core/test/src/com/google/zxing/common/reedsolomon/ReedSolomonDecoderDataMatrixTestCase.java

   1 /*
   2  * Copyright 2008 ZXing authors
   3  *
   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
   7  *
   8  *      http://www.apache.org/licenses/LICENSE-2.0
   9  *
  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.
  15  */
  16
  17 package com.google.zxing.common.reedsolomon;
  18
  19 import org.junit.Test;
  20
  21 import java.util.Random;
  22
  23 /**
  24  * @author Sean Owen
  25  * @author sanfordsquires
  26  */
  27 public final class ReedSolomonDecoderDataMatrixTestCase extends AbstractReedSolomonTestCase {
  28
  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_ECC_BYTES = DM_CODE_TEST_WITH_EC.length - DM_CODE_TEST.length;
  32   private static final int DM_CODE_CORRECTABLE = DM_CODE_ECC_BYTES / 2;
  33
  34   private final ReedSolomonDecoder dmRSDecoder = new ReedSolomonDecoder(GF256.DATA_MATRIX_FIELD);
  35
  36   @Test
  37   public void testNoError() throws ReedSolomonException {
  38     int[] received = new int[DM_CODE_TEST_WITH_EC.length];
  39     System.arraycopy(DM_CODE_TEST_WITH_EC, 0, received, 0, received.length);
  40     // no errors
  41     checkQRRSDecode(received);
  42   }
  43
  44   @Test
  45   public void testOneError() throws ReedSolomonException {
  46     int[] received = new int[DM_CODE_TEST_WITH_EC.length];
  47     Random random = getRandom();
  48     for (int i = 0; i < received.length; i++) {
  49       System.arraycopy(DM_CODE_TEST_WITH_EC, 0, received, 0, received.length);
  50       received[i] = random.nextInt(256);
  51       checkQRRSDecode(received);
  52     }
  53   }
  54
  55   @Test
  56   public void testMaxErrors() throws ReedSolomonException {
  57     int[] received = new int[DM_CODE_TEST_WITH_EC.length];
  58     Random random = getRandom();
  59     for (int test : DM_CODE_TEST) { // # iterations is kind of arbitrary
  60       System.arraycopy(DM_CODE_TEST_WITH_EC, 0, received, 0, received.length);
  61       corrupt(received, DM_CODE_CORRECTABLE, random);
  62       checkQRRSDecode(received);
  63     }
  64   }
  65
  66   @Test
  67   public void testTooManyErrors() {
  68     int[] received = new int[DM_CODE_TEST_WITH_EC.length];
  69     System.arraycopy(DM_CODE_TEST_WITH_EC, 0, received, 0, received.length);
  70     Random random = getRandom();
  71     corrupt(received, DM_CODE_CORRECTABLE + 1, random);
  72     try {
  73       checkQRRSDecode(received);
  74       fail("Should not have decoded");
  75     } catch (ReedSolomonException rse) {
  76       // good
  77     }
  78   }
  79
  80   private void checkQRRSDecode(int[] received) throws ReedSolomonException {
  81     dmRSDecoder.decode(received, DM_CODE_ECC_BYTES);
  82     for (int i = 0; i < DM_CODE_TEST.length; i++) {
  83       assertEquals(received[i], DM_CODE_TEST[i]);
  84     }
  85   }
  86
  87 }