formats/bmff/embedder.h

// Copyright 2026 Google LLC
//
// 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
//
//    https://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.
//

#ifndef THIRD_PARTY_CREDENTIO_FORMATS_BMFF_EMBEDDER_H_
#define THIRD_PARTY_CREDENTIO_FORMATS_BMFF_EMBEDDER_H_

#include <cstdint>
#include <vector>

#include "absl/status/status.h"
#include "absl/status/statusor.h"
#include "absl/strings/string_view.h"
#include "formats/byte_range.h"
#include "proto/bmff_based_hash_assertion.pb.h"
#include "riegeli/bytes/reader.h"
#include "riegeli/bytes/writer.h"
#include "utils/byte_instruction.h"

namespace credentio {

// Embedder for inserting a C2PA manifest store into a BMFF file.
class BmffEmbedder {
 public:
  // Reads through the source, locating where the manifest should be inserted
  // and where any atoms needing offset adjustment are located. Simultaneously
  // computes the hard binding hash of the asset.
  absl::StatusOr<std::vector<ByteInstruction>> InspectAndHash(
      riegeli::Reader& source, uint64_t manifest_store_size,
      const ByteRange& insertion_point, bool can_replace_manifest,
      BmffBasedHashAssertion& assertion) const;
};

// Calculates the size of the C2PA (UUID) box in the BMFF format.
int64_t CalculateC2paSizeBmff(uint64_t manifest_store_size);
// Writes the C2PA manifest store to the output in the BMFF format at the
// current position and returns the offset of the appended box.
//
// NOTE: This shall be called before the first 'mdat' box in the file and
// before any 'moov' box in the file. To accommodate major_brand and
// compatible_brand verification, it shall be called after the 'ftyp' box.
//
// BMFF files with Merkle tree content bindings are not supported.
absl::Status WriteC2paBmff(absl::string_view manifest_store,
                           riegeli::Writer& output);

// Creates a free box in the BMFF format at the current position.
absl::Status CreateFreeBox(uint64_t size, riegeli::Writer& output);

}  // namespace credentio

#endif  // THIRD_PARTY_CREDENTIO_FORMATS_BMFF_EMBEDDER_H_