/src/libheif/libheif/box.cc

Source
/*
 * HEIF codec.
 * Copyright (c) 2017 Dirk Farin <dirk.farin@gmail.com>
 *
 * This file is part of libheif.
 *
 * libheif is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version.
 *
 * libheif is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with libheif.  If not, see <http://www.gnu.org/licenses/>.
 */
#include "libheif/heif.h"
#include <cstddef>
#include <cstdint>
#include "box.h"
#include "security_limits.h"
#include "nclx.h"
#include "codecs/jpeg_boxes.h"
#include "codecs/jpeg2000_boxes.h"
#include "codecs/hevc_boxes.h"
#include "image-items/mask_image.h"
#include "codecs/vvc_boxes.h"
#include "codecs/avc_boxes.h"
#include "codecs/avif_boxes.h"
#include "image-items/tiled.h"
#include "sequences/seq_boxes.h"

#include <iomanip>
#include <utility>
#include <iostream>
#include <algorithm>
#include <cstring>
#include <set>
#include <cassert>
#include <array>
#include <mutex>


#if WITH_UNCOMPRESSED_CODEC
#include "codecs/uncompressed/unc_boxes.h"
#endif

#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif

#if !defined(_WIN32)
#include <unistd.h>
#else
#include <fcntl.h>
#include <io.h>
#endif


Fraction::Fraction(int32_t num, int32_t den)
{
  // Reduce resolution of fraction until we are in a safe range.
  // We need this as adding fractions may lead to very large denominators
  // (e.g. 0x10000 * 0x10000 > 0x100000000 -> overflow, leading to integer 0)

  numerator = num;
  denominator = den;

  while (denominator > MAX_FRACTION_VALUE || denominator < -MAX_FRACTION_VALUE) {
    numerator /= 2;
    denominator /= 2;
  }

  while (denominator > 1 && (numerator > MAX_FRACTION_VALUE || numerator < -MAX_FRACTION_VALUE)) {
    numerator /= 2;
    denominator /= 2;
  }
}

Fraction::Fraction(uint32_t num, uint32_t den)
{
  assert(num <= (uint32_t) std::numeric_limits<int32_t>::max());
  assert(den <= (uint32_t) std::numeric_limits<int32_t>::max());

  *this = Fraction(int32_t(num), int32_t(den));
}

Fraction::Fraction(int64_t num, int64_t den)
{
  while (num < std::numeric_limits<int32_t>::min() || num > std::numeric_limits<int32_t>::max() ||
         den < std::numeric_limits<int32_t>::min() || den > std::numeric_limits<int32_t>::max()) {
    num = (num + (num>=0 ? 1 : -1)) / 2;
    den = (den + (den>=0 ? 1 : -1)) / 2;
  }

  numerator = static_cast<int32_t>(num);
  denominator = static_cast<int32_t>(den);
}

Fraction Fraction::operator+(const Fraction& b) const
{
  if (denominator == b.denominator) {
    int64_t n = int64_t{numerator} + b.numerator;
    int64_t d = denominator;
    return Fraction{n,d};
  }
  else {
    int64_t n = int64_t{numerator} * b.denominator + int64_t{b.numerator} * denominator;
    int64_t d = int64_t{denominator} * b.denominator;
    return Fraction{n,d};
  }
}

Fraction Fraction::operator-(const Fraction& b) const
{
  if (denominator == b.denominator) {
    int64_t n = int64_t{numerator} - b.numerator;
    int64_t d = denominator;
    return Fraction{n,d};
  }
  else {
    int64_t n = int64_t{numerator} * b.denominator - int64_t{b.numerator} * denominator;
    int64_t d = int64_t{denominator} * b.denominator;
    return Fraction{n,d};
  }
}

Fraction Fraction::operator+(int v) const
{
  return Fraction{numerator + v * int64_t(denominator), int64_t(denominator)};
}

Fraction Fraction::operator-(int v) const
{
  return Fraction{numerator - v * int64_t(denominator), int64_t(denominator)};
}

Fraction Fraction::operator/(int v) const
{
  return Fraction{int64_t(numerator), int64_t(denominator) * v};
}

int32_t Fraction::round_down() const
{
  return numerator / denominator;
}

int32_t Fraction::round_up() const
{
  return int32_t((numerator + int64_t(denominator) - 1) / denominator);
}

int32_t Fraction::round() const
{
  return int32_t((numerator + int64_t(denominator) / 2) / denominator);
}

bool Fraction::is_valid() const
{
  return denominator != 0;
}


BoxHeader::BoxHeader() = default;


std::vector<uint8_t> BoxHeader::get_type() const
{
  if (m_type == fourcc("uuid")) {
    return m_uuid_type;
  }
  else {
    std::vector<uint8_t> type(4);
    type[0] = static_cast<uint8_t>((m_type >> 24) & 0xFF);
    type[1] = static_cast<uint8_t>((m_type >> 16) & 0xFF);
    type[2] = static_cast<uint8_t>((m_type >> 8) & 0xFF);
    type[3] = static_cast<uint8_t>((m_type >> 0) & 0xFF);
    return type;
  }
}


std::string BoxHeader::get_type_string() const
{
  if (m_type == fourcc("uuid")) {
    // 8-4-4-4-12

    std::ostringstream sstr;
    sstr << std::hex;
    sstr << std::setfill('0');

    for (int i = 0; i < 16; i++) {
      if (i == 4 || i == 6 || i == 8 || i == 10) {
        sstr << '-';
      }

      sstr << std::setw(2);
      sstr << ((int) m_uuid_type[i]);
    }

    return sstr.str();
  }
  else {
    return fourcc_to_string(m_type);
  }
}


std::vector<uint8_t> BoxHeader::get_uuid_type() const
{
  if (m_type != fourcc("uuid")) {
    return {};
  }

  return m_uuid_type;
}


void BoxHeader::set_uuid_type(const std::vector<uint8_t>& type)
{
  m_type = fourcc("uuid");
  m_uuid_type = type;
}


Error BoxHeader::parse_header(BitstreamRange& range)
{
  StreamReader::grow_status status;
  status = range.wait_for_available_bytes(8);
  if (status != StreamReader::grow_status::size_reached) {
    // TODO: return recoverable error at timeout
    return Error(heif_error_Invalid_input,
                 heif_suberror_End_of_data);
  }

  m_size = range.read32();
  m_type = range.read32();

  m_header_size = 8;

  if (m_size == 1) {
    status = range.wait_for_available_bytes(8);
    if (status != StreamReader::grow_status::size_reached) {
      // TODO: return recoverable error at timeout
      return Error(heif_error_Invalid_input,
                   heif_suberror_End_of_data);
    }

    uint64_t high = range.read32();
    uint64_t low = range.read32();

    m_size = (high << 32) | low;
    m_header_size += 8;

    std::stringstream sstr;
    sstr << "Box size " << m_size << " exceeds security limit.";

    if (m_size > MAX_LARGE_BOX_SIZE) {
      return Error(heif_error_Memory_allocation_error,
                   heif_suberror_Security_limit_exceeded,
                   sstr.str());
    }
  }

  if (m_type == fourcc("uuid")) {
    status = range.wait_for_available_bytes(16);
    if (status != StreamReader::grow_status::size_reached) {
      // TODO: return recoverable error at timeout
      return Error(heif_error_Invalid_input,
                   heif_suberror_End_of_data);
    }

    if (range.prepare_read(16)) {
      m_uuid_type.resize(16);
      bool success = range.get_istream()->read((char*) m_uuid_type.data(), 16);
      assert(success);
      (void) success;
    }

    m_header_size += 16;
  }

  return range.get_error();
}


int Box::calculate_header_size(bool data64bit) const
{
  int header_size = 8;  // does not include "FullBox" fields.

