API that returns a newly allocated buffer as an output argument (not return value) are error-prone.
- Users forget to release the newly allocated buffer
- Or the call `delete` instead of `delete[]`
But some of those API need to call `realloc` on the buffer.
But `realloc` is only valid if the buffer was previously allocated with `malloc`.
If a buffer needs to be re-allocated using a C++ API, then `std::vector<char*>` should be used instead...
So, this patch does:
- Migrates the API from `new []` / `delete[]` to `malloc()` / `free()`
- Fixes all the memory issues: incorrect deallocs and memory leaks
- Updates the documentation
- And fixes misc issues with the API: removes `cc` from the ZipUtils class.
Replaces more `int` with `long` where it makes sense.
Also , it repalces some `unsigned long` with `long` for "lenght"
values as described in our c++ guideline
Huabing.Xu