VOID NTAPI RamDiskLoadVirtualFile ( IN PCHAR FileName )
Definition at line 121 of file ramdisk.c.
{
    ULONG RamFile;
    ULONG TotalRead, ChunkSize, Count;
    PCHAR MsgBuffer = "Loading ramdisk...";
    ULONG PercentPerChunk, Percent;
    FILEINFORMATION Information;
    LARGE_INTEGER Position;
    LONG ret;

    //
    // Display progress
    //
    UiDrawProgressBarCenter(1, 100, MsgBuffer);

    //
    // Try opening the ramdisk file
    //
    ret = ArcOpen(FileName, OpenReadOnly, &RamFile);
    if (ret == ESUCCESS)
    {
        //
        // Get the file size
        //
        ret = ArcGetFileInformation(RamFile, &Information);
        if (ret != ESUCCESS)
        {
            ArcClose(RamFile);
            return;
        }

        //
        // For now, limit RAM disks to 4GB
        //
        if (Information.EndingAddress.HighPart != 0)
        {
            UiMessageBox("RAM disk too big\n");
            ArcClose(RamFile);
            return;
        }
        gRamDiskSize = Information.EndingAddress.LowPart;

        //
        // Allocate memory for it
        //
        ChunkSize = 8 * 1024 * 1024;
        if (gRamDiskSize < ChunkSize)
            Percent = PercentPerChunk = 0;
        else
            Percent = PercentPerChunk = 100 / (gRamDiskSize / ChunkSize);
        gRamDiskBase = MmAllocateMemoryWithType(gRamDiskSize, LoaderXIPRom);
        if (!gRamDiskBase)
        {
            UiMessageBox("Failed to allocate memory for RAM disk\n");
            ArcClose(RamFile);
            return;
        }

        //
        // Read it in chunks
        //
        for (TotalRead = 0; TotalRead < gRamDiskSize; TotalRead += ChunkSize)
        {
            //
            // Check if we're at the last chunk
            //
            if ((gRamDiskSize - TotalRead) < ChunkSize)
            {
                //
                // Only need the actual data required
                //
                ChunkSize = gRamDiskSize - TotalRead;
            }

            //
            // Draw progress
            //
            UiDrawProgressBarCenter(Percent, 100, MsgBuffer);
            Percent += PercentPerChunk;

            //
            // Copy the contents
            //
            Position.HighPart = 0;
            Position.LowPart = TotalRead;
            ret = ArcSeek(RamFile, &Position, SeekAbsolute);
            if (ret == ESUCCESS)
            {
                ret = ArcRead(RamFile,
                              (PVOID)((ULONG_PTR)gRamDiskBase + TotalRead),
                              ChunkSize,
                              &Count);
            }

            //
            // Check for success
            //
            if (ret != ESUCCESS || Count != ChunkSize)
            {
                MmFreeMemory(gRamDiskBase);
                gRamDiskBase = NULL;
                gRamDiskSize = 0;
                ArcClose(RamFile);
                UiMessageBox("Failed to read ramdisk\n");
                return;
            }
        }

        ArcClose(RamFile);

        // Register a new device for the ramdisk
        FsRegisterDevice("ramdisk(0)", &RamDiskVtbl);
    }
}
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