CIBlockCMLImport::CheckFileByName

function CheckFileByName($file, $fields = null)
{
	$external_id = $file;
	$fileName = bx_basename($file);
	if (!empty($fields) && $fileName != "")
	{
		if (empty($this->arElementFiles))
		{
			$this->arElementFiles = array();
			$ID = array();
			foreach ($this->arElementFilesId as $fileId)
			{
				foreach($fileId as $value)
					$ID[$value] = $value;
			}
			$rsFile = CFile::GetList(array(), array(
				"@ID" => implode(",", $ID),
			));
			while ($arFile = $rsFile->Fetch())
			{
				$arFile["~ORIGINAL_NAME"] = preg_replace("/(\.resize[0-9]+\.)/", ".", $arFile["ORIGINAL_NAME"]);
				$this->arElementFiles[$arFile["ID"]] = $arFile;
			}
		}

		foreach ($fields as $fieldId)
		{
			if (isset($this->arElementFilesId[$fieldId]))
			{
				foreach ($this->arElementFilesId[$fieldId] as $fileId)
				{
					if (isset($this->arElementFiles[$fileId]))
					{
						if ($this->arElementFiles[$fileId]["EXTERNAL_ID"] === $external_id)
							return $fileId;
						if ($this->arElementFiles[$fileId]["~ORIGINAL_NAME"] === $fileName)
							return $fileId;
					}
				}
			}
		}
	}
	return false;
}