Merge pull request #178 from davidgiven/mac

Add support for exporting to DiskCopy 4.2 Mac disk image

arch/macintosh/decoder.cc

@@ -121,7 +121,7 @@ uint8_t decode_side(uint8_t side)
      * bit 5) and also whether we're above track 0x3f (in bit 6).
      */
 
-    return !!(side & 0x40);
+    return !!(side & 0x20);
 }
 
 AbstractDecoder::RecordType MacintoshDecoder::advanceToNextRecord()

doc/disk-macintosh.md

@@ -45,22 +45,20 @@ Reading discs
 Just do:
 
 ```
-fluxengine read mac
+fluxengine read mac -o mac.diskcopy
 ```
 
-You should end up with an `mac.img` which is 1001888 bytes long (for a normal
-DD disk). If you want the single-sided variety, use `-s :s=0`.
+You should end up with a `mac.diskcopy` file which is compatible with DiskCopy
+4.2, which most Mac emulators support.
 
-**Big warning!** The image may not work in an emulator. Mac disk images are
-complicated due to the way the tracks are different sizes and the odd sector
-size. FluxEngine chooses to store them in a simple 524 x 12 x 2 x 80 layout,
-with holes where missing sectors should be. This was easiest. If anyone can
-suggest a better way, please [get in
-touch](https://github.com/davidgiven/fluxengine/issues/new).
-
-The 12 bytes of metadata _follow_ the 512 bytes of user payload in the sector
-image. If you don't want it, specify a geometry in the output file with a
-512-byte sectore size like `-o mac.img:c=80:h=1:s=12:b=512`.
+**Big warning!** Mac disk images are complicated due to the way the tracks are
+different sizes and the odd sector size. If you use a normal `.img` file, then
+FluxEngine will store them in a simple 524 x 12 x 2 x 80 layout, with holes
+where missing sectors should be; this was easiest, but is unlikely to work with
+most Mac emulators and other software. In these files, the The 12 bytes of
+metadata _follow_ the 512 bytes of user payload in the sector image. If you
+don't want it, specify a geometry in the output file with a 512-byte sectore
+size like `-o mac.img:c=80:h=1:s=12:b=512`.
 
 Useful references
 -----------------
@@ -74,3 +72,7 @@ Useful references
 
   - [Les Disquettes et le drive Disk II](http://www.hackzapple.com/DISKII/DISKIITECH.HTM), an
     epicly detailed writeup of the Apple II disk format (which is closely related)
+
+  - [The DiskCopy 4.2
+	format](https://www.discferret.com/wiki/Apple_DiskCopy_4.2), described on
+	the DiskFerret website.

doc/using.md

@@ -117,6 +117,10 @@ exact format varies according to the extension:
     FluxEngine's D64 support is currently limited to write only. It will work
     with up to 40 logical tracks.
 
+  - `.diskcopy`: a Macintosh DiskCopy 4.2 file. This is a special-purpose
+	format due to the weird layout of Mac GCR disks, but it can also support
+	720kB and 1440kB IBM disks (although there's no real benefit).
+
 ### High density disks
 
 High density disks use a different magnetic medium to low and double density

lib/bytes.h

@@ -1,6 +1,8 @@
 #ifndef BYTES_H
 #define BYTES_H
 
+#include <string.h>
+
 class ByteReader;
 class ByteWriter;
 
@@ -10,6 +12,7 @@ public:
     Bytes();
     Bytes(unsigned size);
     Bytes(const uint8_t* ptr, size_t len);
+    Bytes(const std::string& data);
     Bytes(std::initializer_list<uint8_t> data);
     Bytes(std::shared_ptr<std::vector<uint8_t>> data);
     Bytes(std::shared_ptr<std::vector<uint8_t>> data, unsigned start, unsigned end);
@@ -271,6 +274,16 @@ public:
 
     ByteWriter& operator += (std::istream& stream);
 
