tree/library/core/src/main/java/com/google/android/exoplayer2/text/subrip/SubripDecoder.java - platform/external/exoplayer - Git at Google

 /*
  * 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 androidx.annotation.Nullable;
 import com.google.android.exoplayer2.text.Cue;
 import com.google.android.exoplayer2.text.SimpleSubtitleDecoder;
 import com.google.android.exoplayer2.text.Subtitle;
 import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.Log;
 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 {

   // Fractional positions for use when alignment tags are present.
   private static final float START_FRACTION = 0.08f;
   private static final float END_FRACTION = 1 - START_FRACTION;
   private static final float MID_FRACTION = 0.5f;

   private static final String TAG = "SubripDecoder";

   // Some SRT files don't include hours or milliseconds in the timecode, so we use optional groups.
   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*");

   // NOTE: Android Studio's suggestion to simplify '\\}' is incorrect [internal: b/144480183].
   private static final Pattern SUBRIP_TAG_PATTERN = Pattern.compile("\\{\\\\.*?\\}");
   private static final String SUBRIP_ALIGNMENT_TAG = "\\{\\\\an[1-9]\\}";

   // Alignment tags for SSA V4+.
   private static final String ALIGN_BOTTOM_LEFT = "{\\an1}";
   private static final String ALIGN_BOTTOM_MID = "{\\an2}";
   private static final String ALIGN_BOTTOM_RIGHT = "{\\an3}";
   private static final String ALIGN_MID_LEFT = "{\\an4}";
   private static final String ALIGN_MID_MID = "{\\an5}";
   private static final String ALIGN_MID_RIGHT = "{\\an6}";
   private static final String ALIGN_TOP_LEFT = "{\\an7}";
   private static final String ALIGN_TOP_MID = "{\\an8}";
   private static final String ALIGN_TOP_RIGHT = "{\\an9}";

   private final StringBuilder textBuilder;
   private final ArrayList<String> tags;

   public SubripDecoder() {
     super("SubripDecoder");
     textBuilder = new StringBuilder();
     tags = new ArrayList<>();
   }

   @Override
   protected Subtitle decode(byte[] bytes, int length, boolean reset) {
     ArrayList<Cue> cues = new ArrayList<>();
     LongArray cueTimesUs = new LongArray();
     ParsableByteArray subripData = new ParsableByteArray(bytes, length);

     @Nullable 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.
       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, /* groupOffset= */ 1));
         cueTimesUs.add(parseTimecode(matcher, /* groupOffset= */ 6));
       } else {
         Log.w(TAG, "Skipping invalid timing: " + currentLine);
         continue;
       }

       // Read and parse the text and tags.
       textBuilder.setLength(0);
       tags.clear();
       currentLine = subripData.readLine();
       while (!TextUtils.isEmpty(currentLine)) {
         if (textBuilder.length() > 0) {
           textBuilder.append("<br>");
         }
         textBuilder.append(processLine(currentLine, tags));
         currentLine = subripData.readLine();
       }

       Spanned text = Html.fromHtml(textBuilder.toString());

       @Nullable String alignmentTag = null;
       for (int i = 0; i < tags.size(); i++) {
         String tag = tags.get(i);
         if (tag.matches(SUBRIP_ALIGNMENT_TAG)) {
           alignmentTag = tag;
           // Subsequent alignment tags should be ignored.
           break;
         }
       }
       cues.add(buildCue(text, alignmentTag));
       cues.add(Cue.EMPTY);
     }

     Cue[] cuesArray = new Cue[cues.size()];
     cues.toArray(cuesArray);
     long[] cueTimesUsArray = cueTimesUs.toArray();
     return new SubripSubtitle(cuesArray, cueTimesUsArray);
   }

