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 java.util.Random;
  20
  21 /**
  22  * @author srowen@google.com (Sean Owen)
  23  * @author sanfordsquires
  24  */
  25 public final class ReedSolomonDecoderDataMatrixTestCase extends AbstractReedSolomonTestCase {
  26
  27   private static final int[] DM_CODE_TEST = { 142, 164, 186 };
  28   private static final int[] DM_CODE_TEST_WITH_EC = { 142, 164, 186, 114, 25, 5, 88, 102 };
  29   private static final int DM_CODE_ECC_BYTES = DM_CODE_TEST_WITH_EC.length - DM_CODE_TEST.length;
  30   private static final int DM_CODE_CORRECTABLE = DM_CODE_ECC_BYTES / 2;
  31
  32   private final ReedSolomonDecoder dmRSDecoder = new ReedSolomonDecoder(GF256.DATA_MATRIX_FIELD);
  33
  34   public void testNoError() throws ReedSolomonException {
  35     int[] received = new int[DM_CODE_TEST_WITH_EC.length];
  36     System.arraycopy(DM_CODE_TEST_WITH_EC, 0, received, 0, received.length);
  37     // no errors
  38     checkQRRSDecode(received);
  39   }
  40
  41   public void testOneError() throws ReedSolomonException {
  42     int[] received = new int[DM_CODE_TEST_WITH_EC.length];
  43     Random random = new Random(0xDEADBEEFL);
  44     for (int i = 0; i < received.length; i++) {
  45       System.arraycopy(DM_CODE_TEST_WITH_EC, 0, received, 0, received.length);
  46       received[i] = random.nextInt(256);
  47       checkQRRSDecode(received);
  48     }
  49   }
  50
  51   public void testMaxErrors() throws ReedSolomonException {
  52     int[] received = new int[DM_CODE_TEST_WITH_EC.length];
  53     Random random = new Random(0xDEADBEEFL);
  54     for (int i = 0; i < DM_CODE_TEST.length; i++) { // # iterations is kind of arbitrary
  55       System.arraycopy(DM_CODE_TEST_WITH_EC, 0, received, 0, received.length);
  56       corrupt(received, DM_CODE_CORRECTABLE, random);
  57       checkQRRSDecode(received);
  58     }
  59   }
  60
  61   public void testTooManyErrors() {
  62     int[] received = new int[DM_CODE_TEST_WITH_EC.length];
  63     System.arraycopy(DM_CODE_TEST_WITH_EC, 0, received, 0, received.length);
  64     Random random = new Random(0xDEADBEEFL);
  65     corrupt(received, DM_CODE_CORRECTABLE + 1, random);
  66     try {
  67       checkQRRSDecode(received);
  68       fail("Should not have decoded");
  69     } catch (ReedSolomonException rse) {
  70       // good
  71     }
  72   }
  73
  74   private void checkQRRSDecode(int[] received) throws ReedSolomonException {
  75     dmRSDecoder.decode(received, DM_CODE_ECC_BYTES);
  76     for (int i = 0; i < DM_CODE_TEST.length; i++) {
  77       assertEquals(received[i], DM_CODE_TEST[i]);
  78     }
  79   }
  80
  81 }