<?php

namespace PhpOffice\PhpSpreadsheet\Reader;


< use InvalidArgumentException;



> use PhpOffice\PhpSpreadsheet\Calculation\Calculation;
> use PhpOffice\PhpSpreadsheet\Cell\Cell;


use PhpOffice\PhpSpreadsheet\Cell\Coordinate;

> use PhpOffice\PhpSpreadsheet\Reader\Csv\Delimiter;
use PhpOffice\PhpSpreadsheet\Shared\StringHelper;
> use PhpOffice\PhpSpreadsheet\Reader\Exception as ReaderException;


use PhpOffice\PhpSpreadsheet\Spreadsheet;

> use PhpOffice\PhpSpreadsheet\Style\NumberFormat;



class Csv extends BaseReader
{

>     const DEFAULT_FALLBACK_ENCODING = 'CP1252';
    const UTF8_BOM = "\xEF\xBB\xBF";
>     const GUESS_ENCODING = 'guess';


    const UTF8_BOM_LEN = 3;
    const UTF16BE_BOM = "\xfe\xff";
    const UTF16BE_BOM_LEN = 2;
    const UTF16BE_LF = "\x00\x0a";
    const UTF16LE_BOM = "\xff\xfe";
    const UTF16LE_BOM_LEN = 2;
    const UTF16LE_LF = "\x0a\x00";
    const UTF32BE_BOM = "\x00\x00\xfe\xff";
    const UTF32BE_BOM_LEN = 4;
    const UTF32BE_LF = "\x00\x00\x00\x0a";
    const UTF32LE_BOM = "\xff\xfe\x00\x00";
    const UTF32LE_BOM_LEN = 4;
    const UTF32LE_LF = "\x0a\x00\x00\x00";

    /**
     * Input encoding.
     *
     * @var string
     */
    private $inputEncoding = 'UTF-8';

    /**

<      * Delimiter.



>      * Fallback encoding if guess strikes out.


     *
     * @var string
     */

>     private $fallbackEncoding = self::DEFAULT_FALLBACK_ENCODING;
    private $delimiter;
> 

>     /**
    /**
>      * Delimiter.
     * Enclosure.
>      *
     *
>      * @var ?string
     * @var string
>      */


     */
    private $enclosure = '"';

    /**
     * Sheet index to read.
     *
     * @var int
     */
    private $sheetIndex = 0;

    /**
     * Load rows contiguously.
     *
     * @var bool
     */
    private $contiguous = false;

    /**
     * The character that can escape the enclosure.
     *
     * @var string
     */
    private $escapeCharacter = '\\';

    /**

>      * Callback for setting defaults in construction.
     * Create a new CSV Reader instance.
>      *
     */
>      * @var ?callable
    public function __construct()
>      */
    {
>     private static $constructorCallback;
        parent::__construct();
> 
    }
>     /**

>      * Attempt autodetect line endings (deprecated after PHP8.1)?
    /**
>      *
     * Set input encoding.
>      * @var bool
     *
>      */
     * @param string $pValue Input encoding, eg: 'UTF-8'
>     private $testAutodetect = true;
     *
> 
     * @return $this
>     /**
     */
>      * @var bool
    public function setInputEncoding($pValue)
>      */
    {
>     protected $castFormattedNumberToNumeric = false;
        $this->inputEncoding = $pValue;
> 

>     /**
        return $this;
>      * @var bool
    }
>      */

>     protected $preserveNumericFormatting = false;
    /**
> 
     * Get input encoding.
>     /** @var bool */
     *
>     private $preserveNullString = false;
     * @return string
> 
     */
>     /**


    public function getInputEncoding()

>         $callback = self::$constructorCallback;
    {
>         if ($callback !== null) {
        return $this->inputEncoding;
>             $callback($this);
    }
>         }



<      * Set input encoding.



>      * Set a callback to change the defaults.



<      * @param string $pValue Input encoding, eg: 'UTF-8'
<      *
<      * @return $this



>      * The callback must accept the Csv Reader object as the first parameter,
>      * and it should return void.



