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55 lines
1.7 KiB
C++
55 lines
1.7 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 "Utility/ImplicitSectors.hpp"
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namespace {
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constexpr int sectors_per_track = 16;
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constexpr int sector_size = 1;
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}
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using namespace Storage::Disk;
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AcornADF::AcornADF(const std::string &file_name) : MFMSectorDump(file_name) {
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// Check that the disk image contains a whole number of sector.
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if(file_.stats().st_size % off_t(128 << sector_size)) throw Error::InvalidFormat;
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// Check that the disk image is at least large enough to hold an ADFS catalogue.
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if(file_.stats().st_size < 7 * off_t(128 << sector_size)) throw Error::InvalidFormat;
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// Check that the initial directory's 'Hugo's are present.
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file_.seek(513, SEEK_SET);
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uint8_t bytes[4];
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file_.read(bytes, 4);
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if(bytes[0] != 'H' || bytes[1] != 'u' || bytes[2] != 'g' || bytes[3] != 'o') throw Error::InvalidFormat;
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file_.seek(0x6fb, SEEK_SET);
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file_.read(bytes, 4);
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if(bytes[0] != 'H' || bytes[1] != 'u' || bytes[2] != 'g' || bytes[3] != 'o') throw Error::InvalidFormat;
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// Pick a number of heads; treat this image as double sided if it's too large to be single-sided.
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head_count_ = 1 + (file_.stats().st_size > sectors_per_track * off_t(128 << sector_size) * 80);
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// Announce disk geometry.
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set_geometry(sectors_per_track, sector_size, 0, true);
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}
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HeadPosition AcornADF::get_maximum_head_position() {
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return HeadPosition(80);
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}
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int AcornADF::get_head_count() {
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return head_count_;
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}
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long AcornADF::get_file_offset_for_position(Track::Address address) {
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return (address.position.as_int() * head_count_ + address.head) * (128 << sector_size) * sectors_per_track;
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}
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