Enum StackMapError

pub enum StackMapError {
    MapFull,
}

StackMap

A fixed-capacity hash map implementation that stores all data on the stack rather than the heap. This provides performance benefits for small maps by eliminating heap allocations and improving cache locality.

Performance Characteristics

• Optimized for small collections (recommended N ≤ 32)
• Zero heap allocations - everything stays on the stack
• Better cache locality than standard HashMap for small data sets
• O(N) worst-case complexity for operations (acceptable for small N)
• Uses linear probing with deleted flags rather than complex tombstone logic

Usage Warning

Since all data is stored on the stack, using large capacity values (N > 32) may cause stack overflow in resource-constrained environments. Choose the capacity parameter carefully based on your expected maximum collection size.

Example

use stackmap::StackMap;

// Create a new map with capacity for 8 entries
let mut map = StackMap::<String, i32, 8>::new();

// Insert some values
map.insert_or_update("one".to_string(), 1).unwrap();
map.insert_or_update("two".to_string(), 2).unwrap();

// Check if a value exists
assert_eq!(map.get(&"one".to_string()), Some(&1));

// Count entries
assert_eq!(map.len(), 2);

Custom error type for StackMap operations

Variants

MapFull

The map is at full capacity and cannot accept more entries. Consider increasing the capacity template parameter or removing unneeded entries.

Trait Implementations

impl Clone for StackMapError

fn clone(&self) -> StackMapError

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for StackMapError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for StackMapError

fn eq(&self, other: &StackMapError) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for StackMapError

impl StructuralPartialEq for StackMapError