', '\#', '\+', '\-', '\.', '\!');
foreach ($escape_sequences as $index => $escape_sequence)
{
if (strpos($text, $escape_sequence) !== FALSE)
{
$code = "\x1A".'\\'.$index;
$text = str_replace($escape_sequence, $code, $text);
$this->escape_sequence_map[$code] = $escape_sequence;
}
}
}
# Extracts link references.
if (preg_match_all('/^[ ]{0,3}\[(.+)\][ ]?:[ ]*\n?[ ]*(.+)$/m', $text, $matches, PREG_SET_ORDER))
{
foreach ($matches as $matches)
{
$this->reference_map[strtolower($matches[1])] = $matches[2];
$text = str_replace($matches[0], '', $text);
}
}
# ~
$text = trim($text, "\n");
$text = preg_replace('/\n\s*\n/', "\n\n", $text);
$text = $this->parse_lines($text);
# Decodes escape sequences (leaves out backslashes).
foreach ($this->escape_sequence_map as $code => $escape_sequence)
{
$text = str_replace($code, $escape_sequence[1], $text);
}
$text = rtrim($text, "\n");
return $text;
}
#
# Private Methods
#
private function parse_lines($text, $context = null)
{
$lines = explode("\n", $text);
$lines []= NULL;
$line_count = count($lines);
$markup = '';
foreach ($lines as $index => $line)
{
# Quick Line
if (isset($line) and $line !== '' and $line[0] >= 'A')
{
$quick_line = $line;
unset($line);
}
# Setext Heading (-)
if (isset($line) and $line !== '' and isset($paragraph) and preg_match('/^[-]+[ ]*$/', $line))
{
$setext_heading_text = $this->parse_inline_elements($paragraph);
$markup .= ''.$setext_heading_text.'
'."\n";
unset($paragraph, $line);
continue;
}
# Rule
if (isset($line) and preg_match('/^[ ]{0,3}([-*_])([ ]{0,2}\1){2,}[ ]*$/', $line))
{
$rule = true;
unset($line);
}
elseif (isset($rule))
{
$markup .= '
'."\n";
unset($rule);
}
# List
# Unlike other types, consequent lines of type "list items" may not
# belong to the same block.
if (isset($line) and $line !== '' and preg_match('/^([ ]{0,3})(\d+[.]|[*+-])[ ](.*)/', $line, $matches)) # list item
{
$list_item_indentation = $matches[1];
$list_item_type = ($matches[2] === '-' or $matches[2] === '+' or $matches[2] === '*')
? 'ul'
: 'ol';
if (isset($list_items)) # subsequent
{
if ($list_item_indentation === $list_indentation and $list_item_type === $list_type)
{
$list_items []= $list_item;
$list_item = $matches[3];
}
else
{
$list_item .= "\n".$line;
}
}
else # first
{
$list_indentation = $list_item_indentation;
$list_type = $list_item_type;
$list_item = $matches[3];
$list_items = array();
}
unset($line);
}
elseif (isset($list_items)) # incomplete list item
{
if (isset($line) and ($line === '' or $line[0] === ' '))
{
$line and $line = preg_replace('/^[ ]{0,4}/', '', $line);;
$list_item .= "\n".$line;
unset($line);
}
else # line is consumed or does not belong to the list item
{
$list_item = rtrim($list_item, "\n");
$list_items []= $list_item;
$markup .= '<'.$list_type.'>'."\n";
foreach ($list_items as $list_item)
{
$list_item_text = strpos($list_item, "\n") !== false
? $this->parse_lines($list_item, 'li')
: $this->parse_inline_elements($list_item);
$markup .= ''.$list_item_text.''."\n";
}
$markup .= ''."\n";
unset($list_items);
}
}
# Code Block
if (isset($line) and $line !== '' and preg_match('/^[ ]{4}(.*)/', $line, $matches))
{
if (isset($code_block))
{
$code_block .= "\n".$matches[1];
}
else
{
$code_block = $matches[1];
}
unset($line);
}
elseif (isset($code_block))
{
if (isset($line) and $line === '')
{
$code_block .= "\n";
# ยป continue;
}
else
{
$code_block = rtrim($code_block);
$code_block_text = htmlentities($code_block, ENT_NOQUOTES);
# Decodes encoded escape sequences if present.
strpos($code_block_text, "\x1A\\") !== FALSE and $code_block_text = strtr($code_block_text, $this->escape_sequence_map);
$markup .= ''.$code_block_text.'
'."\n";
unset($code_block);
}
}
# Quote Block
if (isset($line) and $line !== '' and preg_match('/^[ ]*>[ ]?(.*)/', $line, $matches))
{
if (isset($blockquote))
{
$blockquote .= "\n".$matches[1];
}
else
{
$blockquote = $matches[1];
}
unset($line);
}
elseif (isset($blockquote))
{
if (isset($line) and $line === '')
{
$blockquote .= "\n";
}
else
{
$blockquote = $this->parse_lines($blockquote);
$markup .= ''."\n".$blockquote.'
