}
		if got.Flags != want.flags {
			t.Errorf("%s: got Flags %#x; want %#x", want.name, got.Flags, want.flags)
		}
		if got.CRC32 != want.crc32 {
			t.Errorf("%s: got CRC32 %#x; want %#x", want.name, got.CRC32, want.crc32)
		}
		if got.CompressedSize64 != want.compressedSize {
			t.Errorf("%s: got CompressedSize64 %d; want %d", want.name, got.CompressedSize64, want.compressedSize)
		}

    HashTestUtils.assertInvariants(Hashing.sha512());
    assertEquals("Hashing.sha512()", Hashing.sha512().toString());
  }

  public void testCrc32() {
    HashTestUtils.assertInvariants(Hashing.crc32());
    assertEquals("Hashing.crc32()", Hashing.crc32().toString());
  }

  public void testAdler32() {
    HashTestUtils.assertInvariants(Hashing.adler32());
    assertEquals("Hashing.adler32()", Hashing.adler32().toString());
  }

		fh.UncompressedSize64 = 0

		ow = dirWriter{}
	} else {
		fh.Flags |= 0x8 // we will write a data descriptor

		fw = &fileWriter{
			zipw:      w.cw,
			compCount: &countWriter{w: w.cw},
			crc32:     crc32.NewIEEE(),
		}
		comp := w.compressor(fh.Method)
		if comp == nil {
			return nil, ErrAlgorithm
		}
		var err error
		fw.comp, err = comp(fw.compCount)
		if err != nil {
			return nil, err

// Returns nil if no checksum.
func (c ChecksumType) Hasher() hash.Hash {
	switch {
	case c.Is(ChecksumCRC32):
		return crc32.NewIEEE()
	case c.Is(ChecksumCRC32C):
		return crc32.New(crc32.MakeTable(crc32.Castagnoli))
	case c.Is(ChecksumSHA1):
		return sha1.New()
	case c.Is(ChecksumSHA256):
		return sha256.New()
	}
	return nil
}

// Trailing return whether the checksum is trailing.

	// Deprecated: Use Modified instead.
	ModifiedTime uint16

	// ModifiedDate is an MS-DOS-encoded date.
	//
	// Deprecated: Use Modified instead.
	ModifiedDate uint16

	// CRC32 is the CRC32 checksum of the file content.
	CRC32 uint32

	// CompressedSize is the compressed size of the file in bytes.
	// If either the uncompressed or compressed size of the file

    return ChecksumType.ADLER_32.hashFunction;
  }

  @Immutable
  enum ChecksumType implements ImmutableSupplier<Checksum> {
    CRC_32("Hashing.crc32()") {
      @Override
      public Checksum get() {
        return new CRC32();
      }
    },
    ADLER_32("Hashing.adler32()") {
      @Override
      public Checksum get() {
        return new Adler32();
      }
    };

				} else {
					err = err1
				}
			} else if r.hash.Sum32() != r.f.CRC32 {
				err = ErrChecksum
			}
		} else {
			// If there's not a data descriptor, we still compare
			// the CRC32 of what we've read against the file header
			// or TOC's CRC32, if it seems like it was set.
			if r.f.CRC32 != 0 && r.hash.Sum32() != r.f.CRC32 {
				err = ErrChecksum
			}
		}
	}
	r.err = err
	return
}

	binary.Write(buf, binary.BigEndian, uint32(headerLength))
	prelude := buf.Bytes()
	binary.Write(buf, binary.BigEndian, crc32.ChecksumIEEE(prelude))
	buf.Write(header)
	if payload != nil {
		buf.Write(payload)
	}
	message := buf.Bytes()
	binary.Write(buf, binary.BigEndian, crc32.ChecksumIEEE(message))

	return buf.Bytes()
}

// Refer genRecordsHeader().
var recordsHeader = []byte{

				}
			}
			f, err := w.CreateHeader(&FileHeader{
				Name:   filename,
				Method: Store,
			})
			if err != nil {
				t.Fatal(err)
			}
			f.(*fileWriter).crc32 = fakeHash32{}
			size := wantOff - fileHeaderLen - uint64(len(filename)) - dataDescriptorLen
			if _, err := io.CopyN(f, zeros{}, int64(size)); err != nil {
				t.Fatal(err)
			}
			if err := w.Close(); err != nil {

func hashOrder(key string, cardinality int) []int {
	if cardinality <= 0 {
		// Returns an empty int slice for cardinality < 0.
		return nil
	}

	nums := make([]int, cardinality)
	keyCrc := crc32.Checksum([]byte(key), crc32.IEEETable)

	start := int(keyCrc % uint32(cardinality))
	for i := 1; i <= cardinality; i++ {
		nums[i-1] = 1 + ((start + i) % cardinality)
	}
	return nums
}