fluxengine/lib/imagewriter/nsiimagewriter.cc

#include "lib/core/globals.h"
#include "lib/config/flags.h"
#include "lib/data/sector.h"
#include "lib/imagewriter/imagewriter.h"
#include "lib/data/image.h"
#include "lib/core/logger.h"
#include "lib/imagewriter/imagewriter.pb.h"
#include <algorithm>
#include <iostream>
#include <fstream>

class NsiImageWriter : public ImageWriter
{
public:
    NsiImageWriter(const ImageWriterProto& config): ImageWriter(config) {}

    void writeImage(const Image& image) override
    {
        const Geometry& geometry = image.getGeometry();
        bool mixedDensity = false;

        size_t trackSize = geometry.numSectors * geometry.sectorSize;

        if (geometry.numTracks * trackSize == 0)
        {
            log("No sectors in output; skipping .nsi image file generation.");
            return;
        }

        log("Writing {} tracks, {} sides, {} sectors, {} ({} bytes/sector), {} "
            "kB total",
            geometry.numTracks,
            geometry.numSides,
            geometry.numSectors,
            geometry.sectorSize == 256 ? "SD" : "DD",
            geometry.sectorSize,
            geometry.numTracks * geometry.numSides * geometry.numSectors *
                geometry.sectorSize / 1024);

        std::ofstream outputFile(
            _config.filename(), std::ios::out | std::ios::binary);
        if (!outputFile.is_open())
            error("cannot open output file");

        unsigned sectorFileOffset;
        for (int track = 0; track < geometry.numTracks * geometry.numSides;
            track++)
        {
            int side = (track < geometry.numTracks) ? 0 : 1;
            for (int sectorId = 0; sectorId < geometry.numSectors; sectorId++)
            {
                const auto& sector =
                    image.get(track % geometry.numTracks, side, sectorId);
                if (sector)
                {
                    if (side == 0)
                    { /* Side 0 is from track 0-34 */
                        sectorFileOffset =
                            track * trackSize + sectorId * geometry.sectorSize;
                    }
                    else
                    { /* Side 1 is from track 70-35 */
                        sectorFileOffset =
                            (geometry.sectorSize * geometry.numSectors *
                                geometry.numTracks) + /* Skip over side 0 */
                            ((geometry.numTracks - 1) -
                                (track % geometry.numTracks)) *
                                (geometry.sectorSize * geometry.numSectors) +
                            (sectorId *
                                geometry.sectorSize); /* Sector offset from
                                                         beginning of track. */
                    }
                    outputFile.seekp(sectorFileOffset, std::ios::beg);
                    if ((geometry.sectorSize == 512) &&
                        (sector->data.size() == 256))
                    {
                        /* North Star DOS provided an upgrade path for disks
                         * formatted as single- density to hold double-density
                         * data without reformatting.  In this case, the four
                         * directory blocks will be single-density but other
                         * areas of the disk are double-density.  This cannot be
                         * accurately represented using a .nsi file, so in these
                         * cases, we pad the sector to 512-bytes, filling with
                         * spaces.
                         */
                        char fill[256];
                        memset(fill, ' ', sizeof(fill));
                        if (mixedDensity == false)
                        {
                            log("Warning: Disk contains mixed "
                                "single/double-density sectors.");
                        }
                        mixedDensity = true;
                        sector->data.slice(0, 256).writeTo(outputFile);
                        outputFile.write(fill, sizeof(fill));
                    }
                    else
                    {
                        sector->data.slice(0, geometry.sectorSize)
                            .writeTo(outputFile);
                    }
                }
            }
        }
    }
};

std::unique_ptr<ImageWriter> ImageWriter::createNsiImageWriter(
    const ImageWriterProto& config)
{
    return std::unique_ptr<ImageWriter>(new NsiImageWriter(config));
}