'."\n";
unset($blockquote);
}
}
# Atx Heading
if (isset($line) and $line !== '' and $line[0] === '#' and preg_match('/^(#{1,6})[ ]*(.+?)[ ]*#*$/', $line, $matches))
{
$atx_heading_level = strlen($matches[1]);
$atx_heading = $this->parse_inline_elements($matches[2]);
unset($line);
}
elseif (isset($atx_heading))
{
$markup .= ''.$atx_heading.''."\n";
unset($atx_heading);
}
# Setext Heading (=)
if (isset($line) and $line !== '' and isset($paragraph) and preg_match('/^[=]+[ ]*$/', $line))
{
$setext_heading_text = $this->parse_inline_elements($paragraph);
$markup .= ''.$setext_heading_text.'
'."\n";
unset($paragraph, $line);
continue;
}
# Paragraph
if (isset($quick_line))
{
$line = $quick_line;
unset($quick_line);
}
if (isset($line) and $line !== '')
{
substr($line, -2) === ' ' and $line = substr_replace($line, '
', -2);
if (isset($paragraph))
{
$paragraph .= "\n".$line;
}
else
{
$paragraph = $line;
}
}
elseif (isset($paragraph))
{
$paragraph_text = $this->parse_inline_elements($paragraph);
if ($context === 'li')
{
if ( ! $markup and $index + 1 === $line_count)
{
$text_is_simple = true;
}
else
{
$markup or $markup .= "\n";
}
$markup .= isset($text_is_simple)
? $paragraph_text
: ''.$paragraph_text.'
'."\n";
}
else
{
$markup .= ''.$paragraph_text.'
'."\n";
}
unset($paragraph);
}
}
return $markup;
}
private function parse_inline_elements($text)
{
$map = array();
$index = 0;
# Code Span
if (strpos($text, '`') !== FALSE and preg_match_all('/`(.+?)`/', $text, $matches, PREG_SET_ORDER))
{
foreach ($matches as $matches)
{
$element_text = $matches[1];
$element_text = htmlentities($element_text, ENT_NOQUOTES);
# Decodes escape sequences.
$this->escape_sequence_map
and strpos($element_text, "\x1A") !== FALSE
and $element_text = strtr($element_text, $this->escape_sequence_map);
# Composes element.
$element = ''.$element_text.'';
# Encodes element.
$code = "\x1A".'$'.$index;
$text = str_replace($matches[0], $code, $text);
$map[$code] = $element;
$index ++;
}
}
# Reference(d) Link / Image
if ($this->reference_map and strpos($text, '[') !== FALSE and preg_match_all('/(!?)\[(.+?)\](?:\n?[ ]?\[(.*?)\])?/ms', $text, $matches, PREG_SET_ORDER))
{
foreach ($matches as $matches)
{
$link_difinition = isset($matches[3]) && $matches[3]
? $matches[3]
: $matches[2]; # implicit
$link_difinition = strtolower($link_difinition);
if (isset($this->reference_map[$link_difinition]))
{
$url = $this->reference_map[$link_difinition];
if ($matches[1]) # image
{
$element = '!['.$matches[2].']('.$url.')
';
}
else # anchor
{
$element_text = $this->parse_inline_elements($matches[2]);
$element = ''.$element_text.'';
}
# ~
$code = "\x1A".'$'.$index;
$text = str_replace($matches[0], $code, $text);
$map[$code] = $element;
$index ++;
}
}
}
# Inline Link / Image
if (strpos($text, '](') !== FALSE and preg_match_all('/(!?)(\[((?:[^][]+|(?2))*)\])\((.*?)\)/', $text, $matches, PREG_SET_ORDER)) # inline
{
foreach ($matches as $matches)
{
if ($matches[1]) # image
{
$element = '!['.$matches[3].']('.$matches[4].')
';
}
else
{
$element_text = $this->parse_inline_elements($matches[3]);
$element = ''.$element_text.'';
}
$element_text = $this->parse_inline_elements($matches[1]);
# ~
$code = "\x1A".'$'.$index;
$text = str_replace($matches[0], $code, $text);
$map[$code] = $element;
$index ++;
}
}
if (strpos($text, '<') !== FALSE and preg_match_all('/<((https?|ftp|dict):[^\^\s]+?)>/i', $text, $matches, PREG_SET_ORDER))
{
foreach ($matches as $matches)
{
$element = ':text';
$element = str_replace(':text', $matches[1], $element);
$element = str_replace(':href', $matches[1], $element);
# ~
$code = "\x1A".'$'.$index;
$text = str_replace($matches[0], $code, $text);
$map[$code] = $element;
$index ++;
}
}
if (strpos($text, '_') !== FALSE)
{
$text = preg_replace('/__(?=\S)(.+?)(?<=\S)__/', '$1', $text);
$text = preg_replace('/_(?=\S)(.+?)(?<=\S)_/', '$1', $text);
}
if (strpos($text, '*') !== FALSE)
{
$text = preg_replace('/\*\*(?=\S)(.+?)(?<=\S)\*\*/', '$1', $text);
$text = preg_replace('/\*(?=\S)(.+?)(?<=\S)\*/', '$1', $text);
}
$text = strtr($text, $map);
return $text;
}
}