use faster sha256 and blake2b implementations

fixes #61

package.json

@@ -30,6 +30,18 @@
       "hash": "QmfJHywXQu98UeZtGJBQrPAR6AtmDjjbe3qjTo9piXHPnx",
       "name": "murmur3",
       "version": "0.0.0"
+    },
+    {
+      "author": "minio",
+      "hash": "QmYmZHLQ4ctyTv84Qfrw39jWzSWvbjo8cb6rkb6oWwzC6T",
+      "name": "sha256-simd",
+      "version": "0.1.0"
+    },
+    {
+      "author": "minio",
+      "hash": "QmctbhjPfFUCFWemafc7LGXUKJuoRm8baJaiQEELMgbUFV",
+      "name": "blake2b-simd",
+      "version": "0.1.0"
     }
   ],
   "gxVersion": "0.9.0",

sum.go

@@ -2,13 +2,13 @@ package multihash
 
 import (
 	"crypto/sha1"
-	"crypto/sha256"
 	"crypto/sha512"
 	"errors"
 	"fmt"
 
-	"github.com/spaolacci/murmur3"
-	blake2b "golang.org/x/crypto/blake2b"
+	blake2b "github.com/minio/blake2b-simd"
+	sha256 "github.com/minio/sha256-simd"
+	murmur3 "github.com/spaolacci/murmur3"
 	blake2s "golang.org/x/crypto/blake2s"
 	sha3 "golang.org/x/crypto/sha3"
 	keccak "leb.io/hashland/keccakpg"
@@ -50,14 +50,11 @@ func Sum(data []byte, code uint64, length int) (Multihash, error) {
 		olen := code - BLAKE2B_MIN + 1
 		switch olen {
 		case 32:
-			out := blake2b.Sum256(data)
-			d = out[:]
+			d = sumBlake2b256(data)
 		case 48:
-			out := blake2b.Sum384(data)
-			d = out[:]
+			d = sumBlake2b384(data)
 		case 64:
-			out := blake2b.Sum512(data)
-			d = out[:]
+			d = sumBlake2b512(data)
 		default:
 			return nil, fmt.Errorf("unsupported length for blake2b: %d", olen)
 		}
@@ -115,6 +112,32 @@ func isBlake2b(code uint64) bool {
 	return code >= BLAKE2B_MIN && code <= BLAKE2B_MAX
 }
 
+func sumBlake2b256(data []byte) []byte {
+	out := blake2b.Sum256(data)
+	return out[:]
+}
+
+const blake2b384Size = 384 / 8
+
+var blake2b384Config = &blake2b.Config{Size: blake2b384Size}
+
+func sumBlake2b384(data []byte) []byte {
+	hasher, err := blake2b.New(blake2b384Config)
+	if err != nil {
+		panic(err)
+	}
+	hasher.Write(data)
+	var out [blake2b384Size]byte
+	copy(out[:], hasher.Sum(nil)[:blake2b384Size])
+	return out[:]
+
+}
+
+func sumBlake2b512(data []byte) []byte {
+	out := blake2b.Sum512(data)
+	return out[:]
+}
+
 func sumID(data []byte) []byte {
 	return data
 }