Struct MassMap 

pub struct MassMap<K, V, R: MassMapReader, H: MassMapHashLoader = MassMapDefaultHashLoader> { /* private fields */ }

Typed view over a MassMapInner.

This wrapper carries the key/value types at compile time while sharing the underlying storage and hashing configuration with other typed views.

Implementations

impl<K, V, R: MassMapReader, H: MassMapHashLoader> MassMap<K, V, R, H>

where K: for<'de> Deserialize<'de> + Eq + Hash, V: for<'de> Deserialize<'de> + Clone,

pub fn load(reader: R) -> Result<Self>

Constructs a massmap from a MassMapReader implementation.

The method validates the leading header (magic number, metadata offset and length) and deserializes MassMapMeta. Any IO or deserialization errors are forwarded to the caller.

pub fn len(&self) -> u64

Returns the number of entries written into this map.

pub fn is_empty(&self) -> bool

Returns true if the map contains no entries.

pub fn bucket_count(&self) -> usize

Returns the number of buckets in the underlying massmap.

This is mainly intended for testing and diagnostics.

pub fn info(&self) -> MassMapInfo

Returns information about the map’s structure and contents.

pub fn get<Q>(&self, k: &Q) -> Result<Option<V>>

where K: Borrow<Q>, Q: Eq + Hash + ?Sized,

Attempts to deserialize the value associated with k.

Keys are hashed using the stored seed and only the relevant bucket is deserialized, minimizing IO when the entry is missing.

Errors

Returns an error if the reader fails to provide the bucket or if the serialized data cannot be deserialized into (K, V) pairs.

pub fn batch_get<Q>( &self, keys: impl IntoIterator<Item = impl Borrow<Q>>, ) -> Result<Vec<Option<V>>>

where K: Borrow<Q>, Q: Eq + Hash + ?Sized,

Performs multiple lookups in a single pass.

The reader is asked to fetch each bucket sequentially; implementations may override MassMapReader::batch_read_at to issue true scatter/gather reads where available. Results preserve the order of keys.

Errors

Returns an error under the same conditions as get.

pub fn iter(&self) -> MassMapIter<'_, K, V, R, H>

Creates an iterator that traverses all entries in the map by bucket order.

The iterator reads each bucket sequentially from the backing storage, deserializes all entries in the bucket, and yields them one at a time. Each bucket is fully loaded into memory before any of its entries are yielded. Iteration stops immediately if a bucket fails to deserialize.

Examples

use massmap::{MassMap, MassMapBuilder};

let entries = [("a", 1), ("b", 2), ("c", 3)];
let file = std::fs::File::create("examples/iter_test.massmap")?;
MassMapBuilder::default().build(&file, entries.iter())?;

let file = std::fs::File::open("examples/iter_test.massmap")?;
let map = MassMap::<String, i32, _>::load(file)?;
let all_entries: Vec<_> = map.iter().collect::<std::io::Result<Vec<_>>>()?;
assert_eq!(all_entries.len(), 3);

pub fn get_bucket(&self, index: usize) -> Result<Vec<(K, V)>>

Retrieves all entries in the specified bucket.

This method is primarily intended for testing and debugging.

Errors

Returns an error if the reader fails to provide the bucket or if the serialized data cannot be deserialized into (K, V) pairs.