<     public function setInputEncoding($pValue)



>     public static function setConstructorCallback(?callable $callback): void



<         $this->inputEncoding = $pValue;



>         self::$constructorCallback = $callback;
>     }
> 
>     public static function getConstructorCallback(): ?callable
>     {
>         return self::$constructorCallback;
>     }
> 
>     public function setInputEncoding(string $encoding): self
>     {
>         $this->inputEncoding = $encoding;



<     /**
<      * Get input encoding.
<      *
<      * @return string
<      */
<     public function getInputEncoding()



>     public function getInputEncoding(): string




>     public function setFallbackEncoding(string $fallbackEncoding): self
    /**
>     {
     * Identify any separator that is explicitly set in the file.
>         $this->fallbackEncoding = $fallbackEncoding;
     */
> 
    protected function checkSeparator(): void
>         return $this;
    {
>     }
        $line = fgets($this->fileHandle);
> 
        if ($line === false) {
>     public function getFallbackEncoding(): string
            return;
>     {
        }
>         return $this->fallbackEncoding;

>     }
        if ((strlen(trim($line, "\r\n")) == 5) && (stripos($line, 'sep=') === 0)) {
> 


            $this->delimiter = substr($line, 4, 1);

            return;
        }

        $this->skipBOM();
    }

    /**
     * Infer the separator if it isn't explicitly set in the file or specified by the user.
     */
    protected function inferSeparator(): void
    {
        if ($this->delimiter !== null) {
            return;
        }


<         $potentialDelimiters = [',', ';', "\t", '|', ':', ' ', '~'];
<         $counts = [];
<         foreach ($potentialDelimiters as $delimiter) {
<             $counts[$delimiter] = [];
<         }
< 
<         // Count how many times each of the potential delimiters appears in each line
<         $numberLines = 0;
<         while (($line = $this->getNextLine()) !== false && (++$numberLines < 1000)) {
<             $countLine = [];
<             for ($i = strlen($line) - 1; $i >= 0; --$i) {
<                 $char = $line[$i];
<                 if (isset($counts[$char])) {
<                     if (!isset($countLine[$char])) {
<                         $countLine[$char] = 0;
<                     }
<                     ++$countLine[$char];
<                 }
<             }
<             foreach ($potentialDelimiters as $delimiter) {
<                 $counts[$delimiter][] = $countLine[$delimiter]
<                     ?? 0;
<             }
<         }



>         $inferenceEngine = new Delimiter($this->fileHandle, $this->escapeCharacter, $this->enclosure);



        // If number of lines is 0, nothing to infer : fall back to the default

<         if ($numberLines === 0) {
<             $this->delimiter = reset($potentialDelimiters);



>         if ($inferenceEngine->linesCounted() === 0) {
>             $this->delimiter = $inferenceEngine->getDefaultDelimiter();


            $this->skipBOM();

            return;
        }


<         // Calculate the mean square deviations for each delimiter (ignoring delimiters that haven't been found consistently)
<         $meanSquareDeviations = [];
<         $middleIdx = floor(($numberLines - 1) / 2);
< 
<         foreach ($potentialDelimiters as $delimiter) {
<             $series = $counts[$delimiter];
<             sort($series);
< 
<             $median = ($numberLines % 2)
<                 ? $series[$middleIdx]
<                 : ($series[$middleIdx] + $series[$middleIdx + 1]) / 2;
< 
<             if ($median === 0) {
<                 continue;
<             }
< 
<             $meanSquareDeviations[$delimiter] = array_reduce(
<                 $series,
<                 function ($sum, $value) use ($median) {
<                     return $sum + ($value - $median) ** 2;
<                 }
<             ) / count($series);
<         }
< 
<         // ... and pick the delimiter with the smallest mean square deviation (in case of ties, the order in potentialDelimiters is respected)
<         $min = INF;
<         foreach ($potentialDelimiters as $delimiter) {
<             if (!isset($meanSquareDeviations[$delimiter])) {
<                 continue;
<             }
< 
<             if ($meanSquareDeviations[$delimiter] < $min) {
<                 $min = $meanSquareDeviations[$delimiter];
<                 $this->delimiter = $delimiter;
<             }
<         }



