C / C++ / MFC

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

// Constants, you'll need to set these up.  Ideally you'd wrap these in a class somewhere
// and treat them like a FILE* object; this example only supports one 'open' file
const char* gFileBase = address at the beginning of your memory mapped file;
size_t gFileSize = size of the file that was memory mapped;

size_t filePtr = 0;
int memfread(void* destination, size_t numBytes)
{
    // Clamp to the end of the 'file'.
    size_t bytesRemaining = gFileSize - filePtr;
    if (numBytes > bytesRemaining)
        numBytes = bytesRemaining;

    // Copy the number of bytes requested out.
    memcpy(destination, gFileBase + filePtr, numBytes);

    // Move the virtual file pointer on.
    filePtr += numBytes;
    
    return numBytes;
}

// Get the base of the foo array.
Foo* fooArray = reinterpret_cast<Foo*>(gFileBase);
// use fooArray as if you'd loaded them normally
// any changes you make are reflected on disk automatically.
// e.g. things like "foo[12].bar = 12;" and so forth