wpdatatables / lib / phpoffice / phpspreadsheet / src / PhpSpreadsheet / Reader / Csv / Delimiter.php

Delimiter.php in wpDataTables – WordPress Data Table, Dynamic Tables & Table Charts Plugin 6.5.1.7, at lib/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Reader/Csv/Delimiter.php

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1	<?php
2
3	namespace PhpOffice\PhpSpreadsheet\Reader\Csv;
4
5	class Delimiter
6	{
7	protected const POTENTIAL_DELIMETERS = [',', ';', "\t", '\|', ':', ' ', '~'];
8
9	/** @var resource */
10	protected $fileHandle;
11
12	/** @var string */
13	protected $escapeCharacter;
14
15	/** @var string */
16	protected $enclosure;
17
18	/** @var array */
19	protected $counts = [];
20
21	/** @var int */
22	protected $numberLines = 0;
23
24	/** @var ?string */
25	protected $delimiter;
26
27	/**
28	* @param resource $fileHandle
29	*/
30	public function __construct($fileHandle, string $escapeCharacter, string $enclosure)
31	{
32	$this->fileHandle = $fileHandle;
33	$this->escapeCharacter = $escapeCharacter;
34	$this->enclosure = $enclosure;
35
36	$this->countPotentialDelimiters();
37	}
38
39	public function getDefaultDelimiter(): string
40	{
41	return self::POTENTIAL_DELIMETERS[0];
42	}
43
44	public function linesCounted(): int
45	{
46	return $this->numberLines;
47	}
48
49	protected function countPotentialDelimiters(): void
50	{
51	$this->counts = array_fill_keys(self::POTENTIAL_DELIMETERS, []);
52	$delimiterKeys = array_flip(self::POTENTIAL_DELIMETERS);
53
54	// Count how many times each of the potential delimiters appears in each line
55	$this->numberLines = 0;
56	while (($line = $this->getNextLine()) !== false && (++$this->numberLines < 1000)) {
57	$this->countDelimiterValues($line, $delimiterKeys);
58	}
59	}
60
61	protected function countDelimiterValues(string $line, array $delimiterKeys): void
62	{
63	$splitString = str_split($line, 1);
64	if (is_array($splitString)) {
65	$distribution = array_count_values($splitString);
66	$countLine = array_intersect_key($distribution, $delimiterKeys);
67
68	foreach (self::POTENTIAL_DELIMETERS as $delimiter) {
69	$this->counts[$delimiter][] = $countLine[$delimiter] ?? 0;
70	}
71	}
72	}
73
74	public function infer(): ?string
75	{
76	// Calculate the mean square deviations for each delimiter
77	// (ignoring delimiters that haven't been found consistently)
78	$meanSquareDeviations = [];
79	$middleIdx = floor(($this->numberLines - 1) / 2);
80
81	foreach (self::POTENTIAL_DELIMETERS as $delimiter) {
82	$series = $this->counts[$delimiter];
83	sort($series);
84
85	$median = ($this->numberLines % 2)
86	? $series[$middleIdx]
87	: ($series[$middleIdx] + $series[$middleIdx + 1]) / 2;
88
89	if ($median === 0) {
90	continue;
91	}
92
93	$meanSquareDeviations[$delimiter] = array_reduce(
94	$series,
95	function ($sum, $value) use ($median) {
96	return $sum + ($value - $median) ** 2;
97	}
98	) / count($series);
99	}
100
101	// ... and pick the delimiter with the smallest mean square deviation
102	// (in case of ties, the order in potentialDelimiters is respected)
103	$min = INF;
104	foreach (self::POTENTIAL_DELIMETERS as $delimiter) {
105	if (!isset($meanSquareDeviations[$delimiter])) {
106	continue;
107	}
108
109	if ($meanSquareDeviations[$delimiter] < $min) {
110	$min = $meanSquareDeviations[$delimiter];
111	$this->delimiter = $delimiter;
112	}
113	}
114
115	return $this->delimiter;
116	}
117
118	/**
119	* Get the next full line from the file.
120	*
121	* @return false\|string
122	*/
123	public function getNextLine()
124	{
125	$line = '';
126	$enclosure = ($this->escapeCharacter === '' ? ''
127	: ('(?<!' . preg_quote($this->escapeCharacter, '/') . ')'))
128	. preg_quote($this->enclosure, '/');
129
130	do {
131	// Get the next line in the file
132	$newLine = fgets($this->fileHandle);
133
134	// Return false if there is no next line
135	if ($newLine === false) {
136	return false;
137	}
138
139	// Add the new line to the line passed in
140	$line = $line . $newLine;
141
142	// Drop everything that is enclosed to avoid counting false positives in enclosures
143	$line = (string) preg_replace('/(' . $enclosure . '.*' . $enclosure . ')/Us', '', $line);
144
145	// See if we have any enclosures left in the line
146	// if we still have an enclosure then we need to read the next line as well
147	} while (preg_match('/(' . $enclosure . ')/', $line) > 0);
148
149	return ($line !== '') ? $line : false;
150	}
151	}
152