Csv.php

<?php

class Csv
{
    public static function fromArray($rows, $delimiter = ',')
    {
        if (empty($rows)) {
            return '';
        }

        // Limit CSV to 32 MB in memory
        $handle = fopen('php://temp/maxmemory:'. (32*1024*1024), 'r+');

        // Write Byte Order Mark for UTF-8
        fputs($handle, chr(0xEF) . chr(0xBB) . chr(0xBF));

        $headers = array_keys(array_values($rows)[0]);
        fputcsv($handle, $headers, $delimiter);

        foreach ($rows as $row) {
            fputcsv($handle, array_values($row), $delimiter);
        }

        rewind($handle);

        return stream_get_contents($handle);
    }

    public static function toArray($csvString, $delimiter = ',')
    {
        $lines = explode("\n", $csvString);

        $rows = [];
        foreach ($lines as $line) {
            $line = self::convertEncoding($line);
            if (!empty($line)) {
                $rows[] = str_getcsv($line, $delimiter);
            }
        }

        $headers = array_shift($rows);

        $data = array_map(function($row) use($headers) {
            return array_combine($headers, $row);
        }, $rows);

        return $data;
    }

    public static function convertEncoding($input)
    {
        return iconv(mb_detect_encoding($input, mb_detect_order(), true), 'UTF-8//IGNORE', $input);
    }
}