crypto/sha1: provide a top-level Sum function

Makes it easy to ask the simple question, what is the hash of this data?

R=golang-dev, rsc, bradfitz
CC=golang-dev
https://golang.org/cl/10571043

diff --git a/src/pkg/crypto/sha1/sha1.go b/src/pkg/crypto/sha1/sha1.go
index 7cfde47dc07dd4353ddb5e4d34cbcd1ffa71e7b9..8eb3f7a798888d288e4fd8bd3ee086375c342261 100644 (file)
--- a/src/pkg/crypto/sha1/sha1.go
+++ b/src/pkg/crypto/sha1/sha1.go
@@ -90,9 +90,13 @@ func (d *digest) Write(p []byte) (nn int, err error) {
 func (d0 *digest) Sum(in []byte) []byte {
        // Make a copy of d0 so that caller can keep writing and summing.
        d := *d0
+       hash := d.checkSum()
+       return append(in, hash[:]...)
+}
 
-       // Padding.  Add a 1 bit and 0 bits until 56 bytes mod 64.
+func (d *digest) checkSum() [Size]byte {
        len := d.len
+       // Padding.  Add a 1 bit and 0 bits until 56 bytes mod 64.
        var tmp [64]byte
        tmp[0] = 0x80
        if len%64 < 56 {
@@ -120,5 +124,13 @@ func (d0 *digest) Sum(in []byte) []byte {
                digest[i*4+3] = byte(s)
        }
 
-       return append(in, digest[:]...)
+       return digest
+}
+
+// Sum returns the SHA1 checksum of the data.
+func Sum(data []byte) [Size]byte {
+       var d digest
+       d.Reset()
+       d.Write(data)
+       return d.checkSum()
 }

diff --git a/src/pkg/crypto/sha1/sha1_test.go b/src/pkg/crypto/sha1/sha1_test.go
index 57cd4313eb27dd44502ddfea6e0341b9a1e12380..61ece671f4fac9783379d8a61161b2749c17b279 100644 (file)
--- a/src/pkg/crypto/sha1/sha1_test.go
+++ b/src/pkg/crypto/sha1/sha1_test.go
@@ -54,6 +54,10 @@ var golden = []sha1Test{
 func TestGolden(t *testing.T) {
        for i := 0; i < len(golden); i++ {
                g := golden[i]
+               s := fmt.Sprintf("%x", Sum([]byte(g.in)))
+               if s != g.out {
+                       t.Fatalf("Sum function: sha1(%s) = %s want %s", g.in, s, g.out)
+               }
                c := New()
                for j := 0; j < 3; j++ {
                        if j < 2 {