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CLK/Storage/Disk/Formats/SSD.cpp

101 lines
3.2 KiB
C++

//
// SSD.cpp
// Clock Signal
//
// Created by Thomas Harte on 18/09/2016.
// Copyright © 2016 Thomas Harte. All rights reserved.
//
#include "SSD.hpp"
#include "../Encodings/MFM.hpp"
using namespace Storage::Disk;
SSD::SSD(const char *file_name) :
Storage::FileHolder(file_name) {
// very loose validation: the file needs to be a multiple of 256 bytes
// and not ungainly large
if(file_stats_.st_size & 255) throw ErrorNotSSD;
if(file_stats_.st_size < 512) throw ErrorNotSSD;
if(file_stats_.st_size > 800*256) throw ErrorNotSSD;
// this has two heads if the suffix is .dsd, one if it's .ssd
head_count_ = (tolower(file_name[strlen(file_name) - 3]) == 'd') ? 2 : 1;
track_count_ = (unsigned int)(file_stats_.st_size / (256 * 10));
if(track_count_ < 40) track_count_ = 40;
else if(track_count_ < 80) track_count_ = 80;
}
SSD::~SSD() {
flush_updates();
}
unsigned int SSD::get_head_position_count() {
return track_count_;
}
unsigned int SSD::get_head_count() {
return head_count_;
}
bool SSD::get_is_read_only() {
return is_read_only_;
}
long SSD::get_file_offset_for_position(unsigned int head, unsigned int position) {
return (position * head_count_ + head) * 256 * 10;
}
std::shared_ptr<Track> SSD::get_uncached_track_at_position(unsigned int head, unsigned int position) {
std::shared_ptr<Track> track;
if(head >= head_count_) return track;
fseek(file_, get_file_offset_for_position(head, position), SEEK_SET);
std::vector<Storage::Encodings::MFM::Sector> sectors;
for(int sector = 0; sector < 10; sector++) {
Storage::Encodings::MFM::Sector new_sector;
new_sector.track = (uint8_t)position;
new_sector.side = 0;
new_sector.sector = (uint8_t)sector;
new_sector.size = 1;
new_sector.data.resize(256);
fread(new_sector.data.data(), 1, 256, file_);
// zero out if this wasn't present in the disk image; it's still appropriate to put a sector
// on disk because one will have been placed during formatting, but there's no reason to leak
// information from outside the emulated machine's world
if(feof(file_)) memset(new_sector.data.data(), 0, 256);
sectors.push_back(std::move(new_sector));
}
if(sectors.size()) return Storage::Encodings::MFM::GetFMTrackWithSectors(sectors);
return track;
}
void SSD::store_updated_track_at_position(unsigned int head, unsigned int position, const std::shared_ptr<Track> &track, std::mutex &file_access_mutex) {
std::vector<uint8_t> parsed_track;
Storage::Encodings::MFM::Parser parser(false, track);
for(unsigned int c = 0; c < 10; c++) {
std::shared_ptr<Storage::Encodings::MFM::Sector> sector = parser.get_sector(0, (uint8_t)position, (uint8_t)c);
if(sector) {
parsed_track.insert(parsed_track.end(), sector->data.begin(), sector->data.end());
} else {
// TODO: what's correct here? Warn the user that whatever has been written to the disk,
// it can no longer be stored as an SSD? If so, warn them by what route?
parsed_track.resize(parsed_track.size() + 256);
}
}
std::lock_guard<std::mutex> lock_guard(file_access_mutex);
long file_offset = get_file_offset_for_position(head, position);
ensure_file_is_at_least_length(file_offset);
fseek(file_, file_offset, SEEK_SET);
fwrite(parsed_track.data(), 1, parsed_track.size(), file_);
}