ListChunk.java
/*
* Copyright 2022 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 androidx.media3.extractor.avi;
import androidx.annotation.Nullable;
import androidx.media3.common.C;
import androidx.media3.common.util.ParsableByteArray;
import com.google.common.collect.ImmutableList;
/** Represents an AVI LIST. */
/* package */ final class ListChunk implements AviChunk {
public static ListChunk parseFrom(int listType, ParsableByteArray body) {
ImmutableList.Builder<AviChunk> builder = new ImmutableList.Builder<>();
int listBodyEndPosition = body.limit();
@C.TrackType int currentTrackType = C.TRACK_TYPE_NONE;
while (body.bytesLeft() > 8) {
int type = body.readLittleEndianInt();
int size = body.readLittleEndianInt();
int innerBoxBodyEndPosition = body.getPosition() + size;
body.setLimit(innerBoxBodyEndPosition);
@Nullable AviChunk aviChunk;
if (type == AviExtractor.FOURCC_LIST) {
int innerListType = body.readLittleEndianInt();
aviChunk = parseFrom(innerListType, body);
} else {
aviChunk = createBox(type, currentTrackType, body);
}
if (aviChunk != null) {
if (aviChunk.getType() == AviExtractor.FOURCC_strh) {
currentTrackType = ((AviStreamHeaderChunk) aviChunk).getTrackType();
}
builder.add(aviChunk);
}
body.setPosition(innerBoxBodyEndPosition);
body.setLimit(listBodyEndPosition);
}
return new ListChunk(listType, builder.build());
}
public final ImmutableList<AviChunk> children;
private final int type;
private ListChunk(int type, ImmutableList<AviChunk> children) {
this.type = type;
this.children = children;
}
@Override
public int getType() {
return type;
}
@Nullable
@SuppressWarnings("unchecked")
public <T extends AviChunk> T getChild(Class<T> c) {
for (AviChunk aviChunk : children) {
if (aviChunk.getClass() == c) {
return (T) aviChunk;
}
}
return null;
}
@Nullable
private static AviChunk createBox(
int chunkType, @C.TrackType int trackType, ParsableByteArray body) {
switch (chunkType) {
case AviExtractor.FOURCC_avih:
return AviMainHeaderChunk.parseFrom(body);
case AviExtractor.FOURCC_strh:
return AviStreamHeaderChunk.parseFrom(body);
case AviExtractor.FOURCC_strf:
return StreamFormatChunk.parseFrom(trackType, body);
case AviExtractor.FOURCC_strn:
return StreamNameChunk.parseFrom(body);
default:
return null;
}
}
}