Function - Filter PDF/print rogue special characters from WYSIWYG "full-paste" or rando DB source

dev_script_filter_char_print.php

<?php

// @last https://3v4l.org/0LHkO

// Start sample
$str = '® ‡ ¼';

echo clean($str, false, false);
// End sample


function clean($str, $strict = true, $punct = true) {
	$base_pool = array(
		'‘' => '&lsquo;',
		'’' => '&rsquo;',
		'‚' => '&sbquo;',
		'“' => '&ldquo;',
		'”' => '&rdquo;',
		'„' => '&bdquo;',
		'©' => '&copy;',
		'®' => '&reg;',
		'™' => '&trade;',
		'°' => '&deg;',
		'•' => '&bull;',
		'–' => '&ndash;',
		'—' => '&mdash;',
		'…' => '&#8230;',
		'¼' => '&#188;',
		'½' => '&#189;',
		'¾' => '&#190;',
		'‰' => '&#8240;',
		'±' => '&#177;',
		'†' => '&#8224;',
		'‡' => '&#8225;',
		'&nbsp;' => ' ',
		'&amp;amp;' => '&amp;'
	);
	
	$strict_pool = array(
		'\'' => '&#39;',
		'"' => '&quot;',
		"\r" => ' ',
		"\n" => ' ',
		"\t" => ' '
	);
	
	// if strict param is true we will clean harder (default true)
	if ($strict) {
		$base_pool = array_merge($strict_pool, $base_pool);
	}
	
	foreach ($base_pool as $key => $value) {
		$str = str_replace($key, $value, $str); // iterate through pool key => values and replace in $str
	}
			
	// if punct param is true we will add spaces after punctuation (default true)
	if ($punct) {
		$str = preg_replace('/([!?,.])(\S)/', '$1 $2', $str); // parse punctuation and add trail space
	}

	$str = preg_replace("/\s+/", ' ', $str); // filter multiple spaces into single
	
	return $str;
}