Non-functional boilerplate of Amiga write support.

arch/amiga/amiga.h

@@ -1,12 +1,17 @@
 #ifndef AMIGA_H
 #define AMIGA_H
 
+#include "encoders/encoders.h"
+
 #define AMIGA_SECTOR_RECORD 0xaaaa44894489LL
 
+#define AMIGA_TRACKS_PER_DISK 80
+#define AMIGA_SECTORS_PER_TRACK 11
 #define AMIGA_RECORD_SIZE 0x21f
 
 class Sector;
 class Fluxmap;
+class SectorSet;
 
 class AmigaDecoder : public AbstractDecoder
 {
@@ -17,4 +22,15 @@ public:
     void decodeSectorRecord();
 };
 
+class AmigaEncoder : public AbstractEncoder
+{
+public:
+	virtual ~AmigaEncoder() {}
+
+public:
+    std::unique_ptr<Fluxmap> encode(int physicalTrack, int physicalSide, const SectorSet& allSectors);
+};
+
+extern FlagGroup amigaEncoderFlags;
+
 #endif

arch/amiga/encoder.cc

@@ -0,0 +1,79 @@
+#include "globals.h"
+#include "record.h"
+#include "decoders/decoders.h"
+#include "encoders/encoders.h"
+#include "amiga.h"
+#include "crc.h"
+#include "sectorset.h"
+#include "writer.h"
+
+FlagGroup amigaEncoderFlags;
+
+static DoubleFlag clockRateUs(
+	{ "--clock-rate" },
+	"Encoded data clock rate (microseconds).",
+	2.00);
+
+static DoubleFlag postIndexGapMs(
+	{ "--post-index-gap" },
+	"Post-index gap before first sector header (milliseconds).",
+	20.0);
+
+static int charToInt(char c)
+{
+	if (isdigit(c))
+		return c - '0';
+	return 10 + tolower(c) - 'a';
+}
+
+static void write_bits(std::vector<bool>& bits, unsigned& cursor, uint64_t data, int width)
+{
+	cursor += width;
+	for (int i=0; i<width; i++)
+	{
+		unsigned pos = cursor - i - 1;
+		if (pos < bits.size())
+			bits[pos] = data & 1;
+		data >>= 1;
+	}
+}
+
+static void write_sector(std::vector<bool> bits, unsigned& cursor, const Sector* sector)
+{
+    write_bits(bits, cursor, AMIGA_SECTOR_RECORD, 6*8);
+
+    Bytes header(4);
+    ByteWriter bw(header);
+    bw.write_8(0xff); /* Amiga 1.0 format byte */
+    bw.write_8(sector->logicalTrack);
+    bw.write_8(sector->logicalSector);
+    bw.write_8(AMIGA_SECTORS_PER_TRACK - sector->logicalSector);
+}
+
+std::unique_ptr<Fluxmap> AmigaEncoder::encode(
+	int physicalTrack, int physicalSide, const SectorSet& allSectors)
+{
+	if ((physicalTrack < 0) || (physicalTrack >= AMIGA_TRACKS_PER_DISK))
+		return std::unique_ptr<Fluxmap>();
+
+	int bitsPerRevolution = 200000.0 / clockRateUs;
+	std::vector<bool> bits(bitsPerRevolution);
+	unsigned cursor = 0;
+
+    fillBitmapTo(bits, cursor, postIndexGapMs * 1000 / clockRateUs, { true, false });
+
+	for (int sectorId=0; sectorId<AMIGA_SECTORS_PER_TRACK; sectorId++)
+	{
+		const auto& sectorData = allSectors.get(physicalTrack, 0, sectorId);
+		write_sector(bits, cursor, sectorData);
+    }
+
+	if (cursor > bits.size())
+		Error() << "track data overrun";
+	fillBitmapTo(bits, cursor, bits.size(), { true, false });
+
+	std::unique_ptr<Fluxmap> fluxmap(new Fluxmap);
+	fluxmap->appendBits(bits, clockRateUs*1e3);
+	return fluxmap;
+}
+

mkninja.sh

@@ -145,6 +145,7 @@ buildlibrary libbackend.a \
 	lib/imagewriter/ldbsimagewriter.cc \
     arch/aeslanier/decoder.cc \
     arch/amiga/decoder.cc \
+    arch/amiga/encoder.cc \
     arch/apple2/decoder.cc \
     arch/brother/decoder.cc \
     arch/brother/encoder.cc \
@@ -213,6 +214,7 @@ buildlibrary libfrontend.a \
     src/fe-seek.cc \
     src/fe-testbulktransport.cc \
     src/fe-upgradefluxfile.cc \
+    src/fe-writeamiga.cc \
     src/fe-writebrother.cc \
     src/fe-writeflux.cc \
     src/fe-writetestpattern.cc \

src/fe-writeamiga.cc

@@ -0,0 +1,23 @@
+#include "globals.h"
+#include "flags.h"
+#include "decoders/decoders.h"
+#include "amiga/amiga.h"
+#include "writer.h"
+#include "fmt/format.h"
+#include "image.h"
+#include <fstream>
+
+static FlagGroup flags { &writerFlags, &amigaEncoderFlags };
+
+int mainWriteAmiga(int argc, const char* argv[])
+{
+    setWriterDefaultInput(":c=80:h=2:s=11:b=512");
+    setWriterDefaultDest(":d=0:t=0-79:s=0-1");
+    flags.parseFlags(argc, argv);
+
+	AmigaEncoder encoder;
+	writeDiskCommand(encoder);
+
+    return 0;
+}
+

src/fluxengine.cc

@@ -28,6 +28,7 @@ extern command_cb mainRpm;
 extern command_cb mainSeek;
 extern command_cb mainTestBulkTransport;
 extern command_cb mainUpgradeFluxFile;
+extern command_cb mainWriteAmiga;
 extern command_cb mainWriteBrother;
 extern command_cb mainWriteFlux;
 extern command_cb mainWriteTestPattern;
@@ -79,6 +80,7 @@ static std::vector<Command> readables =
 
 static std::vector<Command> writeables =
 {
+    { "amiga",         mainWriteAmiga,    "Writes Amiga disks.", },
     { "brother",       mainWriteBrother,  "Writes 120kB and 240kB Brother word processor disks.", },
 };