diff options
Diffstat (limited to 'mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/text/webvtt/WebvttParserUtil.java')
-rw-r--r-- | mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/text/webvtt/WebvttParserUtil.java | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/text/webvtt/WebvttParserUtil.java b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/text/webvtt/WebvttParserUtil.java new file mode 100644 index 0000000000..b87d014de0 --- /dev/null +++ b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/text/webvtt/WebvttParserUtil.java @@ -0,0 +1,119 @@ +/* + * 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 org.mozilla.thirdparty.com.google.android.exoplayer2.text.webvtt; + +import androidx.annotation.Nullable; +import org.mozilla.thirdparty.com.google.android.exoplayer2.ParserException; +import org.mozilla.thirdparty.com.google.android.exoplayer2.util.ParsableByteArray; +import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Util; +import java.util.regex.Matcher; +import java.util.regex.Pattern; + +/** + * Utility methods for parsing WebVTT data. + */ +public final class WebvttParserUtil { + + private static final Pattern COMMENT = Pattern.compile("^NOTE([ \t].*)?$"); + private static final String WEBVTT_HEADER = "WEBVTT"; + + private WebvttParserUtil() {} + + /** + * Reads and validates the first line of a WebVTT file. + * + * @param input The input from which the line should be read. + * @throws ParserException If the line isn't the start of a valid WebVTT file. + */ + public static void validateWebvttHeaderLine(ParsableByteArray input) throws ParserException { + int startPosition = input.getPosition(); + if (!isWebvttHeaderLine(input)) { + input.setPosition(startPosition); + throw new ParserException("Expected WEBVTT. Got " + input.readLine()); + } + } + + /** + * Returns whether the given input is the first line of a WebVTT file. + * + * @param input The input from which the line should be read. + */ + public static boolean isWebvttHeaderLine(ParsableByteArray input) { + @Nullable String line = input.readLine(); + return line != null && line.startsWith(WEBVTT_HEADER); + } + + /** + * Parses a WebVTT timestamp. + * + * @param timestamp The timestamp string. + * @return The parsed timestamp in microseconds. + * @throws NumberFormatException If the timestamp could not be parsed. + */ + public static long parseTimestampUs(String timestamp) throws NumberFormatException { + long value = 0; + String[] parts = Util.splitAtFirst(timestamp, "\\."); + String[] subparts = Util.split(parts[0], ":"); + for (String subpart : subparts) { + value = (value * 60) + Long.parseLong(subpart); + } + value *= 1000; + if (parts.length == 2) { + value += Long.parseLong(parts[1]); + } + return value * 1000; + } + + /** + * Parses a percentage string. + * + * @param s The percentage string. + * @return The parsed value, where 1.0 represents 100%. + * @throws NumberFormatException If the percentage could not be parsed. + */ + public static float parsePercentage(String s) throws NumberFormatException { + if (!s.endsWith("%")) { + throw new NumberFormatException("Percentages must end with %"); + } + return Float.parseFloat(s.substring(0, s.length() - 1)) / 100; + } + + /** + * Reads lines up to and including the next WebVTT cue header. + * + * @param input The input from which lines should be read. + * @return A {@link Matcher} for the WebVTT cue header, or null if the end of the input was + * reached without a cue header being found. In the case that a cue header is found, groups 1, + * 2 and 3 of the returned matcher contain the start time, end time and settings list. + */ + @Nullable + public static Matcher findNextCueHeader(ParsableByteArray input) { + @Nullable String line; + while ((line = input.readLine()) != null) { + if (COMMENT.matcher(line).matches()) { + // Skip until the end of the comment block. + while ((line = input.readLine()) != null && !line.isEmpty()) {} + } else { + Matcher cueHeaderMatcher = WebvttCueParser.CUE_HEADER_PATTERN.matcher(line); + if (cueHeaderMatcher.matches()) { + return cueHeaderMatcher; + } + } + } + return null; + } + +} |