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

//
//  PlusTooBIN.cpp
//  Clock Signal
//
//  Created by Thomas Harte on 04/06/2019.
//  Copyright © 2019 Thomas Harte. All rights reserved.
//

#include "PlusTooBIN.hpp"

#include "../../Track/PCMTrack.hpp"
#include "../../Encodings/AppleGCR/Encoder.hpp"

using namespace Storage::Disk;

namespace {
const long sector_size = 1024;
}

PlusTooBIN::PlusTooBIN(const std::string &file_name) :
	file_(file_name) {
	// BIN isn't really meant to be an emulator file format, it's primarily
	// a convenience for the PlusToo Macintosh clone. So validation is
	// fairly light.
	if(file_.stats().st_size != 1638400)
		throw Error::InvalidFormat;
}

HeadPosition PlusTooBIN::get_maximum_head_position() {
	return HeadPosition(80);
}

int PlusTooBIN::get_head_count() {
	return 2;
}

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

	const auto start_position = Encodings::AppleGCR::Macintosh::sectors_in_track(address.position.as_int());
	const long file_offset = long(start_position.start * 2 + address.head * start_position.start) * sector_size;
	file_.seek(file_offset, SEEK_SET);

	const auto track_contents = file_.read(std::size_t(sector_size * start_position.length));
	const std::size_t number_of_bits = std::size_t(sector_size * start_position.length * 8);

	return std::shared_ptr<PCMTrack>(new PCMTrack(PCMSegment(number_of_bits, track_contents)));
}