01: /*
02: * Licensed to the Apache Software Foundation (ASF) under one or more
03: * contributor license agreements. See the NOTICE file distributed with
04: * this work for additional information regarding copyright ownership.
05: * The ASF licenses this file to You under the Apache License, Version 2.0
06: * (the "License"); you may not use this file except in compliance with
07: * the License. You may obtain a copy of the License at
08: *
09: * http://www.apache.org/licenses/LICENSE-2.0
10: *
11: * Unless required by applicable law or agreed to in writing, software
12: * distributed under the License is distributed on an "AS IS" BASIS,
13: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14: * See the License for the specific language governing permissions and
15: * limitations under the License.
16: */
17:
18: package java.util.zip;
19:
20: /**
21: * Interface to types that can compute a checksum value of given data.
22: */
23: public interface Checksum {
24:
25: /**
26: * Answers the computed checksum value so far.
27: *
28: * @return the checksum value
29: */
30: public long getValue();
31:
32: /**
33: * Reinitialize the checksum computation to its starting value.
34: */
35: public void reset();
36:
37: /**
38: * Update the checksum value based on the given byte array
39: *
40: * @param buf
41: * the data used to update the checksum
42: * @param off
43: * the starting point for data values
44: * @param nbytes
45: * the number of bytes to consider
46: */
47: public void update(byte[] buf, int off, int nbytes);
48:
49: /**
50: * Update the checksum value based on the given data value.
51: *
52: * @param val
53: * a single byte value
54: */
55: public void update(int val);
56: }
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