diff options
Diffstat (limited to 'mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/ogg/OggPacket.java')
-rw-r--r-- | mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/ogg/OggPacket.java | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/ogg/OggPacket.java b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/ogg/OggPacket.java new file mode 100644 index 0000000000..1f3bf38c73 --- /dev/null +++ b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/ogg/OggPacket.java @@ -0,0 +1,155 @@ +/* + * 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.extractor.ogg; + +import org.mozilla.thirdparty.com.google.android.exoplayer2.C; +import org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.ExtractorInput; +import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Assertions; +import org.mozilla.thirdparty.com.google.android.exoplayer2.util.ParsableByteArray; +import java.io.IOException; +import java.util.Arrays; + +/** + * OGG packet class. + */ +/* package */ final class OggPacket { + + private final OggPageHeader pageHeader = new OggPageHeader(); + private final ParsableByteArray packetArray = new ParsableByteArray( + new byte[OggPageHeader.MAX_PAGE_PAYLOAD], 0); + + private int currentSegmentIndex = C.INDEX_UNSET; + private int segmentCount; + private boolean populated; + + /** + * Resets this reader. + */ + public void reset() { + pageHeader.reset(); + packetArray.reset(); + currentSegmentIndex = C.INDEX_UNSET; + populated = false; + } + + /** + * Reads the next packet of the ogg stream. In case of an {@code IOException} the caller must make + * sure to pass the same instance of {@code ParsableByteArray} to this method again so this reader + * can resume properly from an error while reading a continued packet spanned across multiple + * pages. + * + * @param input The {@link ExtractorInput} to read data from. + * @return {@code true} if the read was successful. The read fails if the end of the input is + * encountered without reading data. + * @throws IOException If reading from the input fails. + * @throws InterruptedException If the thread is interrupted. + */ + public boolean populate(ExtractorInput input) throws IOException, InterruptedException { + Assertions.checkState(input != null); + + if (populated) { + populated = false; + packetArray.reset(); + } + + while (!populated) { + if (currentSegmentIndex < 0) { + // We're at the start of a page. + if (!pageHeader.populate(input, true)) { + return false; + } + int segmentIndex = 0; + int bytesToSkip = pageHeader.headerSize; + if ((pageHeader.type & 0x01) == 0x01 && packetArray.limit() == 0) { + // After seeking, the first packet may be the remainder + // part of a continued packet which has to be discarded. + bytesToSkip += calculatePacketSize(segmentIndex); + segmentIndex += segmentCount; + } + input.skipFully(bytesToSkip); + currentSegmentIndex = segmentIndex; + } + + int size = calculatePacketSize(currentSegmentIndex); + int segmentIndex = currentSegmentIndex + segmentCount; + if (size > 0) { + if (packetArray.capacity() < packetArray.limit() + size) { + packetArray.data = Arrays.copyOf(packetArray.data, packetArray.limit() + size); + } + input.readFully(packetArray.data, packetArray.limit(), size); + packetArray.setLimit(packetArray.limit() + size); + populated = pageHeader.laces[segmentIndex - 1] != 255; + } + // Advance now since we are sure reading didn't throw an exception. + currentSegmentIndex = segmentIndex == pageHeader.pageSegmentCount ? C.INDEX_UNSET + : segmentIndex; + } + return true; + } + + /** + * An OGG Packet may span multiple pages. Returns the {@link OggPageHeader} of the last page read, + * or an empty header if the packet has yet to be populated. + * + * <p>Note that the returned {@link OggPageHeader} is mutable and may be updated during subsequent + * calls to {@link #populate(ExtractorInput)}. + * + * @return the {@code PageHeader} of the last page read or an empty header if the packet has yet + * to be populated. + */ + public OggPageHeader getPageHeader() { + return pageHeader; + } + + /** + * Returns a {@link ParsableByteArray} containing the packet's payload. + */ + public ParsableByteArray getPayload() { + return packetArray; + } + + /** + * Trims the packet data array. + */ + public void trimPayload() { + if (packetArray.data.length == OggPageHeader.MAX_PAGE_PAYLOAD) { + return; + } + packetArray.data = Arrays.copyOf(packetArray.data, Math.max(OggPageHeader.MAX_PAGE_PAYLOAD, + packetArray.limit())); + } + + /** + * Calculates the size of the packet starting from {@code startSegmentIndex}. + * + * @param startSegmentIndex the index of the first segment of the packet. + * @return Size of the packet. + */ + private int calculatePacketSize(int startSegmentIndex) { + segmentCount = 0; + int size = 0; + while (startSegmentIndex + segmentCount < pageHeader.pageSegmentCount) { + int segmentLength = pageHeader.laces[startSegmentIndex + segmentCount++]; + size += segmentLength; + if (segmentLength != 255) { + // packets end at first lace < 255 + break; + } + } + return size; + } + +} |