $quote_style can be set to ENT_COMPAT to encode " to
 * &quot;, or ENT_QUOTES to do both. Default is ENT_NOQUOTES where no quotes are encoded.
 *
 * @since 1.2.2
 *
 * @param string $string The text which is to be encoded.
 * @param mixed $quote_style Optional. Converts double quotes if set to ENT_COMPAT, both single and double if set to ENT_QUOTES or none if set to ENT_NOQUOTES. Also compatible with old values; converting single quotes if set to 'single', double if set to 'double' or both if otherwise set. Default is ENT_NOQUOTES.
 * @param string $charset Optional. The character encoding of the string. Default is false.
 * @param boolean $double_encode Optional. Whether or not to encode existing html entities. Default is false.
 * @return string The encoded text with HTML entities.
 */
function wp_specialchars( $string, $quote_style = ENT_NOQUOTES, $charset = false, $double_encode = false )
{
	$string = (string) $string;

	if ( 0 === strlen( $string ) ) {
		return '';
	}

	// Don't bother if there are no specialchars - saves some processing
	if ( !preg_match( '/[&<>"\']/', $string ) ) {
		return $string;
	}

	// Account for the previous behaviour of the function when the $quote_style is not an accepted value
	if ( empty( $quote_style ) ) {
		$quote_style = ENT_NOQUOTES;
	} elseif ( !in_array( $quote_style, array( 0, 2, 3, 'single', 'double' ), true ) ) {
		$quote_style = ENT_QUOTES;
	}

	// Store the site charset as a static to avoid multiple calls to wp_load_alloptions()
	if ( !$charset ) {
		static $_charset;
		if ( !isset( $_charset ) ) {
			$alloptions = wp_load_alloptions();
			$_charset = isset( $alloptions['blog_charset'] ) ? $alloptions['blog_charset'] : '';
		}
		$charset = $_charset;
	}
	if ( in_array( $charset, array( 'utf8', 'utf-8', 'UTF8' ) ) ) {
		$charset = 'UTF-8';
	}

	$_quote_style = $quote_style;

	if ( $quote_style === 'double' ) {
		$quote_style = ENT_COMPAT;
		$_quote_style = ENT_COMPAT;
	} elseif ( $quote_style === 'single' ) {
		$quote_style = ENT_NOQUOTES;
	}

	// Handle double encoding ourselves
	if ( !$double_encode ) {
		$string = wp_specialchars_decode( $string, $_quote_style );
		$string = preg_replace( '/&(#?x?[0-9]+|[a-z]+);/i', '|wp_entity|$1|/wp_entity|', $string );
	}

	$string = @htmlspecialchars( $string, $quote_style, $charset );

	// Handle double encoding ourselves
	if ( !$double_encode ) {
		$string = str_replace( array( '|wp_entity|', '|/wp_entity|' ), array( '&', ';' ), $string );
	}

	// Backwards compatibility
	if ( 'single' === $_quote_style ) {
		$string = str_replace( "'", '&#039;', $string );
	}

	return $string;
}

/**
 * Converts a number of HTML entities into their special characters.
 *
 * Specifically deals with: &, <, >, ", and '.
 *
 * $quote_style can be set to ENT_COMPAT to decode " entities,
 * or ENT_QUOTES to do both " and '. Default is ENT_NOQUOTES where no quotes are decoded.
 *
 * @since 2.8
 *
 * @param string $string The text which is to be decoded.
 * @param mixed $quote_style Optional. Converts double quotes if set to ENT_COMPAT, both single and double if set to ENT_QUOTES or none if set to ENT_NOQUOTES. Also compatible with old wp_specialchars() values; converting single quotes if set to 'single', double if set to 'double' or both if otherwise set. Default is ENT_NOQUOTES.
 * @return string The decoded text without HTML entities.
 */
function wp_specialchars_decode( $string, $quote_style = ENT_NOQUOTES )
{
	$string = (string) $string;

	if ( 0 === strlen( $string ) ) {
		return '';
	}

	// Don't bother if there are no entities - saves a lot of processing
	if ( strpos( $string, '&' ) === false ) {
		return $string;
	}

	// Match the previous behaviour of wp_specialchars() when the $quote_style is not an accepted value
	if ( empty( $quote_style ) ) {
		$quote_style = ENT_NOQUOTES;
	} elseif ( !in_array( $quote_style, array( 0, 2, 3, 'single', 'double' ), true ) ) {
		$quote_style = ENT_QUOTES;
	}

	// More complete than get_html_translation_table( HTML_SPECIALCHARS )
	$single = array( '&#039;'  => '\'', '&#x27;' => '\'' );
	$single_preg = array( '/&#0*39;/'  => '&#039;', '/&#x0*27;/i' => '&#x27;' );
	$double = array( '&quot;' => '"', '&#034;'  => '"', '&#x22;' => '"' );
	$double_preg = array( '/&#0*34;/'  => '&#034;', '/&#x0*22;/i' => '&#x22;' );
	$others = array( '&lt;'   => '<', '&#060;'  => '<', '&gt;'   => '>', '&#062;'  => '>', '&amp;'  => '&', '&#038;'  => '&', '&#x26;' => '&' );
	$others_preg = array( '/&#0*60;/'  => '&#060;', '/&#0*62;/'  => '&#062;', '/&#0*38;/'  => '&#038;', '/&#x0*26;/i' => '&#x26;' );

	if ( $quote_style === ENT_QUOTES ) {
		$translation = array_merge( $single, $double, $others );
		$translation_preg = array_merge( $single_preg, $double_preg, $others_preg );
	} elseif ( $quote_style === ENT_COMPAT || $quote_style === 'double' ) {
		$translation = array_merge( $double, $others );
		$translation_preg = array_merge( $double_preg, $others_preg );
	} elseif ( $quote_style === 'single' ) {
		$translation = array_merge( $single, $others );
		$translation_preg = array_merge( $single_preg, $others_preg );
	} elseif ( $quote_style === ENT_NOQUOTES ) {
		$translation = $others;
		$translation_preg = $others_preg;
	}

	// Remove zero padding on numeric entities
	$string = preg_replace( array_keys( $translation_preg ), array_values( $translation_preg ), $string );

	// Replace characters according to translation table
	return strtr( $string, $translation );
}