  if (get_short_type() == fourcc("uuid")) {
    header_size += 16;
  }

  if (data64bit) {
    header_size += 8;
  }

  return header_size;
}


size_t Box::reserve_box_header_space(StreamWriter& writer, bool data64bit) const
{
  size_t start_pos = writer.get_position();

  int header_size = calculate_header_size(data64bit);

  writer.skip(header_size);

  return start_pos;
}


size_t FullBox::reserve_box_header_space(StreamWriter& writer, bool data64bit) const
{
  size_t start_pos = Box::reserve_box_header_space(writer, data64bit);

  writer.skip(4);

  return start_pos;
}


Error FullBox::write_header(StreamWriter& writer, size_t total_size, bool data64bit) const
{
  auto err = Box::write_header(writer, total_size, data64bit);
  if (err) {
    return err;
  }

  assert((get_flags() & ~0x00FFFFFFU) == 0);

  writer.write32((get_version() << 24) | get_flags());

  return Error::Ok;
}


Error Box::prepend_header(StreamWriter& writer, size_t box_start, bool data64bit) const
{
  size_t total_size = writer.data_size() - box_start;

  writer.set_position(box_start);

  auto err = write_header(writer, total_size, data64bit);

  writer.set_position_to_end();  // Note: should we move to the end of the box after writing the header?

  return err;
}


Error Box::write_header(StreamWriter& writer, size_t total_size, bool data64bit) const
{
  bool large_size = (total_size > 0xFFFFFFFF);

  // --- write header

  if (large_size && !data64bit) {
    // Note: as an alternative, we could return an error here. If it fails, the user has to try again with 64 bit.
    writer.insert(8);
  }

  if (large_size) {
    writer.write32(1);
  }
  else {
    assert(total_size <= 0xFFFFFFFF);
    writer.write32((uint32_t) total_size);
  }

  writer.write32(get_short_type());

  if (large_size) {
    writer.write64(total_size);
  }

  if (get_short_type() == fourcc("uuid")) {
    assert(get_type().size() == 16);
    writer.write(get_type());
  }

  return Error::Ok;
}


std::string BoxHeader::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << indent << "Box: " << get_type_string();
  const char* debug_name = debug_box_name();
  if (debug_name) {
    sstr << " ----- (" << debug_name << ")\n";
  }
  else {
    sstr << " -----\n";
  }

  sstr << indent << "size: " << get_box_size() << "   (header size: " << get_header_size() << ")\n";

  return sstr.str();
}


Error Box::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  // skip box

  if (get_box_size() == size_until_end_of_file) {
    range.skip_to_end_of_file();
  }
  else {
    uint64_t content_size = get_box_size() - get_header_size();

    assert(MAX_BOX_SIZE <= SIZE_MAX);

    if (content_size > MAX_BOX_SIZE) {
      return Error(heif_error_Invalid_input,
                   heif_suberror_Invalid_box_size);
    }

    if (range.prepare_read(static_cast<size_t>(content_size))) {
      range.get_istream()->seek_cur(get_box_size() - get_header_size());
    }
  }

  // Note: seekg() clears the eof flag and it will not be set again afterwards,
  // hence we have to test for the fail flag.

  return range.get_error();
}


Error FullBox::parse_full_box_header(BitstreamRange& range)
{
  uint32_t data = range.read32();
  m_version = static_cast<uint8_t>(data >> 24);
  m_flags = data & 0x00FFFFFF;
  //m_is_full_box = true;

  m_header_size += 4;

  return range.get_error();
}


Error Box::read(BitstreamRange& range, std::shared_ptr<Box>* result, const heif_security_limits* limits)
{
  BoxHeader hdr;
  Error err = hdr.parse_header(range);
  if (err) {
    return err;
  }

  if (range.error()) {
    return range.get_error();
  }

  result->reset();

  std::shared_ptr<Box> box;

  switch (hdr.get_short_type()) {
    case fourcc("ftyp"):
      box = std::make_shared<Box_ftyp>();
      break;

    case fourcc("free"):
    case fourcc("skip"):
      box = std::make_shared<Box_free>();
      break;

    case fourcc("meta"):
      box = std::make_shared<Box_meta>();
      break;

    case fourcc("hdlr"):
      box = std::make_shared<Box_hdlr>();
      break;

    case fourcc("pitm"):
      box = std::make_shared<Box_pitm>();
      break;

    case fourcc("iloc"):
      box = std::make_shared<Box_iloc>();
      break;

    case fourcc("iinf"):
      box = std::make_shared<Box_iinf>();
      break;

    case fourcc("infe"):
      box = std::make_shared<Box_infe>();
      break;

    case fourcc("iprp"):
      box = std::make_shared<Box_iprp>();
      break;

    case fourcc("ipco"):
      box = std::make_shared<Box_ipco>();
      break;

    case fourcc("ipma"):
      box = std::make_shared<Box_ipma>();
      break;

    case fourcc("ispe"):
      box = std::make_shared<Box_ispe>();
      break;

    case fourcc("auxC"):
      box = std::make_shared<Box_auxC>();
      break;

    case fourcc("irot"):
      box = std::make_shared<Box_irot>();
      break;

    case fourcc("imir"):
      box = std::make_shared<Box_imir>();
      break;

    case fourcc("clap"):
      box = std::make_shared<Box_clap>();
      break;

    case fourcc("iscl"):
      box = std::make_shared<Box_iscl>();
      break;

    case fourcc("iref"):
      box = std::make_shared<Box_iref>();
      break;

    case fourcc("rref"):
      box = std::make_shared<Box_rref>();
      break;

    case fourcc("hvcC"):
      box = std::make_shared<Box_hvcC>();
      break;

    case fourcc("hvc1"):
      box = std::make_shared<Box_hvc1>();
      break;

    case fourcc("av1C"):
      box = std::make_shared<Box_av1C>();
      break;

    case fourcc("av01"):
      box = std::make_shared<Box_av01>();
      break;

    case fourcc("vvcC"):
      box = std::make_shared<Box_vvcC>();
      break;

