uploadID := r.Form.Get(xhttp.UploadID)
	partIDString := r.Form.Get(xhttp.PartNumber)

	partID, err := strconv.Atoi(partIDString)
	if err != nil || partID <= 0 {
		writeErrorResponse(ctx, w, errorCodes.ToAPIErr(ErrInvalidPart), r.URL)
		return
	}

	// check partID with maximum part ID for multipart objects
	if isMaxPartID(partID) {
		writeErrorResponse(ctx, w, errorCodes.ToAPIErr(ErrInvalidMaxParts), r.URL)
		return
	}

	if err := checkNewMultipartArgs(ctx, srcBucket, srcObject); err != nil {
		return PartInfo{}, err
	}

	return z.PutObjectPart(ctx, destBucket, destObject, uploadID, partID,
		srcInfo.PutObjReader, dstOpts)
}

		var cp []CompletePart
		cumulativeSum := int64(0)
		for i, partLen := range partSizes {
			partID := i + 1
			partSrc := NewDummyDataGen(partLen, cumulativeSum)
			cumulativeSum += partLen
			req, errP := newTestSignedRequestV4(http.MethodPut,
				getPutObjectPartURL("", bucketName, objectName, upID, fmt.Sprintf("%d", partID)),
				partLen, partSrc, creds.AccessKey, creds.SecretKey, metadata)
			if errP != nil {

		// Test case  1-4.
		// Cases with invalid bucket name.
		{bucketName: ".test", objName: "obj", PartID: 1, expectedError: fmt.Errorf("%s", "Bucket name invalid: .test")},
		{bucketName: "------", objName: "obj", PartID: 1, expectedError: fmt.Errorf("%s", "Bucket name invalid: ------")},
		{
			bucketName: "$this-is-not-valid-too", objName: "obj", PartID: 1,
			expectedError: fmt.Errorf("%s", "Bucket name invalid: $this-is-not-valid-too"),
		},

}

// EncryptMultiPart encrypts an io.Reader which must be the body of
// multi-part PUT request. It derives an unique encryption key from
// the partID and the object key.
func EncryptMultiPart(r io.Reader, partID int, key ObjectKey) io.Reader {
	partKey := key.DerivePartKey(uint32(partID))
	return EncryptSinglePart(r, ObjectKey(partKey))
}

// DecryptSinglePart decrypts an io.Writer which must an object

	metadata       map[string]string

	partDecRelOffset, partEncRelOffset int64

	copySource bool
	// Customer Key
	customerKeyHeader string
}

func (d *DecryptBlocksReader) buildDecrypter(partID int) error {
	m := cloneMSS(d.metadata)
	// Initialize the first decrypter; new decrypters will be
	// initialized in Read() operation as needed.
	var key []byte
	var err error
	if d.copySource {

		partNumber := partI.Number
		if partID != partNumber {
			internalLogIf(ctx, fmt.Errorf("part.%d.meta has incorrect corresponding part number: expected %d, got %d", partID, partID, partI.Number))
			return oi, InvalidPart{
				PartNumber: partID,
			}
		}

		// Add the current part.
		fi.AddObjectPart(partI.Number, partI.ETag, partI.Size, partI.ActualSize, partI.ModTime, partI.Index, partI.Checksums)
	}

	CopyObjectPart(ctx context.Context, srcBucket, srcObject, destBucket, destObject string, uploadID string, partID int,
		startOffset int64, length int64, srcInfo ObjectInfo, srcOpts, dstOpts ObjectOptions) (info PartInfo, err error)
	PutObjectPart(ctx context.Context, bucket, object, uploadID string, partID int, data *PutObjReader, opts ObjectOptions) (info PartInfo, err error)

func (s *erasureSets) PutObjectPart(ctx context.Context, bucket, object, uploadID string, partID int, data *PutObjReader, opts ObjectOptions) (info PartInfo, err error) {
	set := s.getHashedSet(object)
	return set.PutObjectPart(ctx, bucket, object, uploadID, partID, data, opts)
}

// GetMultipartInfo - return multipart metadata info uploaded at hashedSet.

	// Create multipart parts.
	// Need parts to be uploaded before CompleteMultiPartUpload can be called tested.
	parts := []struct {
		bucketName      string
		objName         string
		uploadID        string
		PartID          int
		inputReaderData string
		inputMd5        string
		inputDataSize   int64
	}{
		// Case 1-4.
		// Creating sequence of parts for same uploadID.