/**
 * Checks for invalid UTF8 in a string.
 *
 * @since 2.8
 *
 * @param string $string The text which is to be checked.
 * @param boolean $strip Optional. Whether to attempt to strip out invalid UTF8. Default is false.
 * @return string The checked text.
 */
function wp_check_invalid_utf8( $string, $strip = false )
{
	$string = (string) $string;

	if ( 0 === strlen( $string ) ) {
		return '';
	}

	// Store the site charset as a static to avoid multiple calls to get_option()
	static $is_utf8;
	if ( !isset( $is_utf8 ) ) {
		$is_utf8 = in_array( get_option( 'blog_charset' ), array( 'utf8', 'utf-8', 'UTF8', 'UTF-8' ) );
	}
	if ( !$is_utf8 ) {
		return $string;
	}

	// Check for support for utf8 in the installed PCRE library once and store the result in a static
	static $utf8_pcre;
	if ( !isset( $utf8_pcre ) ) {
		$utf8_pcre = @preg_match( '/^./u', 'a' );
	}
	// We can't demand utf8 in the PCRE installation, so just return the string in those cases
	if ( !$utf8_pcre ) {
		return $string;
	}

	// preg_match fails when it encounters invalid UTF8 in $string
	if ( 1 === @preg_match( '/^./us', $string ) ) {
		return $string;
	}

	// Attempt to strip the bad chars if requested (not recommended)
	if ( $strip && function_exists( 'iconv' ) ) {
		return iconv( 'utf-8', 'utf-8', $string );
	}

	return '';
}

/**
 * Encode the Unicode values to be used in the URI.
 *
 * @since 1.5.0
 *
 * @param string $utf8_string
 * @param int $length Max length of the string
 * @return string String with Unicode encoded for URI.
 */
function utf8_uri_encode( $utf8_string, $length = 0 ) {
	$unicode = '';
	$values = array();
	$num_octets = 1;
	$unicode_length = 0;

	$string_length = strlen( $utf8_string );
	for ($i = 0; $i < $string_length; $i++ ) {

		$value = ord( $utf8_string[ $i ] );

		if ( $value < 128 ) {
			if ( $length && ( $unicode_length >= $length ) )
				break;
			$unicode .= chr($value);
			$unicode_length++;
		} else {
			if ( count( $values ) == 0 ) $num_octets = ( $value < 224 ) ? 2 : 3;

			$values[] = $value;

			if ( $length && ( $unicode_length + ($num_octets * 3) ) > $length )
				break;
			if ( count( $values ) == $num_octets ) {
				if ($num_octets == 3) {
					$unicode .= '%' . dechex($values[0]) . '%' . dechex($values[1]) . '%' . dechex($values[2]);
					$unicode_length += 9;
				} else {
					$unicode .= '%' . dechex($values[0]) . '%' . dechex($values[1]);
					$unicode_length += 6;
				}

				$values = array();
				$num_octets = 1;
			}
		}
	}

	return $unicode;
}

/**
 * Converts all accent characters to ASCII characters.
 *
 * If there are no accent characters, then the string given is just returned.
 *
 * @since 1.2.1
 *
 * @param string $string Text that might have accent characters
 * @return string Filtered string with replaced "nice" characters.
 */
function remove_accents($string) {
	if ( !preg_match('/[\x80-\xff]/', $string) )
		return $string;

