CLK/Storage/Disk/DiskImage/Formats/MacintoshIMG.hpp

//
//  MacintoshIMG.hpp
//  Clock Signal
//
//  Created by Thomas Harte on 02/06/2019.
//  Copyright © 2019 Thomas Harte. All rights reserved.
//

#ifndef MacintoshIMG_hpp
#define MacintoshIMG_hpp

#include "../DiskImage.hpp"
#include "../../../FileHolder.hpp"

namespace Storage {
namespace Disk {

/*!
	Provides a @c DiskImage containing either:

		*	a disk imaged by Apple's Disk Copy 4.2: sector contents (optionally plus tag data),
			in either an Apple GCR or standard MFM encoding; or
		*	a raw sector dump of a Macintosh GCR disk.
*/
class MacintoshIMG: public DiskImage {
	public:
		/*!
			Construct a @c MacintoshIMG containing content from the file with name @c file_name.

			@throws Error::InvalidFormat if this file doesn't appear to be in Disk Copy 4.2 format.
		*/
		MacintoshIMG(const std::string &file_name);

		enum class FixedType {
			GCR
		};
		/*!
			Constructs a @c MacintoshIMG without attempting to autodetect whether this is a raw
			image or a Disk Copy 4.2 image; if GCR is specified and the file size checks out then
			it is accepted as a GCR image.

			If @c offset and @c length are specified and non-zero, only that portion of the file
			will be modified.
		*/
		MacintoshIMG(const std::string &file_name, FixedType type, size_t offset = 0, off_t length = -1);

		// implemented to satisfy @c Disk
		HeadPosition get_maximum_head_position() final;
		int get_head_count() final;
		bool get_is_read_only() final;

		std::shared_ptr<::Storage::Disk::Track> get_track_at_position(::Storage::Disk::Track::Address address) final;
		void set_tracks(const std::map<Track::Address, std::shared_ptr<Track>> &tracks) final;

	private:
		Storage::FileHolder file_;

		enum class Encoding {
			GCR400,
			GCR800,
			MFM720,
			MFM1440
		} encoding_;
		uint8_t format_;

		std::vector<uint8_t> data_;
		std::vector<uint8_t> tags_;
		bool is_diskCopy_file_ = false;
		std::mutex buffer_mutex_;

		uint32_t checksum(const std::vector<uint8_t> &, size_t bytes_to_skip = 0);
		void construct_raw_gcr(size_t offset, off_t length);
		long raw_offset_ = 0;
};

}
}

#endif /* DiskCopy42_hpp */