ContentBlockReader.h

/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * 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.
 */
 
#pragma once
 
#include <memory>
 
#include <vrs/DataLayout.h>
#include <vrs/DataLayoutConventions.h>
#include <vrs/StreamPlayer.h>
#include <vrs/VrsExport.h>
 
namespace vrs {
 
using std::unique_ptr;
 
class ContentBlock;
class RecordFormatStreamPlayer;
struct RecordFormatReader;
 
class VRS_API ContentBlockReader {
 public:
  static unique_ptr<ContentBlockReader>
  build(const RecordFormat& recordFormat, size_t blockIndex, unique_ptr<DataLayout>&& blockLayout);
 
  virtual ~ContentBlockReader();
 
  virtual bool readBlock(const CurrentRecord&, RecordFormatStreamPlayer&) = 0;
 
 protected:
  ContentBlockReader(const RecordFormat& recordFormat, size_t blockIndex)
      : recordFormat_(recordFormat), blockIndex_(blockIndex) {}
  bool findNextContentBlockSpec(const CurrentRecord& record, RecordFormatStreamPlayer& player);
  size_t findContentBlockSize(const CurrentRecord& record, RecordFormatStreamPlayer& player);
  uint32_t findAudioSampleCount(const CurrentRecord& record, RecordFormatStreamPlayer& player);
 
  const RecordFormat& recordFormat_;
  const size_t blockIndex_;
  unique_ptr<datalayout_conventions::NextContentBlockSpec> contentBlockSpec_;
};
 
class VRS_API ImageBlockReader : public ContentBlockReader {
 public:
  ImageBlockReader(const RecordFormat& recordFormat, size_t blockIndex)
      : ContentBlockReader(recordFormat, blockIndex) {}
 
  bool readBlock(const CurrentRecord&, RecordFormatStreamPlayer&) override;
 
 protected:
  bool
  onImageFound(const CurrentRecord& rec, RecordFormatStreamPlayer& player, const ContentBlock& cb);
 
  datalayout_conventions::ImageSpec imageSpec_;
  unique_ptr<datalayout_conventions::VideoFrameSpec> videoFrameSpec_;
};
 
class VRS_API AudioBlockReader : public ContentBlockReader {
 public:
  AudioBlockReader(const RecordFormat& recordFormat, size_t blockIndex)
      : ContentBlockReader(recordFormat, blockIndex) {}
 
  bool readBlock(const CurrentRecord&, RecordFormatStreamPlayer&) override;
 
 protected:
  bool readAudioContentBlock(const CurrentRecord&, RecordFormatStreamPlayer&, const ContentBlock&);
  bool findAudioSpec(
      const CurrentRecord&,
      RecordFormatStreamPlayer&,
      RecordFormatReader*,
      size_t indexUpperLimit,
      size_t lastIndexToCheck,
      bool& readNextBlock);
  bool audioContentFromAudioSpec(
      const CurrentRecord&,
      RecordFormatStreamPlayer&,
      ContentBlock& outAudioContentBlock);
  bool tryCurrentAudioSpec(const CurrentRecord&, RecordFormatStreamPlayer&, bool& readNextBlock);
 
  datalayout_conventions::AudioSpec audioSpec_;
};
 
class VRS_API CustomBlockReader : public ContentBlockReader {
 public:
  CustomBlockReader(const RecordFormat& recordFormat, size_t blockIndex)
      : ContentBlockReader(recordFormat, blockIndex) {}
 
  bool readBlock(const CurrentRecord&, RecordFormatStreamPlayer&) override;
};
 
class VRS_API UnsupportedBlockReader : public ContentBlockReader {
 public:
  UnsupportedBlockReader(const RecordFormat& recordFormat, size_t blockIndex)
      : ContentBlockReader(recordFormat, blockIndex) {}
 
  bool readBlock(const CurrentRecord&, RecordFormatStreamPlayer&) override;
};
 
class VRS_API EmptyBlockReader : public ContentBlockReader {
 public:
  EmptyBlockReader(const RecordFormat& recordFormat, size_t blockIndex)
      : ContentBlockReader(recordFormat, blockIndex) {}
 
  bool readBlock(const CurrentRecord&, RecordFormatStreamPlayer&) override;
};
 
class VRS_API DataLayoutBlockReader : public ContentBlockReader {
 public:
  DataLayoutBlockReader(
      const RecordFormat& recordFormat,
      size_t blockIndex,
      unique_ptr<DataLayout>&& blockLayout)
      : ContentBlockReader(recordFormat, blockIndex), blockLayout_{std::move(blockLayout)} {}
 
  bool readBlock(const CurrentRecord&, RecordFormatStreamPlayer&) override;
 
  bool mapToBlockLayout(DataLayout& desiredLayout) {
    if (blockLayout_) {
      desiredLayout.mapLayout(*blockLayout_);
      return true;
    }
    return false;
  }
 
 private:
  unique_ptr<DataLayout> blockLayout_;
};
 
} // namespace vrs