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78 lines
2.0 KiB
C++
78 lines
2.0 KiB
C++
//
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// AcornADF.cpp
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// Clock Signal
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//
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// Created by Thomas Harte on 25/09/2016.
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// Copyright © 2016 Thomas Harte. All rights reserved.
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//
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#include "AcornADF.hpp"
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#include <sys/stat.h>
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#include "../Encodings/MFM.hpp"
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namespace {
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static const unsigned int sectors_per_track = 16;
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static const unsigned int bytes_per_sector = 256;
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}
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using namespace Storage::Disk;
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AcornADF::AcornADF(const char *file_name) :
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Storage::FileHolder(file_name)
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{
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// very loose validation: the file needs to be a multiple of 256 bytes
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// and not ungainly large
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if(file_stats_.st_size % bytes_per_sector) throw ErrorNotAcornADF;
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if(file_stats_.st_size < 7 * bytes_per_sector) throw ErrorNotAcornADF;
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// check that the initial directory's 'Hugo's are present
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fseek(file_, 513, SEEK_SET);
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uint8_t bytes[4];
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fread(bytes, 1, 4, file_);
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if(bytes[0] != 'H' || bytes[1] != 'u' || bytes[2] != 'g' || bytes[3] != 'o') throw ErrorNotAcornADF;
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fseek(file_, 0x6fb, SEEK_SET);
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fread(bytes, 1, 4, file_);
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if(bytes[0] != 'H' || bytes[1] != 'u' || bytes[2] != 'g' || bytes[3] != 'o') throw ErrorNotAcornADF;
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}
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unsigned int AcornADF::get_head_position_count()
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{
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return 80;
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}
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unsigned int AcornADF::get_head_count()
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{
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return 1;
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}
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std::shared_ptr<Track> AcornADF::get_uncached_track_at_position(unsigned int head, unsigned int position)
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{
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std::shared_ptr<Track> track;
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if(head >= 2) return track;
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long file_offset = (position * 1 + head) * bytes_per_sector * sectors_per_track;
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fseek(file_, file_offset, SEEK_SET);
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std::vector<Storage::Encodings::MFM::Sector> sectors;
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for(int sector = 0; sector < sectors_per_track; sector++)
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{
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Storage::Encodings::MFM::Sector new_sector;
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new_sector.track = (uint8_t)position;
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new_sector.side = (uint8_t)head;
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new_sector.sector = (uint8_t)sector;
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new_sector.data.resize(bytes_per_sector);
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fread(&new_sector.data[0], 1, bytes_per_sector, file_);
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if(feof(file_))
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break;
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sectors.push_back(std::move(new_sector));
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}
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if(sectors.size()) return Storage::Encodings::MFM::GetMFMTrackWithSectors(sectors);
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return track;
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}
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