Extract (some) Writer classes to separate files.

TODO: PNGWriter could probably reuse this stuff too, but...

firmware/application/io_file.hpp

@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2016 Jared Boone, ShareBrained Technology, Inc.
+ *
+ * This file is part of PortaPack.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#pragma once
+
+#include "io.hpp"
+
+#include "file.hpp"
+#include "optional.hpp"
+
+#include <cstdint>
+
+class FileWriter : public Writer {
+public:
+	FileWriter() = default;
+
+	FileWriter(const FileWriter&) = delete;
+	FileWriter& operator=(const FileWriter&) = delete;
+	FileWriter(FileWriter&& file) = delete;
+	FileWriter& operator=(FileWriter&&) = delete;
+
+	Optional<File::Error> create(const std::filesystem::path& filename) {
+		return file.create(filename);
+	}
+
+	File::Result<File::Size> write(const void* const buffer, const File::Size bytes) override {
+		auto write_result = file.write(buffer, bytes) ;
+		if( write_result.is_ok() ) {
+			bytes_written += write_result.value();
+		}
+		return write_result;
+	}
+
+protected:
+	File file;
+	uint64_t bytes_written { 0 };
+};
+
+using RawFileWriter = FileWriter;