   /**
    * Trims and removes tags from the given line. The removed tags are added to {@code tags}.
    *
    * @param line The line to process.
    * @param tags A list to which removed tags will be added.
    * @return The processed line.
    */
   private String processLine(String line, ArrayList<String> tags) {
     line = line.trim();

     int removedCharacterCount = 0;
     StringBuilder processedLine = new StringBuilder(line);
     Matcher matcher = SUBRIP_TAG_PATTERN.matcher(line);
     while (matcher.find()) {
       String tag = matcher.group();
       tags.add(tag);
       int start = matcher.start() - removedCharacterCount;
       int tagLength = tag.length();
       processedLine.replace(start, /* end= */ start + tagLength, /* str= */ "");
       removedCharacterCount += tagLength;
     }

     return processedLine.toString();
   }

   /**
    * Build a {@link Cue} based on the given text and alignment tag.
    *
    * @param text The text.
    * @param alignmentTag The alignment tag, or {@code null} if no alignment tag is available.
    * @return Built cue
    */
   private Cue buildCue(Spanned text, @Nullable String alignmentTag) {
     if (alignmentTag == null) {
       return new Cue(text);
     }

     // Horizontal alignment.
     @Cue.AnchorType int positionAnchor;
     switch (alignmentTag) {
       case ALIGN_BOTTOM_LEFT:
       case ALIGN_MID_LEFT:
       case ALIGN_TOP_LEFT:
         positionAnchor = Cue.ANCHOR_TYPE_START;
         break;
       case ALIGN_BOTTOM_RIGHT:
       case ALIGN_MID_RIGHT:
       case ALIGN_TOP_RIGHT:
         positionAnchor = Cue.ANCHOR_TYPE_END;
         break;
       case ALIGN_BOTTOM_MID:
       case ALIGN_MID_MID:
       case ALIGN_TOP_MID:
       default:
         positionAnchor = Cue.ANCHOR_TYPE_MIDDLE;
         break;
     }

     // Vertical alignment.
     @Cue.AnchorType int lineAnchor;
     switch (alignmentTag) {
       case ALIGN_BOTTOM_LEFT:
       case ALIGN_BOTTOM_MID:
       case ALIGN_BOTTOM_RIGHT:
         lineAnchor = Cue.ANCHOR_TYPE_END;
         break;
       case ALIGN_TOP_LEFT:
       case ALIGN_TOP_MID:
       case ALIGN_TOP_RIGHT:
         lineAnchor = Cue.ANCHOR_TYPE_START;
         break;
       case ALIGN_MID_LEFT:
       case ALIGN_MID_MID:
       case ALIGN_MID_RIGHT:
       default:
         lineAnchor = Cue.ANCHOR_TYPE_MIDDLE;
         break;
     }

     return new Cue(
         text,
         /* textAlignment= */ null,
         getFractionalPositionForAnchorType(lineAnchor),
         Cue.LINE_TYPE_FRACTION,
         lineAnchor,
         getFractionalPositionForAnchorType(positionAnchor),
         positionAnchor,
         Cue.DIMEN_UNSET);
   }

   private static long parseTimecode(Matcher matcher, int groupOffset) {
     @Nullable String hours = matcher.group(groupOffset + 1);
     long timestampMs = hours != null ? Long.parseLong(hours) * 60 * 60 * 1000 : 0;
     timestampMs +=
         Long.parseLong(Assertions.checkNotNull(matcher.group(groupOffset + 2))) * 60 * 1000;
     timestampMs += Long.parseLong(Assertions.checkNotNull(matcher.group(groupOffset + 3))) * 1000;
     @Nullable String millis = matcher.group(groupOffset + 4);
     if (millis != null) {
       timestampMs += Long.parseLong(millis);
     }
     return timestampMs * 1000;
   }

   /* package */ static float getFractionalPositionForAnchorType(@Cue.AnchorType int anchorType) {
     switch (anchorType) {
       case Cue.ANCHOR_TYPE_START:
         return SubripDecoder.START_FRACTION;
       case Cue.ANCHOR_TYPE_MIDDLE:
         return SubripDecoder.MID_FRACTION;
       case Cue.ANCHOR_TYPE_END:
         return SubripDecoder.END_FRACTION;
       case Cue.TYPE_UNSET:
       default:
         // Should never happen.
         throw new IllegalArgumentException();
     }
   }
 }
	/*
	* 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 androidx.annotation.Nullable;
	import com.google.android.exoplayer2.text.Cue;
	import com.google.android.exoplayer2.text.SimpleSubtitleDecoder;
	import com.google.android.exoplayer2.text.Subtitle;
	import com.google.android.exoplayer2.util.Assertions;
	import com.google.android.exoplayer2.util.Log;
	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 {

