content: /*
   * Copyright (C) 2017 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.android.exoplayer2.util.Util.castNonNull;
  import static java.lang.Math.min;
  
  import android.net.Uri;
  import android.util.Base64;
  import androidx.annotation.Nullable;
  import com.google.android.exoplayer2.C;
  import com.google.android.exoplayer2.ParserException;
  import com.google.android.exoplayer2.PlaybackException;
  import com.google.android.exoplayer2.util.Assertions;
  import com.google.android.exoplayer2.util.Util;
  import com.google.common.base.Charsets;
  import java.io.IOException;
  import java.net.URLDecoder;
  
  /** A {@link DataSource} for reading data URLs, as defined by RFC 2397. */
  public final class DataSchemeDataSource extends BaseDataSource {
  
    public static final String SCHEME_DATA = "data";
  
    @Nullable private DataSpec dataSpec;
    @Nullable private byte[] data;
    private int readPosition;
    private int bytesRemaining;
  
    public DataSchemeDataSource() {
      super(/* isNetwork= */ false);
    }
  
    @Override
    public long open(DataSpec dataSpec) throws IOException {
      transferInitializing(dataSpec);
      this.dataSpec = dataSpec;
      Uri uri = dataSpec.uri;
      String scheme = uri.getScheme();
      Assertions.checkArgument(SCHEME_DATA.equals(scheme), "Unsupported scheme: " + scheme);
      String[] uriParts = Util.split(uri.getSchemeSpecificPart(), ",");
      if (uriParts.length != 2) {
        throw ParserException.createForMalformedDataOfUnknownType(
            "Unexpected URI format: " + uri, /* cause= */ null);
      }
      String dataString = uriParts[1];
      if (uriParts[0].contains(";base64")) {
        try {
          data = Base64.decode(dataString, /* flags= */ Base64.DEFAULT);
        } catch (IllegalArgumentException e) {
          throw ParserException.createForMalformedDataOfUnknownType(
              "Error while parsing Base64 encoded string: " + dataString, e);
        }
      } else {
        // TODO: Add support for other charsets.
        data = Util.getUtf8Bytes(URLDecoder.decode(dataString, Charsets.US_ASCII.name()));
      }
      if (dataSpec.position > data.length) {
        data = null;
        throw new DataSourceException(PlaybackException.ERROR_CODE_IO_READ_POSITION_OUT_OF_RANGE);
      }
      readPosition = (int) dataSpec.position;
      bytesRemaining = data.length - readPosition;
      if (dataSpec.length != C.LENGTH_UNSET) {
        bytesRemaining = (int) min(bytesRemaining, dataSpec.length);
      }
      transferStarted(dataSpec);
      return dataSpec.length != C.LENGTH_UNSET ? dataSpec.length : bytesRemaining;
    }
  
    @Override
    public int read(byte[] buffer, int offset, int length) {
      if (length == 0) {
        return 0;
      }
      if (bytesRemaining == 0) {
        return C.RESULT_END_OF_INPUT;
      }
      length = min(length, bytesRemaining);
      System.arraycopy(castNonNull(data), readPosition, buffer, offset, length);
      readPosition += length;
      bytesRemaining -= length;
      bytesTransferred(length);
      return length;
    }
  
    @Override
    @Nullable
    public Uri getUri() {
      return dataSpec != null ? dataSpec.uri : null;
    }
  
    @Override
    public void close() {
      if (data != null) {
        data = null;
        transferEnded();
      }
      dataSpec = null;
    }
  }
  