>         $this->delimiter = $inferenceEngine->infer();



        // If no delimiter could be detected, fall back to the default
        if ($this->delimiter === null) {

<             $this->delimiter = reset($potentialDelimiters);



>             $this->delimiter = $inferenceEngine->getDefaultDelimiter();


        }

        $this->skipBOM();
    }

    /**

<      * Get the next full line from the file.
<      *
<      * @return false|string
<      */
<     private function getNextLine()
<     {
<         $line = '';
<         $enclosure = ($this->escapeCharacter === '' ? ''
<             : ('(?<!' . preg_quote($this->escapeCharacter, '/') . ')'))
<             . preg_quote($this->enclosure, '/');
< 
<         do {
<             // Get the next line in the file
<             $newLine = fgets($this->fileHandle);
< 
<             // Return false if there is no next line
<             if ($newLine === false) {
<                 return false;
<             }
< 
<             // Add the new line to the line passed in
<             $line = $line . $newLine;
< 
<             // Drop everything that is enclosed to avoid counting false positives in enclosures
<             $line = preg_replace('/(' . $enclosure . '.*' . $enclosure . ')/Us', '', $line);
< 
<             // See if we have any enclosures left in the line
<             // if we still have an enclosure then we need to read the next line as well
<         } while (preg_match('/(' . $enclosure . ')/', $line) > 0);
< 
<         return $line;
<     }
< 
<     /**


     * Return worksheet info (Name, Last Column Letter, Last Column Index, Total Rows, Total Columns).

<      *
<      * @param string $pFilename
<      *
<      * @return array


     */

<     public function listWorksheetInfo($pFilename)



>     public function listWorksheetInfo(string $filename): array


    {
        // Open file

<         $this->openFileOrMemory($pFilename);



>         $this->openFileOrMemory($filename);


        $fileHandle = $this->fileHandle;

        // Skip BOM, if any
        $this->skipBOM();
        $this->checkSeparator();
        $this->inferSeparator();

        $worksheetInfo = [];
        $worksheetInfo[0]['worksheetName'] = 'Worksheet';
        $worksheetInfo[0]['lastColumnLetter'] = 'A';
        $worksheetInfo[0]['lastColumnIndex'] = 0;
        $worksheetInfo[0]['totalRows'] = 0;
        $worksheetInfo[0]['totalColumns'] = 0;

        // Loop through each line of the file in turn

<         while (($rowData = fgetcsv($fileHandle, 0, $this->delimiter, $this->enclosure, $this->escapeCharacter)) !== false) {



>         $rowData = fgetcsv($fileHandle, 0, $this->delimiter ?? '', $this->enclosure, $this->escapeCharacter);
>         while (is_array($rowData)) {


            ++$worksheetInfo[0]['totalRows'];
            $worksheetInfo[0]['lastColumnIndex'] = max($worksheetInfo[0]['lastColumnIndex'], count($rowData) - 1);

>             $rowData = fgetcsv($fileHandle, 0, $this->delimiter ?? '', $this->enclosure, $this->escapeCharacter);


        }

        $worksheetInfo[0]['lastColumnLetter'] = Coordinate::stringFromColumnIndex($worksheetInfo[0]['lastColumnIndex'] + 1);
        $worksheetInfo[0]['totalColumns'] = $worksheetInfo[0]['lastColumnIndex'] + 1;

        // Close file
        fclose($fileHandle);

        return $worksheetInfo;
    }

    /**
     * Loads Spreadsheet from file.

