43 lines
992 B
Rust
43 lines
992 B
Rust
use blake2_rfc::blake2b::Blake2b;
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use std::io::{self, Read};
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/// Abstraction over a reader which hashes the data being read.
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pub struct HashReader<R: Read> {
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reader: R,
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hasher: Blake2b,
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}
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impl<R: Read> HashReader<R> {
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/// Construct a new `HashReader` given an existing `reader` by value.
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pub fn new(reader: R) -> Self {
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HashReader {
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reader: reader,
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hasher: Blake2b::new(64),
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}
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}
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/// Destroy this reader and return the hash of what was read.
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pub fn into_hash(self) -> String {
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let hash = self.hasher.finalize();
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let mut s = String::new();
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for c in hash.as_bytes().iter() {
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s += &format!("{:02x}", c);
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}
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s
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}
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}
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impl<R: Read> Read for HashReader<R> {
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fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
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let bytes = self.reader.read(buf)?;
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if bytes > 0 {
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self.hasher.update(&buf[0..bytes]);
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}
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Ok(bytes)
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}
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}
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