simplify test for em strong

Prior to PHP 5.4.0 the default encoding for `htmlentities()`
and `htmlspecialchars` is "ISO-8859-1". For PHP 5.4+ is "UTF-8".

This ensures always the right encoding is used no matter the PHP version
and the locale settings.

Parsedown.php

@@ -568,7 +568,7 @@ class Parsedown
 				case 'code_block':
 				case 'fenced_code_block':
 
-					$text = htmlentities($element['text'], ENT_NOQUOTES);
+					$text = htmlspecialchars($element['text'], ENT_NOQUOTES, 'UTF-8');
 
 					strpos($text, "\x1A\\") !== FALSE and $text = strtr($text, $this->escape_sequence_map);
 
@@ -634,7 +634,7 @@ class Parsedown
 			foreach ($matches as $matches)
 			{
 				$element_text = $matches[1];
-				$element_text = htmlentities($element_text, ENT_NOQUOTES);
+				$element_text = htmlspecialchars($element_text, ENT_NOQUOTES, 'UTF-8');
 
 				# decodes escape sequences
 
@@ -779,14 +779,19 @@ class Parsedown
 
 		if (strpos($text, '_') !== FALSE)
 		{
-			$text = preg_replace('/__(?=\S)(.+?)(?<=\S)__(?!_)/s', '<strong>$1</strong>', $text);
+			$text = preg_replace('/__(?=\S)([^_]+?)(?<=\S)__/s', '<strong>$1</strong>', $text, -1, $count);
+			$count or $text = preg_replace('/__(?=\S)(.+?)(?<=\S)__(?!_)/s', '<strong>$1</strong>', $text);
+
 			$text = preg_replace('/\b_(?=\S)(.+?)(?<=\S)_\b/s', '<em>$1</em>', $text);
 		}
 
 		if (strpos($text, '*') !== FALSE)
 		{
-			$text = preg_replace('/\*\*(?=\S)(.+?)(?<=\S)\*\*(?!\*)/s', '<strong>$1</strong>', $text);
+			$text = preg_replace('/\*\*(?=\S)([^*]+?)(?<=\S)\*\*/s', '<strong>$1</strong>', $text, -1, $count);
-			$text = preg_replace('/\*(?=\S)(.+?)(?<=\S)\*/s', '<em>$1</em>', $text);
+			$count or $text = preg_replace('/\*\*(?=\S)(.+?)(?<=\S)\*\*(?!\*)/s', '<strong>$1</strong>', $text);
+
+			$text = preg_replace('/\*(?=\S)([^*]+?)(?<=\S)\*/s', '<em>$1</em>', $text, -1, $count);
+			$count or $text = preg_replace('/\*(?=\S)(.+?)(?<=\S)\*(?!\*)/s', '<em>$1</em>', $text);
 		}
 
 		$text = strtr($text, $map);

README.md

@@ -1,6 +1,6 @@
 ## Parsedown
 
-Fast, consistent and easy to use [Markdown][1] parser for PHP.
+Fast and consistent [Markdown][1] parser for PHP.
 
 [Home](http://parsedown.org) · [Demo](http://parsedown.org/explorer/) · [Tests](http://parsedown.org/tests/)
 

tests/data/em_strong.html

@@ -1,5 +1,4 @@
-<p><strong><em>em strong</em></strong></p>
+<p><strong><em>em strong</em> strong</strong></p>
-<p><strong><em>one</em> at the start</strong></p>
+<p><strong>strong <em>em strong</em></strong></p>
-<p><strong>one at the <em>end</em></strong></p>
+<p><strong>strong <em>em strong</em> strong</strong></p>
-<p><strong>one <em>in the</em> middle</strong></p>
+<p><strong>strong <em>em strong</em></strong></p>
-<p><strong>one with <em>asterisks</em></strong></p>

tests/data/em_strong.md

@@ -1,9 +1,7 @@
-___em strong___
+___em strong_ strong__
 
-___one_ at the start__
+__strong _em strong___
 
-__one at the _end___
+__strong _em strong_ strong__
 
-__one _in the_ middle__
+**strong *em strong***
-
-**one with *asterisks***

tests/data/special_characters.html

@@ -1,4 +1,5 @@
 <p>AT&amp;T has an ampersand in their name</p>
+<pre><code>Let's play some cards ♠ ♣ ♥ ♦</code></pre>
 <p>AT&amp;T is another way to write it</p>
 <p>this &amp; that</p>
 <p>4 &lt; 5 and 6 > 5</p>

tests/data/special_characters.md

@@ -1,5 +1,7 @@
 AT&T has an ampersand in their name
 
+    Let's play some cards ♠ ♣ ♥ ♦
+
 AT&T is another way to write it
 
 this & that

tests/data/strong_em.html

@@ -0,0 +1,6 @@
+<p><em><strong>strong em</strong></em> </p>
+<p><em>em <strong>strong em</strong></em></p>
+<p><em><strong>strong em</strong> em</em></p>
+<p><em><strong>strong em</strong></em></p>
+<p><em>em <strong>strong em</strong></em></p>
+<p><em><strong>strong em</strong> em</em></p>

tests/data/strong_em.md

@@ -0,0 +1,11 @@
+***strong em*** 
+
+*em **strong em***
+
+***strong em** em*
+
+___strong em___
+
+_em __strong em___
+
+___strong em__ em_