32-bit unsigned overflow in MemoryOutputStream::prepareToWrite

General JUCE discussion
1

There’s a problem when writing streams greater than 32-bit to a juce::MemoryBlock.
The problem is here:

        if (storageNeeded >= blockToUse->getSize())
            blockToUse->ensureSize ((storageNeeded + jmin (storageNeeded / 2, (size_t) (1024 * 1024)) + 32) & ~31u);

That last ~31u is a 32-bit unsigned int so will wrap values around to that range.

The cleanest solution would be to use the uz suffix but I think just static_casting it to size_t should also work?

Here’s a godbolt showing the problem and the fix: Compiler Explorer

3

Thanks! Fixed here:

4

Thanks!