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<?php
/**
* This file is part of CodeIgniter 4 framework.
*
* (c) CodeIgniter Foundation <admin@codeigniter.com>
*
* For the full copyright and license information, please view
* the LICENSE file that was distributed with this source code.
*/
namespace CodeIgniter\Typography;
/**
* Typography Class
*/
class Typography
{
/**
* Block level elements that should not be wrapped inside <p> tags
*
* @var string
*/
public $blockElements = 'address|blockquote|div|dl|fieldset|form|h\d|hr|noscript|object|ol|p|pre|script|table|ul';
/**
* Elements that should not have <p> and <br /> tags within them.
*
* @var string
*/
public $skipElements = 'p|pre|ol|ul|dl|object|table|h\d';
/**
* Tags we want the parser to completely ignore when splitting the string.
*
* @var string
*/
public $inlineElements = 'a|abbr|acronym|b|bdo|big|br|button|cite|code|del|dfn|em|i|img|ins|input|label|map|kbd|q|samp|select|small|span|strong|sub|sup|textarea|tt|var';
/**
* array of block level elements that require inner content to be within another block level element
*
* @var array
*/
public $innerBlockRequired = ['blockquote'];
/**
* the last block element parsed
*
* @var string
*/
public $lastBlockElement = '';
/**
* whether or not to protect quotes within { curly braces }
*
* @var bool
*/
public $protectBracedQuotes = false;
/**
* Auto Typography
*
* This function converts text, making it typographically correct:
* - Converts double spaces into paragraphs.
* - Converts single line breaks into <br /> tags
* - Converts single and double quotes into correctly facing curly quote entities.
* - Converts three dots into ellipsis.
* - Converts double dashes into em-dashes.
* - Converts two spaces into entities
*
* @param bool $reduceLinebreaks whether to reduce more then two consecutive newlines to two
*/
public function autoTypography(string $str, bool $reduceLinebreaks = false): string
{
if ($str === '') {
return '';
}
// Standardize Newlines to make matching easier
if (strpos($str, "\r") !== false) {
$str = str_replace(["\r\n", "\r"], "\n", $str);
}
// Reduce line breaks. If there are more than two consecutive linebreaks
// we'll compress them down to a maximum of two since there's no benefit to more.
if ($reduceLinebreaks === false) {
$str = preg_replace("/\n\n+/", "\n\n", $str);
}
// HTML comment tags don't conform to patterns of normal tags, so pull them out separately, only if needed
$htmlComments = [];
if (strpos($str, '<!--') !== false && preg_match_all('#(<!\-\-.*?\-\->)#s', $str, $matches)) {
for ($i = 0, $total = count($matches[0]); $i < $total; $i++) {
$htmlComments[] = $matches[0][$i];
$str = str_replace($matches[0][$i], '{@HC' . $i . '}', $str);
}
}
// match and yank <pre> tags if they exist. It's cheaper to do this separately since most content will
// not contain <pre> tags, and it keeps the PCRE patterns below simpler and faster
if (strpos($str, '<pre') !== false) {
$str = preg_replace_callback('#<pre.*?>.*?</pre>#si', [$this, 'protectCharacters'], $str);
}
// Convert quotes within tags to temporary markers.
$str = preg_replace_callback('#<.+?>#si', [$this, 'protectCharacters'], $str);
// Do the same with braces if necessary
if ($this->protectBracedQuotes === false) {
$str = preg_replace_callback('#\{.+?\}#si', [$this, 'protectCharacters'], $str);
}
// Convert "ignore" tags to temporary marker. The parser splits out the string at every tag
// it encounters. Certain inline tags, like image tags, links, span tags, etc. will be
// adversely affected if they are split out so we'll convert the opening bracket < temporarily to: {@TAG}
$str = preg_replace('#<(/*)(' . $this->inlineElements . ')([ >])#i', '{@TAG}\\1\\2\\3', $str);
/* Split the string at every tag. This expression creates an array with this prototype:
*
* [array]
* {
* [0] = <opening tag>
* [1] = Content...
