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diff --git a/third_party/rust/digest/src/lib.rs b/third_party/rust/digest/src/lib.rs
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+//! This crate provides traits which describe funcionality of cryptographic hash
+//! functions.
+//!
+//! Traits in this repository can be separatedin two levels:
+//! - Low level traits: `Input`, `BlockInput`, `Reset`, `FixedOutput`,
+//! `VariableOutput`, `ExtendableOutput`. These traits atomically describe
+//! available functionality of hash function implementations.
+//! - Convinience trait: `Digest`, `DynDigest`. They are wrappers around
+//! low level traits for most common hash-function use-cases.
+//!
+//! Additionally hash functions implement traits from `std`: `Default`, `Clone`,
+//! `Write`. (the latter depends on enabled-by-default `std` crate feature)
+//!
+//! The `Digest` trait is the most commonly used trait.
+#![no_std]
+#![doc(html_logo_url =
+    "https://raw.githubusercontent.com/RustCrypto/meta/master/logo_small.png")]
+pub extern crate generic_array;
+#[cfg(feature = "std")]
+#[macro_use] extern crate std;
+#[cfg(feature = "dev")]
+pub extern crate blobby;
+use generic_array::{GenericArray, ArrayLength};
+#[cfg(feature = "std")]
+use std::vec::Vec;
+
+mod digest;
+mod dyn_digest;
+mod errors;
+#[cfg(feature = "dev")]
+pub mod dev;
+
+pub use errors::InvalidOutputSize;
+pub use digest::Digest;
+#[cfg(feature = "std")]
+pub use dyn_digest::DynDigest;
+
+/// Trait for processing input data
+pub trait Input {
+    /// Digest input data.
+    ///
+    /// This method can be called repeatedly, e.g. for processing streaming
+    /// messages.
+    fn input<B: AsRef<[u8]>>(&mut self, data: B);
+
+    /// Digest input data in a chained manner.
+    fn chain<B: AsRef<[u8]>>(mut self, data: B) -> Self where Self: Sized {
+        self.input(data);
+        self
+    }
+}
+
+/// Trait to indicate that digest function processes data in blocks of size
+/// `BlockSize`.
+///
+/// The main usage of this trait is for implementing HMAC generically.
+pub trait BlockInput {
+    type BlockSize: ArrayLength<u8>;
+}
+
+/// Trait for returning digest result with the fixed size
+pub trait FixedOutput {
+    type OutputSize: ArrayLength<u8>;
+
+    /// Retrieve result and consume hasher instance.
+    fn fixed_result(self) -> GenericArray<u8, Self::OutputSize>;
+}
+
+/// Trait for returning digest result with the varaible size
+pub trait VariableOutput: core::marker::Sized {
+    /// Create new hasher instance with the given output size.
+    ///
+    /// It will return `Err(InvalidOutputSize)` in case if hasher can not return
+    /// specified output size. It will always return an error if output size
+    /// equals to zero.
+    fn new(output_size: usize) -> Result<Self, InvalidOutputSize>;
+
+    /// Get output size of the hasher instance provided to the `new` method
+    fn output_size(&self) -> usize;
+
+    /// Retrieve result via closure and consume hasher.
+    ///
+    /// Closure is guaranteed to be called, length of the buffer passed to it
+    /// will be equal to `output_size`.
+    fn variable_result<F: FnOnce(&[u8])>(self, f: F);
+
+    /// Retrieve result into vector and consume hasher.
+    #[cfg(feature = "std")]
+    fn vec_result(self) -> Vec<u8> {
+        let mut buf = Vec::with_capacity(self.output_size());
+        self.variable_result(|res| buf.extend_from_slice(res));
+        buf
+    }
+}
+
+/// Trait for decribing readers which are used to extract extendable output
+/// from XOF (extendable-output function) result.
+pub trait XofReader {
+    /// Read output into the `buffer`. Can be called unlimited number of times.
+    fn read(&mut self, buffer: &mut [u8]);
+}
+
+/// Trait which describes extendable-output functions (XOF).
+pub trait ExtendableOutput: core::marker::Sized {
+    type Reader: XofReader;
+
+    /// Retrieve XOF reader and consume hasher instance.
+    fn xof_result(self) -> Self::Reader;
+
+    /// Retrieve result into vector of specified length.
+    #[cfg(feature = "std")]
+    fn vec_result(self, n: usize) -> Vec<u8> {
+        let mut buf = vec![0u8; n];
+        self.xof_result().read(&mut buf);
+        buf
+    }
+}
+
+/// Trait for resetting hash instances
+pub trait Reset {
+    /// Reset hasher instance to its initial state and return current state.
+    fn reset(&mut self);
+}
+
+#[macro_export]
+/// Implements `std::io::Write` trait for implementator of `Input`
+macro_rules! impl_write {
+    ($hasher:ident) => {
+        #[cfg(feature = "std")]
+        impl ::std::io::Write for $hasher {
+            fn write(&mut self, buf: &[u8]) -> ::std::io::Result<usize> {
+                Input::input(self, buf);
+                Ok(buf.len())
+            }
+
+            fn flush(&mut self) -> ::std::io::Result<()> {
+                Ok(())
+            }
+        }
+    }
+}