1 files changed, 37 insertions, 0 deletions
diff --git a/src/pkg/hash/hash.go b/src/pkg/hash/hash.go
new file mode 100644
index 000000000..3536c0b6a
--- /dev/null
+++ b/src/pkg/hash/hash.go
@@ -0,0 +1,37 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package hash provides interfaces for hash functions.
+package hash
+
+import "io"
+
+// Hash is the common interface implemented by all hash functions.
+type Hash interface {
+	// Write adds more data to the running hash.
+	// It never returns an error.
+	io.Writer
+
+	// Sum returns the current hash, without changing the
+	// underlying hash state.
+	Sum() []byte
+
+	// Reset resets the hash to one with zero bytes written.
+	Reset()
+
+	// Size returns the number of bytes Sum will return.
+	Size() int
+}
+
+// Hash32 is the common interface implemented by all 32-bit hash functions.
+type Hash32 interface {
+	Hash
+	Sum32() uint32
+}
+
+// Hash64 is the common interface implemented by all 64-bit hash functions.
+type Hash64 interface {
+	Hash
+	Sum64() uint64
+}