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_CORRECTABLE = (DM_CODE_TEST_WITH_EC.length - DM_CODE_TEST.length) / 2;
  30
  31   private final ReedSolomonDecoder dmRSDecoder = new ReedSolomonDecoder(GF256.DATA_MATRIX_FIELD);
  32
  33   public void testNoError() throws ReedSolomonException {
  34     int[] received = new int[DM_CODE_TEST_WITH_EC.length];
  35     System.arraycopy(DM_CODE_TEST_WITH_EC, 0, received, 0, received.length);
  36     // no errors
  37     checkQRRSDecode(received);
  38   }
  39
  40   public void testOneError() throws ReedSolomonException {
  41     int[] received = new int[DM_CODE_TEST_WITH_EC.length];
  42     Random random = new Random(0xDEADBEEFL);
  43     for (int i = 0; i < received.length; i++) {
  44       System.arraycopy(DM_CODE_TEST_WITH_EC, 0, received, 0, received.length);
  45       received[i] = random.nextInt(256);
  46       checkQRRSDecode(received);
  47     }
  48   }
  49
  50   public void testMaxErrors() throws ReedSolomonException {
  51     int[] received = new int[DM_CODE_TEST_WITH_EC.length];
  52     Random random = new Random(0xDEADBEEFL);
  53     for (int i = 0; i < DM_CODE_TEST.length; i++) { // # iterations is kind of arbitrary
  54       System.arraycopy(DM_CODE_TEST_WITH_EC, 0, received, 0, received.length);
  55       corrupt(received, DM_CODE_CORRECTABLE, random);
  56       checkQRRSDecode(received);
  57     }
  58   }
  59
  60   public void testTooManyErrors() {
  61     int[] received = new int[DM_CODE_TEST_WITH_EC.length];
  62     System.arraycopy(DM_CODE_TEST_WITH_EC, 0, received, 0, received.length);
  63     Random random = new Random(0xDEADBEEFL);
  64     corrupt(received, DM_CODE_CORRECTABLE + 1, random);
  65     try {
  66       checkQRRSDecode(received);
  67       fail("Should not have decoded");
  68     } catch (ReedSolomonException rse) {
  69       // good
  70     }
  71   }
  72
  73   private void checkQRRSDecode(int[] received) throws ReedSolomonException {
  74     dmRSDecoder.decode(received, 2 * DM_CODE_CORRECTABLE);
  75     for (int i = 0; i < DM_CODE_TEST.length; i++) {
  76       assertEquals(received[i], DM_CODE_TEST[i]);
  77     }
  78   }
  79
  80 }