"fmt"
	"hash/crc32"
	"hash/crc64"
	"math/bits"
)

// AddPart will merge a part checksum into the current,
// as if the content of each was appended.
// The size of the content that produced the second checksum must be provided.
// Not all checksum types can be merged, use the CanMerge method to check.
// Checksum types must match.
func (c *Checksum) AddPart(other Checksum, size int64) error {
	if !other.Type.CanMerge() {

			if !cs.Valid() {
				return oi, InvalidPart{
					PartNumber: part.PartNumber,
				}
			}
			if checksumType.FullObjectRequested() {
				if err := checksum.AddPart(*cs, expPart.ActualSize); err != nil {
					return oi, InvalidPart{
						PartNumber: part.PartNumber,
						ExpETag:    "<nil>",
						GotETag:    err.Error(),
					}
				}
			}