We can now decode IBM MFM disks all the way to an image, although with no CRC

checking as yet.

lib/image.cc

@@ -0,0 +1,40 @@
+#include "globals.h"
+#include "image.h"
+#include "fmt/format.h"
+#include <algorithm>
+#include <iostream>
+#include <fstream>
+
+void writeSectorsToFile(const std::vector<std::unique_ptr<Sector>>& sectors, const std::string& filename)
+{
+    /* Count the tracks, sides and sectors. */
+
+    int trackCount = 0;
+    int sideCount = 0;
+    int sectorCount = 0;
+    size_t sectorSize = 0;
+    for (auto& sector : sectors)
+    {
+        trackCount = std::max(sector->track()+1, trackCount);
+        sideCount = std::max(sector->side()+1, sideCount);
+        sectorCount = std::max(sector->sector()+1, sectorCount);
+        sectorSize = std::max(sector->data().size(), sectorSize);
+    }
+
+    size_t sideSize = sectorCount * sectorSize;
+    size_t trackSize = sideSize * sideCount;
+
+    std::cout << fmt::format("{} tracks, {} sides, {} sectors, {} bytes per sector, {} kB total",
+        trackCount, sideCount, sectorCount, sectorSize,
+        trackCount * sideCount * sectorCount * sectorSize / 1024);
+
+    std::ofstream outputFile(filename, std::ios::out | std::ios::binary);
+    if (!outputFile.is_open())
+        Error() << "cannot open output file";
+
+    for (auto& sector : sectors)
+    {
+        outputFile.seekp(sector->track()*trackSize + sector->side()*sideSize + sector->sector()*sectorSize, std::ios::beg);
+        outputFile.write((const char*) &sector->data().at(0), sector->data().size());
+    }
+}