1 files changed, 69 insertions, 0 deletions
diff --git a/object/id/object_format_details.go b/object/id/object_format_details.go
new file mode 100644
index 00000000..d0278602
--- /dev/null
+++ b/object/id/object_format_details.go
@@ -0,0 +1,69 @@
+package id
+
+import (
+	"crypto/sha1" //#nosec:G505
+	"crypto/sha256"
+	"hash"
+)
+
+type objectFormatDetails struct {
+	name string
+	size int
+	sum  func([]byte) ObjectID
+	new  func() hash.Hash
+}
+
+func (objectFormat ObjectFormat) details() objectFormatDetails {
+	return objectFormatTable[objectFormat]
+}
+
+//nolint:gochecknoglobals
+var objectFormatTable = [...]objectFormatDetails{
+	ObjectFormatUnknown: {}, //nolint:exhaustruct
+	ObjectFormatSHA1: {
+		name: "sha1",
+		size: sha1.Size,
+		sum: func(data []byte) ObjectID {
+			sum := sha1.Sum(data) //#nosec G401
+
+			var id ObjectID
+			copy(id.data[:], sum[:])
+			id.objectFormat = ObjectFormatSHA1
+
+			return id
+		},
+		new: sha1.New,
+	},
+	ObjectFormatSHA256: {
+		name: "sha256",
+		size: sha256.Size,
+		sum: func(data []byte) ObjectID {
+			sum := sha256.Sum256(data)
+
+			var id ObjectID
+			copy(id.data[:], sum[:])
+			id.objectFormat = ObjectFormatSHA256
+
+			return id
+		},
+		new: sha256.New,
+	},
+}
+
+// maxObjectIDSize MUST be >= the largest supported object format size.
+const maxObjectIDSize = sha256.Size
+
+var (
+	//nolint:gochecknoglobals
+	objectFormatByName = map[string]ObjectFormat{}
+	//nolint:gochecknoglobals
+	supportedObjectFormats []ObjectFormat
+)
+
+func init() { //nolint:gochecknoinits
+	for objectFormat := ObjectFormatUnknown + 1; int(objectFormat) < len(objectFormatTable); objectFormat++ {
+		info := &objectFormatTable[objectFormat]
+		objectFormatByName[info.name] = objectFormat
+		supportedObjectFormats = append(supportedObjectFormats, objectFormat)
+	}
+}