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Added overdue Reed-Solomon tests

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git-svn-id: https://zxing.googlecode.com/svn/trunk@293 59b500cc-1b3d-0410-9834-0bbf25fbcc57
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srowen 2008-03-17 20:48:32 +00:00
parent 379c3a8cc0
commit 7129e6a5ee
1 changed files with 91 additions and 0 deletions
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core/test/src/com/google/zxing/common/reedsolomon/ReedSolomonDecoderTestCase.java Normal file
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/*
* Copyright 2008 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.zxing.common.reedsolomon;
import junit.framework.TestCase;
import java.util.BitSet;
import java.util.Random;
/**
* @author srowen@google.com (Sean Owen)
*/
public final class ReedSolomonDecoderTestCase extends TestCase {
/** See ISO 18004, Appendix I, from which this example is taken. */
private static final int[] QR_CODE_TEST =
{ 0x10, 0x20, 0x0C, 0x56, 0x61, 0x80, 0xEC, 0x11, 0xEC,
0x11, 0xEC, 0x11, 0xEC, 0x11, 0xEC, 0x11, 0xA5 };
private static final int[] QR_CODE_TEST_WITH_EC =
{ 0x10, 0x20, 0x0C, 0x56, 0x61, 0x80, 0xEC, 0x11, 0xEC,
0x11, 0xEC, 0x11, 0xEC, 0x11, 0xEC, 0x11, 0xA5, 0x24,
0xD4, 0xC1, 0xED, 0x36, 0xC7, 0x87, 0x2C, 0x55 };
private static final int QR_CODE_CORRECTABLE = (QR_CODE_TEST_WITH_EC.length - QR_CODE_TEST.length) / 2;
private final ReedSolomonDecoder qrRSDecoder = new ReedSolomonDecoder(GF256.QR_CODE_FIELD);
public void testNoError() throws ReedSolomonException {
int[] received = new int[QR_CODE_TEST_WITH_EC.length];
System.arraycopy(QR_CODE_TEST_WITH_EC, 0, received, 0, received.length);
// no errors
checkQRRSDecode(received);
}
public void testMaxErrors() throws ReedSolomonException {
int[] received = new int[QR_CODE_TEST_WITH_EC.length];
Random random = new Random(0xDEADBEEFL);
for (int i = 0; i < QR_CODE_TEST.length; i++) { // # iterations is kind of arbitrary
System.arraycopy(QR_CODE_TEST_WITH_EC, 0, received, 0, received.length);
corrupt(received, QR_CODE_CORRECTABLE, random);
checkQRRSDecode(received);
}
}
public void testTooManyErrors() {
int[] received = new int[QR_CODE_TEST_WITH_EC.length];
System.arraycopy(QR_CODE_TEST_WITH_EC, 0, received, 0, received.length);
Random random = new Random(0xDEADBEEFL);
corrupt(received, QR_CODE_CORRECTABLE + 1, random);
try {
checkQRRSDecode(received);
fail("Should not have decoded");
} catch (ReedSolomonException rse) {
// good
}
}
private void checkQRRSDecode(int[] received) throws ReedSolomonException {
qrRSDecoder.decode(received, 2*QR_CODE_CORRECTABLE);
for (int i = 0; i < QR_CODE_TEST.length; i++) {
assertEquals(received[i], QR_CODE_TEST[i]);
}
}
private static void corrupt(int[] received, int howMany, Random random) {
BitSet corrupted = new BitSet(received.length);
for (int j = 0; j < howMany; j++) {
int location = random.nextInt(received.length);
if (corrupted.get(location)) {
j--;
} else {
corrupted.set(location);
int newByte = random.nextInt(256);
received[location] = newByte;
}
}
}
}