How do I allocate memory for ZIP struct?-CodePudding

I found a ZIP library that I want to re-write with WinAPI calls. I have almost done it, but I can't allocate memory for a TState structure.

state = new TState(); works fine!

state = (TState*)HeapAlloc(GetProcessHeap(), 0, sizeof(TState)); breaks archives!

If I change HeapAlloc() to malloc(), nothing changes!

So, what am I doing wrong?

CodePudding user response：

TState contains some non-trivial members (namely: TTreeState ts and TDeflateState ds) that have their own constructors which are called properly by new, but which are not called by malloc()/HealAlloc(). As such, you would need to use placement-new to properly construct a TState object inside of your allocated memory, eg:

buffer = HeapAlloc(GetProcessHeap(), 0, sizeof(TState)); // or malloc()
state = new(buffer) TState;
...
state->~TState();
HeapFree(GetProcessHeap(), 0, buffer); // or free()

Otherwise, you will have to re-write TTreeState and TDeflateState to make them into trivial types (ie, remove their constructors). You will just have to initialize their data members manually after you have allocated each TState instance.