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modules/x13import/tools/Spout/Common/Helper/EncodingHelper.php

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+<?php
+
+namespace Box\Spout\Common\Helper;
+
+use Box\Spout\Common\Exception\EncodingConversionException;
+
+/**
+ * Class EncodingHelper
+ * This class provides helper functions to work with encodings.
+ *
+ * @package Box\Spout\Common\Helper
+ */
+class EncodingHelper
+{
+    /** Definition of the encodings that can have a BOM */
+    const ENCODING_UTF8     = 'UTF-8';
+    const ENCODING_UTF16_LE = 'UTF-16LE';
+    const ENCODING_UTF16_BE = 'UTF-16BE';
+    const ENCODING_UTF32_LE = 'UTF-32LE';
+    const ENCODING_UTF32_BE = 'UTF-32BE';
+
+    /** Definition of the BOMs for the different encodings */
+    const BOM_UTF8     = "\xEF\xBB\xBF";
+    const BOM_UTF16_LE = "\xFF\xFE";
+    const BOM_UTF16_BE = "\xFE\xFF";
+    const BOM_UTF32_LE = "\xFF\xFE\x00\x00";
+    const BOM_UTF32_BE = "\x00\x00\xFE\xFF";
+
+    /** @var \Box\Spout\Common\Helper\GlobalFunctionsHelper Helper to work with global functions */
+    protected $globalFunctionsHelper;
+
+    /** @var array Map representing the encodings supporting BOMs (key) and their associated BOM (value) */
+    protected $supportedEncodingsWithBom;
+
+    /**
+     * @param \Box\Spout\Common\Helper\GlobalFunctionsHelper $globalFunctionsHelper
+     */
+    public function __construct($globalFunctionsHelper)
+    {
+        $this->globalFunctionsHelper = $globalFunctionsHelper;
+
+        $this->supportedEncodingsWithBom = [
+            self::ENCODING_UTF8     => self::BOM_UTF8,
+            self::ENCODING_UTF16_LE => self::BOM_UTF16_LE,
+            self::ENCODING_UTF16_BE => self::BOM_UTF16_BE,
+            self::ENCODING_UTF32_LE => self::BOM_UTF32_LE,
+            self::ENCODING_UTF32_BE => self::BOM_UTF32_BE,
+        ];
+    }
+
+    /**
+     * Returns the number of bytes to use as offset in order to skip the BOM.
+     *
+     * @param resource $filePointer Pointer to the file to check
+     * @param string $encoding Encoding of the file to check
+     * @return int Bytes offset to apply to skip the BOM (0 means no BOM)
+     */
+    public function getBytesOffsetToSkipBOM($filePointer, $encoding)
+    {
+        $byteOffsetToSkipBom = 0;
+
+        if ($this->hasBOM($filePointer, $encoding)) {
+            $bomUsed = $this->supportedEncodingsWithBom[$encoding];
+
+            // we skip the N first bytes
+            $byteOffsetToSkipBom = strlen($bomUsed);
+        }
+
+        return $byteOffsetToSkipBom;
+    }
+
+    /**
+     * Returns whether the file identified by the given pointer has a BOM.
+     *
+     * @param resource $filePointer Pointer to the file to check
+     * @param string $encoding Encoding of the file to check
+     * @return bool TRUE if the file has a BOM, FALSE otherwise
+     */
+    protected function hasBOM($filePointer, $encoding)
+    {
+        $hasBOM = false;
+
+        $this->globalFunctionsHelper->rewind($filePointer);
+
+        if (array_key_exists($encoding, $this->supportedEncodingsWithBom)) {
+            $potentialBom = $this->supportedEncodingsWithBom[$encoding];
+            $numBytesInBom = strlen($potentialBom);
+
+            $hasBOM = ($this->globalFunctionsHelper->fgets($filePointer, $numBytesInBom + 1) === $potentialBom);
+        }
+
+        return $hasBOM;
+    }
+
+    /**
+     * Attempts to convert a non UTF-8 string into UTF-8.
+     *
+     * @param string $string Non UTF-8 string to be converted
+     * @param string $sourceEncoding The encoding used to encode the source string
+     * @return string The converted, UTF-8 string
+     * @throws \Box\Spout\Common\Exception\EncodingConversionException If conversion is not supported or if the conversion failed
+     */
+    public function attemptConversionToUTF8($string, $sourceEncoding)
+    {
+        return $this->attemptConversion($string, $sourceEncoding, self::ENCODING_UTF8);
+    }
+
+    /**
+     * Attempts to convert a UTF-8 string into the given encoding.
+     *
+     * @param string $string UTF-8 string to be converted
+     * @param string $targetEncoding The encoding the string should be re-encoded into
+     * @return string The converted string, encoded with the given encoding
+     * @throws \Box\Spout\Common\Exception\EncodingConversionException If conversion is not supported or if the conversion failed
+     */
+    public function attemptConversionFromUTF8($string, $targetEncoding)
+    {
+        return $this->attemptConversion($string, self::ENCODING_UTF8, $targetEncoding);
+    }
+
+    /**
+     * Attempts to convert the given string to the given encoding.
+     * Depending on what is installed on the server, we will try to iconv or mbstring.
+     *
+     * @param string $string string to be converted
+     * @param string $sourceEncoding The encoding used to encode the source string
+     * @param string $targetEncoding The encoding the string should be re-encoded into
+     * @return string The converted string, encoded with the given encoding
+     * @throws \Box\Spout\Common\Exception\EncodingConversionException If conversion is not supported or if the conversion failed
+     */
+    protected function attemptConversion($string, $sourceEncoding, $targetEncoding)
+    {
+        // if source and target encodings are the same, it's a no-op
+        if ($sourceEncoding === $targetEncoding) {
+            return $string;
+        }
+
+        $convertedString = null;
+
+        if ($this->canUseIconv()) {
+            $convertedString = $this->globalFunctionsHelper->iconv($string, $sourceEncoding, $targetEncoding);
+        } else if ($this->canUseMbString()) {
+            $convertedString = $this->globalFunctionsHelper->mb_convert_encoding($string, $sourceEncoding, $targetEncoding);
+        } else {
+            throw new EncodingConversionException("The conversion from $sourceEncoding to $targetEncoding is not supported. Please install \"iconv\" or \"PHP Intl\".");
+        }
+
+        if ($convertedString === false) {
+            throw new EncodingConversionException("The conversion from $sourceEncoding to $targetEncoding failed.");
+        }
+
+        return $convertedString;
+    }
+
+    /**
+     * Returns whether "iconv" can be used.
+     *
+     * @return bool TRUE if "iconv" is available and can be used, FALSE otherwise
+     */
+    protected function canUseIconv()
+    {
+        return $this->globalFunctionsHelper->function_exists('iconv');
+    }
+
+    /**
+     * Returns whether "mb_string" functions can be used.
+     * These functions come with the PHP Intl package.
+     *
+     * @return bool TRUE if "mb_string" functions are available and can be used, FALSE otherwise
+     */
+    protected function canUseMbString()
+    {
+        return $this->globalFunctionsHelper->function_exists('mb_convert_encoding');
+    }
+}