static-id 0.1.1

A memory-efficient library for handling interned identifiers
Documentation

StaticId

This Rust library provides an extremely memory-efficient implementation of StaticId for handling interned identifiers with optimal performance.

Features

  • StaticId: A highly optimized, interned identifier type combining a code and a venue.
  • Exceptional memory efficiency: Each StaticId is represented by a single 64-bit pointer.
  • Ultra-fast comparisons: Equality checks and hashing operations only compare 8 bytes, regardless of the actual string length.
  • Lazy evaluation: The actual string data is only accessed during serialization.
  • Serialization and deserialization support using Serde.

Memory Efficiency and Performance

The key features of StaticId are its memory efficiency and performance:

  1. Compact Representation: Each StaticId is stored as a single 64-bit pointer, regardless of the length of the underlying strings.
  2. Fast Comparisons: Equality checks and hash computations only compare the 64-bit pointers, making these operations extremely fast and constant-time.
  3. Lazy Evaluation: The actual string data is only accessed when necessary (e.g., during serialization), minimizing unnecessary memory access.

Limitations

  • The code component of a StaticId cannot exceed 32 bytes.
  • The venue component of a StaticId cannot exceed 16 bytes.
  • Attempting to create a StaticId with components exceeding these limits will result in truncation.

Usage

StaticId combines a Code (up to 32 bytes) and a Venue (up to 16 bytes) into an interned identifier:

use crate::StaticId;

// Create from string slices
let id = StaticId::from_str("AAPL", "NASDAQ");

// Create from byte slices
let id_bytes = StaticId::from_bytes(b"AAPL", b"NASDAQ");

assert_eq!(id.get_id().code.as_str(), "AAPL");
assert_eq!(id.get_id().venue.as_str(), "NASDAQ");

// Get the length of the combined code and venue
println!("Length: {}", id.len());  // Outputs the sum of code and venue lengths

// Get the number of unique StaticIds in the cache
println!("Cache size: {}", StaticId::cache_len());

// Fast equality check (compares only 8 bytes)
let id2 = StaticId::from_str("AAPL", "NASDAQ");
assert_eq!(id, id2);

// Memory usage
println!("Size of StaticId: {} bytes", std::mem::size_of::<StaticId>());  // Outputs: 8 bytes

Installation

Add this to your Cargo.toml:

[dependencies]

static_id = "0.1"

Performance Considerations

  • The first creation of a StaticId with unique content will involve allocation and interning. Subsequent creations of StaticIds with the same content will reuse the interned value.
  • While creation and interning have some overhead, subsequent operations like equality checks and hashing are extremely fast.
  • The library uses a global cache for interning, which is protected by a mutex. In highly concurrent scenarios, this could potentially become a bottleneck.
  • The cache_len() method allows you to monitor the size of the intern cache, which can be useful for understanding memory usage in your application.

License

This project is licensed under [LICENSE NAME] - see the LICENSE.md file for details.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.