	if (seems_utf8($string)) {
		$chars = array(
		// Decompositions for Latin-1 Supplement
		chr(195).chr(128) => 'A', chr(195).chr(129) => 'A',
		chr(195).chr(130) => 'A', chr(195).chr(131) => 'A',
		chr(195).chr(132) => 'A', chr(195).chr(133) => 'A',
		chr(195).chr(135) => 'C', chr(195).chr(136) => 'E',
		chr(195).chr(137) => 'E', chr(195).chr(138) => 'E',
		chr(195).chr(139) => 'E', chr(195).chr(140) => 'I',
		chr(195).chr(141) => 'I', chr(195).chr(142) => 'I',
		chr(195).chr(143) => 'I', chr(195).chr(145) => 'N',
		chr(195).chr(146) => 'O', chr(195).chr(147) => 'O',
		chr(195).chr(148) => 'O', chr(195).chr(149) => 'O',
		chr(195).chr(150) => 'O', chr(195).chr(153) => 'U',
		chr(195).chr(154) => 'U', chr(195).chr(155) => 'U',
		chr(195).chr(156) => 'U', chr(195).chr(157) => 'Y',
		chr(195).chr(159) => 's', chr(195).chr(160) => 'a',
		chr(195).chr(161) => 'a', chr(195).chr(162) => 'a',
		chr(195).chr(163) => 'a', chr(195).chr(164) => 'a',
		chr(195).chr(165) => 'a', chr(195).chr(167) => 'c',
		chr(195).chr(168) => 'e', chr(195).chr(169) => 'e',
		chr(195).chr(170) => 'e', chr(195).chr(171) => 'e',
		chr(195).chr(172) => 'i', chr(195).chr(173) => 'i',
		chr(195).chr(174) => 'i', chr(195).chr(175) => 'i',
		chr(195).chr(177) => 'n', chr(195).chr(178) => 'o',
		chr(195).chr(179) => 'o', chr(195).chr(180) => 'o',
		chr(195).chr(181) => 'o', chr(195).chr(182) => 'o',
		chr(195).chr(182) => 'o', chr(195).chr(185) => 'u',
		chr(195).chr(186) => 'u', chr(195).chr(187) => 'u',
		chr(195).chr(188) => 'u', chr(195).chr(189) => 'y',
		chr(195).chr(191) => 'y',
		// Decompositions for Latin Extended-A
		chr(196).chr(128) => 'A', chr(196).chr(129) => 'a',
		chr(196).chr(130) => 'A', chr(196).chr(131) => 'a',
		chr(196).chr(132) => 'A', chr(196).chr(133) => 'a',
		chr(196).chr(134) => 'C', chr(196).chr(135) => 'c',
		chr(196).chr(136) => 'C', chr(196).chr(137) => 'c',
		chr(196).chr(138) => 'C', chr(196).chr(139) => 'c',
		chr(196).chr(140) => 'C', chr(196).chr(141) => 'c',
		chr(196).chr(142) => 'D', chr(196).chr(143) => 'd',
		chr(196).chr(144) => 'D', chr(196).chr(145) => 'd',
		chr(196).chr(146) => 'E', chr(196).chr(147) => 'e',
		chr(196).chr(148) => 'E', chr(196).chr(149) => 'e',
		chr(196).chr(150) => 'E', chr(196).chr(151) => 'e',
		chr(196).chr(152) => 'E', chr(196).chr(153) => 'e',
		chr(196).chr(154) => 'E', chr(196).chr(155) => 'e',
		chr(196).chr(156) => 'G', chr(196).chr(157) => 'g',
		chr(196).chr(158) => 'G', chr(196).chr(159) => 'g',
		chr(196).chr(160) => 'G', chr(196).chr(161) => 'g',
		chr(196).chr(162) => 'G', chr(196).chr(163) => 'g',
		chr(196).chr(164) => 'H', chr(196).chr(165) => 'h',
		chr(196).chr(166) => 'H', chr(196).chr(167) => 'h',
		chr(196).chr(168) => 'I', chr(196).chr(169) => 'i',
		chr(196).chr(170) => 'I', chr(196).chr(171) => 'i',
		chr(196).chr(172) => 'I', chr(196).chr(173) => 'i',
		chr(196).chr(174) => 'I', chr(196).chr(175) => 'i',
		chr(196).chr(176) => 'I', chr(196).chr(177) => 'i',
		chr(196).chr(178) => 'IJ',chr(196).chr(179) => 'ij',
		chr(196).chr(180) => 'J', chr(196).chr(181) => 'j',
		chr(196).chr(182) => 'K', chr(196).chr(183) => 'k',
		chr(196).chr(184) => 'k', chr(196).chr(185) => 'L',
		chr(196).chr(186) => 'l', chr(196).chr(187) => 'L',
		chr(196).chr(188) => 'l', chr(196).chr(189) => 'L',
		chr(196).chr(190) => 'l', chr(196).chr(191) => 'L',
		chr(197).chr(128) => 'l', chr(197).chr(129) => 'L',
		chr(197).chr(130) => 'l', chr(197).chr(131) => 'N',
		chr(197).chr(132) => 'n', chr(197).chr(133) => 'N',
		chr(197).chr(134) => 'n', chr(197).chr(135) => 'N',
		chr(197).chr(136) => 'n', chr(197).chr(137) => 'N',
		chr(197).chr(138) => 'n', chr(197).chr(139) => 'N',
		chr(197).chr(140) => 'O', chr(197).chr(141) => 'o',
		chr(197).chr(142) => 'O', chr(197).chr(143) => 'o',
		chr(197).chr(144) => 'O', chr(197).chr(145) => 'o',
		chr(197).chr(146) => 'OE',chr(197).chr(147) => 'oe',
		chr(197).chr(148) => 'R',chr(197).chr(149) => 'r',
		chr(197).chr(150) => 'R',chr(197).chr(151) => 'r',
		chr(197).chr(152) => 'R',chr(197).chr(153) => 'r',
		chr(197).chr(154) => 'S',chr(197).chr(155) => 's',
		chr(197).chr(156) => 'S',chr(197).chr(157) => 's',
		chr(197).chr(158) => 'S',chr(197).chr(159) => 's',
		chr(197).chr(160) => 'S', chr(197).chr(161) => 's',
		chr(197).chr(162) => 'T', chr(197).chr(163) => 't',
		chr(197).chr(164) => 'T', chr(197).chr(165) => 't',
		chr(197).chr(166) => 'T', chr(197).chr(167) => 't',
		chr(197).chr(168) => 'U', chr(197).chr(169) => 'u',
		chr(197).chr(170) => 'U', chr(197).chr(171) => 'u',
		chr(197).chr(172) => 'U', chr(197).chr(173) => 'u',
		chr(197).chr(174) => 'U', chr(197).chr(175) => 'u',
		chr(197).chr(176) => 'U', chr(197).chr(177) => 'u',
		chr(197).chr(178) => 'U', chr(197).chr(179) => 'u',
		chr(197).chr(180) => 'W', chr(197).chr(181) => 'w',
		chr(197).chr(182) => 'Y', chr(197).chr(183) => 'y',
		chr(197).chr(184) => 'Y', chr(197).chr(185) => 'Z',
		chr(197).chr(186) => 'z', chr(197).chr(187) => 'Z',
		chr(197).chr(188) => 'z', chr(197).chr(189) => 'Z',
		chr(197).chr(190) => 'z', chr(197).chr(191) => 's',
		// Euro Sign
		chr(226).chr(130).chr(172) => 'E',
		// GBP (Pound) Sign
		chr(194).chr(163) => '');

		$string = strtr($string, $chars);
	} else {
		// Assume ISO-8859-1 if not UTF-8
		$chars['in'] = chr(128).chr(131).chr(138).chr(142).chr(154).chr(158)
			.chr(159).chr(162).chr(165).chr(181).chr(192).chr(193).chr(194)
			.chr(195).chr(196).chr(197).chr(199).chr(200).chr(201).chr(202)
			.chr(203).chr(204).chr(205).chr(206).chr(207).chr(209).chr(210)
			.chr(211).chr(212).chr(213).chr(214).chr(216).chr(217).chr(218)
			.chr(219).chr(220).chr(221).chr(224).chr(225).chr(226).chr(227)
			.chr(228).chr(229).chr(231).chr(232).chr(233).chr(234).chr(235)
			.chr(236).chr(237).chr(238).chr(239).chr(241).chr(242).chr(243)
			.chr(244).chr(245).chr(246).chr(248).chr(249).chr(250).chr(251)
			.chr(252).chr(253).chr(255);

		$chars['out'] = "EfSZszYcYuAAAAAACEEEEIIIINOOOOOOUUUUYaaaaaaceeeeiiiinoooooouuuuyy";

