From 244d10ac25d1adc0f10e089f8d457269b109897d Mon Sep 17 00:00:00 2001
From: siddharth <s@ricketyspace.net>
Date: Sun, 10 Oct 2021 11:18:25 -0400
Subject: lib: move sha arithmetic functions to hash.go

---
 lib/hash.go | 19 +++++++++++++++++++
 lib/sha1.go | 35 ++++++++---------------------------
 2 files changed, 27 insertions(+), 27 deletions(-)

diff --git a/lib/hash.go b/lib/hash.go
index f0f4625..363d3d6 100644
--- a/lib/hash.go
+++ b/lib/hash.go
@@ -28,6 +28,25 @@ func shaMessageBlocks(pm []byte) [][]uint32 {
 	return mbs
 }
 
+// (a + b + ...) mod 2^32
+func shaAdd(n ...uint32) uint32 {
+	sum := uint64(0)
+	for _, v := range n {
+		sum += uint64(v)
+	}
+	return uint32(sum & 0xFFFFFFFF)
+}
+
+// Circular Right Shift
+func shaRotr(x uint32, n uint) uint32 {
+	return (x >> n) | (x << (32 - n))
+}
+
+// Circular Left Shift
+func shaRotl(x uint32, n uint) uint32 {
+	return (x << n) | (x >> (32 - n))
+}
+
 // Returns Merkle–Damgård padding in bytes for length of mesage `l`
 // bytes.
 func MDPadding(l int) []byte {
diff --git a/lib/sha1.go b/lib/sha1.go
index 5010bfb..e4ab369 100644
--- a/lib/sha1.go
+++ b/lib/sha1.go
@@ -21,25 +21,6 @@ var sha1IHashValues []uint32 = []uint32{
 	0xc3d2e1f0,
 }
 
-// (a + b + ...) mod 2^32
-func sha1Add(n ...uint32) uint32 {
-	sum := uint64(0)
-	for _, v := range n {
-		sum += uint64(v)
-	}
-	return uint32(sum & 0xFFFFFFFF)
-}
-
-// Circular Right Shift
-func sha1Rotr(x uint32, n uint) uint32 {
-	return (x >> n) | (x << (32 - n))
-}
-
-// Circular Left Shift
-func sha1Rotl(x uint32, n uint) uint32 {
-	return (x << n) | (x >> (32 - n))
-}
-
 // SHA-1 - Function f_t(x, y, z)
 func sha1FT(t int, x, y, z uint32) uint32 {
 	switch {
@@ -83,7 +64,7 @@ func sha1MessageSchedule(mb []uint32) []uint32 {
 		if t <= 15 {
 			w = append(w, mb[t])
 		} else {
-			w = append(w, sha1Rotl(w[t-3]^w[t-8]^w[t-14]^w[t-16], 1))
+			w = append(w, shaRotl(w[t-3]^w[t-8]^w[t-14]^w[t-16], 1))
 		}
 	}
 	return w
@@ -142,21 +123,21 @@ func (s *Sha1) Hash() []byte {
 		e := h[4]
 
 		for t := 0; t <= 79; t++ {
-			tmp := sha1Add(sha1Rotl(a, 5), sha1FT(t, b, c, d),
+			tmp := shaAdd(shaRotl(a, 5), sha1FT(t, b, c, d),
 				e, sha1KT(t), w[t])
 			e = d
 			d = c
-			c = sha1Rotl(b, 30)
+			c = shaRotl(b, 30)
 			b = a
 			a = tmp
 		}
 
 		// Compute intermediate hash values.
-		h[0] = sha1Add(a, h[0])
-		h[1] = sha1Add(b, h[1])
-		h[2] = sha1Add(c, h[2])
-		h[3] = sha1Add(d, h[3])
-		h[4] = sha1Add(e, h[4])
+		h[0] = shaAdd(a, h[0])
+		h[1] = shaAdd(b, h[1])
+		h[2] = shaAdd(c, h[2])
+		h[3] = shaAdd(d, h[3])
+		h[4] = shaAdd(e, h[4])
 	}
 
 	// Slurp sha1 digest from hash values.
-- 
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