<      *
<      * @param string $pFilename
<      *
<      * @return Spreadsheet


     */

<     public function load($pFilename)



>     protected function loadSpreadsheetFromFile(string $filename): Spreadsheet


    {
        // Create new Spreadsheet
        $spreadsheet = new Spreadsheet();

        // Load into this instance

<         return $this->loadIntoExisting($pFilename, $spreadsheet);



>         return $this->loadIntoExisting($filename, $spreadsheet);


    }


<     private function openFileOrMemory($pFilename): void



>     /**
>      * Loads Spreadsheet from string.
>      */
>     public function loadSpreadsheetFromString(string $contents): Spreadsheet
>     {
>         // Create new Spreadsheet
>         $spreadsheet = new Spreadsheet();
> 
>         // Load into this instance
>         return $this->loadStringOrFile('data://text/plain,' . urlencode($contents), $spreadsheet, true);
>     }
> 
>     private function openFileOrMemory(string $filename): void


    {
        // Open file

<         $fhandle = $this->canRead($pFilename);



>         $fhandle = $this->canRead($filename);


        if (!$fhandle) {

<             throw new Exception($pFilename . ' is an Invalid Spreadsheet file.');



>             throw new Exception($filename . ' is an Invalid Spreadsheet file.');


        }

<         $this->openFile($pFilename);



>         if ($this->inputEncoding === self::GUESS_ENCODING) {
>             $this->inputEncoding = self::guessEncoding($filename, $this->fallbackEncoding);
>         }
>         $this->openFile($filename);


        if ($this->inputEncoding !== 'UTF-8') {
            fclose($this->fileHandle);

<             $entireFile = file_get_contents($pFilename);
<             $this->fileHandle = fopen('php://memory', 'r+b');



>             $entireFile = file_get_contents($filename);
>             $fileHandle = fopen('php://memory', 'r+b');
>             if ($fileHandle !== false && $entireFile !== false) {
>                 $this->fileHandle = $fileHandle;


            $data = StringHelper::convertEncoding($entireFile, 'UTF-8', $this->inputEncoding);
            fwrite($this->fileHandle, $data);
            $this->skipBOM();
        }
    }

>     }

> 
    /**
>     public function setTestAutoDetect(bool $value): self
     * Loads PhpSpreadsheet from file into PhpSpreadsheet instance.
>     {
     *
>         $this->testAutodetect = $value;
     * @param string $pFilename
> 
     *
>         return $this;
     * @return Spreadsheet
>     }
     */
> 
    public function loadIntoExisting($pFilename, Spreadsheet $spreadsheet)
>     private function setAutoDetect(?string $value): ?string
    {
>     {
        $lineEnding = ini_get('auto_detect_line_endings');
>         $retVal = null;
        ini_set('auto_detect_line_endings', true);
>         if ($value !== null && $this->testAutodetect) {

>             $retVal2 = @ini_set('auto_detect_line_endings', $value);
        // Open file
>             if (is_string($retVal2)) {
        $this->openFileOrMemory($pFilename);
>                 $retVal = $retVal2;
        $fileHandle = $this->fileHandle;
>             }

>         }
        // Skip BOM, if any
> 
        $this->skipBOM();
>         return $retVal;
        $this->checkSeparator();
>     }
        $this->inferSeparator();
> 

>     public function castFormattedNumberToNumeric(
        // Create new PhpSpreadsheet object
>         bool $castFormattedNumberToNumeric,
        while ($spreadsheet->getSheetCount() <= $this->sheetIndex) {
>         bool $preserveNumericFormatting = false
            $spreadsheet->createSheet();
>     ): void {
        }
>         $this->castFormattedNumberToNumeric = $castFormattedNumberToNumeric;
        $sheet = $spreadsheet->setActiveSheetIndex($this->sheetIndex);
>         $this->preserveNumericFormatting = $preserveNumericFormatting;

>     }
        // Set our starting row based on whether we're in contiguous mode or not
> 
        $currentRow = 1;
>     /**
        $outRow = 0;
>      * Open data uri for reading.

