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Extend .ADF support as far as my knowledge currently goes.

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This commit is contained in:
Thomas Harte 2024-02-24 15:07:45 -05:00
parent 82abebec6e
commit c56e82207a
1 changed files with 52 additions and 20 deletions
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68
Storage/Disk/DiskImage/Formats/AcornADF.cpp
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@ -51,32 +51,64 @@ AcornADF::AcornADF(const std::string &file_name) : MFMSectorDump(file_name) {
//
// So then .ADF files might be track-interleaved and might not be.
switch(size) {
default:
const auto has_identifier = [&](long location, bool permit_hugo, bool permit_nick) -> bool {
file_.seek(location, SEEK_SET);
uint8_t bytes[4];
file_.read(bytes, 4);
return
(permit_hugo && !memcmp(bytes, "Hugo", 4)) ||
(permit_nick && !memcmp(bytes, "Nick", 4));
};
const auto file_size = file_.stats().st_size;
Encodings::MFM::Density density = Encodings::MFM::Density::Double;
if(has_identifier(513, true, false)) {
// One of:
//
// ADFS-S: 1 side, 40 tracks, 16 sectors, 256 bytes = 160K old map, old dir
// ADFS-M: 1 side, 80 tracks, 16 sectors, 256 bytes = 320K old map, old dir
// ADFS-L: 2 sides, 80 tracks, 16 sectors, 256 bytes = 640K old map, old dir
head_count_ = file_.stats().st_size > 80*16*256 ? 2 : 1;
sector_size_ = 1;
sectors_per_track_ = 16;
break;
} else if(has_identifier(1025, true, true)) {
// ADFS-D: 80 tracks, 2 sides, 5 sectors, 1024 bytes = 800K old map, new dir
head_count_ = 2;
sector_size_ = 3;
sectors_per_track_ = 5;
} else if(has_identifier(2049, false, true)) {
// One of:
//
// ADFS-E: 80 tracks, 2 sides, 5 sectors, 1024 bytes = 800K new map, new dir
// ADFS-F: 80 tracks, 2 sides, 10 sectors, 1024 bytes = 1600K new map, new dir
// ADFS-G: 80 tracks, 2 sides, 20 sectors, 1024 bytes = 3200K new map, new dir
head_count_ = 2;
sector_size_ = 3;
if(file_size > 80*2*10*1024) {
sectors_per_track_ = 20;
density = Encodings::MFM::Density::High; // Or, presumably, higher than high?
} else if(file_size > 80*2*10*1024) {
sectors_per_track_ = 10;
density = Encodings::MFM::Density::High;
} else {
sectors_per_track_ = 5;
}
} else {
throw Error::InvalidFormat;
}
// TODO: possibly this image is side-interleaved if sectors per track is less than 16.
// Figure that out.
// Check that the disk image is at least large enough to hold an ADFS catalogue.
if(file_.stats().st_size < 7 * sizeT(128 << sector_size_)) throw Error::InvalidFormat;
// Check that the initial directory's 'Hugo's or 'Nick's are present.
// TODO: check other locations, to pick sector size and count.
file_.seek(513, SEEK_SET);
uint8_t bytes[4];
file_.read(bytes, 4);
if(memcmp(bytes, "Hugo", 4) && memcmp(bytes, "Nick", 4)) throw Error::InvalidFormat;
file_.seek(0x6fb, SEEK_SET);
file_.read(bytes, 4);
if(memcmp(bytes, "Hugo", 4) && memcmp(bytes, "Nick", 4)) throw Error::InvalidFormat;
// Pick a number of heads; treat this image as double sided if it's too large to be single-sided.
head_count_ = 1 + (file_.stats().st_size > sectors_per_track_ * sizeT(128 << sector_size_) * 80);
// Announce disk geometry.
set_geometry(sectors_per_track_, sector_size_, 0, Encodings::MFM::Density::Double);
set_geometry(sectors_per_track_, sector_size_, 0, density);
}
HeadPosition AcornADF::get_maximum_head_position() {