google/leveldb ? reverse-engineered prompt

Build me a fast embedded key value storage library in C++ that works like a simple local database.

I want it to store arbitrary byte keys and values, keep everything sorted by key, and support the basic things I’d expect, like put, get, delete, atomic write batches, snapshots for a consistent read, and forward and backward iteration. It should be a library, not a server, and it should only allow one process to open a database at a time.

Please include a clean CMake build, the public headers, a few basic examples or tests, and make sure it works on Linux and Windows. Use compression by default if it’s available, and keep the code and API stable and simple. If you need current build or compression details, look up the latest docs online and follow the project style closely.