Add Go hash.Hash interface for SM3

go/gmssl/sm3/sm3.go

@@ -0,0 +1,57 @@
+package sm3
+
+import (
+	"gmssl"
+	"hash"
+)
+
+type digest struct {
+	ctx *gmssl.DigestContext
+}
+
+func New() hash.Hash {
+	d := new(digest)
+	ctx, err := gmssl.NewDigestContext("SM3", nil)
+	if err != nil {
+		return nil
+	}
+	d.ctx = ctx
+	return d
+}
+
+func (d *digest) BlockSize() int {
+	ret, err := gmssl.GetDigestBlockSize("SM3")
+	if err != nil {
+		return 0
+	}
+	return ret
+}
+
+func (d *digest) Size() int {
+	ret, err := gmssl.GetDigestLength("SM3")
+	if err != nil {
+		return 0
+	}
+	return ret
+}
+
+func (d *digest) Reset() {
+	err := d.ctx.Reset()
+	if err != nil {
+		// do something?
+	}
+}
+
+func (d *digest) Write(p []byte) (int, error) {
+	err := d.ctx.Update(p)
+	return len(p), err
+}
+
+func (d *digest) Sum(in []byte) []byte {
+	d.ctx.Update(in)
+	ret, err := d.ctx.Final()
+	if err != nil {
+		return nil
+	}
+	return ret
+}