	// Fractional positions for use when alignment tags are present.
	private static final float START_FRACTION = 0.08f;
	private static final float END_FRACTION = 1 - START_FRACTION;
	private static final float MID_FRACTION = 0.5f;

	private static final String TAG = "SubripDecoder";

	// Some SRT files don't include hours or milliseconds in the timecode, so we use optional groups.
	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");

	// NOTE: Android Studio's suggestion to simplify '\\}' is incorrect [internal: b/144480183].
	private static final Pattern SUBRIP_TAG_PATTERN = Pattern.compile("\\{\\\\.*?\\}");
	private static final String SUBRIP_ALIGNMENT_TAG = "\\{\\\\an[1-9]\\}";

	// Alignment tags for SSA V4+.
	private static final String ALIGN_BOTTOM_LEFT = "{\\an1}";
	private static final String ALIGN_BOTTOM_MID = "{\\an2}";
	private static final String ALIGN_BOTTOM_RIGHT = "{\\an3}";
	private static final String ALIGN_MID_LEFT = "{\\an4}";
	private static final String ALIGN_MID_MID = "{\\an5}";
	private static final String ALIGN_MID_RIGHT = "{\\an6}";
	private static final String ALIGN_TOP_LEFT = "{\\an7}";
	private static final String ALIGN_TOP_MID = "{\\an8}";
	private static final String ALIGN_TOP_RIGHT = "{\\an9}";

	private final StringBuilder textBuilder;
	private final ArrayList<String> tags;

	public SubripDecoder() {
	super("SubripDecoder");
	textBuilder = new StringBuilder();
	tags = new ArrayList<>();
	}

	@Override
	protected Subtitle decode(byte[] bytes, int length, boolean reset) {
	ArrayList<Cue> cues = new ArrayList<>();
	LongArray cueTimesUs = new LongArray();
	ParsableByteArray subripData = new ParsableByteArray(bytes, length);

	@Nullable 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.
	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, /* groupOffset= */ 1));
	cueTimesUs.add(parseTimecode(matcher, /* groupOffset= */ 6));
	} else {
	Log.w(TAG, "Skipping invalid timing: " + currentLine);
	continue;
	}

	// Read and parse the text and tags.
	textBuilder.setLength(0);
	tags.clear();
	currentLine = subripData.readLine();
	while (!TextUtils.isEmpty(currentLine)) {
	if (textBuilder.length() > 0) {
	textBuilder.append("<br>");
	}
	textBuilder.append(processLine(currentLine, tags));
	currentLine = subripData.readLine();
	}

	Spanned text = Html.fromHtml(textBuilder.toString());

	@Nullable String alignmentTag = null;
	for (int i = 0; i < tags.size(); i++) {
	String tag = tags.get(i);
	if (tag.matches(SUBRIP_ALIGNMENT_TAG)) {
	alignmentTag = tag;
	// Subsequent alignment tags should be ignored.
	break;
	}
	}
	cues.add(buildCue(text, alignmentTag));
	cues.add(Cue.EMPTY);
	}

	Cue[] cuesArray = new Cue[cues.size()];
	cues.toArray(cuesArray);
	long[] cueTimesUsArray = cueTimesUs.toArray();
	return new SubripSubtitle(cuesArray, cueTimesUsArray);
	}

