Viewing file:  Delimiter.php (4.5 KB) -rw-r--r--
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<?php
namespace PhpOffice\PhpSpreadsheet\Reader\Csv;
class Delimiter
{
protected const POTENTIAL_DELIMETERS = [',', ';', "\t", '|', ':', ' ', '~'];
/** @var resource */
protected $fileHandle;
/** @var string */
protected $escapeCharacter;
/** @var string */
protected $enclosure;
/** @var array */
protected $counts = [];
/** @var int */
protected $numberLines = 0;
/** @var ?string */
protected $delimiter;
/**
* @param resource $fileHandle
*/
public function __construct($fileHandle, string $escapeCharacter, string $enclosure)
{
$this->fileHandle = $fileHandle;
$this->escapeCharacter = $escapeCharacter;
$this->enclosure = $enclosure;
$this->countPotentialDelimiters();
}
public function getDefaultDelimiter(): string
{
return self::POTENTIAL_DELIMETERS[0];
}
public function linesCounted(): int
{
return $this->numberLines;
}
protected function countPotentialDelimiters(): void
{
$this->counts = array_fill_keys(self::POTENTIAL_DELIMETERS, []);
$delimiterKeys = array_flip(self::POTENTIAL_DELIMETERS);
// Count how many times each of the potential delimiters appears in each line
$this->numberLines = 0;
while (($line = $this->getNextLine()) !== false && (++$this->numberLines < 1000)) {
$this->countDelimiterValues($line, $delimiterKeys);
}
}
protected function countDelimiterValues(string $line, array $delimiterKeys): void
{
$splitString = str_split($line, 1);
if (is_array($splitString)) {
$distribution = array_count_values($splitString);
$countLine = array_intersect_key($distribution, $delimiterKeys);
foreach (self::POTENTIAL_DELIMETERS as $delimiter) {
$this->counts[$delimiter][] = $countLine[$delimiter] ?? 0;
}
}
}
public function infer(): ?string
{
// Calculate the mean square deviations for each delimiter
// (ignoring delimiters that haven't been found consistently)
$meanSquareDeviations = [];
$middleIdx = floor(($this->numberLines - 1) / 2);
foreach (self::POTENTIAL_DELIMETERS as $delimiter) {
$series = $this->counts[$delimiter];
sort($series);
$median = ($this->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 (self::POTENTIAL_DELIMETERS as $delimiter) {
if (!isset($meanSquareDeviations[$delimiter])) {
continue;
}
if ($meanSquareDeviations[$delimiter] < $min) {
$min = $meanSquareDeviations[$delimiter];
$this->delimiter = $delimiter;
}
}
return $this->delimiter;
}
/**
* Get the next full line from the file.
*
* @return false|string
*/
public 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 = (string) 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 !== '') ? $line : false;
}
}
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