BzTree

BzTree(concurrent B-tree) implementation for Rust based on paper BzTree: A High-Performance Latch-free Range Index for Non-Volatile Memory.
Current implementation doesn't support non-volatile memory and supposed to be used only as in-memory(not persistent) data structure.
BzTree uses MwCAS crate to get access to multi-word CAS.

Examples

```rust use bztree::BzTree;

let tree = BzTree::new(); let guard = crossbeam_epoch::pin();

let key1 = "key1".tostring(); assert!(tree.insert(key1.clone(), 1, &guard)); assert!(!tree.insert(key1.clone(), 5, &guard)); tree.upsert(key1.clone(), 10, &guard);

assert!(matches!(tree.delete(&key1, &guard), Some(&10)));

let key2 = "key2".tostring(); tree.insert(key2.clone(), 2, &guard); assert!(tree.compute(&key2, |(_, v)| Some(v + 1), &guard)); assert!(matches!(tree.get(&key2, &guard), Some(&3)));

assert!(tree.compute(&key2, |(_, v)| { if *v == 3 { None } else { Some(v + 1) } }, &guard)); assert!(matches!(tree.get(&key2, &guard), None)); ```