libipld_base/
hash.rs

1//! Hash types.
2use crate::cid::Cid;
3use crate::error::BlockError;
4use core::hash::{BuildHasher, Hasher};
5use multihash::Multihash;
6use std::collections::{HashMap, HashSet};
7
8/// Trait for hash type markers.
9pub trait Hash {
10    /// The multihash code.
11    const CODE: multihash::Code;
12
13    /// Computes the multihash of a byte slice.
14    fn digest(bytes: &[u8]) -> Multihash;
15}
16
17macro_rules! hash {
18    ($name:ident) => {
19        /// $name
20        #[derive(Clone, Debug, Hash, PartialEq, Eq)]
21        pub struct $name;
22
23        #[allow(clippy::derive_hash_xor_eq)]
24        impl Hash for $name {
25            const CODE: multihash::Code = multihash::Code::$name;
26
27            fn digest(bytes: &[u8]) -> Multihash {
28                multihash::$name::digest(bytes)
29            }
30        }
31    };
32}
33
34hash!(Identity);
35hash!(Sha1);
36hash!(Sha2_256);
37hash!(Sha2_512);
38hash!(Sha3_224);
39hash!(Sha3_256);
40hash!(Sha3_384);
41hash!(Sha3_512);
42hash!(Keccak224);
43hash!(Keccak256);
44hash!(Keccak384);
45hash!(Keccak512);
46hash!(Blake2b256);
47hash!(Blake2b512);
48hash!(Blake2s128);
49hash!(Blake2s256);
50//hash!(Murmur3_32);
51//hash!(Murmur3_128X64);
52
53/// Compute digest of bytes.
54pub fn digest(code: multihash::Code, bytes: &[u8]) -> Result<Multihash, BlockError> {
55    Ok(match code {
56        multihash::Code::Identity => multihash::Identity::digest(bytes),
57        multihash::Code::Sha1 => multihash::Sha1::digest(bytes),
58        multihash::Code::Sha2_256 => multihash::Sha2_256::digest(bytes),
59        multihash::Code::Sha2_512 => multihash::Sha2_512::digest(bytes),
60        multihash::Code::Sha3_224 => multihash::Sha3_224::digest(bytes),
61        multihash::Code::Sha3_256 => multihash::Sha3_256::digest(bytes),
62        multihash::Code::Sha3_384 => multihash::Sha3_384::digest(bytes),
63        multihash::Code::Sha3_512 => multihash::Sha3_512::digest(bytes),
64        multihash::Code::Keccak224 => multihash::Keccak224::digest(bytes),
65        multihash::Code::Keccak256 => multihash::Keccak256::digest(bytes),
66        multihash::Code::Keccak384 => multihash::Keccak384::digest(bytes),
67        multihash::Code::Keccak512 => multihash::Keccak512::digest(bytes),
68        multihash::Code::Blake2b256 => multihash::Blake2b256::digest(bytes),
69        multihash::Code::Blake2b512 => multihash::Blake2b512::digest(bytes),
70        multihash::Code::Blake2s128 => multihash::Blake2s128::digest(bytes),
71        multihash::Code::Blake2s256 => multihash::Blake2s256::digest(bytes),
72        //multihash::Code::Murmur3_32 => multihash::Murmur3_32::digest(bytes),
73        //multihash::Code::Murmur3_128X64 => multihash::Murmur3_128X64::digest(bytes),
74        code => return Err(BlockError::UnsupportedMultihash(code)),
75    })
76}
77
78/// A hasher builder for cid hasher.
79#[derive(Clone, Default)]
80pub struct BuildCidHasher;
81
82impl BuildHasher for BuildCidHasher {
83    type Hasher = CidHasher;
84
85    fn build_hasher(&self) -> Self::Hasher {
86        CidHasher(None)
87    }
88}
89
90/// A hasher that avoids rehashing cids by using the fact that they already
91/// contain a hash.
92pub struct CidHasher(Option<u64>);
93
94impl Hasher for CidHasher {
95    fn finish(&self) -> u64 {
96        self.0.unwrap()
97    }
98
99    fn write(&mut self, bytes: &[u8]) {
100        let mut b = [0u8; 8];
101        b.clone_from_slice(&bytes[..8]);
102        self.0 = Some(u64::from_be_bytes(b));
103    }
104
105    fn write_u64(&mut self, i: u64) {
106        self.0 = Some(i);
107    }
108}
109
110/// A HashMap for Cid's
111pub type CidHashMap<V> = HashMap<Cid, V, BuildCidHasher>;
112/// A HashSet for Cid's
113pub type CidHashSet = HashSet<Cid, BuildCidHasher>;
libipld_base/hash.rs

libipld_base/
hash.rs
