What can happen if I'm being charged with larceny in a building and possession of a controlled substance?

It sounds like you need to hire an attorney and fight the case. The penalty for larceny in a building is typically from probation up to 2 years 8 months to 4 years. The penalty for possession of a controlled substance is the same, except for marijuana, which has a max penalty of 1 year. The penalties go up if they charge "with intent to deliver." With no criminal record, you have a reasonable shot at getting probation with no jail if you want to make a deal. If you are innocent you should probably fight the charges.

So little info provided limits my reply but...Hire a local criminal attorney or ask for a court appointed attorney. There are many options even for those with no criminal history to handle such matters depending on charges, allegations & proofs offered by prosecuting authority.