From d7974d2277b030dab9c63a213c26c59c55656250 Mon Sep 17 00:00:00 2001
From: Kevin Atkinson <k@kevina.org>
Date: Sat, 25 Aug 2018 02:32:22 -0400
Subject: [PATCH] Export version() method, various other code cleanups.

---
 cid.go      | 40 ++++++++++++++++++----------------------
 cid_test.go | 29 +++++------------------------
 2 files changed, 23 insertions(+), 46 deletions(-)

diff --git a/cid.go b/cid.go
index 099dd63..12fa3bd 100644
--- a/cid.go
+++ b/cid.go
@@ -165,19 +165,7 @@ func newCid(version, codecType uint64, mhash mh.Multihash) Cid {
 // - hash mh.Multihash
 type Cid string
 
-var EmptyCid = Cid(string([]byte{}))
-
-func (c Cid) version() uint64 {
-	v, _ := binary.Uvarint([]byte(c))
-	return v
-}
-
-func (c Cid) codec() uint64 {
-	bytes := []byte(c)
-	_, n := binary.Uvarint(bytes)
-	codec, _ := binary.Uvarint(bytes[n:])
-	return codec
-}
+var EmptyCid = Cid("")
 
 // Parse is a short-hand function to perform Decode, Cast etc... on
 // a generic interface{} type.
@@ -310,16 +298,25 @@ func Cast(data []byte) (Cid, error) {
 	return Cid(data[0 : n+cn+len(h)]), nil
 }
 
+// Version returns the Cid version.
+func (c Cid) Version() uint64 {
+	v, _ := binary.Uvarint([]byte(c))
+	return v
+}
+
 // Type returns the multicodec-packed content type of a Cid.
 func (c Cid) Type() uint64 {
-	return c.codec()
+	bytes := []byte(c)
+	_, n := binary.Uvarint(bytes)
+	codec, _ := binary.Uvarint(bytes[n:])
+	return codec
 }
 
 // String returns the default string representation of a
 // Cid. Currently, Base58 is used as the encoding for the
 // multibase string.
 func (c Cid) String() string {
-	switch c.version() {
+	switch c.Version() {
 	case 0:
 		return c.Hash().B58String()
 	case 1:
@@ -337,7 +334,7 @@ func (c Cid) String() string {
 // String returns the string representation of a Cid
 // encoded is selected base
 func (c Cid) StringOfBase(base mbase.Encoding) (string, error) {
-	switch c.version() {
+	switch c.Version() {
 	case 0:
 		if base != mbase.Base58BTC {
 			return "", ErrInvalidEncoding
@@ -354,7 +351,7 @@ func (c Cid) StringOfBase(base mbase.Encoding) (string, error) {
 // when applicable.  Version 0 Cid's are always in Base58 as they do
 // not take a multibase prefix.
 func (c Cid) Encode(base mbase.Encoder) string {
-	switch c.version() {
+	switch c.Version() {
 	case 0:
 		return c.Hash().B58String()
 	case 1:
@@ -379,7 +376,7 @@ func (c Cid) Hash() mh.Multihash {
 // The output of bytes can be parsed back into a Cid
 // with Cast().
 func (c Cid) Bytes() []byte {
-	switch c.version() {
+	switch c.Version() {
 	case 0:
 		return c.bytesV0()
 	case 1:
@@ -401,8 +398,7 @@ func (c Cid) bytesV1() []byte {
 // In order for two Cids to be considered equal, the
 // Version, the Codec and the Multihash must match.
 func (c Cid) Equals(o Cid) bool {
-	// TODO: can we use regular string equality?
-	return bytes.Equal([]byte(c), []byte(o))
+	return c == o
 }
 
 // UnmarshalJSON parses the JSON representation of a Cid.
@@ -461,8 +457,8 @@ func (c Cid) Prefix() Prefix {
 	return Prefix{
 		MhType:   dec.Code,
 		MhLength: dec.Length,
-		Version:  c.version(),
-		Codec:    c.codec(),
+		Version:  c.Version(),
+		Codec:    c.Type(),
 	}
 }
 
diff --git a/cid_test.go b/cid_test.go
index 0b7f343..ab1e668 100644
--- a/cid_test.go
+++ b/cid_test.go
@@ -38,11 +38,11 @@ var tCodecs = map[uint64]string{
 }
 
 func assertEqual(t *testing.T, a, b Cid) {
-	if a.codec() != b.codec() {
+	if a.Type() != b.Type() {
 		t.Fatal("mismatch on type")
 	}
 
-	if a.version() != b.version() {
+	if a.Version() != b.Version() {
 		t.Fatal("mismatch on version")
 	}
 
@@ -171,7 +171,7 @@ func TestV0Handling(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	if cid.version() != 0 {
+	if cid.Version() != 0 {
 		t.Fatal("should have gotten version 0 cid")
 	}
 
@@ -341,8 +341,8 @@ func TestParse(t *testing.T) {
 		if err != nil {
 			return err
 		}
-		if cid.version() != 0 {
-			return fmt.Errorf("expected version 0, got %s", string(cid.version()))
+		if cid.Version() != 0 {
+			return fmt.Errorf("expected version 0, got %s", string(cid.Version()))
 		}
 		actual := cid.Hash().B58String()
 		if actual != expected {
@@ -446,22 +446,3 @@ func BenchmarkStringV1(b *testing.B) {
 		b.FailNow()
 	}
 }
-
-// making sure we don't allocate when returning bytes
-func BenchmarkBytesV1(b *testing.B) {
-	data := []byte("this is some test content")
-	hash, _ := mh.Sum(data, mh.SHA2_256, -1)
-	cid := NewCidV1(Raw, hash)
-
-	b.ReportAllocs()
-	b.ResetTimer()
-
-	count := 0
-	for i := 0; i < b.N; i++ {
-		count += len(cid.Bytes())
-		count += len([]byte(cid))
-	}
-	if count != 36*2*b.N {
-		b.FailNow()
-	}
-}