B-tree
FriendlyCSharp.Databases is a cross-platform C library implementing generic B-tree data structures for in-memory storage. It offers four B-tree variants: FcsBTreeN, FcsFastBTreeN, FcsLockBTreeN, and FcsFastLockBTreeN, each supporting generic key-value pairs with sorted keys and duplicate keys. The library provides methods for adding, finding, searching, updating, deleting, and navigating records, with fast variants offering optimized traversal operations and lock variants supporting thread-safe concurrent access. The B-tree implementation can serve as a replacement for NoSQL in-memory databases in real-time scenarios such as Firebase, Redis Cache, SAP HANA, and other OLTP systems. The structure ensures logarithmic time complexity for searches, insertions, deletions, and sequential access. Designed for .NET Standard 1.1, the library is suitable for building high-performance cache layers, embedding database functionality into applications, and prototyping data storage solutions. Source code is available on GitH