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CLK/Storage/Disk/Formats/OricMFMDSK.cpp
2017-08-24 22:18:44 -04:00

129 lines
3.4 KiB
C++

//
// OricMFMDSK.cpp
// Clock Signal
//
// Created by Thomas Harte on 21/11/2016.
// Copyright © 2016 Thomas Harte. All rights reserved.
//
#include "OricMFMDSK.hpp"
#include "../PCMTrack.hpp"
#include "../Encodings/MFM.hpp"
using namespace Storage::Disk;
OricMFMDSK::OricMFMDSK(const char *file_name) :
Storage::FileHolder(file_name) {
if(!check_signature("MFM_DISK", 8))
throw ErrorNotOricMFMDSK;
head_count_ = fgetc32le();
track_count_ = fgetc32le();
geometry_type_ = fgetc32le();
if(geometry_type_ < 1 || geometry_type_ > 2)
throw ErrorNotOricMFMDSK;
}
OricMFMDSK::~OricMFMDSK() {
flush_updates();
}
unsigned int OricMFMDSK::get_head_position_count() {
return track_count_;
}
unsigned int OricMFMDSK::get_head_count() {
return head_count_;
}
bool OricMFMDSK::get_is_read_only() {
return is_read_only_;
}
long OricMFMDSK::get_file_offset_for_position(unsigned int head, unsigned int position) {
long seek_offset = 0;
switch(geometry_type_) {
case 1:
seek_offset = (head * track_count_) + position;
break;
case 2:
seek_offset = (position * track_count_ * head_count_) + head;
break;
}
return (seek_offset * 6400) + 256;
}
std::shared_ptr<Track> OricMFMDSK::get_uncached_track_at_position(unsigned int head, unsigned int position) {
fseek(file_, get_file_offset_for_position(head, position), SEEK_SET);
PCMSegment segment;
// The file format omits clock bits. So it's not a genuine MFM capture.
// A consumer must contextually guess when an FB, FC, etc is meant to be a control mark.
size_t track_offset = 0;
uint8_t last_header[6] = {0, 0, 0, 0, 0, 0};
std::unique_ptr<Encodings::MFM::Encoder> encoder = Encodings::MFM::GetMFMEncoder(segment.data);
bool did_sync = false;
while(track_offset < 6250) {
uint8_t next_byte = (uint8_t)fgetc(file_);
track_offset++;
switch(next_byte) {
default: {
encoder->add_byte(next_byte);
if(did_sync) {
switch(next_byte) {
default: break;
case 0xfe:
for(int byte = 0; byte < 6; byte++) {
last_header[byte] = (uint8_t)fgetc(file_);
encoder->add_byte(last_header[byte]);
track_offset++;
if(track_offset == 6250) break;
}
break;
case 0xfb:
for(int byte = 0; byte < (128 << last_header[3]) + 2; byte++) {
encoder->add_byte((uint8_t)fgetc(file_));
track_offset++;
if(track_offset == 6250) break;
}
break;
}
}
did_sync = false;
}
break;
case 0xa1: // a synchronisation mark that implies a sector or header coming
encoder->output_short(Storage::Encodings::MFM::MFMSync);
did_sync = true;
break;
case 0xc2: // an 'ordinary' synchronisation mark
encoder->output_short(Storage::Encodings::MFM::MFMIndexSync);
break;
}
}
segment.number_of_bits = (unsigned int)(segment.data.size() * 8);
std::shared_ptr<PCMTrack> track(new PCMTrack(segment));
return track;
}
void OricMFMDSK::store_updated_track_at_position(unsigned int head, unsigned int position, const std::shared_ptr<Track> &track, std::mutex &file_access_mutex) {
Storage::Encodings::MFM::Parser parser(true, track);
std::vector<uint8_t> parsed_track = parser.get_track(0);
long file_offset = get_file_offset_for_position(head, position);
std::lock_guard<std::mutex> lock_guard(file_access_mutex);
fseek(file_, file_offset, SEEK_SET);
size_t track_size = std::min((size_t)6400, parsed_track.size());
fwrite(parsed_track.data(), 1, track_size, file_);
}