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.text.subrip;
  
  import android.text.Html;
  import android.text.Spanned;
  import android.text.TextUtils;
  import android.util.Log;
  import com.google.android.exoplayer2.text.Cue;
  import com.google.android.exoplayer2.text.SimpleSubtitleDecoder;
  import com.google.android.exoplayer2.util.LongArray;
  import com.google.android.exoplayer2.util.ParsableByteArray;
  import java.util.ArrayList;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  /**
   * A {@link SimpleSubtitleDecoder} for SubRip.
   */
  public final class SubripDecoder extends SimpleSubtitleDecoder {
  
    private static final String TAG = "SubripDecoder";
  
    private static final String SUBRIP_TIMECODE = "(?:(\\d+):)?(\\d+):(\\d+),(\\d+)";
    private static final Pattern SUBRIP_TIMING_LINE =
        Pattern.compile("\\s*(" + SUBRIP_TIMECODE + ")\\s*-->\\s*(" + SUBRIP_TIMECODE + ")?\\s*");
  
    private final StringBuilder textBuilder;
  
    public SubripDecoder() {
      super("SubripDecoder");
      textBuilder = new StringBuilder();
    }
  
    @Override
    protected SubripSubtitle decode(byte[] bytes, int length, boolean reset) {
      ArrayList<Cue> cues = new ArrayList<>();
      LongArray cueTimesUs = new LongArray();
      ParsableByteArray subripData = new ParsableByteArray(bytes, length);
      String currentLine;
  
      while ((currentLine = subripData.readLine()) != null) {
        if (currentLine.length() == 0) {
          // Skip blank lines.
          continue;
        }
  
        // Parse the index line as a sanity check.
        try {
          Integer.parseInt(currentLine);
        } catch (NumberFormatException e) {
          Log.w(TAG, "Skipping invalid index: " + currentLine);
          continue;
        }
  
        // Read and parse the timing line.
        boolean haveEndTimecode = false;
        currentLine = subripData.readLine();
        if (currentLine == null) {
          Log.w(TAG, "Unexpected end");
          break;
        }
  
        Matcher matcher = SUBRIP_TIMING_LINE.matcher(currentLine);
        if (matcher.matches()) {
          cueTimesUs.add(parseTimecode(matcher, 1));
          if (!TextUtils.isEmpty(matcher.group(6))) {
            haveEndTimecode = true;
            cueTimesUs.add(parseTimecode(matcher, 6));
          }
        } else {
          Log.w(TAG, "Skipping invalid timing: " + currentLine);
          continue;
        }
  
        // Read and parse the text.
        textBuilder.setLength(0);
        while (!TextUtils.isEmpty(currentLine = subripData.readLine())) {
          if (textBuilder.length() > 0) {
            textBuilder.append("<br>");
          }
          textBuilder.append(currentLine.trim());
        }
  
        Spanned text = Html.fromHtml(textBuilder.toString());
        cues.add(new Cue(text));
        if (haveEndTimecode) {
          cues.add(null);
        }
      }
  
      Cue[] cuesArray = new Cue[cues.size()];
      cues.toArray(cuesArray);
      long[] cueTimesUsArray = cueTimesUs.toArray();
      return new SubripSubtitle(cuesArray, cueTimesUsArray);
    }
  
    private static long parseTimecode(Matcher matcher, int groupOffset) {
      long timestampMs = Long.parseLong(matcher.group(groupOffset + 1)) * 60 * 60 * 1000;
      timestampMs += Long.parseLong(matcher.group(groupOffset + 2)) * 60 * 1000;
      timestampMs += Long.parseLong(matcher.group(groupOffset + 3)) * 1000;
      timestampMs += Long.parseLong(matcher.group(groupOffset + 4));
      return timestampMs * 1000;
    }
  
  }
  