		$string = strtr($string, $chars['in'], $chars['out']);
		$double_chars['in'] = array(chr(140), chr(156), chr(198), chr(208), chr(222), chr(223), chr(230), chr(240), chr(254));
		$double_chars['out'] = array('OE', 'oe', 'AE', 'DH', 'TH', 'ss', 'ae', 'dh', 'th');
		$string = str_replace($double_chars['in'], $double_chars['out'], $string);
	}

	return $string;
}

/**
 * Filters certain characters from the file name.
 *
 * Turns all strings to lowercase removing most characters except alphanumeric
 * with spaces, dashes and periods. All spaces and underscores are converted to
 * dashes. Multiple dashes are converted to a single dash. Finally, if the file
 * name ends with a dash, it is removed.
 *
 * @since 2.1.0
 *
 * @param string $name The file name
 * @return string Sanitized file name
 */
function sanitize_file_name( $name ) { // Like sanitize_title, but with periods
	$name = strtolower( $name );
	$name = preg_replace('/&.+?;/', '', $name); // kill entities
	$name = str_replace( '_', '-', $name );
	$name = preg_replace('/[^a-z0-9\s-.]/', '', $name);
	$name = preg_replace('/\s+/', '-', $name);
	$name = preg_replace('|-+|', '-', $name);
	$name = trim($name, '-');
	return $name;
}

/**
 * Sanitize username stripping out unsafe characters.
 *
 * If $strict is true, only alphanumeric characters (as well as _, space, ., -,
 * @) are returned.
 * Removes tags, octets, entities, and if strict is enabled, will remove all
 * non-ASCII characters. After sanitizing, it passes the username, raw username
 * (the username in the parameter), and the strict parameter as parameters for
 * the filter.
 *
 * @since 2.0.0
 * @uses apply_filters() Calls 'sanitize_user' hook on username, raw username,
 *		and $strict parameter.
 *
 * @param string $username The username to be sanitized.
 * @param bool $strict If set limits $username to specific characters. Default false.
 * @return string The sanitized username, after passing through filters.
 */
function sanitize_user( $username, $strict = false ) {
	$raw_username = $username;
	$username = strip_tags($username);
	// Kill octets
	$username = preg_replace('|%([a-fA-F0-9][a-fA-F0-9])|', '', $username);
	$username = preg_replace('/&.+?;/', '', $username); // Kill entities

	// If strict, reduce to ASCII for max portability.
	if ( $strict )
		$username = preg_replace('|[^a-z0-9 _.\-@]|i', '', $username);

	// Consolidate contiguous whitespace
	$username = preg_replace('|\s+|', ' ', $username);

	return apply_filters('sanitize_user', $username, $raw_username, $strict);
}

/**
 * Sanitizes title or use fallback title.
 *
 * Specifically, HTML and PHP tags are stripped. Further actions can be added
 * via the plugin API. If $title is empty and $fallback_title is set, the latter
 * will be used.
 *
 * @since 1.0.0
 *
 * @param string $title The string to be sanitized.
 * @param string $fallback_title Optional. A title to use if $title is empty.
 * @return string The sanitized string.
 */
function sanitize_title($title, $fallback_title = '') {
	$title = strip_tags($title);
	$title = apply_filters('sanitize_title', $title);

	if ( '' === $title || false === $title )
		$title = $fallback_title;

	return $title;
}

/**
 * Sanitizes title, replacing whitespace with dashes.
 *
 * Limits the output to alphanumeric characters, underscore (_) and dash (-).
 * Whitespace becomes a dash.
 *
 * @since 1.2.0
 *
 * @param string $title The title to be sanitized.
 * @return string The sanitized title.
 */
function sanitize_title_with_dashes($title) {
	$title = strip_tags($title);
	// Preserve escaped octets.
	$title = preg_replace('|%([a-fA-F0-9][a-fA-F0-9])|', '---$1---', $title);
	// Remove percent signs that are not part of an octet.
	$title = str_replace('%', '', $title);
	// Restore octets.
	$title = preg_replace('|---([a-fA-F0-9][a-fA-F0-9])---|', '%$1', $title);

	$title = remove_accents($title);
	if (seems_utf8($title)) {
		if (function_exists('mb_strtolower')) {
			$title = mb_strtolower($title, 'UTF-8');
		}
		$title = utf8_uri_encode($title, 200);
	}

	$title = strtolower($title);
	$title = preg_replace('/&.+?;/', '', $title); // kill entities
	$title = preg_replace('/[^%a-z0-9 _-]/', '', $title);
	$title = preg_replace('/\s+/', '-', $title);
	$title = preg_replace('|-+|', '-', $title);
	$title = trim($title, '-');

	return $title;
}

/**
 * Ensures a string is a valid SQL order by clause.
 *
 * Accepts one or more columns, with or without ASC/DESC, and also accepts
 * RAND().
 *
 * @since 2.5.1
 *
 * @param string $orderby Order by string to be checked.
 * @return string|false Returns the order by clause if it is a match, false otherwise.
 */
function sanitize_sql_orderby( $orderby ){
	preg_match('/^\s*([a-z0-9_]+(\s+(ASC|DESC))?(\s*,\s*|\s*$))+|^\s*RAND\(\s*\)\s*$/i', $orderby, $obmatches);
	if ( !$obmatches )
		return false;
	return $orderby;
}

/**
 * Converts a number of characters from a string.
 *
 * Metadata tags <<title>> and <<category>> are removed, <<br>> and <<hr>> are
 * converted into correct XHTML and Unicode characters are converted to the
 * valid range.
 *
 * @since 0.71
 *
 * @param string $content String of characters to be converted.
 * @param string $deprecated Not used.
 * @return string Converted string.
 */
function convert_chars($content, $deprecated = '') {
	// Translation of invalid Unicode references range to valid range
	$wp_htmltranswinuni = array(
	'&#128;' => '&#8364;', // the Euro sign
	'&#129;' => '',
	'&#130;' => '&#8218;', // these are Windows CP1252 specific characters
	'&#131;' => '&#402;',  // they would look weird on non-Windows browsers
	'&#132;' => '&#8222;',
	'&#133;' => '&#8230;',
	'&#134;' => '&#8224;',
	'&#135;' => '&#8225;',
	'&#136;' => '&#710;',
	'&#137;' => '&#8240;',
	'&#138;' => '&#352;',
	'&#139;' => '&#8249;',
	'&#140;' => '&#338;',
	'&#141;' => '',
	'&#142;' => '&#382;',
	'&#143;' => '',
	'&#144;' => '',
	'&#145;' => '&#8216;',
	'&#146;' => '&#8217;',
	'&#147;' => '&#8220;',
	'&#148;' => '&#8221;',
	'&#149;' => '&#8226;',
	'&#150;' => '&#8211;',
	'&#151;' => '&#8212;',
	'&#152;' => '&#732;',
	'&#153;' => '&#8482;',
	'&#154;' => '&#353;',
	'&#155;' => '&#8250;',
	'&#156;' => '&#339;',
	'&#157;' => '',
	'&#158;' => '',
	'&#159;' => '&#376;'
	);

