', '\#', '\+', '\-', '\.', '\!');
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 = $this->parse_blocks($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 $text;
}
#
# Private Methods
#
private function parse_blocks($text)
{
$text = trim($text, "\n");
# Divides text into blocks.
$blocks = preg_split('/\n\s*\n/', $text);
# Makes sure compound blocks get rendered.
$blocks []= NULL;
$markup = '';
# Parses blocks.
foreach ($blocks as $block)
{
if (isset($block) and $block[0] >= 'A')
{
$quick_block = $block;
unset($block);
}
# List
if (isset($block) and preg_match('/^([ ]{0,3})(\d+[.]|[*+-])[ ]/', $block, $matches)) # list item
{
if (isset($list)) # subsequent
{
$list .= "\n\n".$block;
}
else # first
{
$list = $block;
$list_indentation = strlen($matches[1]);
list($list_type, $list_marker_pattern) = ($matches[2] === '-' or $matches[2] === '+' or $matches[2] === '*')
? array('ul', '[*+-]')
: array('ol', '\d+[.]');
}
unset($block);
}
elseif (isset($block) and isset($list) and $block[0] === ' ') # list item block
{
$list .= "\n\n".$block;
unset($block);
}
elseif (isset($list))
{
$markup .= '<'.$list_type.'>'."\n";
$list_items = preg_split('/^([ ]{'.$list_indentation.'})'.$list_marker_pattern.'[ ]/m', $list, -1, PREG_SPLIT_NO_EMPTY);
foreach ($list_items as $list_item)
{
$markup .= '';
if (strpos($list_item, "\n\n")) # sparse
{
$list_item = trim($list_item, "\n");
if (strpos($list_item, "\n\n"))
{
$list_item = preg_replace('/^[ ]{0,4}/m', '', $list_item);
$list_item = $this->parse_blocks($list_item);
}
else
{
$list_item = $this->parse_lines($list_item, TRUE);
}
$markup .= "\n".$list_item;
}
else # dense
{
$list_item = trim($list_item, "\n");
$list_item = strpos($list_item, "\n")
? $this->parse_lines($list_item)
: $this->parse_inline_elements($list_item);
$markup .= $list_item;
}
$markup .= ''."\n";
}
$markup .= ''."\n";
unset($list);
}
# Code Block
if (isset($block) and strlen($block) > 4 and $block[0] === ' ' and $block[1] === ' ' and $block[2] === ' ' and $block[3] === ' ')
{
if (isset($code_block))
{
$code_block .= "\n\n".$block;
}
else
{
$code_block = $block;
}
unset($block);
}
elseif (isset($code_block))
{
$code_block_text = preg_replace('/^[ ]{4}/m', '', $code_block);
$code_block_text = htmlentities($code_block_text, 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($code_block);
}
# Atx Heading
if (isset($block) and $block[0] === '#' and preg_match('/^(#{1,6})[ ]*(.+?)[ ]*#*$/', $block, $matches))
{
$level = strlen($matches[1]);
$heading = $this->parse_inline_elements($matches[2]);
$markup .= ''.$heading.''."\n";
continue;
}
# Quote Block
if (isset($block) and preg_match('/^[ ]{0,3}>/', $block))
{
$block = preg_replace('/^[ ]{0,3}>[ ]?/m', '', $block);
$block = $this->parse_blocks($block);
$markup .= ''."\n".$block.'
'."\n";
continue;
}
# Horizontal Line
if (isset($block) and preg_match('/^[ ]{0,3}([-*_])([ ]{0,2}\1){2,}$/', $block))
{
$markup .= '
'."\n";
continue;
}
# ~
if (isset($quick_block))
{
$block = $quick_block;
unset ($quick_block);
}
#
# Paragraph
if (isset($block))
{
if (strpos($block, "\n"))
{
$markup .= $this->parse_lines($block, TRUE);
}
else
{
$element_text = $this->parse_inline_elements($block);
$element = ''.$element_text.'
'."\n";
$markup .= $element;
}
}
}
return $markup;
}
private function parse_lines($text, $paragraph_based = FALSE)
{
$text = trim($text, "\n");
$lines = explode("\n", $text);
$lines []= NULL;
$markup = '';
foreach ($lines as $line)
{
if (isset($line) and $line === '')
{
unset($line);
}
# Paragraph
if (isset($line) and $line[0] >= 'A')
{
$quick_line = $line;
unset($line);
}
# List
if (isset($line) and preg_match('/^([ ]*)(\d+[.]|[*+-])[ ](.*)/', $line, $matches)) # list item
{
$list_item_indentation = strlen($matches[1]);
$list_item_type = ($matches[2] === '-' or $matches[2] === '+' or $matches[2] === '*')
? 'ul'
: 'ol';
if (isset($list)) # subsequent
{
if ($list_item_indentation === $list_indentation and $list_item_type === $list_type)
{
# Adds last list item to the list.
$list []= $list_item;
# Creates a separate list item.
$list_item = $matches[3];
}
else
{
# Adds line to the current list item.
$list_item .= "\n".$line;
}
}
else # first
{
$list = array();
$list_indentation = $list_item_indentation;
$list_type = $list_item_type;
$list_item = $matches[3];
}
unset($line);
}
else
{
if (isset($list))
{
$list []= $list_item;
$markup .= '<'.$list_type.'>'."\n";
foreach ($list as $list_item)
{
$list_item_text = strpos($list_item, "\n")
? $this->parse_lines($list_item)
: $this->parse_inline_elements($list_item);
$markup .= ''.$list_item_text.''."\n";
}
$markup .= ''."\n";
unset($list);
}
}
# Quote Block
if (isset($line) and preg_match('/^[ ]*>[ ]?(.*)/', $line, $matches))
{
if (isset($quote))
{
$quote .= "\n".$matches[1];
}
else
{
$quote = $matches[1];
}
unset($line);
}
else
{
if (isset($quote))
{
$quote = $this->parse_blocks($quote);
$markup .= ''."\n".$quote.'
'."\n";
unset($quote);
}
}
# Atx Heading
if (isset($atx_heading))
{
$markup .= ''.$atx_heading.''."\n";
unset($atx_heading);
}
if (isset($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($line);
}
# Setext Heading
if (isset($line) and isset($paragraph))
{
$setext_characters = array('=', '-');
foreach ($setext_characters as $index => $setext_character)
{
if ($line[0] === $setext_character and preg_match('/^['.$setext_character.']+[ ]*$/', $line))
{
$setext_heading_level = $index + 1;
$setext_heading_text = $this->parse_inline_elements($paragraph);
$markup .= ''.$setext_heading_text.''."\n";
unset($paragraph, $line);
continue 2;
}
}
}
# Paragraph
if (isset($quick_line))
{
$line = $quick_line;
unset($quick_line);
}
if (isset($line))
{
substr($line, -2) === ' '
and $line = substr($line, 0, -2)
and $line .= '
';
if (isset($paragraph))
{
$paragraph .= "\n".$line;
}
else
{
$paragraph = $line;
}
}
else
{
if (isset($paragraph))
{
$paragraph_text = $this->parse_inline_elements($paragraph);
$markup .= $markup === '' && $paragraph_based === FALSE
? $paragraph_text
: ''.$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('/(!?)\[(.+?)\](?:[ ]?\[(.*?)\])?/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 or strpos($text, '_') !== FALSE)
{
$text = preg_replace('/(\*\*|__)(.+?[*_]*)(?<=\S)\1/', '$2', $text);
$text = preg_replace('/(\*|_)(.+?)(?<=\S)\1/', '$2', $text);
}
$text = strtr($text, $map);
return $text;
}
}