Your IP : 216.73.216.95
<?php
namespace Box\Spout\Common\Helper\Escaper;
/**
* Class XLSX
* Provides functions to escape and unescape data for XLSX files
*/
class XLSX implements EscaperInterface
{
/** @var bool Whether the escaper has already been initialized */
private $isAlreadyInitialized = false;
/** @var string Regex pattern to detect control characters that need to be escaped */
private $escapableControlCharactersPattern;
/** @var string[] Map containing control characters to be escaped (key) and their escaped value (value) */
private $controlCharactersEscapingMap;
/** @var string[] Map containing control characters to be escaped (value) and their escaped value (key) */
private $controlCharactersEscapingReverseMap;
/**
* Initializes the control characters if not already done
*/
protected function initIfNeeded()
{
if (!$this->isAlreadyInitialized) {
$this->escapableControlCharactersPattern = $this->getEscapableControlCharactersPattern();
$this->controlCharactersEscapingMap = $this->getControlCharactersEscapingMap();
$this->controlCharactersEscapingReverseMap = array_flip($this->controlCharactersEscapingMap);
$this->isAlreadyInitialized = true;
}
}
/**
* Escapes the given string to make it compatible with XLSX
*
* @param string $string The string to escape
* @return string The escaped string
*/
public function escape($string)
{
$this->initIfNeeded();
$escapedString = $this->escapeControlCharacters($string);
// @NOTE: Using ENT_QUOTES as XML entities ('<', '>', '&') as well as
// single/double quotes (for XML attributes) need to be encoded.
$escapedString = htmlspecialchars($escapedString, ENT_QUOTES, 'UTF-8');
return $escapedString;
}
/**
* Unescapes the given string to make it compatible with XLSX
*
* @param string $string The string to unescape
* @return string The unescaped string
*/
public function unescape($string)
{
$this->initIfNeeded();
// ==============
// = WARNING =
// ==============
// It is assumed that the given string has already had its XML entities decoded.
// This is true if the string is coming from a DOMNode (as DOMNode already decode XML entities on creation).
// Therefore there is no need to call "htmlspecialchars_decode()".
$unescapedString = $this->unescapeControlCharacters($string);
return $unescapedString;
}
/**
* @return string Regex pattern containing all escapable control characters
*/
protected function getEscapableControlCharactersPattern()
{
// control characters values are from 0 to 1F (hex values) in the ASCII table
// some characters should not be escaped though: "\t", "\r" and "\n".
return '[\x00-\x08' .
// skipping "\t" (0x9) and "\n" (0xA)
'\x0B-\x0C' .
// skipping "\r" (0xD)
'\x0E-\x1F]';
}
/**
* Builds the map containing control characters to be escaped
* mapped to their escaped values.
* "\t", "\r" and "\n" don't need to be escaped.
*
* NOTE: the logic has been adapted from the XlsxWriter library (BSD License)
* @see https://github.com/jmcnamara/XlsxWriter/blob/f1e610f29/xlsxwriter/sharedstrings.py#L89
*
* @return string[]
*/
protected function getControlCharactersEscapingMap()
{
$controlCharactersEscapingMap = [];
// control characters values are from 0 to 1F (hex values) in the ASCII table
for ($charValue = 0x00; $charValue <= 0x1F; $charValue++) {
$character = chr($charValue);
if (preg_match("/{$this->escapableControlCharactersPattern}/", $character)) {
$charHexValue = dechex($charValue);
$escapedChar = '_x' . sprintf('%04s', strtoupper($charHexValue)) . '_';
$controlCharactersEscapingMap[$escapedChar] = $character;
}
}
return $controlCharactersEscapingMap;
}
/**
* Converts PHP control characters from the given string to OpenXML escaped control characters
*
* Excel escapes control characters with _xHHHH_ and also escapes any
* literal strings of that type by encoding the leading underscore.
* So "\0" -> _x0000_ and "_x0000_" -> _x005F_x0000_.
*
* NOTE: the logic has been adapted from the XlsxWriter library (BSD License)
* @see https://github.com/jmcnamara/XlsxWriter/blob/f1e610f29/xlsxwriter/sharedstrings.py#L89
*
* @param string $string String to escape
* @return string
*/
protected function escapeControlCharacters($string)
{
$escapedString = $this->escapeEscapeCharacter($string);
// if no control characters
if (!preg_match("/{$this->escapableControlCharactersPattern}/", $escapedString)) {
return $escapedString;
}
return preg_replace_callback("/({$this->escapableControlCharactersPattern})/", function ($matches) {
return $this->controlCharactersEscapingReverseMap[$matches[0]];
}, $escapedString);
}
/**
* Escapes the escape character: "_x0000_" -> "_x005F_x0000_"
*
* @param string $string String to escape
* @return string The escaped string
*/
protected function escapeEscapeCharacter($string)
{
return preg_replace('/_(x[\dA-F]{4})_/', '_x005F_$1_', $string);
}
/**
* Converts OpenXML escaped control characters from the given string to PHP control characters
*
* Excel escapes control characters with _xHHHH_ and also escapes any
* literal strings of that type by encoding the leading underscore.
* So "_x0000_" -> "\0" and "_x005F_x0000_" -> "_x0000_"
*
* NOTE: the logic has been adapted from the XlsxWriter library (BSD License)
* @see https://github.com/jmcnamara/XlsxWriter/blob/f1e610f29/xlsxwriter/sharedstrings.py#L89
*
* @param string $string String to unescape
* @return string
*/
protected function unescapeControlCharacters($string)
{
$unescapedString = $string;
foreach ($this->controlCharactersEscapingMap as $escapedCharValue => $charValue) {
// only unescape characters that don't contain the escaped escape character for now
$unescapedString = preg_replace("/(?<!_x005F)($escapedCharValue)/", $charValue, $unescapedString);
}
return $this->unescapeEscapeCharacter($unescapedString);
}
/**
* Unecapes the escape character: "_x005F_x0000_" => "_x0000_"
*
* @param string $string String to unescape
* @return string The unescaped string
*/
protected function unescapeEscapeCharacter($string)
{
return preg_replace('/_x005F(_x[\dA-F]{4}_)/', '$1', $string);
}
}