2 * Copyright 2008 ZXing authors
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 package com.google.zxing.common.reedsolomon;
19 import junit.framework.TestCase;
21 import java.util.BitSet;
22 import java.util.Random;
25 * @author srowen@google.com (Sean Owen)
27 public final class ReedSolomonDecoderDataMatrixTestCase extends TestCase {
29 private static final int[] DM_CODE_TEST = { 142, 164, 186 };
30 private static final int[] DM_CODE_TEST_WITH_EC = { 142, 164, 186, 114, 25, 5, 88, 102 };
31 private static final int DM_CODE_CORRECTABLE = (DM_CODE_TEST_WITH_EC.length - DM_CODE_TEST.length) / 2;
33 private final ReedSolomonDecoder dmRSDecoder = new ReedSolomonDecoder(GF256.DATA_MATRIX_FIELD);
35 public void testNoError() throws ReedSolomonException {
36 int[] received = new int[DM_CODE_TEST_WITH_EC.length];
37 System.arraycopy(DM_CODE_TEST_WITH_EC, 0, received, 0, received.length);
39 checkQRRSDecode(received);
42 public void testOneError() throws ReedSolomonException {
43 int[] received = new int[DM_CODE_TEST_WITH_EC.length];
44 Random random = new Random(0xDEADBEEFL);
45 for (int i = 0; i < received.length; i++) {
46 System.arraycopy(DM_CODE_TEST_WITH_EC, 0, received, 0, received.length);
47 received[i] = random.nextInt(256);
48 checkQRRSDecode(received);
52 public void testMaxErrors() throws ReedSolomonException {
53 int[] received = new int[DM_CODE_TEST_WITH_EC.length];
54 Random random = new Random(0xDEADBEEFL);
55 for (int i = 0; i < DM_CODE_TEST.length; i++) { // # iterations is kind of arbitrary
56 System.arraycopy(DM_CODE_TEST_WITH_EC, 0, received, 0, received.length);
57 // TODO we aren't testing max errors really since there is a known bug here
58 corrupt(received, DM_CODE_CORRECTABLE - 1, random);
59 checkQRRSDecode(received);
63 public void testTooManyErrors() {
64 int[] received = new int[DM_CODE_TEST_WITH_EC.length];
65 System.arraycopy(DM_CODE_TEST_WITH_EC, 0, received, 0, received.length);
66 Random random = new Random(0xDEADBEEFL);
67 corrupt(received, DM_CODE_CORRECTABLE + 1, random);
69 checkQRRSDecode(received);
70 fail("Should not have decoded");
71 } catch (ReedSolomonException rse) {
76 private void checkQRRSDecode(int[] received) throws ReedSolomonException {
77 dmRSDecoder.decode(received, 2 * DM_CODE_CORRECTABLE, true);
78 for (int i = 0; i < DM_CODE_TEST.length; i++) {
79 assertEquals(received[i], DM_CODE_TEST[i]);
83 private static void corrupt(int[] received, int howMany, Random random) {
84 BitSet corrupted = new BitSet(received.length);
85 for (int j = 0; j < howMany; j++) {
86 int location = random.nextInt(received.length);
87 if (corrupted.get(location)) {
90 corrupted.set(location);
91 int newByte = random.nextInt(256);
92 received[location] = newByte;