Module historical 

A historical wrapper around crate::bitmap::Prunable that maintains snapshots via diff-based batching.

The Historical bitmap maintains one full crate::bitmap::Prunable bitmap (the current/head state). All historical states and batch mutations are represented as diffs, not full bitmap clones.

Examples

Basic Batching

let mut bitmap: BitMap<4> = BitMap::new();

// Create and commit a batch
bitmap.with_batch(1, |batch| {
    batch.push(true);
    batch.push(false);
}).unwrap();

assert_eq!(bitmap.len(), 2);
assert!(bitmap.get_bit(0));
assert!(!bitmap.get_bit(1));

Read-Through Semantics

let mut bitmap: BitMap<4> = BitMap::new();
bitmap.with_batch(1, |batch| { batch.push(false); }).unwrap();

// Before modification
assert!(!bitmap.get_bit(0));

{
    let mut batch = bitmap.start_batch();
    batch.set_bit(0, true);

    // Read through batch sees the modification
    assert!(batch.get_bit(0));

    batch.commit(2).unwrap();
}

// After commit, modification is in current
assert!(bitmap.get_bit(0));

Abort on Drop

let len_before = bitmap.len();

{
    let mut batch = bitmap.start_batch();
    batch.push(true);
    batch.push(false);
    // Drop without commit = automatic abort
}

assert_eq!(bitmap.len(), len_before); // Unchanged

Commit History Management

for i in 1..=5 {
    bitmap.with_batch(i, |batch| {
        batch.push(true);
    }).unwrap();
}

assert_eq!(bitmap.commits().count(), 5);

// Prune old commits
bitmap.prune_commits_before(3);
assert_eq!(bitmap.commits().count(), 3);

Structs

BatchGuard

Guard for an active batch on a historical bitmap.

BitMap

A historical bitmap that maintains one actual bitmap plus diffs for history and batching.

Enums

Error

Errors that can occur in Historical bitmap operations.