	/**
	* Trims and removes tags from the given line. The removed tags are added to {@code tags}.
	*
	* @param line The line to process.
	* @param tags A list to which removed tags will be added.
	* @return The processed line.
	*/
	private String processLine(String line, ArrayList<String> tags) {
	line = line.trim();

	int removedCharacterCount = 0;
	StringBuilder processedLine = new StringBuilder(line);
	Matcher matcher = SUBRIP_TAG_PATTERN.matcher(line);
	while (matcher.find()) {
	String tag = matcher.group();
	tags.add(tag);
	int start = matcher.start() - removedCharacterCount;
	int tagLength = tag.length();
	processedLine.replace(start, /* end= / start + tagLength, / str= */ "");
	removedCharacterCount += tagLength;
	}

	return processedLine.toString();
	}

	/**
	* Build a {@link Cue} based on the given text and alignment tag.
	*
	* @param text The text.
	* @param alignmentTag The alignment tag, or {@code null} if no alignment tag is available.
	* @return Built cue
	*/
	private Cue buildCue(Spanned text, @Nullable String alignmentTag) {
	if (alignmentTag == null) {
	return new Cue(text);
	}

	// Horizontal alignment.
	@Cue.AnchorType int positionAnchor;
	switch (alignmentTag) {
	case ALIGN_BOTTOM_LEFT:
	case ALIGN_MID_LEFT:
	case ALIGN_TOP_LEFT:
	positionAnchor = Cue.ANCHOR_TYPE_START;
	break;
	case ALIGN_BOTTOM_RIGHT:
	case ALIGN_MID_RIGHT:
	case ALIGN_TOP_RIGHT:
	positionAnchor = Cue.ANCHOR_TYPE_END;
	break;
	case ALIGN_BOTTOM_MID:
	case ALIGN_MID_MID:
	case ALIGN_TOP_MID:
	default:
	positionAnchor = Cue.ANCHOR_TYPE_MIDDLE;
	break;
	}

	// Vertical alignment.
	@Cue.AnchorType int lineAnchor;
	switch (alignmentTag) {
	case ALIGN_BOTTOM_LEFT:
	case ALIGN_BOTTOM_MID:
	case ALIGN_BOTTOM_RIGHT:
	lineAnchor = Cue.ANCHOR_TYPE_END;
	break;
	case ALIGN_TOP_LEFT:
	case ALIGN_TOP_MID:
	case ALIGN_TOP_RIGHT:
	lineAnchor = Cue.ANCHOR_TYPE_START;
	break;
	case ALIGN_MID_LEFT:
	case ALIGN_MID_MID:
	case ALIGN_MID_RIGHT:
	default:
	lineAnchor = Cue.ANCHOR_TYPE_MIDDLE;
	break;
	}

	return new Cue(
	text,
	/* textAlignment= */ null,
	getFractionalPositionForAnchorType(lineAnchor),
	Cue.LINE_TYPE_FRACTION,
	lineAnchor,
	getFractionalPositionForAnchorType(positionAnchor),
	positionAnchor,
	Cue.DIMEN_UNSET);
	}

	private static long parseTimecode(Matcher matcher, int groupOffset) {
	@Nullable String hours = matcher.group(groupOffset + 1);
	long timestampMs = hours != null ? Long.parseLong(hours) * 60 * 60 * 1000 : 0;
	timestampMs +=
	Long.parseLong(Assertions.checkNotNull(matcher.group(groupOffset + 2))) * 60 * 1000;
	timestampMs += Long.parseLong(Assertions.checkNotNull(matcher.group(groupOffset + 3))) * 1000;
	@Nullable String millis = matcher.group(groupOffset + 4);
	if (millis != null) {
	timestampMs += Long.parseLong(millis);
	}
	return timestampMs * 1000;
	}

	/* package */ static float getFractionalPositionForAnchorType(@Cue.AnchorType int anchorType) {
	switch (anchorType) {
	case Cue.ANCHOR_TYPE_START:
	return SubripDecoder.START_FRACTION;
	case Cue.ANCHOR_TYPE_MIDDLE:
	return SubripDecoder.MID_FRACTION;
	case Cue.ANCHOR_TYPE_END:
	return SubripDecoder.END_FRACTION;
	case Cue.TYPE_UNSET:
	default:
	// Should never happen.
	throw new IllegalArgumentException();
	}
	}
	}