CLK/Storage/Disk/DiskImage/Formats/MFMSectorDump.cpp

//
//  MFMSectorDump.cpp
//  Clock Signal
//
//  Created by Thomas Harte on 30/09/2017.
//  Copyright 2017 Thomas Harte. All rights reserved.
//

#include "MFMSectorDump.hpp"

#include "Utility/ImplicitSectors.hpp"

using namespace Storage::Disk;

MFMSectorDump::MFMSectorDump(const std::string &file_name) : file_(file_name) {}

void MFMSectorDump::set_geometry(int sectors_per_track, uint8_t sector_size, uint8_t first_sector, Encodings::MFM::Density density) {
	sectors_per_track_ = sectors_per_track;
	sector_size_ = sector_size;
	density_ = density;
	first_sector_ = first_sector;
}

std::shared_ptr<Track> MFMSectorDump::get_track_at_position(Track::Address address) {
	if(address.head >= get_head_count()) return nullptr;
	if(address.position.as_largest() >= get_maximum_head_position().as_largest()) return nullptr;

	uint8_t sectors[(128 << sector_size_)*sectors_per_track_];
	const long file_offset = get_file_offset_for_position(address);

	{
		std::lock_guard lock_guard(file_.get_file_access_mutex());
		file_.seek(file_offset, SEEK_SET);
		file_.read(sectors, sizeof(sectors));
	}

	return track_for_sectors(
		sectors,
		sectors_per_track_,
		uint8_t(address.position.as_int()),
		uint8_t(address.head),
		first_sector_,
		sector_size_,
		density_);
}

void MFMSectorDump::set_tracks(const std::map<Track::Address, std::shared_ptr<Track>> &tracks) {
	uint8_t parsed_track[(128 << sector_size_)*sectors_per_track_];

	// TODO: it would be more efficient from a file access and locking point of view to parse the sectors
	// in one loop, then write in another.

	for(const auto &track : tracks) {
		decode_sectors(
			*track.second,
			parsed_track,
			first_sector_,
			first_sector_ + uint8_t(sectors_per_track_-1),
			sector_size_,
			density_);
		const long file_offset = get_file_offset_for_position(track.first);

		std::lock_guard lock_guard(file_.get_file_access_mutex());
		file_.ensure_is_at_least_length(file_offset);
		file_.seek(file_offset, SEEK_SET);
		file_.write(parsed_track, sizeof(parsed_track));
	}
	file_.flush();
}

bool MFMSectorDump::get_is_read_only() {
	return file_.get_is_known_read_only();
}