ckb-rust-std

A collection of no_std compatible modules ported from Rust's standard library, with an initial focus on the io module. This crate provides essential functionality for no_std environments while maintaining API compatibility with std. Additional modules may be added in future releases.

Background

Currently, Rust lacks a standard no_std I/O implementation (see rust#48331 and rfcs#2262). While we await an official implementation, this crate provides the necessary I/O functionality for no_std environments.

Features

• Full no_std io module compatibility for embedded and bare-metal environments
• Compatible with stable Rust (no nightly features required)
• Drop-in replacement for std::io with identical semantics and API
• Comprehensive I/O traits and types ported from the standard library

Rust Error Compatibility

For Rust versions prior to 1.81.0, core::error::Error is not available in no_std environments. To maintain compatibility:

• For Rust >= 1.81.0: No special configuration needed
• For Rust < 1.81.0: Add the rust_before_181 feature flag in your Cargo.toml:

  [dependencies]
  ckb-rust-std = { version = "...", features = ["rust_before_181"] }
  

We strongly recommend using Rust 1.81 or later as it provides better error handling features.

Frequently Asked Questions

What version of std::io is this ported from?

This crate is ported from Rust 1.81's std::io implementation.

Where is the API documentation?

Since this is a direct port of std::io, we refer users to the official Rust std::io documentation. All traits, types, and functions maintain identical behavior and semantics to their std counterparts.

How to adopt official core::io if it is implemented?

When an official core::io implementation becomes available, migration should be straightforward:

1. Due to identical behavior and semantics, you can simply replace imports from ckb-rust-std::io with core::io
2. Update your Cargo.toml dependencies to remove this crate
3. No behavioral changes will be required in your code

For example:

// Before
use ckb_rust_std::io::{Read, Write};

// After
use core::io::{Read, Write};

What features are removed compared to std::io?

• Optimized implementations of copy() for specific types, due to the lack of specialization in stable Rust
• Optimized SizeHint implementations for certain iterators, due to the lack of specialization in stable Rust
• Vectored I/O operations (read_vectored() and related functions) due to limited use cases in no_std environments
• Error code representations (repr)
• The stdio module