* [2] = <closing tag>
* Etc...
* }
*/
$chunks = preg_split('/(<(?:[^<>]+(?:"[^"]*"|\'[^\']*\')?)+>)/', $str, -1, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);
// Build our finalized string. We cycle through the array, skipping tags, and processing the contained text
$str = '';
$process = true;
for ($i = 0, $c = count($chunks) - 1; $i <= $c; $i++) {
// Are we dealing with a tag? If so, we'll skip the processing for this cycle.
// Well also set the "process" flag which allows us to skip <pre> tags and a few other things.
if (preg_match('#<(/*)(' . $this->blockElements . ').*?>#', $chunks[$i], $match)) {
if (preg_match('#' . $this->skipElements . '#', $match[2])) {
$process = ($match[1] === '/');
}
if ($match[1] === '') {
$this->lastBlockElement = $match[2];
}
$str .= $chunks[$i];
continue;
}
if ($process === false) {
$str .= $chunks[$i];
continue;
}
// Force a newline to make sure end tags get processed by _format_newlines()
if ($i === $c) {
$chunks[$i] .= "\n";
}
// Convert Newlines into <p> and <br /> tags
$str .= $this->formatNewLines($chunks[$i]);
}
// No opening block level tag? Add it if needed.
if (! preg_match('/^\s*<(?:' . $this->blockElements . ')/i', $str)) {
$str = preg_replace('/^(.*?)<(' . $this->blockElements . ')/i', '<p>$1</p><$2', $str);
}
// Convert quotes, elipsis, em-dashes, non-breaking spaces, and ampersands
$str = $this->formatCharacters($str);
foreach ($htmlComments as $i => $htmlComment) {
// remove surrounding paragraph tags, but only if there's an opening paragraph tag
// otherwise HTML comments at the ends of paragraphs will have the closing tag removed
// if '<p>{@HC1}' then replace <p>{@HC1}</p> with the comment, else replace only {@HC1} with the comment
$str = preg_replace('#(?(?=<p>\{@HC' . $i . '\})<p>\{@HC' . $i . '\}(\s*</p>)|\{@HC' . $i . '\})#s', $htmlComment, $str);
}
// Final clean up
$table = [
// If the user submitted their own paragraph tags within the text
// we will retain them instead of using our tags.
'/(<p[^>*?]>)<p>/' => '$1', // <?php BBEdit syntax coloring bug fix
// Reduce multiple instances of opening/closing paragraph tags to a single one
'#(</p>)+#' => '</p>',
'/(<p>\W*<p>)+/' => '<p>',
// Clean up stray paragraph tags that appear before block level elements
'#<p></p><(' . $this->blockElements . ')#' => '<$1',
// Clean up stray non-breaking spaces preceeding block elements
'#( \s*)+<(' . $this->blockElements . ')#' => ' <$2',
// Replace the temporary markers we added earlier
'/\{@TAG\}/' => '<',
'/\{@DQ\}/' => '"',
'/\{@SQ\}/' => "'",
'/\{@DD\}/' => '--',
'/\{@NBS\}/' => ' ',
// An unintended consequence of the _format_newlines function is that
// some of the newlines get truncated, resulting in <p> tags
// starting immediately after <block> tags on the same line.
// This forces a newline after such occurrences, which looks much nicer.
