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// Copyright (c) 2019-2021 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
// This is the generic version with no architecture optimizations.
// In its own file so that an architecture
// optimized verision can be substituted
module sha1
import math.bits
const (
_k0 = 0x5A827999
_k1 = 0x6ED9EBA1
_k2 = 0x8F1BBCDC
_k3 = 0xCA62C1D6
)
fn block_generic(mut dig Digest, p_ []byte) {
unsafe {
mut p := p_
mut w := []u32{len: (16)}
mut h0 := dig.h[0]
mut h1 := dig.h[1]
mut h2 := dig.h[2]
mut h3 := dig.h[3]
mut h4 := dig.h[4]
for p.len >= chunk {
// Can interlace the computation of w with the
// rounds below if needed for speed.
for i in 0 .. 16 {
j := i * 4
w[i] = u32(p[j] << 24) | u32(p[j + 1] << 16) | u32(p[j + 2] << 8) | u32(p[j + 3])
}
mut a := h0
mut b := h1
mut c := h2
mut d := h3
mut e := h4
// Each of the four 20-iteration rounds
// differs only in the computation of f and
// the choice of K (_k0, _k1, etc).
mut i := 0
for i < 16 {
f := b & c | (~b) & d
t := bits.rotate_left_32(a, 5) + f + e + w[i & 0xf] + u32(sha1._k0)
e = d
d = c
c = bits.rotate_left_32(b, 30)
b = a
a = t
i++
}
for i < 20 {
tmp := w[(i - 3) & 0xf] ^ w[(i - 8) & 0xf] ^ w[(i - 14) & 0xf] ^ w[i & 0xf]
w[i & 0xf] = (tmp << 1) | (tmp >> (32 - 1))
f := b & c | (~b) & d
t := bits.rotate_left_32(a, 5) + f + e + w[i & 0xf] + u32(sha1._k0)
e = d
d = c
c = bits.rotate_left_32(b, 30)
b = a
a = t
i++
}
for i < 40 {
tmp := w[(i - 3) & 0xf] ^ w[(i - 8) & 0xf] ^ w[(i - 14) & 0xf] ^ w[i & 0xf]
w[i & 0xf] = (tmp << 1) | (tmp >> (32 - 1))
f := b ^ c ^ d
t := bits.rotate_left_32(a, 5) + f + e + w[i & 0xf] + u32(sha1._k1)
e = d
d = c
c = bits.rotate_left_32(b, 30)
b = a
a = t
i++
}
for i < 60 {
tmp := w[(i - 3) & 0xf] ^ w[(i - 8) & 0xf] ^ w[(i - 14) & 0xf] ^ w[i & 0xf]
w[i & 0xf] = (tmp << 1) | (tmp >> (32 - 1))
f := ((b | c) & d) | (b & c)
t := bits.rotate_left_32(a, 5) + f + e + w[i & 0xf] + u32(sha1._k2)
e = d
d = c
c = bits.rotate_left_32(b, 30)
b = a
a = t
i++
}
for i < 80 {
tmp := w[(i - 3) & 0xf] ^ w[(i - 8) & 0xf] ^ w[(i - 14) & 0xf] ^ w[i & 0xf]
w[i & 0xf] = (tmp << 1) | (tmp >> (32 - 1))
f := b ^ c ^ d
t := bits.rotate_left_32(a, 5) + f + e + w[i & 0xf] + u32(sha1._k3)
e = d
d = c
c = bits.rotate_left_32(b, 30)
b = a
a = t
i++
}
h0 += a
h1 += b
h2 += c
h3 += d
h4 += e
if chunk >= p.len {
p = []
} else {
p = p[chunk..]
}
}
dig.h[0] = h0
dig.h[1] = h1
dig.h[2] = h2
dig.h[3] = h3
dig.h[4] = h4
}
}
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