	// Remove metadata tags
	$content = preg_replace('/<title>(.+?)<\/title>/','',$content);
	$content = preg_replace('/<category>(.+?)<\/category>/','',$content);

	// Converts lone & characters into &#38; (a.k.a. &amp;)
	$content = preg_replace('/&([^#])(?![a-z1-4]{1,8};)/i', '&#038;$1', $content);

	// Fix Word pasting
	$content = strtr($content, $wp_htmltranswinuni);

	// Just a little XHTML help
	$content = str_replace('<br>', '<br />', $content);
	$content = str_replace('<hr>', '<hr />', $content);

	return $content;
}

/**
 * Fixes javascript bugs in browsers.
 *
 * Converts unicode characters to HTML numbered entities.
 *
 * @since 1.5.0
 * @uses $is_macIE
 * @uses $is_winIE
 *
 * @param string $text Text to be made safe.
 * @return string Fixed text.
 */
function funky_javascript_fix($text) {
	// Fixes for browsers' javascript bugs
	global $is_macIE, $is_winIE;

	/** @todo use preg_replace_callback() instead */
	if ( $is_winIE || $is_macIE )
		$text =  preg_replace("/\%u([0-9A-F]{4,4})/e",  "'&#'.base_convert('\\1',16,10).';'", $text);

	return $text;
}

/**
 * Will only balance the tags if forced to and the option is set to balance tags.
 *
 * The option 'use_balanceTags' is used for whether the tags will be balanced.
 * Both the $force parameter and 'use_balanceTags' option will have to be true
 * before the tags will be balanced.
 *
 * @since 0.71
 *
 * @param string $text Text to be balanced
 * @param bool $force Forces balancing, ignoring the value of the option. Default false.
 * @return string Balanced text
 */
function balanceTags( $text, $force = false ) {
	if ( !$force && get_option('use_balanceTags') == 0 )
		return $text;
	return force_balance_tags( $text );
}

/**
 * Balances tags of string using a modified stack.
 *
 * @since 2.0.4
 *
 * @author Leonard Lin <leonard@acm.org>
 * @license GPL v2.0
 * @copyright November 4, 2001
 * @version 1.1
 * @todo Make better - change loop condition to $text in 1.2
 * @internal Modified by Scott Reilly (coffee2code) 02 Aug 2004
 *		1.1  Fixed handling of append/stack pop order of end text
 *			 Added Cleaning Hooks
 *		1.0  First Version
 *
 * @param string $text Text to be balanced.
 * @return string Balanced text.
 */
function force_balance_tags( $text ) {
	$tagstack = array(); $stacksize = 0; $tagqueue = ''; $newtext = '';
	$single_tags = array('br', 'hr', 'img', 'input'); //Known single-entity/self-closing tags
	$nestable_tags = array('blockquote', 'div', 'span'); //Tags that can be immediately nested within themselves

	# WP bug fix for comments - in case you REALLY meant to type '< !--'
	$text = str_replace('< !--', '<    !--', $text);
	# WP bug fix for LOVE <3 (and other situations with '<' before a number)
	$text = preg_replace('#<([0-9]{1})#', '&lt;$1', $text);

	while (preg_match("/<(\/?\w*)\s*([^>]*)>/",$text,$regex)) {
		$newtext .= $tagqueue;

		$i = strpos($text,$regex[0]);
		$l = strlen($regex[0]);

		// clear the shifter
		$tagqueue = '';
		// Pop or Push
		if ( isset($regex[1][0]) && '/' == $regex[1][0] ) { // End Tag
			$tag = strtolower(substr($regex[1],1));
			// if too many closing tags
			if($stacksize <= 0) {
				$tag = '';
				//or close to be safe $tag = '/' . $tag;
			}
			// if stacktop value = tag close value then pop
			else if ($tagstack[$stacksize - 1] == $tag) { // found closing tag
				$tag = '</' . $tag . '>'; // Close Tag
				// Pop
				array_pop ($tagstack);
				$stacksize--;
			} else { // closing tag not at top, search for it
				for ($j=$stacksize-1;$j>=0;$j--) {
					if ($tagstack[$j] == $tag) {
					// add tag to tagqueue
						for ($k=$stacksize-1;$k>=$j;$k--){
							$tagqueue .= '</' . array_pop ($tagstack) . '>';
							$stacksize--;
						}
						break;
					}
				}
				$tag = '';
			}
		} else { // Begin Tag
			$tag = strtolower($regex[1]);

			// Tag Cleaning

			// If self-closing or '', don't do anything.
			if((substr($regex[2],-1) == '/') || ($tag == '')) {
			}
			// ElseIf it's a known single-entity tag but it doesn't close itself, do so
			elseif ( in_array($tag, $single_tags) ) {
				$regex[2] .= '/';
			} else {	// Push the tag onto the stack
				// If the top of the stack is the same as the tag we want to push, close previous tag
				if (($stacksize > 0) && !in_array($tag, $nestable_tags) && ($tagstack[$stacksize - 1] == $tag)) {
					$tagqueue = '</' . array_pop ($tagstack) . '>';
					$stacksize--;
				}
				$stacksize = array_push ($tagstack, $tag);
			}

			// Attributes
			$attributes = $regex[2];
			if($attributes) {
				$attributes = ' '.$attributes;
			}
			$tag = '<'.$tag.$attributes.'>';
			//If already queuing a close tag, then put this tag on, too
			if ($tagqueue) {
				$tagqueue .= $tag;
				$tag = '';
			}
		}
		$newtext .= substr($text,0,$i) . $tag;
		$text = substr($text,$i+$l);
	}

	// Clear Tag Queue
	$newtext .= $tagqueue;

	// Add Remaining text
	$newtext .= $text;

	// Empty Stack
	while($x = array_pop($tagstack)) {
		$newtext .= '</' . $x . '>'; // Add remaining tags to close
	}

