Struct scc::TreeIndex

pub struct TreeIndex<K, V> where
    K: Clone + Ord + Send + Sync,
    V: Clone + Send + Sync,  { /* fields omitted */ }

A scalable concurrent tree map implementation.

scc::TreeIndex is a B+ tree variant that is optimized for read operations. Read operations, such as scan, read, are neither blocked nor interrupted by all the other types of operations. Write operations, such as insert, remove, do not block if they do not entail structural changes to the tree.

Implementations

impl<K, V> TreeIndex<K, V> where
    K: Clone + Ord + Send + Sync,
    V: Clone + Send + Sync, 

pub fn new() -> TreeIndex<K, V>

Creates an empty TreeIndex instance.

Examples

use scc::TreeIndex;

let treeindex: TreeIndex<u64, u32> = TreeIndex::new();

let result = treeindex.read(&1, |key, value| *value);
assert!(result.is_none());

pub fn insert(&self, mut key: K, mut value: V) -> Result<(), (K, V)>

Inserts a a key-value pair.

Examples

use scc::TreeIndex;

let treeindex: TreeIndex<u64, u32> = TreeIndex::new();

let result = treeindex.insert(1, 10);
assert!(result.is_ok());

let result = treeindex.insert(1, 11);
assert_eq!(result.err().unwrap(), (1, 11));

let result = treeindex.read(&1, |key, value| *value);
assert_eq!(result.unwrap(), 10);

pub fn remove(&self, key: &K) -> bool

Removes a key-value pair.

Examples

use scc::TreeIndex;

let treeindex: TreeIndex<u64, u32> = TreeIndex::new();

let result = treeindex.remove(&1);
assert!(!result);

let result = treeindex.insert(1, 10);
assert!(result.is_ok());

let result = treeindex.remove(&1);
assert!(result);

pub fn read<U, F: FnOnce(&K, &V) -> U>(&self, key: &K, f: F) -> Option<U>

Reads a key-value pair.

Examples

use scc::TreeIndex;

let treeindex: TreeIndex<u64, u32> = TreeIndex::new();

let result = treeindex.read(&1, |key, value| *value);
assert!(result.is_none());

let result = treeindex.insert(1, 10);
assert!(result.is_ok());

let result = treeindex.read(&1, |key, value| *value);
assert_eq!(result.unwrap(), 10);

pub fn clear(&self)

Clears the TreeIndex.

Examples

use scc::TreeIndex;

let treeindex: TreeIndex<u64, u32> = TreeIndex::new();

for key in 0..16u64 {
    let result = treeindex.insert(key, 10);
    assert!(result.is_ok());
}

treeindex.clear();

let result = treeindex.len();
assert_eq!(result, 0);

pub fn len(&self) -> usize

Returns the size of the TreeIndex.

It internally scans all the leaf nodes, and therefore the time complexity is O(N).

Examples

use scc::TreeIndex;

let treeindex: TreeIndex<u64, u32> = TreeIndex::new();

for key in 0..16u64 {
    let result = treeindex.insert(key, 10);
    assert!(result.is_ok());
}

let result = treeindex.len();
assert_eq!(result, 16);

pub fn depth(&self) -> usize

Returns the depth of the TreeIndex.

Examples

use scc::TreeIndex;

let treeindex: TreeIndex<u64, u32> = TreeIndex::new();

for key in 0..16u64 {
    let result = treeindex.insert(key, 10);
    assert!(result.is_ok());
}

let result = treeindex.depth();
assert_eq!(result, 1);

pub fn iter(&self) -> Scanner<'_, K, V>

Returns a Scanner.

The returned Scanner starts scanning from the minimum key-value pair.

Examples

use scc::TreeIndex;

let treeindex: TreeIndex<u64, u32> = TreeIndex::new();

let result = treeindex.insert(1, 10);
assert!(result.is_ok());

let result = treeindex.insert(2, 11);
assert!(result.is_ok());

let result = treeindex.insert(3, 13);
assert!(result.is_ok());

let mut scanner = treeindex.iter();
assert_eq!(scanner.next().unwrap(), (&1, &10));
assert_eq!(scanner.next().unwrap(), (&2, &11));
assert_eq!(scanner.next().unwrap(), (&3, &13));
assert!(scanner.next().is_none());

pub fn from(&self, key: &K) -> Option<Scanner<'_, K, V>>

Returns a Scanner that starts from the given key if it exists.

In case the key does not exist, and there is a key that is greater than the given key, a Scanner pointing to the key is returned.

Examples

use scc::TreeIndex;

let treeindex: TreeIndex<u64, u32> = TreeIndex::new();

let result = treeindex.insert(1, 10);
assert!(result.is_ok());

let result = treeindex.insert(2, 11);
assert!(result.is_ok());

let result = treeindex.insert(3, 13);
assert!(result.is_ok());

if let Some(mut scanner) = treeindex.from(&2) {
    assert_eq!(scanner.get().unwrap(), (&2, &11));
    assert_eq!(scanner.next().unwrap(), (&3, &13));
    assert!(scanner.next().is_none());
}

impl<K, V> TreeIndex<K, V> where
    K: Clone + Display + Ord + Send + Sync,
    V: Clone + Display + Send + Sync, 

pub fn print<T: Write>(&self, output: &mut T) -> Result<()>

Prints the TreeIndex contents to the given output in the DOT language.

Examples

use scc::TreeIndex;

let treeindex: TreeIndex<u64, u32> = TreeIndex::new();

let result = treeindex.insert(1, 10);
assert!(result.is_ok());

treeindex.print(&mut std::io::stdout());

Trait Implementations

impl<K, V> Default for TreeIndex<K, V> where
    K: Clone + Ord + Send + Sync,
    V: Clone + Send + Sync, 

fn default() -> Self

Creates a TreeIndex instance with the default parameters.

Examples

use scc::TreeIndex;

let treeindex: TreeIndex<u64, u32> = Default::default();

let result = treeindex.read(&1, |key, value| *value);
assert!(result.is_none());

impl<K, V> Drop for TreeIndex<K, V> where
    K: Clone + Ord + Send + Sync,
    V: Clone + Send + Sync, 

fn drop(&mut self)

Executes the destructor for this type.