formats/bmff/offset_adjustment.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_OFFSET_ADJUSTMENT_H_
#define THIRD_PARTY_CREDENTIO_FORMATS_BMFF_OFFSET_ADJUSTMENT_H_

#include <cstdint>
#include <vector>

#include "absl/status/status.h"
#include "absl/status/statusor.h"
#include "formats/bmff/box_header.h"
#include "riegeli/bytes/reader.h"
#include "riegeli/bytes/writer.h"

namespace credentio {

struct IlocExtent {
  uint64_t index = 0;
  uint64_t offset = 0;
  uint64_t length = 0;
};

struct IlocItem {
  uint32_t item_id = 0;
  uint16_t construction_method = 0;  // Present if version 1 or 2
  uint16_t data_reference_index = 0;
  uint64_t base_offset = 0;
  std::vector<IlocExtent> extents;
};

struct IlocBox {
  uint8_t offset_size = 0;
  uint8_t length_size = 0;
  uint8_t base_offset_size = 0;
  uint8_t index_size = 0;
  std::vector<IlocItem> items;
};

struct StcoBox {
  std::vector<uint32_t> offsets;
};

struct Co64Box {
  std::vector<uint64_t> offsets;
};

struct SaioBox {
  uint32_t aux_info_type = 0;
  uint32_t aux_info_type_parameter = 0;
  std::vector<uint64_t> offsets;
};

// Parses the ILOC box payload from the reader.
// The reader should be positioned at the start of the box payload (after the
// header).
absl::StatusOr<IlocBox> ParseIloc(riegeli::Reader& reader,
                                  const BmffBoxHeader& header);

// Serializes the ILOC box payload to the writer.
absl::Status SerializeIloc(const IlocBox& box, const BmffBoxHeader& header,
                           riegeli::Writer& writer);

// Adjusts the offsets in the ILOC box.
// Only extents with data_reference_index == 0 are adjusted.
void AdjustOffsets(IlocBox& box, int64_t adjustment);

// Parses the STCO box payload from the reader.
absl::StatusOr<StcoBox> ParseStco(riegeli::Reader& reader);

// Serializes the STCO box payload to the writer.
absl::Status SerializeStco(const StcoBox& box, riegeli::Writer& writer);

// Adjusts the offsets in the STCO box.
void AdjustOffsets(StcoBox& box, int64_t adjustment);

// Parses the CO64 box payload from the reader.
absl::StatusOr<Co64Box> ParseCo64(riegeli::Reader& reader);

// Serializes the CO64 box payload to the writer.
absl::Status SerializeCo64(const Co64Box& box, riegeli::Writer& writer);

// Adjusts the offsets in the CO64 box.
void AdjustOffsets(Co64Box& box, int64_t adjustment);

// Parses the SAIO box payload from the reader.
absl::StatusOr<SaioBox> ParseSaio(riegeli::Reader& reader,
                                  const BmffBoxHeader& header);

// Serializes the SAIO box payload to the writer.
absl::Status SerializeSaio(const SaioBox& box, const BmffBoxHeader& header,
                           riegeli::Writer& writer);

// Adjusts the offsets in the SAIO box.
void AdjustOffsets(SaioBox& box, int64_t adjustment);

}  // namespace credentio

#endif  // THIRD_PARTY_CREDENTIO_FORMATS_BMFF_OFFSET_ADJUSTMENT_H_