	// WP fix for the bug with HTML comments
	$newtext = str_replace("< !--","<!--",$newtext);
	$newtext = str_replace("<    !--","< !--",$newtext);

	return $newtext;
}

/**
 * Acts on text which is about to be edited.
 *
 * Unless $richedit is set, it is simply a holder for the 'format_to_edit'
 * filter. If $richedit is set true htmlspecialchars() will be run on the
 * content, converting special characters to HTMl entities.
 *
 * @since 0.71
 *
 * @param string $content The text about to be edited.
 * @param bool $richedit Whether or not the $content should pass through htmlspecialchars(). Default false.
 * @return string The text after the filter (and possibly htmlspecialchars()) has been run.
 */
function format_to_edit($content, $richedit = false) {
	$content = apply_filters('format_to_edit', $content);
	if (! $richedit )
		$content = htmlspecialchars($content);
	return $content;
}

/**
 * Holder for the 'format_to_post' filter.
 *
 * @since 0.71
 *
 * @param string $content The text to pass through the filter.
 * @return string Text returned from the 'format_to_post' filter.
 */
function format_to_post($content) {
	$content = apply_filters('format_to_post', $content);
	return $content;
}

/**
 * Add leading zeros when necessary.
 *
 * If you set the threshold to '4' and the number is '10', then you will get
 * back '0010'. If you set the number to '4' and the number is '5000', then you
 * will get back '5000'.
 *
 * Uses sprintf to append the amount of zeros based on the $threshold parameter
 * and the size of the number. If the number is large enough, then no zeros will
 * be appended.
 *
 * @since 0.71
 *
 * @param mixed $number Number to append zeros to if not greater than threshold.
 * @param int $threshold Digit places number needs to be to not have zeros added.
 * @return string Adds leading zeros to number if needed.
 */
function zeroise($number, $threshold) {
	return sprintf('%0'.$threshold.'s', $number);
}

/**
 * Adds backslashes before letters and before a number at the start of a string.
 *
 * @since 0.71
 *
 * @param string $string Value to which backslashes will be added.
 * @return string String with backslashes inserted.
 */
function backslashit($string) {
	$string = preg_replace('/^([0-9])/', '\\\\\\\\\1', $string);
	$string = preg_replace('/([a-z])/i', '\\\\\1', $string);
	return $string;
}

/**
 * Appends a trailing slash.
 *
 * Will remove trailing slash if it exists already before adding a trailing
 * slash. This prevents double slashing a string or path.
 *
 * The primary use of this is for paths and thus should be used for paths. It is
 * not restricted to paths and offers no specific path support.
 *
 * @since 1.2.0
 * @uses untrailingslashit() Unslashes string if it was slashed already.
 *
 * @param string $string What to add the trailing slash to.
 * @return string String with trailing slash added.
 */
function trailingslashit($string) {
	return untrailingslashit($string) . '/';
}

/**
 * Removes trailing slash if it exists.
 *
 * The primary use of this is for paths and thus should be used for paths. It is
 * not restricted to paths and offers no specific path support.
 *
 * @since 2.2.0
 *
 * @param string $string What to remove the trailing slash from.
 * @return string String without the trailing slash.
 */
function untrailingslashit($string) {
	return rtrim($string, '/');
}

/**
 * Adds slashes to escape strings.
 *
 * Slashes will first be removed if magic_quotes_gpc is set, see {@link
 * http://www.php.net/magic_quotes} for more details.
 *
 * @since 0.71
 *
 * @param string $gpc The string returned from HTTP request data.
 * @return string Returns a string escaped with slashes.
 */
function addslashes_gpc($gpc) {
	global $wpdb;

	if (get_magic_quotes_gpc()) {
		$gpc = stripslashes($gpc);
	}

	return $wpdb->escape($gpc);
}

/**
 * Navigates through an array and removes slashes from the values.
 *
 * If an array is passed, the array_map() function causes a callback to pass the
 * value back to the function. The slashes from this value will removed.
 *
 * @since 2.0.0
 *
 * @param array|string $value The array or string to be striped.
 * @return array|string Stripped array (or string in the callback).
 */
function stripslashes_deep($value) {
	$value = is_array($value) ? array_map('stripslashes_deep', $value) : stripslashes($value);
	return $value;
}

/**
 * Navigates through an array and encodes the values to be used in a URL.
 *
 * Uses a callback to pass the value of the array back to the function as a
 * string.
 *
 * @since 2.2.0
 *
 * @param array|string $value The array or string to be encoded.
 * @return array|string $value The encoded array (or string from the callback).
 */
function urlencode_deep($value) {
	$value = is_array($value) ? array_map('urlencode_deep', $value) : urlencode($value);
	return $value;
}

/**
 * Converts email addresses characters to HTML entities to block spam bots.
 *
 * @since 0.71
 *
 * @param string $emailaddy Email address.
 * @param int $mailto Optional. Range from 0 to 1. Used for encoding.
 * @return string Converted email address.
 */
function antispambot($emailaddy, $mailto=0) {
	$emailNOSPAMaddy = '';
	srand ((float) microtime() * 1000000);
	for ($i = 0; $i < strlen($emailaddy); $i = $i + 1) {
		$j = floor(rand(0, 1+$mailto));
		if ($j==0) {
			$emailNOSPAMaddy .= '&#'.ord(substr($emailaddy,$i,1)).';';
		} elseif ($j==1) {
			$emailNOSPAMaddy .= substr($emailaddy,$i,1);
		} elseif ($j==2) {
			$emailNOSPAMaddy .= '%'.zeroise(dechex(ord(substr($emailaddy, $i, 1))), 2);
		}
	}
	$emailNOSPAMaddy = str_replace('@','&#64;',$emailNOSPAMaddy);
	return $emailNOSPAMaddy;
}

/**
 * Callback to convert URI match to HTML A element.
 *
 * This function was backported from 2.5.0 to 2.3.2. Regex callback for {@link
 * make_clickable()}.
 *
 * @since 2.3.2
 * @access private
 *
 * @param array $matches Single Regex Match.
 * @return string HTML A element with URI address.
 */
function _make_url_clickable_cb($matches) {
	$url = $matches[2];
	$url = clean_url($url);
	if ( empty($url) )
		return $matches[0];
	return $matches[1] . "<a href=\"$url\" rel=\"nofollow\">$url</a>";
}

