Debugging Memory Errors with Custom Allocators

Listing 3: A possible implementation of the access rights control method for the class shown in Listing 2

void Victim::setMemoryAccessMode(MemoryAccessMode mode)
{
    int flags(MEM_ACCESS_DENIED);

    // convert clean C++ enum to old C-style integer bitmask:
    switch(mode)
    {
    case readOnly:
        flags = MEM_ACCESS_READ;
        break;

    case readWrite:
        flags = MEM_ACCESS_READ | MEM_ACCESS_WRITE;
        break;

    default:
        throw ("incorrect access mode specification");
    }
    protect_memory(charArray_, sizeof(charArray_), flags);
    protect_memory(&intData_[0],
        intData_.capacity() * sizeof(int), flags);

    protect_memory(this, sizeof(*this), flags);
    // In order for the line above to work, we may need to
    // take extra actions, such as defining operator new.
    // A concrete incarnation of protect_memory [8] may require
    // the memory to be page-aligned.
}
— End of Listing —