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Merge pull request #357 from tdaede/d88

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Add minimal D88 image format reader.
This commit is contained in:
David Given
2021-12-03 11:59:28 +00:00
committed by GitHub
parent 91e794add1 8a3cd14723
commit d8465f4374
6 changed files with 157 additions and 0 deletions
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11
doc/using.md
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@@ -267,6 +267,17 @@ FluxEngine also supports a number of file system image formats. When using the
Read from a [FDI image file](https://www.pc98.org/project/doc/hdi.html),
commonly used by PC-98 emulators. **Read Only.**
- `<filename.d88>`
Read from a [D88 image file](https://www.pc98.org/project/doc/d88.html),
commonly used by various Japanese PC emulators, including the NEC PC-88. **Read Only.**
FluxEngine is currently limited to reading only the first floppy image in a
D88 file.
In addition, it only supports a limited subset of D88 features and will
reject files not in that subset.
- `<filename.ldbs>`
Write to a [LDBS generic image

138
lib/imagereader/d88imagereader.cc Normal file
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@@ -0,0 +1,138 @@
#include "globals.h"
#include "flags.h"
#include "sector.h"
#include "imagereader/imagereader.h"
#include "image.h"
#include "lib/config.pb.h"
#include "imagereader/imagereaderimpl.h"
#include "fmt/format.h"
#include <algorithm>
#include <iostream>
#include <fstream>
// reader based on this partial documentation of the D88 format:
// https://www.pc98.org/project/doc/d88.html
class D88ImageReader : public ImageReader
{
public:
D88ImageReader(const ImageReaderProto& config):
ImageReader(config)
{}
std::unique_ptr<Image> readImage()
{
std::ifstream inputFile(_config.filename(), std::ios::in | std::ios::binary);
if (!inputFile.is_open())
Error() << "cannot open input file";
Bytes header(0x24); // read first entry of track table as well
inputFile.read((char*) header.begin(), header.size());
// the DIM header technically has a bit field for sectors present,
// however it is currently ignored by this reader
std::string diskName = header.slice(0, 0x16);
if (diskName[0])
std::cout << "D88: disk name: " << diskName << "\n";
ByteReader headerReader(header);
// media flag indicates media density, currently unused
char mediaFlag = headerReader.seek(0x1b).read_8();
inputFile.seekg( 0, std::ios::end );
int fileSize = inputFile.tellg();
int diskSize = headerReader.seek(0x1c).read_le32();
if (diskSize > fileSize)
std::cout << "D88: found multiple disk images. Only using first\n";
int trackTableEnd = headerReader.seek(0x20).read_le32();
int trackTableSize = trackTableEnd - 0x20;
Bytes trackTable(trackTableSize);
inputFile.seekg(0x20);
inputFile.read((char*) trackTable.begin(), trackTable.size());
ByteReader trackTableReader(trackTable);
int diskSectorsPerTrack = -1;
int diskSectorSize = -1;
std::unique_ptr<Image> image(new Image);
for (int track = 0; track < trackTableSize / 4; track++)
{
int trackOffset = trackTableReader.seek(track * 4).read_le32();
if (trackOffset == 0) continue;
int currentTrackOffset = trackOffset;
int currentTrackCylinder = -1;
int currentSectorsInTrack = 0xffff; // don't know # of sectors until we read the first one
for (int sectorInTrack = 0; sectorInTrack < currentSectorsInTrack; sectorInTrack++){
Bytes sectorHeader(0x10);
inputFile.read((char*) sectorHeader.begin(), sectorHeader.size());
ByteReader sectorHeaderReader(sectorHeader);
char cylinder = sectorHeaderReader.seek(0).read_8();
char head = sectorHeaderReader.seek(1).read_8();
char sectorId = sectorHeaderReader.seek(2).read_8();
int sectorSize = 128 << sectorHeaderReader.seek(3).read_8();
int sectorsInTrack = sectorHeaderReader.seek(4).read_le16();
int mfm = sectorHeaderReader.seek(6).read_8();
int ddam = sectorHeaderReader.seek(7).read_8();
int fddStatusCode = sectorHeaderReader.seek(8).read_8();
// D88 provides much more sector information that is currently ignored
if (ddam != 0)
Error() << "D88: nonzero ddam currently unsupported";
if (fddStatusCode != 0)
Error() << "D88: nonzero fdd status codes are currently unsupported";
if (currentSectorsInTrack == 0xffff) {
currentSectorsInTrack = sectorsInTrack;
} else if (currentSectorsInTrack != sectorsInTrack) {
Error() << "D88: mismatched number of sectors in track";
}
if (diskSectorsPerTrack < 0) {
diskSectorsPerTrack = sectorsInTrack;
} else if (diskSectorsPerTrack != sectorsInTrack) {
Error() << "D88: varying numbers of sectors per track is currently unsupported";
}
if (diskSectorSize < 0) {
diskSectorSize = sectorSize;
} else if (diskSectorSize != sectorSize) {
Error() << "D88: variable sector sizes are currently unsupported";
}
if (mfm != 0)
Error() << "D88: Non-MFM sectors are currenty unsupported";
if (currentTrackCylinder < 0) {
currentTrackCylinder = cylinder;
} else if (currentTrackCylinder != cylinder) {
Error() << "D88: all sectors in a track must belong to the same cylinder";
}
Bytes data(sectorSize);
inputFile.read((char*) data.begin(), data.size());
const auto& sector = image->put(cylinder, head, sectorId);
sector->status = Sector::OK;
sector->logicalTrack = cylinder;
sector->physicalCylinder = cylinder;
sector->logicalSide = sector->physicalHead = head;
sector->logicalSector = sectorId;
sector->data = data;
}
}
image->calculateSize();
const Geometry& geometry = image->getGeometry();
std::cout << fmt::format("D88: read {} tracks, {} sides\n",
geometry.numTracks, geometry.numSides);
return image;
}
};
std::unique_ptr<ImageReader> ImageReader::createD88ImageReader(
const ImageReaderProto& config)
{
return std::unique_ptr<ImageReader>(new D88ImageReader(config));
}

