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.upstream;
  
  import static com.google.common.truth.Truth.assertThat;
  import static java.lang.Math.min;
  import static org.junit.Assert.fail;
  
  import android.net.Uri;
  import androidx.test.ext.junit.runners.AndroidJUnit4;
  import com.google.android.exoplayer2.C;
  import java.io.IOException;
  import org.junit.Test;
  import org.junit.runner.RunWith;
  
  /** Unit tests for {@link ByteArrayDataSource}. */
  @RunWith(AndroidJUnit4.class)
  public final class ByteArrayDataSourceTest {
  
    private static final byte[] TEST_DATA = new byte[] {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
    private static final byte[] TEST_DATA_ODD = new byte[] {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
  
    @Test
    public void fullReadSingleBytes() {
      readTestData(TEST_DATA, 0, C.LENGTH_UNSET, 1, 0, 1, false);
    }
  
    @Test
    public void fullReadAllBytes() {
      readTestData(TEST_DATA, 0, C.LENGTH_UNSET, 100, 0, 100, false);
    }
  
    @Test
    public void limitReadSingleBytes() {
      // Limit set to the length of the data.
      readTestData(TEST_DATA, 0, TEST_DATA.length, 1, 0, 1, false);
      // And less.
      readTestData(TEST_DATA, 0, 6, 1, 0, 1, false);
    }
  
    @Test
    public void fullReadTwoBytes() {
      // Try with the total data length an exact multiple of the size of each individual read.
      readTestData(TEST_DATA, 0, C.LENGTH_UNSET, 2, 0, 2, false);
      // And not.
      readTestData(TEST_DATA_ODD, 0, C.LENGTH_UNSET, 2, 0, 2, false);
    }
  
    @Test
    public void limitReadTwoBytes() {
      // Try with the limit an exact multiple of the size of each individual read.
      readTestData(TEST_DATA, 0, 6, 2, 0, 2, false);
      // And not.
      readTestData(TEST_DATA, 0, 7, 2, 0, 2, false);
    }
  
    @Test
    public void readFromValidOffsets() {
      // Read from an offset without bound.
      readTestData(TEST_DATA, 1, C.LENGTH_UNSET, 1, 0, 1, false);
      // And with bound.
      readTestData(TEST_DATA, 1, 6, 1, 0, 1, false);
      // Read from the last possible offset without bound.
      readTestData(TEST_DATA, TEST_DATA.length, C.LENGTH_UNSET, 1, 0, 1, false);
      // And with bound.
      readTestData(TEST_DATA, TEST_DATA.length, 1, 1, 0, 1, false);
    }
  
    @Test
    public void readFromInvalidOffsets() {
      // Read from first invalid offset and check failure without bound.
      readTestData(TEST_DATA, TEST_DATA.length + 1, C.LENGTH_UNSET, 1, 0, 1, true);
      // And with bound.
      readTestData(TEST_DATA, TEST_DATA.length + 1, 1, 1, 0, 1, true);
    }
  
    /**
     * Tests reading from a {@link ByteArrayDataSource} with various parameters.
     *
     * @param testData The data that the {@link ByteArrayDataSource} will wrap.
     * @param dataOffset The offset from which to read data.
     * @param dataLength The total length of data to read.
     * @param outputBufferLength The length of the target buffer for each read.
     * @param writeOffset The offset into {@code outputBufferLength} for each read.
     * @param maxReadLength The maximum length of each read.
     * @param expectFailOnOpen Whether it is expected that opening the source will fail.
     */
    private void readTestData(
        byte[] testData,
        int dataOffset,
        int dataLength,
        int outputBufferLength,
        int writeOffset,
        int maxReadLength,
        boolean expectFailOnOpen) {
      int expectedFinalBytesRead = testData.length - dataOffset;
      if (dataLength != C.LENGTH_UNSET) {
        expectedFinalBytesRead = min(expectedFinalBytesRead, dataLength);
      }
      ByteArrayDataSource dataSource = new ByteArrayDataSource(testData);
      boolean opened = false;
      try {
        // Open the source.
        long length = dataSource.open(new DataSpec(Uri.EMPTY, dataOffset, dataLength));
        opened = true;
        assertThat(expectFailOnOpen).isFalse();
  
        // Verify the resolved length is as we expect.
        assertThat(length)
            .isEqualTo(dataLength != C.LENGTH_UNSET ? dataLength : expectedFinalBytesRead);
  
        byte[] outputBuffer = new byte[outputBufferLength];
        int accumulatedBytesRead = 0;
        while (true) {
          // Calculate a valid length for the next read, constraining by the specified output buffer
          // length, write offset and maximum write length input parameters.
          int requestedReadLength = min(maxReadLength, outputBufferLength - writeOffset);
          assertThat(requestedReadLength).isGreaterThan(0);
  
          int bytesRead = dataSource.read(outputBuffer, writeOffset, requestedReadLength);
          if (bytesRead != C.RESULT_END_OF_INPUT) {
            assertThat(bytesRead).isGreaterThan(0);
            assertThat(bytesRead).isAtMost(requestedReadLength);
            // Check the data read was correct.
            for (int i = 0; i < bytesRead; i++) {
              assertThat(outputBuffer[writeOffset + i])
                  .isEqualTo(testData[dataOffset + accumulatedBytesRead + i]);
            }
            // Check that we haven't read more data than we were expecting.
            accumulatedBytesRead += bytesRead;
            assertThat(accumulatedBytesRead).isAtMost(expectedFinalBytesRead);
            // If we haven't read all of the bytes the request should have been satisfied in full.
            assertThat(
                    accumulatedBytesRead == expectedFinalBytesRead
                        || bytesRead == requestedReadLength)
                .isTrue();
          } else {
            // We're done. Check we read the expected number of bytes.
            assertThat(accumulatedBytesRead).isEqualTo(expectedFinalBytesRead);
            return;
          }
        }
      } catch (IOException e) {
        if (expectFailOnOpen && !opened) {
          // Expected.
          return;
        }
        // Unexpected failure.
        fail();
      }
    }
  }
  