<?php
/**
* @package s9e\TextFormatter
* @copyright Copyright (c) 2010-2021 The s9e authors
* @license http://www.opensource.org/licenses/mit-license.php The MIT License
*/
namespace s9e\TextFormatter;
use DOMDocument;
use DOMXPath;
abstract class Utils
{
/**
* Return every value used in given attribute from given tag
*
* Will include duplicate values
*
* @param string $xml Parsed text
* @param string $tagName Target tag's name
* @param string $attrName Target attribute's name
* @return string[] Attribute values
*/
public static function getAttributeValues($xml, $tagName, $attrName)
{
$values = [];
if (strpos($xml, $tagName) !== false)
{
$regexp = '((?<=<)' . preg_quote($tagName) . '(?= )[^>]*? ' . preg_quote($attrName) . '="\\K[^"]*+)';
preg_match_all($regexp, $xml, $matches);
foreach ($matches[0] as $value)
{
$values[] = html_entity_decode($value, ENT_QUOTES, 'UTF-8');
}
}
return $values;
}
/**
* Replace Unicode characters outside the BMP with XML entities
*
* @param string $str Original string
* @return string String with SMP characters encoded
*/
public static function encodeUnicodeSupplementaryCharacters($str)
{
return preg_replace_callback(
'([\\xF0-\\xF4]...)S',
__CLASS__ . '::encodeUnicodeSupplementaryCharactersCallback',
$str
);
}
/**
* Strip the formatting of an intermediate representation and return plain text
*
* This will remove start tags and end tags but will keep the text content of everything else
*
* @param string $xml Intermediate representation
* @return string Plain text
*/
public static function removeFormatting($xml)
{
$dom = self::loadXML($xml);
$xpath = new DOMXPath($dom);
foreach ($xpath->query('//e | //s') as $node)
{
$node->parentNode->removeChild($node);
}
return $dom->documentElement->textContent;
}
/**
* Remove all tags at given nesting level
*
* @param string $xml Intermediate representation
* @param string $tagName Tag's name (case-sensitive)
* @param integer $nestingLevel Minimum nesting level
* @return string Updated intermediate representation
*/
public static function removeTag($xml, $tagName, $nestingLevel = 0)
{
if (strpos($xml, $tagName) === false)
{
return $xml;
}
$dom = self::loadXML($xml);
$xpath = new DOMXPath($dom);
$query = '//' . $tagName . '[count(ancestor::' . $tagName . ') >= ' . $nestingLevel . ']';
$nodes = $xpath->query($query);
foreach ($nodes as $node)
{
$node->parentNode->removeChild($node);
}
return self::saveXML($dom);
}
/**
* Replace the attributes of all tags of given name in given XML
*
* @param string $xml Original XML
* @param string $tagName Target tag's name
* @param callable $callback Callback used to process attributes. Receives the old attributes
* as an array, should return the new attributes as an array
* @return string Modified XML
*/
public static function replaceAttributes($xml, $tagName, callable $callback)
{
if (strpos($xml, $tagName) === false)
{
return $xml;
}
return preg_replace_callback(
'((?<=<)' . preg_quote($tagName) . '(?=[ />])\\K[^>]*+)',
function ($m) use ($callback)
{
$str = self::serializeAttributes($callback(self::parseAttributes($m[0])));
if (substr($m[0], -1) === '/')
{
$str .= '/';
}
return $str;
},
$xml
);
}
/**
* Encode given Unicode character into an XML entity
*
* @param string[] $m Array of captures
* @return string Encoded character
*/
protected static function encodeUnicodeSupplementaryCharactersCallback(array $m)
{
$utf8 = $m[0];
$cp = (ord($utf8[0]) << 18) + (ord($utf8[1]) << 12) + (ord($utf8[2]) << 6) + ord($utf8[3]) - 0x3C82080;
return '&#' . $cp . ';';
}
/**
* Create a return a new DOMDocument loaded with given XML
*
* @param string $xml Source XML
* @return DOMDocument
*/
protected static function loadXML($xml)
{
// Activate small nodes allocation and relax LibXML's hardcoded limits if applicable
$flags = (LIBXML_VERSION >= 20700) ? LIBXML_COMPACT | LIBXML_PARSEHUGE : 0;
$dom = new DOMDocument;
$dom->loadXML($xml, $flags);
return $dom;
}
/**
* Parse the attributes contained in given XML
*
* @param string $xml XML string, normally a start tag
* @return array Associative array of attribute values
*/
protected static function parseAttributes($xml)
{
$attributes = [];
if (strpos($xml, '="') !== false)
{
preg_match_all('(([^ =]++)="([^"]*))', $xml, $matches);
foreach ($matches[1] as $i => $attrName)
{
$attributes[$attrName] = html_entity_decode($matches[2][$i], ENT_QUOTES, 'UTF-8');
}
}
return $attributes;
}
/**
* Serialize given DOMDocument
*
* @param DOMDocument $dom
* @return string
*/
protected static function saveXML(DOMDocument $dom)
{
return self::encodeUnicodeSupplementaryCharacters($dom->saveXML($dom->documentElement));
}
/**
* Serialize an array of attribute values
*
* @param array $attributes Associative array of attribute values
* @return string Attributes, sorted by name and serialized to XML
*/
protected static function serializeAttributes(array $attributes)
{
$xml = '';
ksort($attributes);
foreach ($attributes as $attrName => $attrValue)
{
$xml .= ' ' . htmlspecialchars($attrName, ENT_QUOTES) . '="' . htmlspecialchars($attrValue, ENT_COMPAT) . '"';
}
// Normalize control characters to what the parser would normally produce
$xml = preg_replace('/\\r\\n?/', "\n", $xml);
$xml = preg_replace('/[\\x00-\\x08\\x0B\\x0C\\x0E-\\x1F]+/S', '', $xml);
$xml = str_replace("\n", ' ', $xml);
return self::encodeUnicodeSupplementaryCharacters($xml);
}
}