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diff --git a/vendor/base16ct/src/lib.rs b/vendor/base16ct/src/lib.rs
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+//! 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),
+    }
+}