1 files changed, 83 insertions, 0 deletions
diff --git a/src/crypto/sha1/sha1block.go b/src/crypto/sha1/sha1block.go
new file mode 100644
index 0000000..321d343
--- /dev/null
+++ b/src/crypto/sha1/sha1block.go
@@ -0,0 +1,83 @@
+// 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.
+
+package sha1
+
+import (
+	"math/bits"
+)
+
+const (
+	_K0 = 0x5A827999
+	_K1 = 0x6ED9EBA1
+	_K2 = 0x8F1BBCDC
+	_K3 = 0xCA62C1D6
+)
+
+// blockGeneric is a portable, pure Go version of the SHA-1 block step.
+// It's used by sha1block_generic.go and tests.
+func blockGeneric(dig *digest, p []byte) {
+	var w [16]uint32
+
+	h0, h1, h2, h3, h4 := dig.h[0], dig.h[1], dig.h[2], dig.h[3], dig.h[4]
+	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])
+		}
+
+		a, b, c, d, e := h0, h1, h2, h3, h4
+
+		// Each of the four 20-iteration rounds
+		// differs only in the computation of f and
+		// the choice of K (_K0, _K1, etc).
+		i := 0
+		for ; i < 16; i++ {
+			f := b&c | (^b)&d
+			t := bits.RotateLeft32(a, 5) + f + e + w[i&0xf] + _K0
+			a, b, c, d, e = t, a, bits.RotateLeft32(b, 30), c, d
+		}
+		for ; i < 20; i++ {
+			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.RotateLeft32(a, 5) + f + e + w[i&0xf] + _K0
+			a, b, c, d, e = t, a, bits.RotateLeft32(b, 30), c, d
+		}
+		for ; i < 40; i++ {
+			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.RotateLeft32(a, 5) + f + e + w[i&0xf] + _K1
+			a, b, c, d, e = t, a, bits.RotateLeft32(b, 30), c, d
+		}
+		for ; i < 60; i++ {
+			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.RotateLeft32(a, 5) + f + e + w[i&0xf] + _K2
+			a, b, c, d, e = t, a, bits.RotateLeft32(b, 30), c, d
+		}
+		for ; i < 80; i++ {
+			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.RotateLeft32(a, 5) + f + e + w[i&0xf] + _K3
+			a, b, c, d, e = t, a, bits.RotateLeft32(b, 30), c, d
+		}
+
+		h0 += a
+		h1 += b
+		h2 += c
+		h3 += d
+		h4 += e
+
+		p = p[chunk:]
+	}
+
+	dig.h[0], dig.h[1], dig.h[2], dig.h[3], dig.h[4] = h0, h1, h2, h3, h4
+}