digest_writer/
lib.rs

1//!
2//!
3#![warn(missing_docs)]
4#![warn(missing_debug_implementations)]
5extern crate digest;
6extern crate generic_array;
7
8use std::io;
9
10use generic_array::{ArrayLength, GenericArray};
11use digest::InvalidLength;
12pub use digest::{Input, BlockInput, FixedOutput, VariableOutput, Digest};
13
14/// A wrapper around Digest type that allows to use Write trait for hashing
15///
16/// # Example
17///
18/// ```rust
19/// extern crate sha2;
20/// extern crate digest;
21/// extern crate digest_writer;
22/// use std::fs::File;
23/// use std::io::{self, Write};
24/// use digest::FixedOutput;
25/// use digest_writer::Writer;
26/// # fn main() {
27/// let mut digest = Writer::new(sha2::Sha256::default());
28/// let mut f = File::open("LICENSE-MIT").unwrap();
29/// io::copy(&mut f, &mut digest).unwrap();
30/// digest.fixed_result();
31/// # }
32/// ```
33#[derive(Debug, Clone, Default)]
34pub struct Writer<D>(D);
35
36impl<D: Input + FixedOutput> Writer<D> {
37    /// Wrap a Digest into a Writer
38    pub fn new(d: D) -> Writer<D> {
39        Writer(d)
40    }
41    /// Returns a reference to underlying Digest object
42    pub fn get_ref(&self) -> &D {
43        &self.0
44    }
45    /// Returns a mutable reference to underlying Digest object
46    pub fn get_mut(&mut self) -> &mut D {
47        &mut self.0
48    }
49    /// Return the original Digest
50    pub fn into_inner(self) -> D {
51        self.0
52    }
53}
54
55impl<D: Input> io::Write for Writer<D> {
56
57    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
58        self.0.process(buf);
59        Ok(buf.len())
60    }
61    fn flush(&mut self) -> io::Result<()> {
62        Ok(())
63    }
64}
65
66impl<D: Input> Input for Writer<D> {
67    fn process(&mut self, input: &[u8]) {
68        self.0.process(input);
69    }
70}
71
72impl<D> BlockInput for Writer<D>
73    where D: BlockInput, D::BlockSize: ArrayLength<u8>
74{
75    type BlockSize = D::BlockSize;
76}
77
78impl<D> FixedOutput for Writer<D>
79    where D: FixedOutput, D::OutputSize: ArrayLength<u8>
80{
81    type OutputSize = D::OutputSize;
82
83    fn fixed_result(self) -> GenericArray<u8, Self::OutputSize> {
84        self.0.fixed_result()
85    }
86}
87
88impl<D: VariableOutput> VariableOutput for Writer<D> {
89    fn new(output_size: usize) -> Result<Writer<D>, InvalidLength> {
90        D::new(output_size).map(Writer)
91    }
92    fn output_size(&self) -> usize {
93        self.0.output_size()
94    }
95    fn variable_result(self, buffer: &mut [u8]) -> Result<&[u8], InvalidLength> {
96        self.0.variable_result(buffer)
97    }
98}
digest_writer/lib.rs

digest_writer/
lib.rs
