Crate base64_turbo 

Base64 Turbo

The fastest memory-safe Base64 implementation.

base64-turbo is a production-grade library engineered for high-throughput systems where CPU cycles are scarce and Undefined Behavior (UB) is unacceptable.

This crate provides runtime CPU detection to utilize AVX512, AVX2, or SSE4.1 intrinsics. It includes a highly optimized scalar fallback for non-SIMD targets and supports no_std environments.

Usage

Add this to your Cargo.toml:

[dependencies]
base64-turbo = "0.1"

Basic API (Allocating)

Standard usage for general applications. Requires the std feature (enabled by default).

use base64_turbo::STANDARD;
 
let data = b"Hello world";
 
// Encode to String
let encoded = STANDARD.encode(data);
assert_eq!(encoded, "SGVsbG8gd29ybGQ=");
 
// Decode to Vec<u8>
let decoded = STANDARD.decode(&encoded).unwrap();
assert_eq!(decoded, data);

Zero-Allocation API (Slice-based)

For low-latency scenarios or no_std environments where heap allocation is undesirable. These methods write directly into a user-provided mutable slice.

use base64_turbo::STANDARD;
 
let input = b"Raw bytes";
let mut output = [0u8; 64]; // Pre-allocated stack buffer
 
// Returns Result<usize, Error> indicating bytes written
let len = STANDARD.encode_into(input, &mut output).unwrap();
 
assert_eq!(&output[..len], b"UmF3IGJ5dGVz");

Feature Flags

This crate is highly configurable via Cargo features:

Feature	Default	Description
std	Yes	Enables String and Vec support. Disable this for no_std environments.
simd	Yes	Enables runtime detection for AVX512, AVX2, and SSE4.1 intrinsics. If disabled or unsupported by hardware, the crate falls back to scalar logic automatically.
unstable	No	Enables access to the raw, unsafe internal functions (e.g. encode_avx2).

Safety & Verification

This crate utilizes unsafe code for SIMD intrinsics and pointer arithmetic to achieve maximum performance. To ensure safety, we employ a “Swiss Cheese” model of verification layers:

• Formal Verification (Kani): Mathematical proofs ensure the kernels never read out of bounds or panic on any input (0..∞ bytes).
• MIRI Audited: All SIMD paths (AVX512, AVX2, SSE4.1) and Scalar fallbacks are verified with MIRI (Undefined Behavior checker) in CI to ensure strict memory safety.
• MemorySanitizer: The codebase is audited with MSan to prevent logic errors derived from reading uninitialized memory.
• Fuzzing: The codebase is fuzz-tested via cargo-fuzz (2.5B+ iterations).

Learn More: Details on our threat model and formal verification strategy.

Structs

Engine

A high-performance, stateless Base64 encoder/decoder.

Enums

Error

Errors that can occur during Base64 encoding or decoding operations.

Constants

STANDARD

Standard Base64 (RFC 4648) with padding (=).

STANDARD_NO_PAD

Standard Base64 (RFC 4648) without padding.

URL_SAFE

URL-Safe Base64 with padding.

URL_SAFE_NO_PAD

URL-Safe Base64 without padding.