Dave Hudson


c8: Improving memory management

2017-04-19 00:00 - 2 min read

One of the things that I don’t like about the current implementation is that it uses some “naked” new and delete operators. The implementation goes to some lengths to hide the use of new and delete so it’s not visible to users of the c8 library, but any time we can do things right it will be better.

While the implementation was designed to be safe, it was actually a little problematic because it had a private pointer that could change meaning. If we were using the small_digits_ array then the pointer would point to that array, but if we weren’t using small_digits_ then the pointer would point to a heap-allocated block. Double meanings are rarely a good idea!

The change today eliminates the double meaning, but is only a first step. In general we’d like to see new and delete removed from all modern C++ codebases, so the next change will probably replace these with std::make_unique, and std::unique_ptr.

Bug squashing

While debugging the revised code I wanted to run valgrind, and dropped the optimization from -O2 to -O1. Doing this exposed a segfault, that turned out to be a stack corruption. Having found that I wanted to improve unit test coverage and then found a couple of places where zero results weren’t handled correctly. Fixed all of these!

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