Use MetaImgFile to allow ATA-based machines to mount multiple disks

Uses the same approach as we do for SCSI (split the hdd_image property
on colons - 45a9d45) to mount multiple
images.

Switches reading of the apm_all_drivers.bin template file to using
direct filesystem operations (since we don't want to go to the JS
side in the Emscripten build).

Author: mihaip

devices/common/ata/atahd.cpp

@@ -31,6 +31,7 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #include <bitset>
 #include <cstring>
 #include <fstream>
+#include <sstream>
 #include <string>
 
 using namespace ata_interface;
@@ -57,7 +58,11 @@ int AtaHardDisk::device_postinit() {
     auto bus_obj = dynamic_cast<IdeChannel*>(gMachineObj->get_comp_by_name(bus_id));
     bus_obj->register_device(dev_num, this);
 
-    this->insert_image(hdd_image_path);
+    std::string single_image_path;
+    std::istringstream hdd_image_stream(hdd_image_path);
+    while (std::getline(hdd_image_stream, single_image_path, ':')) {
+        this->insert_image(single_image_path);
+    }
 
     return 0;
 }

devices/common/ata/atahd.h

@@ -25,7 +25,7 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #define ATA_HARD_DISK_H
 
 #include <devices/common/ata/atabasedevice.h>
-#include <utils/imgfile.h>
+#include <utils/metaimgfile.h>
 
 #include <string>
 
@@ -60,7 +60,7 @@ class AtaHardDisk : public AtaBaseDevice
     void        calc_chs_params();
 
 private:
-    ImgFile     hdd_img;
+    MetaImgFile hdd_img;
     uint64_t    img_size = 0;
     uint32_t    total_sectors = 0;
     uint64_t    cur_fpos = 0;

utils/metaimgfile.cpp

@@ -23,6 +23,7 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #include <memaccess.h>
 #include <loguru.hpp>
 
+#include <fstream>
 #include <limits>
 
 // ================================================================================================
@@ -562,14 +563,17 @@ void MetaImgFile::append_chunk(std::unique_ptr<FileMetaChunk> file)
 void MetaImgFile::reserve_partitions(int partitions_to_reserve)
 {
     if (this->max_partitions == 0) {
-        ImgFile partitions;
-        if (!partitions.open("apm_all_drivers.bin")) {
+        std::ifstream partitions;
+        partitions.open("apm_all_drivers.bin", std::ios::in | std::ios::binary);
+        if (partitions.fail()) {
             ABORT_F("MetaImgFile: Missing file \"apm_all_drivers.bin\"");
             return;
         }
-        uint64_t partitions_size = partitions.size();
+        partitions.seekg(0, std::ios::end);
+        size_t partitions_size = partitions.tellg();
         auto data = std::unique_ptr<uint8_t[]>(new uint8_t[partitions_size]);
-        partitions.read(&data[0], 0, partitions_size);
+        partitions.seekg(0, std::ios::beg);
+        partitions.read((char*)data.get(), partitions_size);
         partitions.close();
 
         Partition part = *(Partition*)&data[this->block_size];