+	ByteWriter& append(const char* data)
+	{
+		return *this += Bytes((const uint8_t*)data, strlen(data));
+	}
+
+	ByteWriter& append(const std::string& data)
+	{
+		return *this += Bytes(data);
+	}
+
     ByteWriter& append(const Bytes data)
     {
         return *this += data;

lib/globals.h

@@ -12,7 +12,7 @@
 #include <set>
 #include <cassert>
 
-typedef int nanoseconds_t;
+typedef double nanoseconds_t;
 class Bytes;
 
 extern double getCurrentTime();

lib/imagewriter/diskcopyimagewriter.cc

@@ -0,0 +1,169 @@
+#include "globals.h"
+#include "flags.h"
+#include "dataspec.h"
+#include "sector.h"
+#include "sectorset.h"
+#include "imagewriter/imagewriter.h"
+#include "fmt/format.h"
+#include "ldbs.h"
+#include <algorithm>
+#include <iostream>
+#include <fstream>
+
+static const char LABEL[] = "FluxEngine image";
+
+static void write_and_update_checksum(ByteWriter& bw, uint32_t& checksum, const Bytes& data)
+{
+	ByteReader br(data);
+	while (!br.eof())
+	{
+		uint32_t i = br.read_be16();
+		checksum += i;
+		checksum = (checksum >> 1) | (checksum << 31);
+		bw.write_be16(i);
+	}
+}
+
+class DiskCopyImageWriter : public ImageWriter
+{
+public:
+	DiskCopyImageWriter(const SectorSet& sectors, const ImageSpec& spec):
+		ImageWriter(sectors, spec)
+	{}
+
+	void writeImage()
+	{
+		bool mfm = false;
+
+		if (spec.bytes == 524)
+		{
+			/* GCR disk */
+		}
+		else if (spec.bytes == 512)
+		{
+			/* MFM disk */
+			mfm = true;
+		}
+		else
+			Error() << "this image is not compatible with the DiskCopy 4.2 format";
+
+
+		std::cout << "writing DiskCopy 4.2 image\n"
+		          << fmt::format("{} tracks, {} heads, {} sectors, {} bytes per sector; {}\n",
+				  		spec.cylinders, spec.heads, spec.sectors, spec.bytes,
+						mfm ? "MFM" : "GCR");
+
+		auto sectors_per_track = [&](int track) -> int
+		{
+			if (mfm)
+				return spec.sectors;
+
+			if (track < 16)
+				return 12;
+			if (track < 32)
+				return 11;
+			if (track < 48)
+				return 10;
+			if (track < 64)
+				return 9;
+			return 8;
+		};
+
+		Bytes image;
+		ByteWriter bw(image);
+
+		/* Write the actual sectr data. */
+
+		uint32_t dataChecksum = 0;
+		uint32_t tagChecksum = 0;
+		uint32_t offset = 0x54;
+		uint32_t sectorDataStart = offset;
+		for (int track = 0; track < spec.cylinders; track++)
+		{
+			for (int head = 0; head < spec.heads; head++)
+			{
+				int sectorCount = sectors_per_track(track);
+				for (int sectorId = 0; sectorId < sectorCount; sectorId++)
+				{
+					const auto& sector = sectors.get(track, head, sectorId);
+					if (sector)
+					{
+						bw.seek(offset);
+						write_and_update_checksum(bw, dataChecksum, sector->data.slice(0, 512));
+					}
+					offset += 512;
+				}
+			}
+		}
+		uint32_t sectorDataEnd = offset;
+		if (!mfm)
+		{
+			for (int track = 0; track < spec.cylinders; track++)
+			{
+				for (int head = 0; head < spec.heads; head++)
+				{
+					int sectorCount = sectors_per_track(track);
+					for (int sectorId = 0; sectorId < sectorCount; sectorId++)
+					{
+						const auto& sector = sectors.get(track, head, sectorId);
+						if (sector)
+						{
+							bw.seek(offset);
+							write_and_update_checksum(bw, tagChecksum, sector->data.slice(512, 12));
+						}
+						offset += 12;
+					}
+				}
+			}
+		}
+		uint32_t tagDataEnd = offset;
+
+		/* Write the header. */
+
+		uint8_t encoding;
+		uint8_t format;
+		if (mfm)
+		{
+			format = 0x22;
+			if (spec.sectors == 18)
+				encoding = 3;
+			else
+				encoding = 2;
+		}
+		else
+		{
+			if (spec.heads == 2)
+			{
+				encoding = 1;
+				format = 0x22;
+			}
+			else
+			{
+				encoding = 0;
+				format = 0x02;
+			}
+		}
+
+		bw.seek(0);
+		bw.write_8(sizeof(LABEL));
+		bw.append(LABEL);
+		bw.seek(0x40);
+		bw.write_be32(sectorDataEnd - sectorDataStart); /* data size */
+		bw.write_be32(tagDataEnd - sectorDataEnd); /* tag size */
+		bw.write_be32(dataChecksum); /* data checksum */
+		bw.write_be32(tagChecksum); /* tag checksum */
+		bw.write_8(encoding); /* encoding */
+		bw.write_8(format); /* format byte */
+		bw.write_be16(0x0100); /* magic number */
+
+		image.writeToFile(spec.filename);
+    }
+};
+
+std::unique_ptr<ImageWriter> ImageWriter::createDiskCopyImageWriter(
+	const SectorSet& sectors, const ImageSpec& spec)
+{
+    return std::unique_ptr<ImageWriter>(new DiskCopyImageWriter(sectors, spec));
+}
+
+

