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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 12:41:41 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 12:41:41 +0000 |
commit | 10ee2acdd26a7f1298c6f6d6b7af9b469fe29b87 (patch) | |
tree | bdffd5d80c26cf4a7a518281a204be1ace85b4c1 /vendor/base16ct/src/lib.rs | |
parent | Releasing progress-linux version 1.70.0+dfsg1-9~progress7.99u1. (diff) | |
download | rustc-10ee2acdd26a7f1298c6f6d6b7af9b469fe29b87.tar.xz rustc-10ee2acdd26a7f1298c6f6d6b7af9b469fe29b87.zip |
Merging upstream version 1.70.0+dfsg2.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'vendor/base16ct/src/lib.rs')
-rw-r--r-- | vendor/base16ct/src/lib.rs | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/vendor/base16ct/src/lib.rs b/vendor/base16ct/src/lib.rs new file mode 100644 index 000000000..413d512d8 --- /dev/null +++ b/vendor/base16ct/src/lib.rs @@ -0,0 +1,118 @@ +//! Pure Rust implementation of Base16 ([RFC 4648], a.k.a. hex). +//! +//! Implements lower and upper case Base16 variants without data-dependent branches +//! or lookup tables, thereby providing portable "best effort" constant-time +//! operation. Not constant-time with respect to message length (only data). +//! +//! Supports `no_std` environments and avoids heap allocations in the core API +//! (but also provides optional `alloc` support for convenience). +//! +//! Based on code from: <https://github.com/Sc00bz/ConstTimeEncoding/blob/master/hex.cpp> +//! +//! # Examples +//! ``` +//! let lower_hex_str = "abcd1234"; +//! let upper_hex_str = "ABCD1234"; +//! let mixed_hex_str = "abCD1234"; +//! let raw = b"\xab\xcd\x12\x34"; +//! +//! let mut buf = [0u8; 16]; +//! // length of return slice can be different from the input buffer! +//! let res = base16ct::lower::decode(lower_hex_str, &mut buf).unwrap(); +//! assert_eq!(res, raw); +//! let res = base16ct::lower::encode(raw, &mut buf).unwrap(); +//! assert_eq!(res, lower_hex_str.as_bytes()); +//! // you also can use `encode_str` and `encode_string` to get +//! // `&str` and `String` respectively +//! let res: &str = base16ct::lower::encode_str(raw, &mut buf).unwrap(); +//! assert_eq!(res, lower_hex_str); +//! +//! let res = base16ct::upper::decode(upper_hex_str, &mut buf).unwrap(); +//! assert_eq!(res, raw); +//! let res = base16ct::upper::encode(raw, &mut buf).unwrap(); +//! assert_eq!(res, upper_hex_str.as_bytes()); +//! +//! // In cases when you don't know if input contains upper or lower +//! // hex-encoded value, then use functions from the `mixed` module +//! let res = base16ct::mixed::decode(lower_hex_str, &mut buf).unwrap(); +//! assert_eq!(res, raw); +//! let res = base16ct::mixed::decode(upper_hex_str, &mut buf).unwrap(); +//! assert_eq!(res, raw); +//! let res = base16ct::mixed::decode(mixed_hex_str, &mut buf).unwrap(); +//! assert_eq!(res, raw); +//! ``` +//! +//! [RFC 4648]: https://tools.ietf.org/html/rfc4648 + +#![no_std] +#![cfg_attr(docsrs, feature(doc_cfg))] +#![warn(missing_docs, rust_2018_idioms)] +#![doc( + html_logo_url = "https://raw.githubusercontent.com/RustCrypto/media/6ee8e381/logo.svg", + html_favicon_url = "https://raw.githubusercontent.com/RustCrypto/media/6ee8e381/logo.svg", + html_root_url = "https://docs.rs/base16ct/0.1.1" +)] + +#[cfg(feature = "alloc")] +#[macro_use] +extern crate alloc; +#[cfg(feature = "std")] +extern crate std; + +/// Function for decoding and encoding lower Base16 (hex) +pub mod lower; +/// Function for decoding mixed Base16 (hex) +pub mod mixed; +/// Function for decoding and encoding upper Base16 (hex) +pub mod upper; + +/// Display formatter for hex. +mod display; +/// Error types. +mod error; + +pub use crate::{ + display::HexDisplay, + error::{Error, Result}, +}; + +#[cfg(feature = "alloc")] +use alloc::{string::String, vec::Vec}; + +/// Compute decoded length of the given hex-encoded input. +#[inline(always)] +pub fn decoded_len(bytes: &[u8]) -> Result<usize> { + if bytes.len() & 1 == 0 { + Ok(bytes.len() / 2) + } else { + Err(Error::InvalidLength) + } +} + +/// Get the length of Base16 (hex) produced by encoding the given bytes. +#[inline(always)] +pub fn encoded_len(bytes: &[u8]) -> usize { + bytes.len() * 2 +} + +fn decode_inner<'a>( + src: &[u8], + dst: &'a mut [u8], + decode_nibble: impl Fn(u8) -> u16, +) -> Result<&'a [u8]> { + let dst = dst + .get_mut(..decoded_len(src)?) + .ok_or(Error::InvalidLength)?; + + let mut err: u16 = 0; + for (src, dst) in src.chunks_exact(2).zip(dst.iter_mut()) { + let byte = (decode_nibble(src[0]) << 4) | decode_nibble(src[1]); + err |= byte >> 8; + *dst = byte as u8; + } + + match err { + 0 => Ok(dst), + _ => Err(Error::InvalidEncoding), + } +} |