How can I Cache ma_sound's into memory?

[m1maker]

Hello. I have a game engine uses miniaudio as sound engine. I have a sound class with ma_sound object, but I don't know how to cache an existing sound, so that when the sound is re-loaded, it does not reload the file again, but loads it from an existing object. Since this is C++, I tried std::map<std::string, ma_sound> sounds;, where string is the filename, however this was throwing exceptions. Is there some way to cache sounds using mimiaudio?

[mackron]

miniaudio supports reference counting. You can just initialize a ma_sound object and hold onto it for as long as you need. That way the reference count will never hit 0 and will never be unloaded.

However, your map is wrong. You need to remember this trip hazard from the documentation:

In miniaudio, objects are transparent structures. Unlike many other libraries, there are no handles to opaque objects which means you need to allocate memory for objects yourself. In the examples presented in this documentation you will often see objects declared on the stack. You need to be careful when translating these examples to your own code so that you don't accidentally declare your objects on the stack and then cause them to become invalid once the function returns. In addition, you must ensure the memory address of your objects remain the same throughout their lifetime. You therefore cannot be making copies of your objects.

So any time you add a new entry to your std::map you're not only making a copy of your ma_sound, it's possible that the internal memory is being moved around which is violating the rule that your ma_sound object must maintain the same address in memory for it's lifetime. Instead you should store pointers to your ma_sound objects and allocate the memory of your individual ma_sound objects on the heap. Then your map becomes std::map<std::string, ma_sound*>.