>      */
        // Loop through each line of the file in turn
>     private function openDataUri(string $filename): void
        while (($rowData = fgetcsv($fileHandle, 0, $this->delimiter, $this->enclosure, $this->escapeCharacter)) !== false) {
>     {
            $noOutputYet = true;
>         $fileHandle = fopen($filename, 'rb');
            $columnLetter = 'A';
>         if ($fileHandle === false) {
            foreach ($rowData as $rowDatum) {
>             // @codeCoverageIgnoreStart
                if ($rowDatum != '' && $this->readFilter->readCell($columnLetter, $currentRow)) {
>             throw new ReaderException('Could not open file ' . $filename . ' for reading.');
                    if ($this->contiguous) {
>             // @codeCoverageIgnoreEnd
                        if ($noOutputYet) {
>         }
                            $noOutputYet = false;
> 
                            ++$outRow;
>         $this->fileHandle = $fileHandle;
                        }
>     }



<      *
<      * @param string $pFilename
<      *
<      * @return Spreadsheet



<     public function loadIntoExisting($pFilename, Spreadsheet $spreadsheet)



>     public function loadIntoExisting(string $filename, Spreadsheet $spreadsheet): Spreadsheet



<         $lineEnding = ini_get('auto_detect_line_endings');
<         ini_set('auto_detect_line_endings', true);



>         return $this->loadStringOrFile($filename, $spreadsheet, false);
>     }
> 
>     /**
>      * Loads PhpSpreadsheet from file into PhpSpreadsheet instance.
>      */
>     private function loadStringOrFile(string $filename, Spreadsheet $spreadsheet, bool $dataUri): Spreadsheet
>     {
>         // Deprecated in Php8.1
>         $iniset = $this->setAutoDetect('1');



<         $this->openFileOrMemory($pFilename);



>         if ($dataUri) {
>             $this->openDataUri($filename);
>         } else {
>             $this->openFileOrMemory($filename);
>         }



<         while (($rowData = fgetcsv($fileHandle, 0, $this->delimiter, $this->enclosure, $this->escapeCharacter)) !== false) {



>         $rowData = fgetcsv($fileHandle, 0, $this->delimiter ?? '', $this->enclosure, $this->escapeCharacter);
>         $valueBinder = Cell::getValueBinder();
>         $preserveBooleanString = method_exists($valueBinder, 'getBooleanConversion') && $valueBinder->getBooleanConversion();
>         while (is_array($rowData)) {



<                 if ($rowDatum != '' && $this->readFilter->readCell($columnLetter, $currentRow)) {



>                 $this->convertBoolean($rowDatum, $preserveBooleanString);
>                 $numberFormatMask = $this->convertFormattedNumber($rowDatum);
>                 if (($rowDatum !== '' || $this->preserveNullString) && $this->readFilter->readCell($columnLetter, $currentRow)) {




>                     // Set basic styling for the value (Note that this could be overloaded by styling in a value binder)
        // Close file
>                     $sheet->getCell($columnLetter . $outRow)->getStyle()
        fclose($fileHandle);
>                         ->getNumberFormat()

>                         ->setFormatCode($numberFormatMask);


        ini_set('auto_detect_line_endings', $lineEnding);

>             $rowData = fgetcsv($fileHandle, 0, $this->delimiter ?? '', $this->enclosure, $this->escapeCharacter);



<         ini_set('auto_detect_line_endings', $lineEnding);



>         $this->setAutoDetect($iniset);


        // Return
        return $spreadsheet;
    }

    /**

<      * Get delimiter.



>      * Convert string true/false to boolean, and null to null-string.


     *

<      * @return string



>      * @param mixed $rowDatum


     */

<     public function getDelimiter()



>     private function convertBoolean(&$rowDatum, bool $preserveBooleanString): void


    {

<         return $this->delimiter;



>         if (is_string($rowDatum) && !$preserveBooleanString) {
>             if (strcasecmp(Calculation::getTRUE(), $rowDatum) === 0 || strcasecmp('true', $rowDatum) === 0) {
>                 $rowDatum = true;
>             } elseif (strcasecmp(Calculation::getFALSE(), $rowDatum) === 0 || strcasecmp('false', $rowDatum) === 0) {
>                 $rowDatum = false;
>             }
>         } else {
>             $rowDatum = $rowDatum ?? '';
>         }


    }

    /**

<      * Set delimiter.
<      *
<      * @param string $delimiter Delimiter, eg: ','



>      * Convert numeric strings to int or float values.