    case fourcc("vvc1"):
      box = std::make_shared<Box_vvc1>();
      break;

    case fourcc("idat"):
      box = std::make_shared<Box_idat>();
      break;

    case fourcc("grpl"):
      box = std::make_shared<Box_grpl>();
      break;

    case fourcc("pymd"):
      box = std::make_shared<Box_pymd>();
      break;

    case fourcc("altr"):
      box = std::make_shared<Box_EntityToGroup>();
      break;

    case fourcc("ster"):
      box = std::make_shared<Box_ster>();
      break;

    case fourcc("dinf"):
      box = std::make_shared<Box_dinf>();
      break;

    case fourcc("dref"):
      box = std::make_shared<Box_dref>();
      break;

    case fourcc("url "):
      box = std::make_shared<Box_url>();
      break;

    case fourcc("colr"):
      box = std::make_shared<Box_colr>();
      break;

    case fourcc("pixi"):
      box = std::make_shared<Box_pixi>();
      break;

    case fourcc("pasp"):
      box = std::make_shared<Box_pasp>();
      break;

    case fourcc("lsel"):
      box = std::make_shared<Box_lsel>();
      break;

    case fourcc("a1op"):
      box = std::make_shared<Box_a1op>();
      break;

    case fourcc("a1lx"):
      box = std::make_shared<Box_a1lx>();
      break;

    case fourcc("clli"):
      box = std::make_shared<Box_clli>();
      break;

    case fourcc("mdcv"):
      box = std::make_shared<Box_mdcv>();
      break;

    case fourcc("amve"):
      box = std::make_shared<Box_amve>();
      break;

    case fourcc("ndwt"):
      box = std::make_shared<Box_ndwt>();
      break;

    case fourcc("cmin"):
      box = std::make_shared<Box_cmin>();
      break;

    case fourcc("cmex"):
      box = std::make_shared<Box_cmex>();
      break;

    case fourcc("udes"):
      box = std::make_shared<Box_udes>();
      break;

    case fourcc("jpgC"):
      box = std::make_shared<Box_jpgC>();
      break;

    case fourcc("mjpg"):
      box = std::make_shared<Box_mjpg>();
      break;

    case fourcc("elng"):
      box = std::make_shared<Box_elng>();
      break;


#if WITH_UNCOMPRESSED_CODEC
    case fourcc("cmpd"):
      box = std::make_shared<Box_cmpd>();
      break;

    case fourcc("uncC"):
      box = std::make_shared<Box_uncC>();
      break;

    case fourcc("cmpC"):
      box = std::make_shared<Box_cmpC>();
      break;

    case fourcc("icef"):
      box = std::make_shared<Box_icef>();
      break;

    case fourcc("cpat"):
      box = std::make_shared<Box_cpat>();
      break;

    case fourcc("splz"):
      box = std::make_shared<Box_splz>();
      break;

    case fourcc("sbpm"):
      box = std::make_shared<Box_sbpm>();
      break;

    case fourcc("snuc"):
      box = std::make_shared<Box_snuc>();
      break;

    case fourcc("cloc"):
      box = std::make_shared<Box_cloc>();
      break;

    case fourcc("uncv"):
      box = std::make_shared<Box_uncv>();
      break;
#endif

    // --- JPEG 2000

    case fourcc("j2kH"):
      box = std::make_shared<Box_j2kH>();
      break;

    case fourcc("cdef"):
      box = std::make_shared<Box_cdef>();
      break;

    case fourcc("cmap"):
      box = std::make_shared<Box_cmap>();
      break;

    case fourcc("pclr"):
      box = std::make_shared<Box_pclr>();
      break;

    case fourcc("j2kL"):
      box = std::make_shared<Box_j2kL>();
      break;

    case fourcc("j2ki"):
      box = std::make_shared<Box_j2ki>();
      break;


    // --- mski

    case fourcc("mskC"):
      box = std::make_shared<Box_mskC>();
      break;

    // --- TAI timestamps

    case fourcc("itai"):
      box = std::make_shared<Box_itai>();
      break;

    case fourcc("taic"):
      box = std::make_shared<Box_taic>();
      break;

    // --- AVC (H.264)

    case fourcc("avcC"):
      box = std::make_shared<Box_avcC>();
      break;

    case fourcc("avc1"):
      box = std::make_shared<Box_avc1>();
      break;

#if HEIF_ENABLE_EXPERIMENTAL_FEATURES
    case fourcc("tilC"):
      box = std::make_shared<Box_tilC>();
      break;
#endif

    case fourcc("mini"):
      box = std::make_shared<Box_mini>();
      break;

    case fourcc("mdat"):
      // avoid generating a 'Box_other'
      box = std::make_shared<Box>();
      break;

    case fourcc("uuid"):
      if (hdr.get_uuid_type() == std::vector<uint8_t>{0x22, 0xcc, 0x04, 0xc7, 0xd6, 0xd9, 0x4e, 0x07, 0x9d, 0x90, 0x4e, 0xb6, 0xec, 0xba, 0xf3, 0xa3}) {
        box = std::make_shared<Box_cmin>();
      }
      else if (hdr.get_uuid_type() == std::vector<uint8_t>{0x43, 0x63, 0xe9, 0x14, 0x5b, 0x7d, 0x4a, 0xab, 0x97, 0xae, 0xbe, 0xa6, 0x98, 0x03, 0xb4, 0x34}) {
        box = std::make_shared<Box_cmex>();
      }
      else if (hdr.get_uuid_type() == std::vector<uint8_t>{0x26, 0x1e, 0xf3, 0x74, 0x1d, 0x97, 0x5b, 0xba, 0xac, 0xbd, 0x9d, 0x2c, 0x8e, 0xa7, 0x35, 0x22}) {
        box = std::make_shared<Box_gimi_content_id>();
      }
#if WITH_UNCOMPRESSED_CODEC
      else if (hdr.get_uuid_type() == std::vector<uint8_t>{0x9d, 0xb9, 0xdd, 0x6e, 0x37, 0x3c, 0x5a, 0x4e, 0x81, 0x10, 0x21, 0xfc, 0x83, 0xa9, 0x11, 0xfd}) {
        box = std::make_shared<Box_gimi_component_content_ids>();
      }
#endif
      else {
        box = std::make_shared<Box_other>(hdr.get_short_type());
      }
      break;

