Remove unsafe usage

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## [0.9.1] - 2020-04-03
+## Changed
+- Improve Go 1.14 compatibility (remove "unsafe" usage).
+
 ## [0.9.0] - 2020-03-08
 ## Changed
 - Replace the unstructured data file for storing key-value pairs with a write-ahead log.

internal/hash/murmurhash32.go

@@ -1,7 +1,7 @@
 package hash
 
 import (
-	"unsafe"
+	"math/bits"
 )
 
 const (
@@ -12,44 +12,38 @@ const (
 // Sum32WithSeed is a port of MurmurHash3_x86_32 function.
 func Sum32WithSeed(data []byte, seed uint32) uint32 {
 	h1 := seed
+	dlen := len(data)
 
-	nblocks := len(data) / 4
-	var p uintptr
-	if len(data) > 0 {
-		p = uintptr(unsafe.Pointer(&data[0]))
-	}
-	p1 := p + uintptr(4*nblocks)
-	for ; p < p1; p += 4 {
-		k1 := *(*uint32)(unsafe.Pointer(p))
+	for len(data) >= 4 {
+		k1 := uint32(data[0]) | uint32(data[1])<<8 | uint32(data[2])<<16 | uint32(data[3])<<24
+		data = data[4:]
 
 		k1 *= c1
-		k1 = (k1 << 15) | (k1 >> 17) // rotl32(k1, 15)
+		k1 = bits.RotateLeft32(k1, 15)
 		k1 *= c2
 
 		h1 ^= k1
-		h1 = (h1 << 13) | (h1 >> 19) // rotl32(h1, 13)
+		h1 = bits.RotateLeft32(h1, 13)
 		h1 = h1*5 + 0xe6546b64
 	}
 
-	tail := data[nblocks*4:]
-
 	var k1 uint32
-	switch len(tail) & 3 {
+	switch len(data) {
 	case 3:
-		k1 ^= uint32(tail[2]) << 16
+		k1 ^= uint32(data[2]) << 16
 		fallthrough
 	case 2:
-		k1 ^= uint32(tail[1]) << 8
+		k1 ^= uint32(data[1]) << 8
 		fallthrough
 	case 1:
-		k1 ^= uint32(tail[0])
+		k1 ^= uint32(data[0])
 		k1 *= c1
-		k1 = (k1 << 15) | (k1 >> 17) // rotl32(k1, 15)
+		k1 = bits.RotateLeft32(k1, 15)
 		k1 *= c2
 		h1 ^= k1
 	}
 
-	h1 ^= uint32(len(data))
+	h1 ^= uint32(dlen)
 
 	h1 ^= h1 >> 16
 	h1 *= 0x85ebca6b

internal/hash/murmurhash32_test.go

@@ -0,0 +1,22 @@
+package hash
+
+import (
+	"testing"
+)
+
+func TestSum32WithSeed(t *testing.T) {
+	// TODO: test all code paths
+	actual := Sum32WithSeed([]byte{1, 2, 3, 4, 5}, 0)
+	expected := uint32(2727459272)
+	if actual != expected {
+		t.Fatalf("expected: %d, actual: %d", expected, actual)
+	}
+}
+
+func BenchmarkSum32WithSeed(b *testing.B) {
+	data := []byte("pogreb_Sum32WithSeed_bench")
+	b.SetBytes(int64(len(data)))
+	for n := 0; n < b.N; n++ {
+		Sum32WithSeed(data, 0)
+	}
+}