CRLF to LF

<?php

namespace Utility;

/**
 * This class replaces CRLF (Windows) endlines
 * with LF (Unix) endlines.
 */
class CSVCleaner
{
	/**
	 * General constants for class.
	 * They pretty much explay themselves.
	 */
	const MAX_STREAM_SIZE = 8192;
	const CRLF_CR         = array("\r\n", "\r");
	const LF              = "\n";

	/**
	 * Default file permissions
	 * to apply after modifying data.
	 * Everything for owner, read and execute for others.
	 * In Octal value.
	 */
	const PERMISSIONS = array(
		'rw_owner'           => 0600,
		'rw_owner_r_all'     => 0644,
		'rwx_owner_rx_group' => 0750,
		'rwx_owner_rx_all'   => 0755
	);

	/**
	 * Replaces CRLF with LF.
	 *
	 * @param  string $file The filepath.
	 * @return bool Wheather the data in file was modified.
	 */
	public static function process($file)
	{
		if (!self::isFileWrittable($file))
		{
			return false;
		}

		$file_size   = filesize($file);
		$handle      = fopen($file, 'rb');

		if ($file_size > self::MAX_STREAM_SIZE)
		{
			$tmp_file = $this->createTempDir();

			// Loops as long as the reading by MAX_STREAM_SIZE chunk finishes.
			while ($processed_data = self::CRLF2LF(fread($handle, self::MAX_STREAM_SIZE)))
			{
				file_put_contents($tmp_file, $processed_data, LOCK_EX | FILE_APPEND);
			}
			fclose($handle);

			if (!self::moveFile($tmp_file, $file) && self::applyPermissions($file, 0755))
			{
				return false;
			}
		}
		else
		{
			// Process data and then save it or return false.
			if (!$processed_data = self::CRLF2LF(fread($handle, $file_size)))
			{
				return false;
			}
			fclose($handle);

			if (!file_put_contents($file, $processed_data) && self::applyPermissions($file, 0755))
			{
				return false;
			}
		}

		return true;
	}

	/**
	 * A function to know if a given filepath
	 * is indeed a file or a directory, and
	 * case being a file, wheather it is writtable or not.
	 *
	 * @param  string $file The filepath.
	 * @return bool         Wheather is writtable or not.
	 */
	public static function isFileWrittable($file = '')
	{
		return !is_dir($file) || file_exists($file) && is_writable($file);
	}

	/**
	 * Creates a temporary directory/file name
	 * using the system's tmp dir.
	 *
	 * @return string The directory/file name.
	 */
	public function createTempDir()
	{
		return tempnam(sys_get_temp_dir(), time());
	}

	/**
	 * Moves a file (filepath) from source -> destination.
	 *
	 * @param  string $source      The source path.
	 * @param  string $destinatino The destination path.
	 * @return bool
	 */
	public static function moveFile($source, $destination)
	{
		return rename($source, $destination);
	}

	/**
	 * Replaces CRLF (\r\n) line return with LF (\n).
	 *
	 * @param  string $data The data to process.
	 * @return mixed
	 */
	private static function CRLF2LF($data)
	{
		if (!$data = str_replace(self::CRLF_CR, self::LF, $data))
		{
			return false;
		}

		return self::applyEncoding($data);
	}

	/**
	 * Applies given permissions.
	 *
	 * @param  string $file       The filepath.
	 * @param  string $permission The permission to apply.
	 * @return bool               Wheather it was applied or not.
	 */
	public static function applyPermissions($file, $permission = 0750)
	{
		if (!in_array($permission, self::PERMISSIONS))
		{
			return false;
		}

		return chmod($file, $permission);
	}

	/**
	 * Converts data to UTF-8.
	 * · Reference: http://php.net/manual/en/function.utf8-encode.php#102382
	 *
	 * @param  mixed  $data     The data to encode.
	 * @param  string $encoding The encoding to use.
	 * @return mixed $data      The encoded data or false.
	 */
	private static function applyEncoding($data, $encoding = 'UTF-8')
	{
		if (!mb_check_encoding($data, $encoding))
		{
			$data = mb_convert_encoding($data, $encoding);
			if (!mb_check_encoding($data, $encoding))
			{
				return false;
			}
		}

		return $data;
	}
}