    // --- sequences

    case fourcc("moov"):
      box = std::make_shared<Box_moov>();
      break;

    case fourcc("mvhd"):
      box = std::make_shared<Box_mvhd>();
      break;

    case fourcc("trak"):
      box = std::make_shared<Box_trak>();
      break;

    case fourcc("tkhd"):
      box = std::make_shared<Box_tkhd>();
      break;

    case fourcc("mdia"):
      box = std::make_shared<Box_mdia>();
      break;

    case fourcc("mdhd"):
      box = std::make_shared<Box_mdhd>();
      break;

    case fourcc("minf"):
      box = std::make_shared<Box_minf>();
      break;

    case fourcc("vmhd"):
      box = std::make_shared<Box_vmhd>();
      break;

    case fourcc("stbl"):
      box = std::make_shared<Box_stbl>();
      break;

    case fourcc("stsd"):
      box = std::make_shared<Box_stsd>();
      break;

    case fourcc("stts"):
      box = std::make_shared<Box_stts>();
      break;

    case fourcc("ctts"):
      box = std::make_shared<Box_ctts>();
      break;

    case fourcc("stsc"):
      box = std::make_shared<Box_stsc>();
      break;

    case fourcc("stco"):
      box = std::make_shared<Box_stco>();
      break;

    case fourcc("stsz"):
      box = std::make_shared<Box_stsz>();
      break;

    case fourcc("stss"):
      box = std::make_shared<Box_stss>();
      break;

    case fourcc("ccst"):
      box = std::make_shared<Box_ccst>();
      break;

    case fourcc("auxi"):
      box = std::make_shared<Box_auxi>();
      break;

    case fourcc("edts"):
      box = std::make_shared<Box_edts>();
      break;

    case fourcc("elst"):
      box = std::make_shared<Box_elst>();
      break;

    case fourcc("sbgp"):
      box = std::make_shared<Box_sbgp>();
      break;

    case fourcc("sgpd"):
      box = std::make_shared<Box_sgpd>();
      break;

    case fourcc("btrt"):
      box = std::make_shared<Box_btrt>();
      break;

    case fourcc("saiz"):
      box = std::make_shared<Box_saiz>();
      break;

    case fourcc("saio"):
      box = std::make_shared<Box_saio>();
      break;

    case fourcc("urim"):
      box = std::make_shared<Box_URIMetaSampleEntry>();
      break;

    case fourcc("uri "):
      box = std::make_shared<Box_uri>();
      break;

    case fourcc("nmhd"):
      box = std::make_shared<Box_nmhd>();
      break;

    case fourcc("tref"):
      box = std::make_shared<Box_tref>();
      break;

    case fourcc("sdtp"):
      box = std::make_shared<Box_sdtp>();
      break;

    // OMAF
    case fourcc("prfr"):
      box = std::make_shared<Box_prfr>();
      break;

    default:
      box = std::make_shared<Box_other>(hdr.get_short_type());
      break;
  }

  box->set_short_header(hdr);

  box->m_debug_box_type = hdr.get_type_string(); // only for debugging


  if (range.get_nesting_level() > MAX_BOX_NESTING_LEVEL) {
    return Error(heif_error_Memory_allocation_error,
                 heif_suberror_Security_limit_exceeded,
                 "Security limit for maximum nesting of boxes has been exceeded");
  }

  if (hdr.has_fixed_box_size()) {
    // Sanity checks
    if (hdr.get_box_size() < hdr.get_header_size()) {
      std::stringstream sstr;
      sstr << "Box size (" << hdr.get_box_size() << " bytes) smaller than header size ("
           << hdr.get_header_size() << " bytes)";

      return {heif_error_Invalid_input,
              heif_suberror_Invalid_box_size,
              sstr.str()};
    }

    // this is >= 0 because of above condition
    auto nBytes = static_cast<uint64_t>(hdr.get_box_size() - hdr.get_header_size());
    if (nBytes > SIZE_MAX) {
      return {heif_error_Memory_allocation_error,
              heif_suberror_Invalid_box_size,
              "Box size too large"};
    }

    // Security check: make sure that box size does not exceed int64 size.

    if (hdr.get_box_size() > (uint64_t) std::numeric_limits<int64_t>::max()) {
      return {heif_error_Invalid_input,
              heif_suberror_Invalid_box_size};
    }

    // --- wait for data to arrive

    auto status = range.wait_for_available_bytes(static_cast<size_t>(nBytes));
    if (status != StreamReader::grow_status::size_reached) {
      // TODO: return recoverable error at timeout
      return {heif_error_Invalid_input,
              heif_suberror_End_of_data};
    }
  }

  auto box_size = static_cast<int64_t>(hdr.get_box_size());
  int64_t box_size_without_header = hdr.has_fixed_box_size() ? (box_size - hdr.get_header_size()) : (int64_t)range.get_remaining_bytes();

  // Box size may not be larger than remaining bytes in parent box.

  if ((int64_t)range.get_remaining_bytes() < box_size_without_header) {
    return {heif_error_Invalid_input,
            heif_suberror_Invalid_box_size};
  }


  // Create child bitstream range and read box from that range.

  BitstreamRange boxrange(range.get_istream(),
                          box_size_without_header,
                          &range);

  err = box->parse(boxrange, limits);
  boxrange.skip_to_end_of_box();

  if (err == Error::Ok) {
    *result = std::move(box);
  }
  else {
    parse_error_fatality fatality = box->get_parse_error_fatality();

    box = std::make_shared<Box_Error>(box->get_short_type(), err, fatality);

    // We return a Box_Error that represents the parse error.
    *result = std::move(box);
  }

  return err;
}


std::string Box::dump(Indent& indent) const
{
  std::ostringstream sstr;

  sstr << BoxHeader::dump(indent);

  return sstr.str();
}


std::string FullBox::dump(Indent& indent) const
{
  std::ostringstream sstr;

  sstr << Box::dump(indent);

  sstr << indent << "version: " << ((int) m_version) << "\n"
       << indent << "flags: " << std::hex << m_flags << "\n";

  return sstr.str();
}


Error Box::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  Error err = write_children(writer);

  prepend_header(writer, box_start);

  return err;
}


bool Box::operator==(const Box& other) const
{
  if (this->get_short_type() != other.get_short_type()) {
    return false;
  }

  StreamWriter writer1;
  StreamWriter writer2;

  this->write(writer1);
  other.write(writer2);

  return writer1.get_data() == writer2.get_data();
}


bool Box::remove_child_box(const std::shared_ptr<const Box>& box)
{
  for (int i=0; i<(int)m_children.size(); i++) {
    if (m_children[i].get() == box.get()) {
      m_children.erase(m_children.begin() + i);
      return true;
    }
  }

  return false;
}


bool Box::equal(const std::shared_ptr<Box>& box1, const std::shared_ptr<Box>& box2)
{
    if (!box1 || !box2) {
        return false;
    }

