Proyectos de Subversion Moodle

<?php

namespace PhpOffice\PhpSpreadsheet\Reader\Csv;

class Delimiter

{

    protected const POTENTIAL_DELIMETERS = [',', ';', "\t", '|', ':', ' ', '~'];

    /** @var resource */

    protected $fileHandle;

    protected string $escapeCharacter;

    protected string $enclosure;

    protected array $counts = [];

    protected int $numberLines = 0;

    protected ?string $delimiter = null;

    /**

     * @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

    {

        $splitString = mb_str_split($line, 1, 'UTF-8');

        $distribution = array_count_values($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,

                fn ($sum, $value): int|float => $sum + ($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;

    }

}