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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// SHA256 block step.
// In its own file so that a faster assembly or C version
// can be substituted easily.
package sha256
import "math/bits"
var _K = []uint32{
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,
}
func blockGeneric(dig *digest, p []byte) {
var w [64]uint32
h0, h1, h2, h3, h4, h5, h6, h7 := dig.h[0], dig.h[1], dig.h[2], dig.h[3], dig.h[4], dig.h[5], dig.h[6], dig.h[7]
for len(p) >= chunk {
// Can interlace the computation of w with the
// rounds below if needed for speed.
for i := 0; i < 16; i++ {
j := i * 4
w[i] = uint32(p[j])<<24 | uint32(p[j+1])<<16 | uint32(p[j+2])<<8 | uint32(p[j+3])
}
for i := 16; i < 64; i++ {
v1 := w[i-2]
t1 := (bits.RotateLeft32(v1, -17)) ^ (bits.RotateLeft32(v1, -19)) ^ (v1 >> 10)
v2 := w[i-15]
t2 := (bits.RotateLeft32(v2, -7)) ^ (bits.RotateLeft32(v2, -18)) ^ (v2 >> 3)
w[i] = t1 + w[i-7] + t2 + w[i-16]
}
a, b, c, d, e, f, g, h := h0, h1, h2, h3, h4, h5, h6, h7
for i := 0; i < 64; i++ {
t1 := h + ((bits.RotateLeft32(e, -6)) ^ (bits.RotateLeft32(e, -11)) ^ (bits.RotateLeft32(e, -25))) + ((e & f) ^ (^e & g)) + _K[i] + w[i]
t2 := ((bits.RotateLeft32(a, -2)) ^ (bits.RotateLeft32(a, -13)) ^ (bits.RotateLeft32(a, -22))) + ((a & b) ^ (a & c) ^ (b & c))
h = g
g = f
f = e
e = d + t1
d = c
c = b
b = a
a = t1 + t2
}
h0 += a
h1 += b
h2 += c
h3 += d
h4 += e
h5 += f
h6 += g
h7 += h
p = p[chunk:]
}
dig.h[0], dig.h[1], dig.h[2], dig.h[3], dig.h[4], dig.h[5], dig.h[6], dig.h[7] = h0, h1, h2, h3, h4, h5, h6, h7
}