    // This was introduced because of j2kH having child boxes.
    // TODO: we might also deduplicate them by comparing all child boxes.
    if (box1->has_child_boxes() || box2->has_child_boxes()) {
      return false;
    }

    return *box1 == *box2;
}


Error Box::read_children(BitstreamRange& range, uint32_t max_number, const heif_security_limits* limits)
{
  uint32_t count = 0;

  while (!range.eof() && !range.error()) {
    std::shared_ptr<Box> box;
    Error error = Box::read(range, &box, limits);
    if (error != Error::Ok && (!box || box->get_parse_error_fatality() == parse_error_fatality::fatal)) {
      return error;
    }

    if (max_number == READ_CHILDREN_ALL) {
      uint32_t max_children;
      if (get_short_type() == fourcc("iinf")) {
        max_children = limits->max_items;
      }
      else {
        max_children = limits->max_children_per_box;
      }

      if (max_children && m_children.size() > max_children) {
        std::stringstream sstr;
        sstr << "Maximum number of child boxes (" << max_children << ") in '" << get_type_string() << "' box exceeded.";

        // Sanity check.
        return Error(heif_error_Memory_allocation_error,
                     heif_suberror_Security_limit_exceeded,
                     sstr.str());
      }
    }

    m_children.push_back(std::move(box));


    // count the new child and end reading new children when we reached the expected number

    count++;

    if (max_number != READ_CHILDREN_ALL &&
        count == max_number) {
      break;
    }
  }

  return range.get_error();
}


Error Box::write_children(StreamWriter& writer) const
{
  for (const auto& child : m_children) {
    Error err = child->write(writer);
    if (err) {
      return err;
    }
  }

  return Error::Ok;
}


std::string Box::dump_children(Indent& indent, bool with_index) const
{
  std::ostringstream sstr;

  bool first = true;
  int idx=1;

  indent++;
  for (const auto& childBox : m_children) {
    if (first) {
      first = false;
    }
    else {
      sstr << indent << "\n";
    }

    if (with_index) {
      sstr << indent << "index: " << idx << "\n";
      idx++;
    }

    sstr << childBox->dump(indent);
  }
  indent--;

  return sstr.str();
}


void Box::derive_box_version_recursive()
{
  derive_box_version();

  for (auto& child : m_children) {
    child->derive_box_version_recursive();
  }
}


void Box::patch_file_pointers_recursively(StreamWriter& writer, size_t offset)
{
  patch_file_pointers(writer, offset);

  for (auto& child : m_children) {
    child->patch_file_pointers_recursively(writer, offset);
  }
}


Error Box_other::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  if (has_fixed_box_size()) {
    size_t len;
    if (get_box_size() >= get_header_size()) {
      auto len64 = get_box_size() - get_header_size();
      if (len64 > MAX_BOX_SIZE) {
        return {heif_error_Invalid_input,
                heif_suberror_Security_limit_exceeded,
                "Box size too large"};
      }

      len = static_cast<size_t>(len64);

      m_data.resize(len);
      range.read(m_data.data(), len);
    }
    else {
      return {heif_error_Invalid_input,
              heif_suberror_Invalid_box_size};
    }
  }
  else {
    // TODO: boxes until end of file (we will probably never need this)
  }

  return range.get_error();
}


Error Box_other::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  if (get_box_size() >= get_header_size()) {
    writer.write(m_data);
    prepend_header(writer, box_start);
    return Error::Ok;
  }
  else {
    return Error(heif_error_Invalid_input,
                 heif_suberror_Invalid_box_size);
  }
}


std::string Box_other::dump(Indent& indent) const
{
  std::ostringstream sstr;

  sstr << BoxHeader::dump(indent);

  // --- show raw box content

  size_t len = 0;
  if (get_box_size() >= get_header_size()) {
    // We can cast because if it does not fit, it would fail during parsing.
    len = static_cast<size_t>(get_box_size() - get_header_size());
  }
  else {
    sstr << indent << "invalid box size " << get_box_size() << " (smaller than header)\n";
    return sstr.str();
  }

  sstr << write_raw_data_as_hex(m_data.data(), len,
                                indent.get_string() + "data: ",
                                indent.get_string() + "      ");

  return sstr.str();
}


std::string Box_Error::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << indent << '\'' << fourcc_to_string(m_box_type_with_parse_error) << "' parse error: " << m_error.message << "\n";
  sstr << indent << "fatality: ";
  switch (m_fatality) {
    case parse_error_fatality::fatal: sstr << "fatal\n"; break;
    case parse_error_fatality::ignorable: sstr << "ignorable\n"; break;
    case parse_error_fatality::optional: sstr << "optional\n"; break;
  }

  return sstr.str();
}

parse_error_fatality Box_Error::get_parse_error_fatality() const
{
  return m_fatality;
}


Error Box_ftyp::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  m_major_brand = range.read32();
  m_minor_version = range.read32();

  uint64_t box_size = get_box_size();
  if (box_size < 8 || box_size - 8 < get_header_size()) {
    // Sanity check.
    return Error(heif_error_Invalid_input,
                 heif_suberror_Invalid_box_size,
                 "ftyp box too small (less than 8 bytes)");
  }

  uint64_t n_minor_brands = (get_box_size() - get_header_size() - 8) / 4;

  if (limits->max_number_of_file_brands && n_minor_brands > limits->max_number_of_file_brands) {
    return {
      heif_error_Memory_allocation_error,
      heif_suberror_Security_limit_exceeded,
      "Number of minor brands in file exceeds security limit"
    };
  }

  for (uint64_t i = 0; i < n_minor_brands && !range.error(); i++) {
    m_compatible_brands.push_back(range.read32());
  }

  return range.get_error();
}


bool Box_ftyp::has_compatible_brand(heif_brand2 brand) const
{
  return std::find(m_compatible_brands.begin(),
                   m_compatible_brands.end(),
                   brand) !=
         m_compatible_brands.end();
}


std::string Box_ftyp::dump(Indent& indent) const
{
  std::ostringstream sstr;

  sstr << BoxHeader::dump(indent);

  sstr << indent << "major brand: " << fourcc_to_string(m_major_brand) << "\n"
       << indent << "minor version: ";
  if (m_minor_version < ('A' << 24)) {
    // This is probably a version number
    sstr << m_minor_version;
  } else {
    // probably a 4CC, as used for mif3
    sstr << fourcc_to_string(m_minor_version);
  }
  sstr << "\n" << indent << "compatible brands: ";

  bool first = true;
  for (uint32_t brand : m_compatible_brands) {
    if (first) { first = false; }
    else { sstr << ','; }

    sstr << fourcc_to_string(brand);
  }
  sstr << "\n";

  return sstr.str();
}


void Box_ftyp::add_compatible_brand(heif_brand2 brand)
{
  if (!has_compatible_brand(brand)) {
    m_compatible_brands.push_back(brand);
  }
}


Error Box_ftyp::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  writer.write32(m_major_brand);
  writer.write32(m_minor_version);

  for (uint32_t b : m_compatible_brands) {
    writer.write32(b);
  }

  prepend_header(writer, box_start);

  return Error::Ok;
}


Error Box_free::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  range.skip_to_end_of_box();
  return range.get_error();
}


std::string Box_free::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << BoxHeader::dump(indent);
  return sstr.str();
}


Error Box_free::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);
  prepend_header(writer, box_start);
  return Error::Ok;
}


