Merge pull request #51 from JustinDrake/master

Add identity

multihash.go

@@ -36,6 +36,7 @@ func (e ErrInconsistentLen) Error() string {
 
 // constants
 const (
+	ID         = 0x00
 	SHA1       = 0x11
 	SHA2_256   = 0x12
 	SHA2_512   = 0x13
@@ -84,6 +85,7 @@ func init() {
 
 // Names maps the name of a hash to the code
 var Names = map[string]uint64{
+	"id":           ID,
 	"sha1":         SHA1,
 	"sha2-256":     SHA2_256,
 	"sha2-512":     SHA2_512,
@@ -104,6 +106,7 @@ var Names = map[string]uint64{
 
 // Codes maps a hash code to it's name
 var Codes = map[uint64]string{
+	ID:           "id",
 	SHA1:         "sha1",
 	SHA2_256:     "sha2-256",
 	SHA2_512:     "sha2-512",
@@ -123,6 +126,7 @@ var Codes = map[uint64]string{
 
 // DefaultLengths maps a hash code to it's default length
 var DefaultLengths = map[uint64]int{
+	ID:           32,
 	SHA1:         20,
 	SHA2_256:     32,
 	SHA2_512:     64,

multihash_test.go

@@ -11,6 +11,7 @@ import (
 // maybe silly, but makes it so changing
 // the table accidentally has to happen twice.
 var tCodes = map[uint64]string{
+	0x00: "id",
 	0x11: "sha1",
 	0x12: "sha2-256",
 	0x13: "sha2-512",
@@ -35,6 +36,7 @@ type TestCase struct {
 }
 
 var testCases = []TestCase{
+	TestCase{"2c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae", 0x00, "id"},
 	TestCase{"0beec7b5ea3f0fdbc95d0dd47f3c5bc275da8a33", 0x11, "sha1"},
 	TestCase{"0beec7b5", 0x11, "sha1"},
 	TestCase{"2c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae", 0x12, "sha2-256"},

sum.go

@@ -63,6 +63,8 @@ func Sum(data []byte, code uint64, length int) (Multihash, error) {
 		}
 	default:
 		switch code {
+		case ID:
+			d = sumID(data)
 		case SHA1:
 			d = sumSHA1(data)
 		case SHA2_256:
@@ -110,6 +112,10 @@ func isBlake2b(code uint64) bool {
 	return code >= BLAKE2B_MIN && code <= BLAKE2B_MAX
 }
 
+func sumID(data []byte) []byte {
+	return data
+}
+
 func sumSHA1(data []byte) []byte {
 	a := sha1.Sum(data)
 	return a[0:20]

sum_test.go

@@ -14,6 +14,7 @@ type SumTestCase struct {
 }
 
 var sumTestCases = []SumTestCase{
+	SumTestCase{ID, 3, "foo", "0003666f6f"},
 	SumTestCase{SHA1, -1, "foo", "11140beec7b5ea3f0fdbc95d0dd47f3c5bc275da8a33"},
 	SumTestCase{SHA1, 10, "foo", "110a0beec7b5ea3f0fdbc95d"},
 	SumTestCase{SHA2_256, -1, "foo", "12202c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae"},