| /* |
| * Copyright (C) 2020 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.metadata; |
| |
| import androidx.annotation.Nullable; |
| import com.google.android.exoplayer2.util.Assertions; |
| import java.nio.ByteBuffer; |
| |
| /** |
| * A {@link MetadataDecoder} base class that validates input buffers and discards any for which |
| * {@link MetadataInputBuffer#isDecodeOnly()} is {@code true}. |
| */ |
| public abstract class SimpleMetadataDecoder implements MetadataDecoder { |
| |
| @Override |
| @Nullable |
| public final Metadata decode(MetadataInputBuffer inputBuffer) { |
| ByteBuffer buffer = Assertions.checkNotNull(inputBuffer.data); |
| Assertions.checkArgument( |
| buffer.position() == 0 && buffer.hasArray() && buffer.arrayOffset() == 0); |
| return inputBuffer.isDecodeOnly() ? null : decode(inputBuffer, buffer); |
| } |
| |
| /** |
| * Called by {@link #decode(MetadataInputBuffer)} after input buffer validation has been |
| * performed, except in the case that {@link MetadataInputBuffer#isDecodeOnly()} is {@code true}. |
| * |
| * @param inputBuffer The input buffer to decode. |
| * @param buffer The input buffer's {@link MetadataInputBuffer#data data buffer}, for convenience. |
| * Validation by {@link #decode} guarantees that {@link ByteBuffer#hasArray()}, {@link |
| * ByteBuffer#position()} and {@link ByteBuffer#arrayOffset()} are {@code true}, {@code 0} and |
| * {@code 0} respectively. |
| * @return The decoded metadata object, or {@code null} if the metadata could not be decoded. |
| */ |
| @Nullable |
| protected abstract Metadata decode(MetadataInputBuffer inputBuffer, ByteBuffer buffer); |
| } |