From 60870290a20eecd4be6d3b16893c183e40cd13a2 Mon Sep 17 00:00:00 2001
From: Sergey Matveev <stargrave@stargrave.org>
Date: Fri, 2 Aug 2019 12:52:40 +0300
Subject: [PATCH] GOST34112012 hashes satisfy Binary(Un)Marshaler

---
 .../gogost/internal/gost34112012/hash.go      | 44 +++++++++++++++++++
 .../gogost/internal/gost34112012/hash_test.go | 23 +++++++++-
 2 files changed, 66 insertions(+), 1 deletion(-)

diff --git a/src/cypherpunks.ru/gogost/internal/gost34112012/hash.go b/src/cypherpunks.ru/gogost/internal/gost34112012/hash.go
index c4d98da..ea35468 100644
--- a/src/cypherpunks.ru/gogost/internal/gost34112012/hash.go
+++ b/src/cypherpunks.ru/gogost/internal/gost34112012/hash.go
@@ -19,11 +19,15 @@
 package gost34112012
 
 import (
+	"bytes"
 	"encoding/binary"
+	"errors"
 )
 
 const (
 	BlockSize = 64
+
+	MarshaledName = "STREEBOG"
 )
 
 var (
@@ -403,3 +407,43 @@ func l(data *[BlockSize]byte) *[BlockSize]byte {
 	}
 	return r
 }
+
+func (h *Hash) MarshalBinary() (data []byte, err error) {
+	data = make([]byte, len(MarshaledName)+1+8+3*BlockSize+len(h.buf))
+	copy(data, []byte(MarshaledName))
+	idx := len(MarshaledName)
+	data[idx] = byte(h.size)
+	idx += 1
+	binary.BigEndian.PutUint64(data[idx:idx+8], h.n)
+	idx += 8
+	copy(data[idx:], h.hsh[:])
+	idx += BlockSize
+	copy(data[idx:], h.chk[:])
+	idx += BlockSize
+	copy(data[idx:], h.tmp[:])
+	idx += BlockSize
+	copy(data[idx:], h.buf)
+	return
+}
+
+func (h *Hash) UnmarshalBinary(data []byte) error {
+	if len(data) < len(MarshaledName)+1+8+3*BlockSize {
+		return errors.New("too short data")
+	}
+	if !bytes.HasPrefix(data, []byte(MarshaledName)) {
+		return errors.New("no hash name prefix")
+	}
+	idx := len(MarshaledName)
+	h.size = int(data[idx])
+	idx += 1
+	h.n = binary.BigEndian.Uint64(data[idx : idx+8])
+	idx += 8
+	copy(h.hsh[:], data[idx:])
+	idx += BlockSize
+	copy(h.chk[:], data[idx:])
+	idx += BlockSize
+	copy(h.tmp[:], data[idx:])
+	idx += BlockSize
+	h.buf = data[idx:]
+	return nil
+}
diff --git a/src/cypherpunks.ru/gogost/internal/gost34112012/hash_test.go b/src/cypherpunks.ru/gogost/internal/gost34112012/hash_test.go
index 1e0df64..5309447 100644
--- a/src/cypherpunks.ru/gogost/internal/gost34112012/hash_test.go
+++ b/src/cypherpunks.ru/gogost/internal/gost34112012/hash_test.go
@@ -19,6 +19,7 @@ package gost34112012
 import (
 	"bytes"
 	"crypto/rand"
+	"encoding"
 	"hash"
 	"testing"
 	"testing/quick"
@@ -27,6 +28,8 @@ import (
 func TestHashInterface(t *testing.T) {
 	h := New(64)
 	var _ hash.Hash = h
+	var _ encoding.BinaryMarshaler = h
+	var _ encoding.BinaryUnmarshaler = h
 }
 
 func TestVectors(t *testing.T) {
@@ -188,12 +191,30 @@ func TestRandom(t *testing.T) {
 		h.Reset()
 		h.Write(data)
 		d1 := h.Sum(nil)
+		h1Raw, err := h.MarshalBinary()
+		if err != nil {
+			return false
+		}
 		h.Reset()
 		for _, c := range data {
 			h.Write([]byte{c})
 		}
 		d2 := h.Sum(nil)
-		return bytes.Compare(d1, d2) == 0
+		if bytes.Compare(d1, d2) != 0 {
+			return false
+		}
+		h2Raw, err := h.MarshalBinary()
+		if err != nil {
+			return false
+		}
+		if bytes.Compare(h1Raw, h2Raw) != 0 {
+			return false
+		}
+		hNew := New(64)
+		if err = hNew.UnmarshalBinary(h1Raw); err != nil {
+			return false
+		}
+		return bytes.Compare(hNew.Sum(nil), d1) == 0
 	}
 	if err := quick.Check(f, nil); err != nil {
 		t.Error(err)
-- 
2.44.0