seyk-embed 0.2.0

Model-independent embedding interfaces and values
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84

// Private, one-shot SHA-256 for the small immutable asset files (FIPS 180-4).
// No cryptographic API is exposed; this keeps seyk-embed dependency-free beyond
// its existing serde/thiserror interfaces. Asset goldens also exercise every hash.
pub(super) fn hex(bytes: &[u8]) -> String {
    const K: [u32; 64] = [
        0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4,
        0xab1c5ed5, 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe,
        0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f,
        0x4a7484aa, 0x5cb0a9dc, 0x76f988da, 0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
        0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc,
        0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, 0xa2bfe8a1, 0xa81a664b,
        0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070, 0x19a4c116,
        0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
        0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7,
        0xc67178f2,
    ];
    let mut state: [u32; 8] = [
        0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab,
        0x5be0cd19,
    ];
    let mut padded = bytes.to_vec();
    padded.push(0x80);
    while padded.len() % 64 != 56 {
        padded.push(0);
    }
    padded.extend_from_slice(&(bytes.len() as u64 * 8).to_be_bytes());
    for block in padded.as_chunks::<64>().0 {
        let mut w = [0u32; 64];
        for (word, chunk) in w.iter_mut().zip(block.as_chunks::<4>().0) {
            *word = u32::from_be_bytes(*chunk);
        }
        for i in 16..64 {
            let x = w[i - 15];
            let y = w[i - 2];
            let s0 = x.rotate_right(7) ^ x.rotate_right(18) ^ (x >> 3);
            let s1 = y.rotate_right(17) ^ y.rotate_right(19) ^ (y >> 10);
            w[i] = w[i - 16]
                .wrapping_add(s0)
                .wrapping_add(w[i - 7])
                .wrapping_add(s1);
        }
        let [mut a, mut b, mut c, mut d, mut e, mut f, mut g, mut h] = state;
        for i in 0..64 {
            let sum1 = e.rotate_right(6) ^ e.rotate_right(11) ^ e.rotate_right(25);
            let choice = (e & f) ^ (!e & g);
            let t1 = h
                .wrapping_add(sum1)
                .wrapping_add(choice)
                .wrapping_add(K[i])
                .wrapping_add(w[i]);
            let sum0 = a.rotate_right(2) ^ a.rotate_right(13) ^ a.rotate_right(22);
            let majority = (a & b) ^ (a & c) ^ (b & c);
            let t2 = sum0.wrapping_add(majority);
            (a, b, c, d, e, f, g, h) = (t1.wrapping_add(t2), a, b, c, d.wrapping_add(t1), e, f, g);
        }
        for (s, v) in state.iter_mut().zip([a, b, c, d, e, f, g, h]) {
            *s = s.wrapping_add(v);
        }
    }
    state.iter().map(|word| format!("{word:08x}")).collect()
}

#[cfg(test)]
mod tests {
    #[test]
    fn standard_vectors_cover_padding_boundaries() {
        for (input, expected) in [
            (
                "",
                "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
            ),
            (
                "abc",
                "ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad",
            ),
            (
                "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq",
                "248d6a61d20638b8e5c026930c3e6039a33ce45964ff2167f6ecedd419db06c1",
            ),
        ] {
            assert_eq!(super::hex(input.as_bytes()), expected);
        }
    }
}