// 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" 	"golang.org/x/crypto/blake2b") const (	marshaledSizeMD5     = 92	marshaledSizeSHA1    = 96	marshaledSizeSHA256  = 108	marshaledSizeSHA512  = 204	marshaledSizeBlake2b = 213 	marshaledSize = marshaledSizeMD5 + marshaledSizeSHA1 + marshaledSizeSHA256 + marshaledSizeSHA512 + marshaledSizeBlake2b) // HashSummer provide a Sums methodtype HashSummer interface {	Sums() (hashMD5, hashSHA1, hashSHA256, hashSHA512, hashBlake2b []byte)} // MultiHasher calculates multiple checksumstype MultiHasher struct {	md5     hash.Hash	sha1    hash.Hash	sha256  hash.Hash	sha512  hash.Hash	blake2b hash.Hash 	combinedWriter io.Writer} // NewMultiHasher creates a multi hasherfunc NewMultiHasher() *MultiHasher {	md5 := md5.New()	sha1 := sha1.New()	sha256 := sha256.New()	sha512 := sha512.New()	blake2b, _ := blake2b.New512(nil) 	combinedWriter := io.MultiWriter(md5, sha1, sha256, sha512, blake2b) 	return &MultiHasher{		md5,		sha1,		sha256,		sha512,		blake2b,		combinedWriter,	}} // MarshalBinary implements encoding.BinaryMarshalerfunc (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	}	blake2bBytes, err := h.blake2b.(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...)	b = append(b, blake2bBytes...)	return b, nil} // UnmarshalBinary implements encoding.BinaryUnmarshalerfunc (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:]	if err := h.sha512.(encoding.BinaryUnmarshaler).UnmarshalBinary(b[:marshaledSizeSHA512]); err != nil {		return err	} 	b = b[marshaledSizeSHA512:]	return h.blake2b.(encoding.BinaryUnmarshaler).UnmarshalBinary(b[:marshaledSizeBlake2b])} // Write implements io.Writerfunc (h *MultiHasher) Write(p []byte) (int, error) {	return h.combinedWriter.Write(p)} // Sums gets the MD5, SHA1, SHA256 and SHA512 checksums of the datafunc (h *MultiHasher) Sums() (hashMD5, hashSHA1, hashSHA256, hashSHA512, hashBlake2b []byte) {	hashMD5 = h.md5.Sum(nil)	hashSHA1 = h.sha1.Sum(nil)	hashSHA256 = h.sha256.Sum(nil)	hashSHA512 = h.sha512.Sum(nil)	hashBlake2b = h.blake2b.Sum(nil)	return hashMD5, hashSHA1, hashSHA256, hashSHA512, hashBlake2b}