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