     *

<      * @return $this



>      * @param mixed $rowDatum


     */

<     public function setDelimiter($delimiter)



>     private function convertFormattedNumber(&$rowDatum): string
>     {
>         $numberFormatMask = NumberFormat::FORMAT_GENERAL;
>         if ($this->castFormattedNumberToNumeric === true && is_string($rowDatum)) {
>             $numeric = str_replace(
>                 [StringHelper::getThousandsSeparator(), StringHelper::getDecimalSeparator()],
>                 ['', '.'],
>                 $rowDatum
>             );
> 
>             if (is_numeric($numeric)) {
>                 $decimalPos = strpos($rowDatum, StringHelper::getDecimalSeparator());
>                 if ($this->preserveNumericFormatting === true) {
>                     $numberFormatMask = (strpos($rowDatum, StringHelper::getThousandsSeparator()) !== false)
>                         ? '#,##0' : '0';
>                     if ($decimalPos !== false) {
>                         $decimals = strlen($rowDatum) - $decimalPos - 1;
>                         $numberFormatMask .= '.' . str_repeat('0', min($decimals, 6));
>                     }
>                 }
> 
>                 $rowDatum = ($decimalPos !== false) ? (float) $numeric : (int) $numeric;
>             }
>         }
> 
>         return $numberFormatMask;
>     }
> 
>     public function getDelimiter(): ?string
>     {
>         return $this->delimiter;
>     }
> 
>     public function setDelimiter(?string $delimiter): self


    {
        $this->delimiter = $delimiter;

        return $this;
    }


<     /**
<      * Get enclosure.
<      *
<      * @return string
<      */
<     public function getEnclosure()



>     public function getEnclosure(): string


    {
        return $this->enclosure;
    }


<     /**
<      * Set enclosure.
<      *
<      * @param string $enclosure Enclosure, defaults to "
<      *
<      * @return $this
<      */
<     public function setEnclosure($enclosure)



>     public function setEnclosure(string $enclosure): self


    {
        if ($enclosure == '') {
            $enclosure = '"';
        }
        $this->enclosure = $enclosure;

        return $this;
    }


<     /**
<      * Get sheet index.
<      *
<      * @return int
<      */
<     public function getSheetIndex()



>     public function getSheetIndex(): int


    {
        return $this->sheetIndex;
    }


<     /**
<      * Set sheet index.
<      *
<      * @param int $pValue Sheet index
<      *
<      * @return $this
<      */
<     public function setSheetIndex($pValue)



>     public function setSheetIndex(int $indexValue): self


    {

<         $this->sheetIndex = $pValue;



>         $this->sheetIndex = $indexValue;



        return $this;
    }


<     /**
<      * Set Contiguous.
<      *
<      * @param bool $contiguous
<      *
<      * @return $this
<      */
<     public function setContiguous($contiguous)



>     public function setContiguous(bool $contiguous): self


    {

<         $this->contiguous = (bool) $contiguous;



>         $this->contiguous = $contiguous;



        return $this;
    }


<     /**
<      * Get Contiguous.
<      *
<      * @return bool
<      */
<     public function getContiguous()



>     public function getContiguous(): bool


    {
        return $this->contiguous;
    }


<     /**
<      * Set escape backslashes.
<      *
<      * @param string $escapeCharacter
<      *
<      * @return $this
<      */
<     public function setEscapeCharacter($escapeCharacter)



>     public function setEscapeCharacter(string $escapeCharacter): self


    {
        $this->escapeCharacter = $escapeCharacter;

        return $this;
    }


<     /**
<      * Get escape backslashes.
<      *
<      * @return string
<      */
<     public function getEscapeCharacter()



>     public function getEscapeCharacter(): string


    {
        return $this->escapeCharacter;
    }

    /**
     * Can the current IReader read the file?