Error Box_meta::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  parse_full_box_header(range);

  if (get_version() != 0) {
    return unsupported_version_error("meta");
  }

  /*
  uint64_t boxSizeLimit;
  if (get_box_size() == BoxHeader::size_until_end_of_file) {
    boxSizeLimit = sizeLimit;
  }
  else {
    boxSizeLimit = get_box_size() - get_header_size();
  }
  */

  return read_children(range, READ_CHILDREN_ALL, limits);
}


std::string Box_meta::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);
  sstr << dump_children(indent);

  return sstr.str();
}


Error FullBox::unsupported_version_error(const char* box) const
{
  std::stringstream sstr;
  sstr << box << " box data version " << ((int) m_version) << " is not implemented yet";

  return {heif_error_Unsupported_feature,
          heif_suberror_Unsupported_data_version,
          sstr.str()};
}


Error Box_hdlr::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  parse_full_box_header(range);

  if (get_version() != 0) {
    return unsupported_version_error("hdlr");
  }

  m_pre_defined = range.read32();
  m_handler_type = range.read32();

  for (int i = 0; i < 3; i++) {
    m_reserved[i] = range.read32();
  }

  m_name = range.read_string();

  return range.get_error();
}


std::string Box_hdlr::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);
  sstr << indent << "pre_defined: " << m_pre_defined << "\n"
       << indent << "handler_type: " << fourcc_to_string(m_handler_type) << "\n"
       << indent << "name: " << m_name << "\n";

  return sstr.str();
}


Error Box_hdlr::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  writer.write32(m_pre_defined);
  writer.write32(m_handler_type);

  for (int i = 0; i < 3; i++) {
    writer.write32(m_reserved[i]);
  }

  writer.write(m_name);

  prepend_header(writer, box_start);

  return Error::Ok;
}


Error Box_pitm::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  parse_full_box_header(range);

  if (get_version() > 1) {
    return unsupported_version_error("pitm");
  }


  if (get_version() == 0) {
    m_item_ID = range.read16();
  }
  else {
    m_item_ID = range.read32();
  }

  return range.get_error();
}


std::string Box_pitm::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);
  sstr << indent << "item_ID: " << m_item_ID << "\n";

  return sstr.str();
}


void Box_pitm::derive_box_version()
{
  if (m_item_ID <= 0xFFFF) {
    set_version(0);
  }
  else {
    set_version(1);
  }
}


Error Box_pitm::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  if (get_version() == 0) {
    assert(m_item_ID <= 0xFFFF);
    writer.write16((uint16_t) m_item_ID);
  }
  else {
    writer.write32(m_item_ID);
  }

  prepend_header(writer, box_start);

  return Error::Ok;
}


Error Box_iloc::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  parse_full_box_header(range);

  if (get_version() > 2) {
    return unsupported_version_error("iloc");
  }

  const int version = get_version();

  uint16_t values4 = range.read16();

  int offset_size = (values4 >> 12) & 0xF;
  int length_size = (values4 >> 8) & 0xF;
  int base_offset_size = (values4 >> 4) & 0xF;
  int index_size = 0;

  if (version == 1 || version == 2) {
    index_size = (values4 & 0xF);
  }

  uint32_t item_count = 0;
  if (version < 2) {
    item_count = range.read16();
  }
  else if (version == 2) {
    item_count = range.read32();
  }

  // Sanity check. (This might be obsolete now as we check for range.error() below).
  if (limits->max_items && item_count > limits->max_items) {
    std::stringstream sstr;
    sstr << "iloc box contains " << item_count << " items, which exceeds the security limit of "
         << limits->max_items << " items.";

    return Error(heif_error_Memory_allocation_error,
                 heif_suberror_Security_limit_exceeded,
                 sstr.str());
  }

  for (uint32_t i = 0; i < item_count; i++) {
    Item item;

    if (range.eof()) {
      std::stringstream sstr;
      sstr << "iloc box should contain " << item_count << " items, but we can only read " << i << " items.";

      return {heif_error_Invalid_input,
              heif_suberror_End_of_data,
              sstr.str()};
    }

    if (version < 2) {
      item.item_ID = range.read16();
    }
    else if (version == 2) {
      item.item_ID = range.read32();
    }

    if (version >= 1) {
      values4 = range.read16();
      item.construction_method = (values4 & 0xF);
    }

    item.data_reference_index = range.read16();

    item.base_offset = 0;
    if (base_offset_size == 4) {
      item.base_offset = range.read32();
    }
    else if (base_offset_size == 8) {
      item.base_offset = ((uint64_t) range.read32()) << 32;
      item.base_offset |= range.read32();
    }

    uint16_t extent_count = range.read16();

    // Sanity check.
    auto max_iloc_extents = limits->max_iloc_extents_per_item;
    if (max_iloc_extents && extent_count > max_iloc_extents) {
      std::stringstream sstr;
      sstr << "Number of extents in iloc box (" << extent_count << ") exceeds security limit ("
           << max_iloc_extents << ")\n";

      return Error(heif_error_Memory_allocation_error,
                   heif_suberror_Security_limit_exceeded,
                   sstr.str());
    }

    for (int e = 0; e < extent_count; e++) {
      Extent extent;

      if (range.eof()) {
        std::stringstream sstr;
        sstr << "iloc item should contain " << extent_count << " extents, but we can only read " << e << " extents.";

        return {heif_error_Invalid_input,
                heif_suberror_End_of_data,
                sstr.str()};
      }

      if ((version == 1 || version == 2) && index_size > 0) {
        if (index_size == 4) {
          extent.index = range.read32();
        }
        else if (index_size == 8) {
          extent.index = ((uint64_t) range.read32()) << 32;
          extent.index |= range.read32();
        }
      }

      extent.offset = 0;
      if (offset_size == 4) {
        extent.offset = range.read32();
      }
      else if (offset_size == 8) {
        extent.offset = ((uint64_t) range.read32()) << 32;
        extent.offset |= range.read32();
      }


      extent.length = 0;
      if (length_size == 4) {
        extent.length = range.read32();
      }
      else if (length_size == 8) {
        extent.length = ((uint64_t) range.read32()) << 32;
        extent.length |= range.read32();
      }

      item.extents.push_back(extent);
    }

    if (!range.error()) {
      m_items.push_back(item);
    }
  }

  return range.get_error();
}


Box_iloc::Box_iloc()
{
  set_short_type(fourcc("iloc"));

