feat(stdlibs): import crypto/sha256 (#580)

stdlibs/crypto/sha256/sha256.gno

@@ -0,0 +1,12 @@
+package sha256
+
+import (
+	isha256 "internal/crypto/sha256"
+)
+
+const Size = 32
+
+// Sum returns the SHA-256 checksum of the data.
+func Sum256(data []byte) [Size]byte {
+	return isha256.Sum256(data)
+}

stdlibs/crypto/sha256/sha256_test.gno

@@ -0,0 +1,17 @@
+package sha256
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"std"
+	"testing"
+)
+
+func TestSha256Sum(t *testing.T) {
+	got := sha256.Sum256([]byte("sha256 this string"))[:]
+	expected := "1af1dfa857bf1d8814fe1af8983c18080019922e557f15a8a0d3db739d77aacb"
+
+	if hex.EncodeToString(got) != expected {
+		t.Errorf("got %v(%T), expected %v(%T)", hex.EncodeToString(got), got, expected, expected)
+	}
+}

stdlibs/internal/crypto/sha256/sha256.gno

@@ -0,0 +1,3 @@
+package sha256
+
+// XXX injected via stdlibs/stdlibs.go

stdlibs/stdlibs.go

@@ -1,6 +1,7 @@
 package stdlibs
 
 import (
+	"crypto/sha256"
 	"math"
 	"reflect"
 	"strconv"
@@ -20,6 +21,33 @@ func InjectNativeMappings(store gno.Store) {
 
 func InjectPackage(store gno.Store, pn *gno.PackageNode) {
 	switch pn.PkgPath {
+	case "internal/crypto/sha256":
+		pn.DefineNative("Sum256",
+			gno.Flds( // params
+				"data", "[]byte",
+			),
+			gno.Flds( // results
+				"bz", "[32]byte",
+			),
+			func(m *gno.Machine) {
+				arg0 := m.LastBlock().GetParams1().TV
+				bz := []byte(nil)
+
+				if arg0.V != nil {
+					slice := arg0.V.(*gno.SliceValue)
+					array := slice.GetBase(m.Store)
+					bz = array.GetReadonlyBytes()[:slice.Length]
+				}
+
+				hash := sha256.Sum256(bz)
+				res0 := gno.Go2GnoValue(
+					m.Alloc,
+					m.Store,
+					reflect.ValueOf(hash),
+				)
+				m.PushValue(res0)
+			},
+		)
 	case "internal/math":
 		pn.DefineNative("Float32bits",
 			gno.Flds( // params