Critique my non-intrusive heap debugger

Question

This is a follow-up to Critique my heap debugger from yesterday. As suggested by bitc, I now keep metadata about the allocated blocks in a separate handwritten hashtable.

Answer 1

Are you using a very weak malloc that doesn't already have this sort of stuff built into it? Because if it's there, you are doubling the overhead for little gain. Also, this kind of system really hurts when doing small object allocation or is ineffective with them as people do 1 alloc and manage the memory themselves.

As far as the code is concerned, it looks like it will do what you say it will do and it looks well designed and is easy to read. But, if you are going to go through the trouble of doing this though, why not catch your buffer over/under flows at the source by using managed containers/pointers/operator[] thingies. That way, you can debug on the spot of the failure instead of finding out at free that something evil has occured.

There are efficiencies to be had that I'm sure others will find, but these are just some thoughts off the top of my head after looking over your code for a few minutes.