  set_use_tmp_file(false);
}


Box_iloc::~Box_iloc()
{
  if (m_use_tmpfile) {
    unlink(m_tmp_filename);
  }
}


void Box_iloc::set_use_tmp_file(bool flag)
{
  m_use_tmpfile = flag;
  if (flag) {
#if !defined(_WIN32)
    strcpy(m_tmp_filename, "/tmp/libheif-XXXXXX");
    m_tmpfile_fd = mkstemp(m_tmp_filename);
#else
    // TODO Currently unused code. Implement when needed.
    assert(false);
#  if 0
    char tmpname[L_tmpnam_s];
    // TODO: check return value (errno_t)
    tmpnam_s(tmpname, L_tmpnam_s);
    _sopen_s(&m_tmpfile_fd, tmpname, _O_CREAT | _O_TEMPORARY | _O_TRUNC | _O_RDWR, _SH_DENYRW, _S_IREAD | _S_IWRITE);
#  endif
#endif
  }
}


std::string Box_iloc::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);

  for (const Item& item : m_items) {
    sstr << indent << "item ID: " << item.item_ID << "\n"
         << indent << "  construction method: " << ((int) item.construction_method) << "\n"
         << indent << "  data_reference_index: " << std::hex
         << item.data_reference_index << std::dec << "\n"
         << indent << "  base_offset: " << item.base_offset << "\n";

    sstr << indent << "  extents: ";
    for (const Extent& extent : item.extents) {
      sstr << extent.offset << "," << extent.length;
      if (extent.index != 0) {
        sstr << ";index=" << extent.index;
      }
      sstr << " ";
    }
    sstr << "\n";
  }

  return sstr.str();
}


Error Box_iloc::read_data(heif_item_id item,
                          const std::shared_ptr<StreamReader>& istr,
                          const std::shared_ptr<Box_idat>& idat,
                          std::vector<uint8_t>* dest,
                          const heif_security_limits* limits) const
{
  return read_data(item, istr, idat, dest, 0, std::numeric_limits<uint64_t>::max(), limits);
}


Error Box_iloc::read_data(heif_item_id item_id,
                          const std::shared_ptr<StreamReader>& istr,
                          const std::shared_ptr<Box_idat>& idat,
                          std::vector<uint8_t>* dest,
                          uint64_t offset, uint64_t size,
                          const heif_security_limits* limits) const
{
  const Item* item = nullptr;
  for (auto& i : m_items) {
    if (i.item_ID == item_id) {
      item = &i;
      break;
    }
  }

  if (!item) {
    std::stringstream sstr;
    sstr << "Item with ID " << item_id << " has no compressed data";

    return Error(heif_error_Invalid_input,
                 heif_suberror_No_item_data,
                 sstr.str());
  }

#if ENABLE_MULTITHREADING_SUPPORT
  static std::mutex read_mutex;

  std::lock_guard<std::mutex> lock(read_mutex);
#endif

  bool limited_size = (size != std::numeric_limits<uint64_t>::max());


  // TODO: this function should always append the data to the output vector as this is used when
  //       the image data is concatenated with data in a configuration box. However, it seems that
  //       this function clears the array in some cases. This should be corrected.

  for (const auto& extent : item->extents) {
    if (item->construction_method == 0) {

      // --- make sure that all data is available

      if (extent.offset > MAX_FILE_POS ||
          item->base_offset > MAX_FILE_POS ||
          extent.length > MAX_FILE_POS) {
        return {heif_error_Invalid_input,
                heif_suberror_Security_limit_exceeded,
                "iloc data pointers out of allowed range"};
      }

      StreamReader::grow_status status = istr->wait_for_file_size(extent.offset + item->base_offset + extent.length);
      if (status == StreamReader::grow_status::size_beyond_eof) {
        // Out-of-bounds
        // TODO: I think we should not clear this. Maybe we want to try reading again later and
        // hence should not lose the data already read.
        dest->clear();

        std::stringstream sstr;
        sstr << "Extent in iloc box references data outside of file bounds "
             << "(points to file position " << extent.offset + item->base_offset << ")\n";

        return {heif_error_Invalid_input,
                heif_suberror_End_of_data,
                sstr.str()};
      }
      else if (status == StreamReader::grow_status::timeout) {
        // TODO: maybe we should introduce some 'Recoverable error' instead of 'Invalid input'
        return {heif_error_Invalid_input,
                heif_suberror_End_of_data};
      }


      // skip to reading offset

      uint64_t skip_len = std::min(offset, extent.length);
      offset -= skip_len;

      uint64_t read_len = std::min(extent.length - skip_len, size);

      if (offset > 0) {
        continue;
      }

      if (read_len == 0) {
        continue;
      }

      size_t old_size = dest->size();

      // --- security check that we do not allocate too much memory

      auto max_memory_block_size = limits->max_memory_block_size;
      if (max_memory_block_size && max_memory_block_size - old_size < read_len) {
        std::stringstream sstr;
        sstr << "iloc box contained " << extent.length << " bytes, total memory size would be "
             << (old_size + extent.length) << " bytes, exceeding the security limit of "
             << max_memory_block_size << " bytes";

        return {heif_error_Memory_allocation_error,
                heif_suberror_Security_limit_exceeded,
                sstr.str()};
      }


      // --- request file range

      uint64_t data_start_pos = extent.offset + item->base_offset + skip_len;
      uint64_t rangeRequestEndPos = istr->request_range(data_start_pos, data_start_pos + read_len);
      if (rangeRequestEndPos == 0) {
        return istr->get_error();
      }

      // --- move file pointer to start of data

      bool success = istr->seek(data_start_pos);
      if (!success) {
        return {heif_error_Invalid_input,
                heif_suberror_Unspecified,
                "Error setting input file position"};
      }


      // --- read data

      dest->resize(static_cast<size_t>(old_size + read_len));
      success = istr->read((char*) dest->data() + old_size, static_cast<size_t>(read_len));
      if (!success) {
        return {heif_error_Invalid_input,
                heif_suberror_Unspecified,
                "Error reading input file"};
      }

      size -= read_len;
    }
    else if (item->construction_method == 1) {
      if (!idat) {
        return {heif_error_Invalid_input,
                heif_suberror_No_idat_box,
                "idat box referenced in iref box is not present in file"};
      }

      Error err = idat->read_data(istr,
                                  extent.offset + item->base_offset,
                                  extent.length,
                                  *dest, limits);
      if (err) {
        return err;
      }

      size -= extent.length;
    }
    else {
      std::stringstream sstr;
      sstr << "Item construction method " << (int) item->construction_method << " not implemented";
      return {heif_error_Unsupported_feature,
              heif_suberror_Unsupported_item_construction_method,
              sstr.str()};
    }
  }

  // --- we could not read all data

  if (limited_size && size > 0) {
    return {heif_error_Invalid_input,
            heif_suberror_End_of_data,
            "Not enough data present in 'iloc' to satisfy request."};
  }

  return Error::Ok;
}


Error Box_iloc::append_data(heif_item_id item_ID,
                            const std::vector<uint8_t>& data,
                            uint8_t construction_method)
{
  // check whether this item ID already exists

  size_t idx;
  for (idx = 0; idx < m_items.size(); idx++) {
    if (m_items[idx].item_ID == item_ID) {
      break;
    }
  }