lib/imagewriter/imagewriter.cc

@@ -13,6 +13,7 @@ std::map<std::string, ImageWriter::Constructor> ImageWriter::formats =
 	{".adf", ImageWriter::createImgImageWriter},
 	{".d64", ImageWriter::createD64ImageWriter},
 	{".d81", ImageWriter::createImgImageWriter},
+	{".diskcopy", ImageWriter::createDiskCopyImageWriter},
 	{".img", ImageWriter::createImgImageWriter},
 	{".ldbs", ImageWriter::createLDBSImageWriter},
 };

lib/imagewriter/imagewriter.h

@@ -29,6 +29,8 @@ private:
 		const SectorSet& sectors, const ImageSpec& spec);
     static std::unique_ptr<ImageWriter> createD64ImageWriter(
 		const SectorSet& sectors, const ImageSpec& spec);
+    static std::unique_ptr<ImageWriter> createDiskCopyImageWriter(
+		const SectorSet& sectors, const ImageSpec& spec);
 
 	static Constructor findConstructor(const ImageSpec& spec);
 

lib/reader.cc

@@ -107,7 +107,7 @@ void Track::readFluxmap()
 	fluxmap = fluxsource->readFlux(physicalTrack, physicalSide);
 	std::cout << fmt::format(
 		"{0} ms in {1} bytes\n",
-            int(fluxmap->duration()/1e6),
+            fluxmap->duration()/1e6,
             fluxmap->bytes());
 	if (outputFluxSink)
 		outputFluxSink->writeFlux(physicalTrack, physicalSide, *fluxmap);

lib/visualiser.cc

@@ -47,8 +47,8 @@ void visualiseSectorsToFile(const SectorSet& sectors, const std::string& filenam
 
             auto drawArc = [&](const std::unique_ptr<Sector>& sector, nanoseconds_t start, nanoseconds_t end, const std::string& colour)
             {
-                start %= period*1000000;
-                end %= period*1000000;
+                start = fmod(start, period*1000000.0);
+                end = fmod(end, period*1000000.0);
                 if (end < start)
                     end += period*1000000;
                 

mkninja.sh

@@ -154,6 +154,7 @@ buildlibrary libbackend.a \
 	lib/imagereader/imagereader.cc \
 	lib/imagereader/imgimagereader.cc \
 	lib/imagewriter/d64imagewriter.cc \
+	lib/imagewriter/diskcopyimagewriter.cc \
 	lib/imagewriter/imagewriter.cc \
 	lib/imagewriter/imgimagewriter.cc \
 	lib/imagewriter/ldbsimagewriter.cc \

src/fe-fluxtoscp.cc

@@ -18,6 +18,11 @@ static SettableFlag fortyTrackMode(
     "set 48 tpi mode; only every other physical track is emitted"
 );
 
+static SettableFlag indexedMode(
+	{ "--indexed", "-i" },
+	"align data to track boundaries"
+);
+
 static SettableFlag singleSided(
     { "--single-sided", "-s" },
     "only emit side 0"
@@ -45,14 +50,18 @@ static void write_le32(uint8_t dest[4], uint32_t v)
     dest[3] = v >> 24;
 }
 
