Automattic / jetpack

				# Fenced code block marker: find matching end marker.

				$fence_indent = strlen($capture[1]); # use captured indent in re

				$fence_re = $capture[2]; # use captured fence in re

				if (preg_match('{^(?>.*\n)*?[ ]{'.($fence_indent).'}'.$fence_re.'[ ]*(?:\n|$)}', $text,

					$matches))

				{

					# End marker found: pass text unchanged until marker.

					$parsed .= $tag . $matches[0];

					$text = substr($text, strlen($matches[0]));

				}

				else {

					# No end marker: just skip it.

					$parsed .= $tag;

				}

			}

			#

			# Check for: Indented code block.

			else if ($tag{0} == "`") {

				# Find corresponding end marker.

				$tag_re = preg_quote($tag);

				if (preg_match('{^(?>.+?|\n(?!\n))*?(?<!`)'.$tag_re.'(?!`)}',

					$text, $matches))

				{

					# End marker found: pass text unchanged until marker.

					$parsed .= $tag . $matches[0];

					$text = substr($text, strlen($matches[0]));

				}

				else {

					# Unmatched marker: just skip it.

					$parsed .= $tag;

				}

			}

			#

			# Check for: Opening Block level tag or