fluentform / app / Services / Spout / Common / Helper / EncodingHelper.php

EncodingHelper.php in Fluent Forms – Customizable Contact Forms, Survey, Quiz, & Conversational Form Builder 6.2.9, at app/Services/Spout/Common/Helper/EncodingHelper.php

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1	<?php
2
3	namespace Box\Spout\Common\Helper;
4
5	use Box\Spout\Common\Exception\EncodingConversionException;
6
7	/**
8	* Class EncodingHelper
9	* This class provides helper functions to work with encodings.
10	*
11	* @package Box\Spout\Common\Helper
12	*/
13	class EncodingHelper
14	{
15	/** Definition of the encodings that can have a BOM */
16	const ENCODING_UTF8 = 'UTF-8';
17	const ENCODING_UTF16_LE = 'UTF-16LE';
18	const ENCODING_UTF16_BE = 'UTF-16BE';
19	const ENCODING_UTF32_LE = 'UTF-32LE';
20	const ENCODING_UTF32_BE = 'UTF-32BE';
21
22	/** Definition of the BOMs for the different encodings */
23	const BOM_UTF8 = "\xEF\xBB\xBF";
24	const BOM_UTF16_LE = "\xFF\xFE";
25	const BOM_UTF16_BE = "\xFE\xFF";
26	const BOM_UTF32_LE = "\xFF\xFE\x00\x00";
27	const BOM_UTF32_BE = "\x00\x00\xFE\xFF";
28
29	/** @var \Box\Spout\Common\Helper\GlobalFunctionsHelper Helper to work with global functions */
30	protected $globalFunctionsHelper;
31
32	/** @var array Map representing the encodings supporting BOMs (key) and their associated BOM (value) */
33	protected $supportedEncodingsWithBom;
34
35	/**
36	* @param \Box\Spout\Common\Helper\GlobalFunctionsHelper $globalFunctionsHelper
37	*/
38	public function __construct($globalFunctionsHelper)
39	{
40	$this->globalFunctionsHelper = $globalFunctionsHelper;
41
42	$this->supportedEncodingsWithBom = [
43	self::ENCODING_UTF8 => self::BOM_UTF8,
44	self::ENCODING_UTF16_LE => self::BOM_UTF16_LE,
45	self::ENCODING_UTF16_BE => self::BOM_UTF16_BE,
46	self::ENCODING_UTF32_LE => self::BOM_UTF32_LE,
47	self::ENCODING_UTF32_BE => self::BOM_UTF32_BE,
48	];
49	}
50
51	/**
52	* Returns the number of bytes to use as offset in order to skip the BOM.
53	*
54	* @param resource $filePointer Pointer to the file to check
55	* @param string $encoding Encoding of the file to check
56	* @return int Bytes offset to apply to skip the BOM (0 means no BOM)
57	*/
58	public function getBytesOffsetToSkipBOM($filePointer, $encoding)
59	{
60	$byteOffsetToSkipBom = 0;
61
62	if ($this->hasBOM($filePointer, $encoding)) {
63	$bomUsed = $this->supportedEncodingsWithBom[$encoding];
64
65	// we skip the N first bytes
66	$byteOffsetToSkipBom = strlen($bomUsed);
67	}
68
69	return $byteOffsetToSkipBom;
70	}
71
72	/**
73	* Returns whether the file identified by the given pointer has a BOM.
74	*
75	* @param resource $filePointer Pointer to the file to check
76	* @param string $encoding Encoding of the file to check
77	* @return bool TRUE if the file has a BOM, FALSE otherwise
78	*/
79	protected function hasBOM($filePointer, $encoding)
80	{
81	$hasBOM = false;
82
83	$this->globalFunctionsHelper->rewind($filePointer);
84
85	if (array_key_exists($encoding, $this->supportedEncodingsWithBom)) {
86	$potentialBom = $this->supportedEncodingsWithBom[$encoding];
87	$numBytesInBom = strlen($potentialBom);
88
89	$hasBOM = ($this->globalFunctionsHelper->fgets($filePointer, $numBytesInBom + 1) === $potentialBom);
90	}
91
92	return $hasBOM;
93	}
94
95	/**
96	* Attempts to convert a non UTF-8 string into UTF-8.
97	*
98	* @param string $string Non UTF-8 string to be converted
99	* @param string $sourceEncoding The encoding used to encode the source string
100	* @return string The converted, UTF-8 string
101	* @throws \Box\Spout\Common\Exception\EncodingConversionException If conversion is not supported or if the conversion failed
102	*/
103	public function attemptConversionToUTF8($string, $sourceEncoding)
104	{
105	return $this->attemptConversion($string, $sourceEncoding, self::ENCODING_UTF8);
106	}
107
108	/**
109	* Attempts to convert a UTF-8 string into the given encoding.
110	*
111	* @param string $string UTF-8 string to be converted
112	* @param string $targetEncoding The encoding the string should be re-encoded into
113	* @return string The converted string, encoded with the given encoding
114	* @throws \Box\Spout\Common\Exception\EncodingConversionException If conversion is not supported or if the conversion failed
115	*/
116	public function attemptConversionFromUTF8($string, $targetEncoding)
117	{
118	return $this->attemptConversion($string, self::ENCODING_UTF8, $targetEncoding);
119	}
120
121	/**
122	* Attempts to convert the given string to the given encoding.
123	* Depending on what is installed on the server, we will try to iconv or mbstring.
124	*
125	* @param string $string string to be converted
126	* @param string $sourceEncoding The encoding used to encode the source string
127	* @param string $targetEncoding The encoding the string should be re-encoded into
128	* @return string The converted string, encoded with the given encoding
129	* @throws \Box\Spout\Common\Exception\EncodingConversionException If conversion is not supported or if the conversion failed
130	*/
131	protected function attemptConversion($string, $sourceEncoding, $targetEncoding)
132	{
133	// if source and target encodings are the same, it's a no-op
134	if ($sourceEncoding === $targetEncoding) {
135	return $string;
136	}
137
138	$convertedString = null;
139
140	if ($this->canUseIconv()) {
141	$convertedString = $this->globalFunctionsHelper->iconv($string, $sourceEncoding, $targetEncoding);
142	} else if ($this->canUseMbString()) {
143	$convertedString = $this->globalFunctionsHelper->mb_convert_encoding($string, $sourceEncoding, $targetEncoding);
144	} else {
145	throw new EncodingConversionException("The conversion from $sourceEncoding to $targetEncoding is not supported. Please install \"iconv\" or \"PHP Intl\".");
146	}
147
148	if ($convertedString === false) {
149	throw new EncodingConversionException("The conversion from $sourceEncoding to $targetEncoding failed.");
150	}
151
152	return $convertedString;
153	}
154
155	/**
156	* Returns whether "iconv" can be used.
157	*
158	* @return bool TRUE if "iconv" is available and can be used, FALSE otherwise
159	*/
160	protected function canUseIconv()
161	{
162	return $this->globalFunctionsHelper->function_exists('iconv');
163	}
164
165	/**
166	* Returns whether "mb_string" functions can be used.
167	* These functions come with the PHP Intl package.
168	*
169	* @return bool TRUE if "mb_string" functions are available and can be used, FALSE otherwise
170	*/
171	protected function canUseMbString()
172	{
173	return $this->globalFunctionsHelper->function_exists('mb_convert_encoding');
174	}
175	}
176