/**
 * Callback to convert URL match to HTML A element.
 *
 * This function was backported from 2.5.0 to 2.3.2. Regex callback for {@link
 * make_clickable()}.
 *
 * @since 2.3.2
 * @access private
 *
 * @param array $matches Single Regex Match.
 * @return string HTML A element with URL address.
 */
function _make_web_ftp_clickable_cb($matches) {
	$ret = '';
	$dest = $matches[2];
	$dest = 'http://' . $dest;
	$dest = clean_url($dest);
	if ( empty($dest) )
		return $matches[0];
	// removed trailing [,;:] from URL
	if ( in_array(substr($dest, -1), array('.', ',', ';', ':')) === true ) {
		$ret = substr($dest, -1);
		$dest = substr($dest, 0, strlen($dest)-1);
	}
	return $matches[1] . "<a href=\"$dest\" rel=\"nofollow\">$dest</a>" . $ret;
}

/**
 * Callback to convert email address match to HTML A element.
 *
 * This function was backported from 2.5.0 to 2.3.2. Regex callback for {@link
 * make_clickable()}.
 *
 * @since 2.3.2
 * @access private
 *
 * @param array $matches Single Regex Match.
 * @return string HTML A element with email address.
 */
function _make_email_clickable_cb($matches) {
	$email = $matches[2] . '@' . $matches[3];
	return $matches[1] . "<a href=\"mailto:$email\">$email</a>";
}

/**
 * Convert plaintext URI to HTML links.
 *
 * Converts URI, www and ftp, and email addresses. Finishes by fixing links
 * within links.
 *
 * @since 0.71
 *
 * @param string $ret Content to convert URIs.
 * @return string Content with converted URIs.
 */
function make_clickable($ret) {
	$ret = ' ' . $ret;
	// in testing, using arrays here was found to be faster
	$ret = preg_replace_callback('#(?<=[\s>])(\()?([\w]+?://(?:[\w\\x80-\\xff\#$%&~/\-=?@\[\](+]|[.,;:](?![\s<])|(?(1)\)(?![\s<])|\)))*)#is', '_make_url_clickable_cb', $ret);
	$ret = preg_replace_callback('#([\s>])((www|ftp)\.[\w\\x80-\\xff\#$%&~/.\-;:=,?@\[\]+]*)#is', '_make_web_ftp_clickable_cb', $ret);
	$ret = preg_replace_callback('#([\s>])([.0-9a-z_+-]+)@(([0-9a-z-]+\.)+[0-9a-z]{2,})#i', '_make_email_clickable_cb', $ret);
	// this one is not in an array because we need it to run last, for cleanup of accidental links within links
	$ret = preg_replace("#(<a( [^>]+?>|>))<a [^>]+?>([^>]+?)</a></a>#i", "$1$3</a>", $ret);
	$ret = trim($ret);
	return $ret;
}

/**
 * Adds rel nofollow string to all HTML A elements in content.
 *
 * @since 1.5.0
 *
 * @param string $text Content that may contain HTML A elements.
 * @return string Converted content.
 */
function wp_rel_nofollow( $text ) {
	global $wpdb;
	// This is a pre save filter, so text is already escaped.
	$text = stripslashes($text);
	$text = preg_replace_callback('|<a (.+?)>|i', 'wp_rel_nofollow_callback', $text);
	$text = $wpdb->escape($text);
	return $text;
}

/**
 * Callback to used to add rel=nofollow string to HTML A element.
 *
 * Will remove already existing rel="nofollow" and rel='nofollow' from the
 * string to prevent from invalidating (X)HTML.
 *
 * @since 2.3.0
 *
 * @param array $matches Single Match
 * @return string HTML A Element with rel nofollow.
 */
function wp_rel_nofollow_callback( $matches ) {
	$text = $matches[1];
	$text = str_replace(array(' rel="nofollow"', " rel='nofollow'"), '', $text);
	return "<a $text rel=\"nofollow\">";
}


/**
 * Convert one smiley code to the icon graphic file equivalent.
 *
 * Looks up one smiley code in the $wpsmiliestrans global array and returns an
 * <img> string for that smiley.
 *
 * @global array $wpsmiliestrans
 * @since 2.8.0
 *
 * @param string $smiley Smiley code to convert to image.
 * @return string Image string for smiley.
 */
function translate_smiley($smiley) {
	global $wpsmiliestrans;

	if (count($smiley) == 0) {
		return '';
	}

	$siteurl = get_option( 'siteurl' );

	$smiley = trim(reset($smiley));
	$img = $wpsmiliestrans[$smiley];
	$smiley_masked = attribute_escape($smiley);

	return " <img src='$siteurl/wp-includes/images/smilies/$img' alt='$smiley_masked' class='wp-smiley' /> ";
}


/**
 * Convert text equivalent of smilies to images.
 *
 * Will only convert smilies if the option 'use_smilies' is true and the global
 * used in the function isn't empty.
 *
 * @since 0.71
 * @uses $wp_smiliessearch
 *
 * @param string $text Content to convert smilies from text.
 * @return string Converted content with text smilies replaced with images.
 */
function convert_smilies($text) {
	global $wp_smiliessearch;
	$output = '';
	if ( get_option('use_smilies') && !empty($wp_smiliessearch) ) {
		// HTML loop taken from texturize function, could possible be consolidated
		$textarr = preg_split("/(<.*>)/U", $text, -1, PREG_SPLIT_DELIM_CAPTURE); // capture the tags as well as in between
		$stop = count($textarr);// loop stuff
		for ($i = 0; $i < $stop; $i++) {
			$content = $textarr[$i];
			if ((strlen($content) > 0) && ('<' != $content{0})) { // If it's not a tag
				$content = preg_replace_callback($wp_smiliessearch, 'translate_smiley', $content);
			}
			$output .= $content;
		}
	} else {
		// return default text.
		$output = $text;
	}
	return $output;
}

/**
 * Checks to see if the text is a valid email address.
 *
 * @since 0.71
 *
 * @param string $user_email The email address to be checked.
 * @return bool Returns true if valid, otherwise false.
 */
function is_email($user_email) {
	$chars = "/^([a-z0-9+_]|\\-|\\.)+@(([a-z0-9_]|\\-)+\\.)+[a-z]{2,6}\$/i";
	if (strpos($user_email, '@') !== false && strpos($user_email, '.') !== false) {
		if (preg_match($chars, $user_email)) {
			return true;
		} else {
			return false;
		}
	} else {
		return false;
	}
}