+static void appendChecksum(uint32_t& checksum, const Bytes& bytes)
+{
+	ByteReader br(bytes);
+	while (!br.eof())
+		checksum += br.read_8();
+}
+
 static int strackno(int track, int side)
 {
     if (fortyTrackMode)
         track /= 2;
-    if (singleSided)
-        return track;
-    else
-        return (track << 1) | side;
+	return (track << 1) | side;
 }
 
 int mainConvertFluxToScp(int argc, const char* argv[])
@@ -90,7 +99,8 @@ int mainConvertFluxToScp(int argc, const char* argv[])
     fileheader.revolutions = 5;
     fileheader.start_track = 0;
     fileheader.end_track = maxStrack;
-    fileheader.flags = SCP_FLAG_INDEXED | (fortyTrackMode ? 0 : SCP_FLAG_96TPI);
+    fileheader.flags = (indexedMode ? SCP_FLAG_INDEXED : 0)
+			| (fortyTrackMode ? 0 : SCP_FLAG_96TPI);
     fileheader.cell_width = 0;
     fileheader.heads = singleSided ? 1 : 0;
 
@@ -104,9 +114,15 @@ int mainConvertFluxToScp(int argc, const char* argv[])
         for (int side = 0; side <= maxside; side++)
         {
             int strack = strackno(track, side);
-            std::cout << fmt::format("FE track {}.{}, SCP track {}: ", track, side, strack) << std::flush;
+            std::cout << fmt::format("{}.{}: ", track, side) << std::flush;
 
             auto fluxmap = sqlReadFlux(inputDb, track, side);
+			if (fluxmap->bytes() == 0)
+			{
+				std::cout << "missing\n";
+				continue;
+			}
+
             ScpTrack trackheader = {0};
             trackheader.track_id[0] = 'T';
             trackheader.track_id[1] = 'R';
@@ -117,6 +133,9 @@ int mainConvertFluxToScp(int argc, const char* argv[])
             Bytes fluxdata;
             ByteWriter fluxdataWriter(fluxdata);
 
+			if (indexedMode)
+				fmr.findEvent(F_BIT_INDEX);
+
             int revolution = 0;
             unsigned revTicks = 0;
             unsigned totalTicks = 0;
@@ -159,7 +178,7 @@ int mainConvertFluxToScp(int argc, const char* argv[])
             trackdataWriter += Bytes((uint8_t*)&trackheader, sizeof(trackheader));
             trackdataWriter += fluxdata;
 
-            std::cout << fmt::format("{} ms in {} bytes\n",
+            std::cout << fmt::format("{:.3f} ms in {} bytes\n",
                 totalTicks * MS_PER_TICK,
                 fluxdata.size());
         }
@@ -167,6 +186,13 @@ int mainConvertFluxToScp(int argc, const char* argv[])
 
     sqlClose(inputDb);
     
+	uint32_t checksum = 0;
+	appendChecksum(checksum,
+		Bytes((const uint8_t*) &fileheader, sizeof(fileheader))
+			.slice(0x10));
+	appendChecksum(checksum, trackdata);
+	write_le32(fileheader.checksum, checksum);
+
     std::cout << "Writing output file...\n";
     std::ofstream of(filenames[1], std::ios::out | std::ios::binary);
     if (!of.is_open())

src/fe-scptoflux.cc

@@ -28,15 +28,11 @@ static void check_for_error()
 
 static int trackno(int strack)
 {
-    if (startSide == endSide)
-        return strack;
     return strack >> 1;
 }
 
 static int headno(int strack)
 {
-    if (startSide == endSide)
-        return startSide;
     return strack & 1;
 }
 
@@ -65,6 +61,8 @@ static void read_header()
 static void read_track(int strack)
 {
     uint32_t offset = Bytes(header.track[strack], 4).reader().read_le32();
+	if (offset == 0)
+		return;
 
     ScpTrack trackheader;
     inputFile.seekg(offset, std::ios::beg);
@@ -112,7 +110,7 @@ static void read_track(int strack)
         inputBytes += datalength*2;
     }
 
-    std::cout << fmt::format(" {} ms in {} input bytes and {} output bytes\n",
+    std::cout << fmt::format(" {:.3f} ms in {} input bytes and {} output bytes\n",
         fluxmap.duration() / 1e6, inputBytes, fluxmap.bytes());
     sqlWriteFlux(outputDb, trackno(strack), headno(strack), fluxmap);
 }