"/><p>\n/" => ">\n<p>",
// Similarly, there might be cases where a closing </block> will follow
// a closing </p> tag, so we'll correct it by adding a newline in between
'#</p></#' => "</p>\n</",
];
// Do we need to reduce empty lines?
if ($reduceLinebreaks === true) {
$table['#<p>\n*</p>#'] = '';
} else {
// If we have empty paragraph tags we add a non-breaking space
// otherwise most browsers won't treat them as true paragraphs
$table['#<p></p>#'] = '<p> </p>';
}
return preg_replace(array_keys($table), $table, $str);
}
/**
* Format Characters
*
* This function mainly converts double and single quotes
* to curly entities, but it also converts em-dashes,
* double spaces, and ampersands
*/
public function formatCharacters(string $str): string
{
static $table;
if (! isset($table)) {
$table = [
// nested smart quotes, opening and closing
// note that rules for grammar (English) allow only for two levels deep
// and that single quotes are _supposed_ to always be on the outside
// but we'll accommodate both
// Note that in all cases, whitespace is the primary determining factor
// on which direction to curl, with non-word characters like punctuation
// being a secondary factor only after whitespace is addressed.
'/\'"(\s|$)/' => '’”$1',
'/(^|\s|<p>)\'"/' => '$1‘“',
'/\'"(\W)/' => '’”$1',
'/(\W)\'"/' => '$1‘“',
'/"\'(\s|$)/' => '”’$1',
'/(^|\s|<p>)"\'/' => '$1“‘',
'/"\'(\W)/' => '”’$1',
'/(\W)"\'/' => '$1“‘',
// single quote smart quotes
'/\'(\s|$)/' => '’$1',
'/(^|\s|<p>)\'/' => '$1‘',
'/\'(\W)/' => '’$1',
'/(\W)\'/' => '$1‘',
// double quote smart quotes
'/"(\s|$)/' => '”$1',
'/(^|\s|<p>)"/' => '$1“',
'/"(\W)/' => '”$1',
'/(\W)"/' => '$1“',
// apostrophes
'/(\w)\'(\w)/' => '$1’$2',
// Em dash and ellipses dots
'/\s?\-\-\s?/' => '—',
'/(\w)\.{3}/' => '$1…',
// double space after sentences
'/(\W) /' => '$1 ',
// ampersands, if not a character entity
'/&(?!#?[a-zA-Z0-9]{2,};)/' => '&',
];
}
return preg_replace(array_keys($table), $table, $str);
}
/**
* Format Newlines
*
* Converts newline characters into either <p> tags or <br />
*/
protected function formatNewLines(string $str): string
{
if ($str === '' || (strpos($str, "\n") === false && ! in_array($this->lastBlockElement, $this->innerBlockRequired, true))) {
return $str;
}
// Convert two consecutive newlines to paragraphs
$str = str_replace("\n\n", "</p>\n\n<p>", $str);
// Convert single spaces to <br /> tags
$str = preg_replace("/([^\n])(\n)([^\n])/", '\\1<br />\\2\\3', $str);
// Wrap the whole enchilada in enclosing paragraphs
if ($str !== "\n") {
// We trim off the right-side new line so that the closing </p> tag
// will be positioned immediately following the string, matching
// the behavior of the opening <p> tag
$str = '<p>' . rtrim($str) . '</p>';
}
// Remove empty paragraphs if they are on the first line, as this
// is a potential unintended consequence of the previous code
return preg_replace('/<p><\/p>(.*)/', '\\1', $str, 1);
}
/**
* Protect Characters
*
* Protects special characters from being formatted later
* We don't want quotes converted within tags so we'll temporarily convert them to {@DQ} and {@SQ}
* and we don't want double dashes converted to emdash entities, so they are marked with {@DD}
* likewise double spaces are converted to {@NBS} to prevent entity conversion
*/
protected function protectCharacters(array $match): string
{
return str_replace(["'", '"', '--', ' '], ['{@SQ}', '{@DQ}', '{@DD}', '{@NBS}'], $match[0]);
}
/**
* Convert newlines to HTML line breaks except within PRE tags
*/
public function nl2brExceptPre(string $str): string
{
$newstr = '';
for ($ex = explode('pre>', $str), $ct = count($ex), $i = 0; $i < $ct; $i++) {
$newstr .= (($i % 2) === 0) ? nl2br($ex[$i]) : $ex[$i];
if ($ct - 1 !== $i) {
$newstr .= 'pre>';
}
}
return $newstr;
}
}
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