/**
 * Convert to ASCII from email subjects.
 *
 * @since 1.2.0
 * @usedby wp_mail() handles charsets in email subjects
 *
 * @param string $string Subject line
 * @return string Converted string to ASCII
 */
function wp_iso_descrambler($string) {
	/* this may only work with iso-8859-1, I'm afraid */
	if (!preg_match('#\=\?(.+)\?Q\?(.+)\?\=#i', $string, $matches)) {
		return $string;
	} else {
		$subject = str_replace('_', ' ', $matches[2]);
		$subject = preg_replace_callback('#\=([0-9a-f]{2})#i', create_function('$match', 'return chr(hexdec(strtolower($match[1])));'), $subject);
		return $subject;
	}
}

/**
 * Returns a date in the GMT equivalent.
 *
 * Requires and returns a date in the Y-m-d H:i:s format. Simply subtracts the
 * value of the 'gmt_offset' option.
 *
 * @since 1.2.0
 *
 * @uses get_option() to retrieve the the value of 'gmt_offset'.
 * @param string $string The date to be converted.
 * @return string GMT version of the date provided.
 */
function get_gmt_from_date($string) {
	preg_match('#([0-9]{1,4})-([0-9]{1,2})-([0-9]{1,2}) ([0-9]{1,2}):([0-9]{1,2}):([0-9]{1,2})#', $string, $matches);
	$string_time = gmmktime($matches[4], $matches[5], $matches[6], $matches[2], $matches[3], $matches[1]);
	$string_gmt = gmdate('Y-m-d H:i:s', $string_time - get_option('gmt_offset') * 3600);
	return $string_gmt;
}

/**
 * Converts a GMT date into the correct format for the blog.
 *
 * Requires and returns in the Y-m-d H:i:s format. Simply adds the value of
 * gmt_offset.
 *
 * @since 1.2.0
 *
 * @param string $string The date to be converted.
 * @return string Formatted date relative to the GMT offset.
 */
function get_date_from_gmt($string) {
	preg_match('#([0-9]{1,4})-([0-9]{1,2})-([0-9]{1,2}) ([0-9]{1,2}):([0-9]{1,2}):([0-9]{1,2})#', $string, $matches);
	$string_time = gmmktime($matches[4], $matches[5], $matches[6], $matches[2], $matches[3], $matches[1]);
	$string_localtime = gmdate('Y-m-d H:i:s', $string_time + get_option('gmt_offset')*3600);
	return $string_localtime;
}

/**
 * Computes an offset in seconds from an iso8601 timezone.
 *
 * @since 1.5.0
 *
 * @param string $timezone Either 'Z' for 0 offset or '±hhmm'.
 * @return int|float The offset in seconds.
 */
function iso8601_timezone_to_offset($timezone) {
	// $timezone is either 'Z' or '[+|-]hhmm'
	if ($timezone == 'Z') {
		$offset = 0;
	} else {
		$sign    = (substr($timezone, 0, 1) == '+') ? 1 : -1;
		$hours   = intval(substr($timezone, 1, 2));
		$minutes = intval(substr($timezone, 3, 4)) / 60;
		$offset  = $sign * 3600 * ($hours + $minutes);
	}
	return $offset;
}

/**
 * Converts an iso8601 date to MySQL DateTime format used by post_date[_gmt].
 *
 * @since 1.5.0
 *
 * @param string $date_string Date and time in ISO 8601 format {@link http://en.wikipedia.org/wiki/ISO_8601}.
 * @param string $timezone Optional. If set to GMT returns the time minus gmt_offset. Default is 'user'.
 * @return string The date and time in MySQL DateTime format - Y-m-d H:i:s.
 */
function iso8601_to_datetime($date_string, $timezone = 'user') {
	$timezone = strtolower($timezone);

	if ($timezone == 'gmt') {

		preg_match('#([0-9]{4})([0-9]{2})([0-9]{2})T([0-9]{2}):([0-9]{2}):([0-9]{2})(Z|[\+|\-][0-9]{2,4}){0,1}#', $date_string, $date_bits);

		if (!empty($date_bits[7])) { // we have a timezone, so let's compute an offset
			$offset = iso8601_timezone_to_offset($date_bits[7]);
		} else { // we don't have a timezone, so we assume user local timezone (not server's!)
			$offset = 3600 * get_option('gmt_offset');
		}

		$timestamp = gmmktime($date_bits[4], $date_bits[5], $date_bits[6], $date_bits[2], $date_bits[3], $date_bits[1]);
		$timestamp -= $offset;

		return gmdate('Y-m-d H:i:s', $timestamp);

	} else if ($timezone == 'user') {
		return preg_replace('#([0-9]{4})([0-9]{2})([0-9]{2})T([0-9]{2}):([0-9]{2}):([0-9]{2})(Z|[\+|\-][0-9]{2,4}){0,1}#', '$1-$2-$3 $4:$5:$6', $date_string);
	}
}

/**
 * Adds a element attributes to open links in new windows.
 *
 * Comment text in popup windows should be filtered through this. Right now it's
 * a moderately dumb function, ideally it would detect whether a target or rel
 * attribute was already there and adjust its actions accordingly.
 *
 * @since 0.71
 *
 * @param string $text Content to replace links to open in a new window.
 * @return string Content that has filtered links.
 */
function popuplinks($text) {
	$text = preg_replace('/<a (.+?)>/i', "<a $1 target='_blank' rel='external'>", $text);
	return $text;
}

/**
 * Strips out all characters that are not allowable in an email.
 *
 * @since 1.5.0
 *
 * @param string $email Email address to filter.
 * @return string Filtered email address.
 */
function sanitize_email($email) {
	return preg_replace('/[^a-z0-9+_.@-]/i', '', $email);
}

/**
 * Determines the difference between two timestamps.
 *
 * The difference is returned in a human readable format such as "1 hour",
 * "5 mins", "2 days".
 *
 * @since 1.5.0
 *
 * @param int $from Unix timestamp from which the difference begins.
 * @param int …