Move MD5Entry type to tests only where it belongs.

It's not part of the package public interface.
Also fixes a number of golint errors in md5crypt.go

Author: abbot

md5crypt.go

@@ -1,31 +1,12 @@
 package auth
 
 import "crypto/md5"
-import "strings"
 
 const itoa64 = "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
 
-var md5_crypt_swaps = [16]int{12, 6, 0, 13, 7, 1, 14, 8, 2, 15, 9, 3, 5, 10, 4, 11}
+var md5CryptSwaps = [16]int{12, 6, 0, 13, 7, 1, 14, 8, 2, 15, 9, 3, 5, 10, 4, 11}
 
-type MD5Entry struct {
-	Magic, Salt, Hash []byte
-}
-
-func NewMD5Entry(e string) *MD5Entry {
-	parts := strings.SplitN(e, "$", 4)
-	if len(parts) != 4 {
-		return nil
-	}
-	return &MD5Entry{
-		Magic: []byte("$" + parts[1] + "$"),
-		Salt:  []byte(parts[2]),
-		Hash:  []byte(parts[3]),
-	}
-}
-
-/*
- MD5 password crypt implementation
-*/
+// MD5Crypt is the MD5 password crypt implementation.
 func MD5Crypt(password, salt, magic []byte) []byte {
 	d := md5.New()
 
@@ -79,7 +60,7 @@ func MD5Crypt(password, salt, magic []byte) []byte {
 	result := make([]byte, 0, 22)
 	v := uint(0)
 	bits := uint(0)
-	for _, i := range md5_crypt_swaps {
+	for _, i := range md5CryptSwaps {
 		v |= (uint(final[i]) << bits)
 		for bits = bits + 8; bits > 6; bits -= 6 {
 			result = append(result, itoa64[v&0x3f])

md5crypt_test.go

@@ -1,6 +1,25 @@
 package auth
 
-import "testing"
+import (
+	"strings"
+	"testing"
+)
+
+type md5entry struct {
+	Magic, Salt, Hash []byte
+}
+
+func newEntry(e string) *md5entry {
+	parts := strings.SplitN(e, "$", 4)
+	if len(parts) != 4 {
+		return nil
+	}
+	return &md5entry{
+		Magic: []byte("$" + parts[1] + "$"),
+		Salt:  []byte(parts[2]),
+		Hash:  []byte(parts[3]),
+	}
+}
 
 func Test_MD5Crypt(t *testing.T) {
 	t.Parallel()
@@ -10,7 +29,7 @@ func Test_MD5Crypt(t *testing.T) {
 		{"topsecret", "$apr1$JI4wh3am$AmhephVqLTUyAVpFQeHZC0"},
 	}
 	for _, tc := range test_cases {
-		e := NewMD5Entry(tc[1])
+		e := newEntry(tc[1])
 		result := MD5Crypt([]byte(tc[0]), e.Salt, e.Magic)
 		if string(result) != tc[1] {
 			t.Fatalf("MD5Crypt returned '%s' instead of '%s'", string(result), tc[1])