qr-base44

Base44 encoder/decoder for arbitrary bytes using a URL-safe QR-compatible alphabet.

• Encoding scheme: 2 bytes -> 3 chars; 1 byte -> 2 chars
• Alphabet: 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ$%*+-./: (44 characters)
• URL-safe: excludes space from Base45 (RFC 9285)
• Public API: byte-oriented operations, no string reinterpretation

Usage

cargo add qr-base44

use qr_base44::{encode, decode};

let data: &[u8] = &[0x01, 0x02, 0xFF];
let s = encode(data);
let back = decode(&s).unwrap();
assert_eq!(back, data);

Features

• URL-safe: Unlike Base45, Base44 removes the space character which can cause issues in URLs
• QR-compatible: Uses a subset of QR Code alphanumeric mode characters
• Efficient: Compact binary encoding with ~1.5x size overhead
• Error handling: Validates input and reports invalid characters, dangling groups, and overflow

Notes

• MSRV: 1.85+ (Rust 2024 edition requirement)
• This crate intentionally encodes/decodes arbitrary bytes, not UTF-8 text. If you have a text string, pass its bytes explicitly.
• Error types include: invalid characters, dangling final character, and numeric overflow.
• Compared to Base45, Base44 is more suitable for use in URLs and QR codes by removing the space character.

Documentation

• 中文文档 (Chinese Documentation)

License

Apache-2.0