1 files changed, 122 insertions, 0 deletions
diff --git a/modules/packages/multi_hasher.go b/modules/packages/multi_hasher.go
new file mode 100644
index 0000000..83a4b5b
--- /dev/null
+++ b/modules/packages/multi_hasher.go
@@ -0,0 +1,122 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package packages
+
+import (
+	"crypto/md5"
+	"crypto/sha1"
+	"crypto/sha256"
+	"crypto/sha512"
+	"encoding"
+	"errors"
+	"hash"
+	"io"
+)
+
+const (
+	marshaledSizeMD5    = 92
+	marshaledSizeSHA1   = 96
+	marshaledSizeSHA256 = 108
+	marshaledSizeSHA512 = 204
+
+	marshaledSize = marshaledSizeMD5 + marshaledSizeSHA1 + marshaledSizeSHA256 + marshaledSizeSHA512
+)
+
+// HashSummer provide a Sums method
+type HashSummer interface {
+	Sums() (hashMD5, hashSHA1, hashSHA256, hashSHA512 []byte)
+}
+
+// MultiHasher calculates multiple checksums
+type MultiHasher struct {
+	md5    hash.Hash
+	sha1   hash.Hash
+	sha256 hash.Hash
+	sha512 hash.Hash
+
+	combinedWriter io.Writer
+}
+
+// NewMultiHasher creates a multi hasher
+func NewMultiHasher() *MultiHasher {
+	md5 := md5.New()
+	sha1 := sha1.New()
+	sha256 := sha256.New()
+	sha512 := sha512.New()
+
+	combinedWriter := io.MultiWriter(md5, sha1, sha256, sha512)
+
+	return &MultiHasher{
+		md5,
+		sha1,
+		sha256,
+		sha512,
+		combinedWriter,
+	}
+}
+
+// MarshalBinary implements encoding.BinaryMarshaler
+func (h *MultiHasher) MarshalBinary() ([]byte, error) {
+	md5Bytes, err := h.md5.(encoding.BinaryMarshaler).MarshalBinary()
+	if err != nil {
+		return nil, err
+	}
+	sha1Bytes, err := h.sha1.(encoding.BinaryMarshaler).MarshalBinary()
+	if err != nil {
+		return nil, err
+	}
+	sha256Bytes, err := h.sha256.(encoding.BinaryMarshaler).MarshalBinary()
+	if err != nil {
+		return nil, err
+	}
+	sha512Bytes, err := h.sha512.(encoding.BinaryMarshaler).MarshalBinary()
+	if err != nil {
+		return nil, err
+	}
+
+	b := make([]byte, 0, marshaledSize)
+	b = append(b, md5Bytes...)
+	b = append(b, sha1Bytes...)
+	b = append(b, sha256Bytes...)
+	b = append(b, sha512Bytes...)
+	return b, nil
+}
+
+// UnmarshalBinary implements encoding.BinaryUnmarshaler
+func (h *MultiHasher) UnmarshalBinary(b []byte) error {
+	if len(b) != marshaledSize {
+		return errors.New("invalid hash state size")
+	}
+
+	if err := h.md5.(encoding.BinaryUnmarshaler).UnmarshalBinary(b[:marshaledSizeMD5]); err != nil {
+		return err
+	}
+
+	b = b[marshaledSizeMD5:]
+	if err := h.sha1.(encoding.BinaryUnmarshaler).UnmarshalBinary(b[:marshaledSizeSHA1]); err != nil {
+		return err
+	}
+
+	b = b[marshaledSizeSHA1:]
+	if err := h.sha256.(encoding.BinaryUnmarshaler).UnmarshalBinary(b[:marshaledSizeSHA256]); err != nil {
+		return err
+	}
+
+	b = b[marshaledSizeSHA256:]
+	return h.sha512.(encoding.BinaryUnmarshaler).UnmarshalBinary(b[:marshaledSizeSHA512])
+}
+
+// Write implements io.Writer
+func (h *MultiHasher) Write(p []byte) (int, error) {
+	return h.combinedWriter.Write(p)
+}
+
+// Sums gets the MD5, SHA1, SHA256 and SHA512 checksums of the data
+func (h *MultiHasher) Sums() (hashMD5, hashSHA1, hashSHA256, hashSHA512 []byte) {
+	hashMD5 = h.md5.Sum(nil)
+	hashSHA1 = h.sha1.Sum(nil)
+	hashSHA256 = h.sha256.Sum(nil)
+	hashSHA512 = h.sha512.Sum(nil)
+	return hashMD5, hashSHA1, hashSHA256, hashSHA512
+}