// use mtime < t+1s instead of mtime <= t to check for unmodified.
	return !objTime.Before(givenTime.Add(1 * time.Second))
}

// canonicalizeETag returns ETag with leading and trailing double-quotes removed,
// if any present
func canonicalizeETag(etag string) string {
	return etagRegex.ReplaceAllString(etag, "$1")
}

// isETagEqual return true if the canonical representations of two ETag strings

// GenETag - generate UUID based ETag
func GenETag() string {
	return ToS3ETag(getMD5Hash([]byte(mustGetUUID())))
}

// ToS3ETag - return checksum to ETag
func ToS3ETag(etag string) string {
	etag = canonicalizeETag(etag)

	if !strings.HasSuffix(etag, "-1") {
		// Tools like s3cmd uses ETag as checksum of data to validate.
		// Append "-1" to indicate ETag is not a checksum.
		etag += "-1"
	}

	return etag
}

				GotETag:    part.ETag,
			}
			return oi, invp
		}
		expPart := currentFI.Parts[partIdx]

		// ensure that part ETag is canonicalized to strip off extraneous quotes
		part.ETag = canonicalizeETag(part.ETag)
		expETag := tryDecryptETag(objectEncryptionKey, expPart.ETag, kind == crypto.S3)
		if expETag != part.ETag {
			invp := InvalidPart{
				PartNumber: part.PartNumber,
				ExpETag:    expETag,

// Create an s3 compatible MD5sum for complete multipart transaction.
func getCompleteMultipartMD5(parts []CompletePart) string {
	var finalMD5Bytes []byte
	for _, part := range parts {
		md5Bytes, err := hex.DecodeString(canonicalizeETag(part.ETag))
		if err != nil {
			finalMD5Bytes = append(finalMD5Bytes, []byte(part.ETag)...)
		} else {
			finalMD5Bytes = append(finalMD5Bytes, md5Bytes...)
		}
	}

	c.Assert(response.StatusCode, http.StatusOK)
	var parts []CompletePart
	for _, part := range completeUploads.Parts {
		part.ETag = canonicalizeETag(part.ETag)
		parts = append(parts, part)
	}
	etag := getCompleteMultipartMD5(parts)
	c.Assert(canonicalizeETag(response.Header.Get(xhttp.ETag)), etag)

			t.Fatalf("Test failed to decode XML response: <ERROR> %v", err)
		}

		parts = append(parts, CompletePart{
			PartNumber: partNumber,
			ETag:       canonicalizeETag(resp.ETag),
		})
	}

	var completeBytes []byte
	// Complete multipart upload parts.
	completeUploads := &CompleteMultipartUpload{
		Parts: parts,
	}