4
lib/imagereader/imagereader.cc
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@@ -17,6 +17,9 @@ std::unique_ptr<ImageReader> ImageReader::create(const ImageReaderProto& config)
case ImageReaderProto::kDim:
return ImageReader::createDimImageReader(config);
case ImageReaderProto::kD88:
return ImageReader::createD88ImageReader(config);
case ImageReaderProto::kFdi:
return ImageReader::createFdiImageReader(config);
@@ -55,6 +58,7 @@ void ImageReader::updateConfigForFilename(ImageReaderProto* proto, const std::st
{".jv3", [&]() { proto->mutable_jv3(); }},
{".d64", [&]() { proto->mutable_d64(); }},
{".d81", [&]() { proto->mutable_img(); }},
{".d88", [&]() { proto->mutable_d88(); }},
{".dim", [&]() { proto->mutable_dim(); }},
{".diskcopy", [&]() { proto->mutable_diskcopy(); }},
{".fdi", [&]() { proto->mutable_fdi(); }},

1
lib/imagereader/imagereader.h
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@@ -26,6 +26,7 @@ public:
static std::unique_ptr<ImageReader> createTd0ImageReader(const ImageReaderProto& config);
static std::unique_ptr<ImageReader> createDimImageReader(const ImageReaderProto& config);
static std::unique_ptr<ImageReader> createFdiImageReader(const ImageReaderProto& config);
static std::unique_ptr<ImageReader> createD88ImageReader(const ImageReaderProto& config);
public:
virtual std::unique_ptr<Image> readImage() = 0;

2
lib/imagereader/imagereader.proto
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@@ -40,6 +40,7 @@ message NsiInputProto {}
message Td0InputProto {}
message DimInputProto {}
message FdiInputProto {}
message D88InputProto {}
message ImageReaderProto {
optional string filename = 1 [(help) = "filename of input sector image"];
@@ -53,6 +54,7 @@ message ImageReaderProto {
Td0InputProto td0 = 8;
DimInputProto dim = 9;
FdiInputProto fdi = 10;
D88InputProto d88 = 11;
}
}

1
mkninja.sh
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@@ -374,6 +374,7 @@ buildlibrary libbackend.a \
lib/imagereader/td0imagereader.cc \
lib/imagereader/dimimagereader.cc \
lib/imagereader/fdiimagereader.cc \
lib/imagereader/d88imagereader.cc \
lib/imagewriter/d64imagewriter.cc \
lib/imagewriter/diskcopyimagewriter.cc \
lib/imagewriter/imagewriter.cc \