<      *
<      * @param string $pFilename
<      *
<      * @return bool


     */

<     public function canRead($pFilename)



>     public function canRead(string $filename): bool


    {
        // Check if file exists
        try {

<             $this->openFile($pFilename);
<         } catch (InvalidArgumentException $e) {



>             $this->openFile($filename);
>         } catch (ReaderException $e) {


            return false;
        }

        fclose($this->fileHandle);

        // Trust file extension if any

<         $extension = strtolower(pathinfo($pFilename, PATHINFO_EXTENSION));



>         $extension = strtolower(/** @scrutinizer ignore-type */ pathinfo($filename, PATHINFO_EXTENSION));


        if (in_array($extension, ['csv', 'tsv'])) {
            return true;
        }

        // Attempt to guess mimetype

<         $type = mime_content_type($pFilename);



>         $type = mime_content_type($filename);


        $supportedTypes = [
            'application/csv',
            'text/csv',
            'text/plain',
            'inode/x-empty',
        ];

        return in_array($type, $supportedTypes, true);
    }

    private static function guessEncodingTestNoBom(string &$encoding, string &$contents, string $compare, string $setEncoding): void
    {
        if ($encoding === '') {
            $pos = strpos($contents, $compare);
            if ($pos !== false && $pos % strlen($compare) === 0) {
                $encoding = $setEncoding;
            }
        }
    }

    private static function guessEncodingNoBom(string $filename): string
    {
        $encoding = '';
        $contents = file_get_contents($filename);
        self::guessEncodingTestNoBom($encoding, $contents, self::UTF32BE_LF, 'UTF-32BE');
        self::guessEncodingTestNoBom($encoding, $contents, self::UTF32LE_LF, 'UTF-32LE');
        self::guessEncodingTestNoBom($encoding, $contents, self::UTF16BE_LF, 'UTF-16BE');
        self::guessEncodingTestNoBom($encoding, $contents, self::UTF16LE_LF, 'UTF-16LE');
        if ($encoding === '' && preg_match('//u', $contents) === 1) {
            $encoding = 'UTF-8';
        }

        return $encoding;
    }

    private static function guessEncodingTestBom(string &$encoding, string $first4, string $compare, string $setEncoding): void
    {
        if ($encoding === '') {
            if ($compare === substr($first4, 0, strlen($compare))) {
                $encoding = $setEncoding;
            }
        }
    }

    private static function guessEncodingBom(string $filename): string
    {
        $encoding = '';
        $first4 = file_get_contents($filename, false, null, 0, 4);
        if ($first4 !== false) {
            self::guessEncodingTestBom($encoding, $first4, self::UTF8_BOM, 'UTF-8');
            self::guessEncodingTestBom($encoding, $first4, self::UTF16BE_BOM, 'UTF-16BE');
            self::guessEncodingTestBom($encoding, $first4, self::UTF32BE_BOM, 'UTF-32BE');
            self::guessEncodingTestBom($encoding, $first4, self::UTF32LE_BOM, 'UTF-32LE');
            self::guessEncodingTestBom($encoding, $first4, self::UTF16LE_BOM, 'UTF-16LE');
        }

        return $encoding;
    }


<     public static function guessEncoding(string $filename, string $dflt = 'CP1252'): string



>     public static function guessEncoding(string $filename, string $dflt = self::DEFAULT_FALLBACK_ENCODING): string


    {
        $encoding = self::guessEncodingBom($filename);
        if ($encoding === '') {
            $encoding = self::guessEncodingNoBom($filename);
        }

        return ($encoding === '') ? $dflt : $encoding;

>     }
    }
> 
}
>     public function setPreserveNullString(bool $value): self
>     {
>         $this->preserveNullString = $value;
> 
>         return $this;
>     }
> 
>     public function getPreserveNullString(): bool
>     {
>         return $this->preserveNullString;