Fix read data overwrite issue

[urbytes21]

No description provided.

[urbytes21]

@bertmelis Could you please help me review this PR ? Thank you.

[bertmelis]

Good catch. Thank you for the fix!

[bertmelis]

I forgot to ask for a change: when advancing the start pointer of the destination, the size has to be adjusted or we risk a buffer overflow.

I can fix this later or you could add another PR?

Something like this?

...
while (size >= pxItemSize) {
...
size -= pxItemSize;
...
}

[urbytes21]

Ah, missed this.
size is the target read size, retVal is the bytes already read,
So I think we should change the loop condition to while (size > retVal) instead of checking pxItemSize.

Thank you