content: /*
   * Copyright (C) 2016 The Android Open Source Project
   *
   * 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.android.exoplayer2.util;
  
  import static com.google.common.truth.Truth.assertThat;
  import static org.junit.Assert.fail;
  
  import androidx.test.ext.junit.runners.AndroidJUnit4;
  import org.junit.Test;
  import org.junit.runner.RunWith;
  
  /** Tests for {@link ParsableNalUnitBitArray}. */
  @RunWith(AndroidJUnit4.class)
  public final class ParsableNalUnitBitArrayTest {
  
    private static final byte[] NO_ESCAPING_TEST_DATA = createByteArray(0, 3, 0, 1, 3, 0, 0);
    private static final byte[] ALL_ESCAPING_TEST_DATA = createByteArray(0, 0, 3, 0, 0, 3, 0, 0, 3);
    private static final byte[] MIX_TEST_DATA = createByteArray(255, 0, 0, 3, 255, 0, 0, 127);
  
    @Test
    public void readNoEscaping() {
      ParsableNalUnitBitArray array =
          new ParsableNalUnitBitArray(NO_ESCAPING_TEST_DATA, 0, NO_ESCAPING_TEST_DATA.length);
      assertThat(array.readBits(24)).isEqualTo(0x000300);
      assertThat(array.readBits(7)).isEqualTo(0);
      assertThat(array.readBit()).isTrue();
      assertThat(array.readBits(24)).isEqualTo(0x030000);
      assertThat(array.canReadBits(1)).isFalse();
      assertThat(array.canReadBits(8)).isFalse();
    }
  
    @Test
    public void readNoEscapingTruncated() {
      ParsableNalUnitBitArray array = new ParsableNalUnitBitArray(NO_ESCAPING_TEST_DATA, 0, 4);
      assertThat(array.canReadBits(32)).isTrue();
      array.skipBits(32);
      assertThat(array.canReadBits(1)).isFalse();
      try {
        array.readBit();
        fail();
      } catch (Exception e) {
        // Expected.
      }
    }
  
    @Test
    public void readAllEscaping() {
      ParsableNalUnitBitArray array =
          new ParsableNalUnitBitArray(ALL_ESCAPING_TEST_DATA, 0, ALL_ESCAPING_TEST_DATA.length);
      assertThat(array.canReadBits(48)).isTrue();
      assertThat(array.canReadBits(49)).isFalse();
      assertThat(array.readBits(15)).isEqualTo(0);
      assertThat(array.readBit()).isFalse();
      assertThat(array.readBits(17)).isEqualTo(0);
      assertThat(array.readBits(15)).isEqualTo(0);
    }
  
    @Test
    public void readMix() {
      ParsableNalUnitBitArray array =
          new ParsableNalUnitBitArray(MIX_TEST_DATA, 0, MIX_TEST_DATA.length);
      assertThat(array.canReadBits(56)).isTrue();
      assertThat(array.canReadBits(57)).isFalse();
      assertThat(array.readBits(7)).isEqualTo(127);
      assertThat(array.readBits(2)).isEqualTo(2);
      assertThat(array.readBits(17)).isEqualTo(3);
      assertThat(array.readBits(7)).isEqualTo(126);
      assertThat(array.readBits(23)).isEqualTo(127);
      assertThat(array.canReadBits(1)).isFalse();
    }
  
    @Test
    public void readExpGolomb() {
      ParsableNalUnitBitArray array = new ParsableNalUnitBitArray(createByteArray(0x9E), 0, 1);
      assertThat(array.canReadExpGolombCodedNum()).isTrue();
      assertThat(array.readUnsignedExpGolombCodedInt()).isEqualTo(0);
      assertThat(array.readUnsignedExpGolombCodedInt()).isEqualTo(6);
      assertThat(array.readUnsignedExpGolombCodedInt()).isEqualTo(0);
      assertThat(array.canReadExpGolombCodedNum()).isFalse();
      try {
        array.readUnsignedExpGolombCodedInt();
        fail();
      } catch (Exception e) {
        // Expected.
      }
    }
  
    @Test
    public void readExpGolombWithEscaping() {
      ParsableNalUnitBitArray array =
          new ParsableNalUnitBitArray(createByteArray(0, 0, 3, 128, 0), 0, 5);
      assertThat(array.canReadExpGolombCodedNum()).isFalse();
      array.skipBit();
      assertThat(array.canReadExpGolombCodedNum()).isTrue();
      assertThat(array.readUnsignedExpGolombCodedInt()).isEqualTo(32767);
      assertThat(array.canReadBits(1)).isFalse();
    }
  
    @Test
    public void reset() {
      ParsableNalUnitBitArray array = new ParsableNalUnitBitArray(createByteArray(0, 0), 0, 2);
      assertThat(array.canReadExpGolombCodedNum()).isFalse();
      assertThat(array.canReadBits(16)).isTrue();
      assertThat(array.canReadBits(17)).isFalse();
      array.reset(createByteArray(0, 0, 3, 0), 0, 4);
      assertThat(array.canReadBits(24)).isTrue();
      assertThat(array.canReadBits(25)).isFalse();
    }
  
    /** Converts an array of integers in the range [0, 255] into an equivalent byte array. */
    // TODO(internal b/161804035): Use TestUtils when it's available in a dependency we can use here.
    private static byte[] createByteArray(int... bytes) {
      byte[] byteArray = new byte[bytes.length];
      for (int i = 0; i < byteArray.length; i++) {
        Assertions.checkState(0x00 <= bytes[i] && bytes[i] <= 0xFF);
        byteArray[i] = (byte) bytes[i];
      }
      return byteArray;
    }
  }
  