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/*
* 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.ParserException;
import org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.ExtractorInput;
import org.mozilla.thirdparty.com.google.android.exoplayer2.util.ParsableByteArray;
import java.io.EOFException;
import java.io.IOException;
/**
* Data object to store header information.
*/
/* package */ final class OggPageHeader {
public static final int EMPTY_PAGE_HEADER_SIZE = 27;
public static final int MAX_SEGMENT_COUNT = 255;
public static final int MAX_PAGE_PAYLOAD = 255 * 255;
public static final int MAX_PAGE_SIZE = EMPTY_PAGE_HEADER_SIZE + MAX_SEGMENT_COUNT
+ MAX_PAGE_PAYLOAD;
private static final int TYPE_OGGS = 0x4f676753;
public int revision;
public int type;
/**
* The absolute granule position of the page. This is the total number of samples from the start
* of the file up to the <em>end</em> of the page. Samples partially in the page that continue on
* the next page do not count.
*/
public long granulePosition;
public long streamSerialNumber;
public long pageSequenceNumber;
public long pageChecksum;
public int pageSegmentCount;
public int headerSize;
public int bodySize;
/**
* Be aware that {@code laces.length} is always {@link #MAX_SEGMENT_COUNT}. Instead use
* {@link #pageSegmentCount} to iterate.
*/
public final int[] laces = new int[MAX_SEGMENT_COUNT];
private final ParsableByteArray scratch = new ParsableByteArray(MAX_SEGMENT_COUNT);
/**
* Resets all primitive member fields to zero.
*/
public void reset() {
revision = 0;
type = 0;
granulePosition = 0;
streamSerialNumber = 0;
pageSequenceNumber = 0;
pageChecksum = 0;
pageSegmentCount = 0;
headerSize = 0;
bodySize = 0;
}
/**
* Peeks an Ogg page header and updates this {@link OggPageHeader}.
*
* @param input The {@link ExtractorInput} to read from.
* @param quiet Whether to return {@code false} rather than throwing an exception if the header
* cannot be populated.
* @return Whether the read was successful. The read fails if the end of the input is encountered
* without reading data.
* @throws IOException If reading data fails or the stream is invalid.
* @throws InterruptedException If the thread is interrupted.
*/
public boolean populate(ExtractorInput input, boolean quiet)
throws IOException, InterruptedException {
scratch.reset();
reset();
boolean hasEnoughBytes = input.getLength() == C.LENGTH_UNSET
|| input.getLength() - input.getPeekPosition() >= EMPTY_PAGE_HEADER_SIZE;
if (!hasEnoughBytes || !input.peekFully(scratch.data, 0, EMPTY_PAGE_HEADER_SIZE, true)) {
if (quiet) {
return false;
} else {
throw new EOFException();
}
}
if (scratch.readUnsignedInt() != TYPE_OGGS) {
if (quiet) {
return false;
} else {
throw new ParserException("expected OggS capture pattern at begin of page");
}
}
revision = scratch.readUnsignedByte();
if (revision != 0x00) {
if (quiet) {
return false;
} else {
throw new ParserException("unsupported bit stream revision");
}
}
type = scratch.readUnsignedByte();
granulePosition = scratch.readLittleEndianLong();
streamSerialNumber = scratch.readLittleEndianUnsignedInt();
pageSequenceNumber = scratch.readLittleEndianUnsignedInt();
pageChecksum = scratch.readLittleEndianUnsignedInt();
pageSegmentCount = scratch.readUnsignedByte();
headerSize = EMPTY_PAGE_HEADER_SIZE + pageSegmentCount;
// calculate total size of header including laces
scratch.reset();
input.peekFully(scratch.data, 0, pageSegmentCount);
for (int i = 0; i < pageSegmentCount; i++) {
laces[i] = scratch.readUnsignedByte();
bodySize += laces[i];
}
return true;
}
}
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