  // item does not exist -> add a new one to the end

  if (idx == m_items.size()) {
    Item item;
    item.item_ID = item_ID;
    item.construction_method = construction_method;

    m_items.push_back(item);
  }

  if (m_items[idx].construction_method != construction_method) {
    // TODO: return error: construction methods do not match
  }

  Extent extent;
  extent.length = data.size();

  if (m_use_tmpfile && construction_method==0) {
#if !defined(_WIN32)
    ssize_t cnt = ::write(m_tmpfile_fd, data.data(), data.size());
#else
    // TODO Currently unused code. Implement when needed.
    assert(false);
#  if 0
    int cnt = _write(m_tmpfile_fd, data.data(), data.size());
#  else
    int cnt = -1;
#  endif
#endif
    if (cnt < 0) {
      std::stringstream sstr;
      sstr << "Could not write to tmp file: error " << errno;
      return {heif_error_Encoding_error,
              heif_suberror_Unspecified,
              sstr.str()};
    }
    else if ((size_t)cnt != data.size()) {
      return {heif_error_Encoding_error,
              heif_suberror_Unspecified,
              "Could not write to tmp file (storage full?)"};
    }
  }
  else {
    if (!m_items[idx].extents.empty()) {
      Extent& e = m_items[idx].extents.back();
      e.data.insert(e.data.end(), data.begin(), data.end());
      e.length = e.data.size();
      return Error::Ok;
    }

    extent.data = data;
  }

  if (construction_method == 1) {
    extent.offset = m_idat_offset;
    extent.length = data.size();

    m_idat_offset += (int) data.size();
  }

  m_items[idx].extents.push_back(std::move(extent));

  return Error::Ok;
}


Error Box_iloc::replace_data(heif_item_id item_ID,
                             uint64_t output_offset,
                             const std::vector<uint8_t>& data,
                             uint8_t construction_method)
{
  assert(construction_method == 0); // TODO

  // check whether this item ID already exists

  size_t idx;
  for (idx = 0; idx < m_items.size(); idx++) {
    if (m_items[idx].item_ID == item_ID) {
      break;
    }
  }

  assert(idx != m_items.size());

  uint64_t data_start = 0;
  for (auto& extent : m_items[idx].extents) {
    if (output_offset >= extent.data.size()) {
      output_offset -= extent.data.size();
    }
    else {
      uint64_t write_n = std::min(extent.data.size() - output_offset,
                                  data.size() - data_start);
      assert(write_n > 0);

      memcpy(extent.data.data() + output_offset, data.data() + data_start, write_n);

      data_start += write_n;
      output_offset = 0;
    }

    if (data_start == data.size()) {
      break;
    }
  }

  return Error::Ok;
}


void Box_iloc::derive_box_version()
{
  int min_version = m_user_defined_min_version;

  if (m_items.size() > 0xFFFF) {
    min_version = std::max(min_version, 2);
  }

  m_offset_size = 0;
  m_length_size = 0;
  m_base_offset_size = 0;
  m_index_size = 0;

  uint64_t total_data_size = 0;

  for (const auto& item : m_items) {
    // check item_ID size
    if (item.item_ID > 0xFFFF) {
      min_version = std::max(min_version, 2);
    }

    // check construction method
    if (item.construction_method != 0) {
      min_version = std::max(min_version, 1);
    }

    total_data_size += item.extents[0].length;

    /* cannot compute this here because values are not set yet
    // base offset size
    if (item.base_offset > 0xFFFFFFFF) {
      m_base_offset_size = std::max(m_base_offset_size, (uint8_t)8);
    }
    else if (item.base_offset > 0) {
      m_base_offset_size = std::max(m_base_offset_size, (uint8_t)4);
    }
*/

    /*
    for (const auto& extent : item.extents) {
      // extent index size

      if (extent.index != 0) {
        min_version = std::max(min_version, 1);
        m_index_size = 4;
      }

      if (extent.index > 0xFFFFFFFF) {
        m_index_size = 8;
      }

      // extent offset size
      if (extent.offset > 0xFFFFFFFF) {
        m_offset_size = 8;
      }
      else {
        m_offset_size = 4;
      }

      // extent length size
      if (extent.length > 0xFFFFFFFF) {
        m_length_size = 8;
      }
      else {
        m_length_size = 4;
      }
    }
      */
  }

  uint64_t maximum_meta_box_size_guess = 0x10000000; // 256 MB
  if (total_data_size + maximum_meta_box_size_guess > 0xFFFFFFFF) {
    m_base_offset_size = 8;
  }
  else {
    m_base_offset_size = 4;
  }

  m_offset_size = 4;
  m_length_size = 4;
  m_index_size = 0;

  // extent.length is already known; extent.offset within an item equals
  // the cumulative length of all preceding extents (they are written sequentially).
  // base_offset absorbs the absolute file position, so extent.offset is relative.
  for (const auto& item : m_items) {
    uint64_t cumulative_offset = 0;
    for (const auto& extent : item.extents) {
      if (cumulative_offset > 0xFFFFFFFF) {
        m_offset_size = 8;
      }
      if (extent.length > 0xFFFFFFFF) {
        m_length_size = 8;
      }
      cumulative_offset += extent.length;
    }
  }

  set_version((uint8_t) min_version);
}


Error Box_iloc::write(StreamWriter& writer) const
{
  // --- write idat

  size_t sum_idat_size = 0;

  for (const auto& item : m_items) {
    if (item.construction_method == 1) {
      for (const auto& extent : item.extents) {
        sum_idat_size += extent.data.size();
      }
    }
  }

  if (sum_idat_size > 0) {
    writer.write32((uint32_t) (sum_idat_size + 8));
    writer.write32(fourcc("idat"));

    for (auto& item : m_items) {
      if (item.construction_method == 1) {
        for (auto& extent : item.extents) {
          writer.write(extent.data);
        }
      }
    }
  }


  // --- write iloc box

  size_t box_start = reserve_box_header_space(writer);

  m_iloc_box_start = writer.get_position();

  int nSkip = 0;

  nSkip += 2;
  nSkip += (get_version() < 2) ? 2 : 4; // item_count

  for (const auto& item : m_items) {
    nSkip += (get_version() < 2) ? 2 : 4; // item_ID
    nSkip += (get_version() >= 1) ? 2 : 0; // construction method
    nSkip += 4 + m_base_offset_size;

    for (const auto& extent : item.extents) {
      (void) extent;

      if (get_version() >= 1) {
        nSkip += m_index_size;
      }

      nSkip += m_offset_size + m_length_size;
    }
  }

  writer.skip(nSkip);
  prepend_header(writer, box_start);

  patch_iloc_header(writer); // Write iloc box. If there is an mdat, it will later be overwritten.

  return Error::Ok;
}


Error Box_iloc::write_mdat_after_iloc(StreamWriter& writer)
{
  // --- compute sum of all mdat data

  size_t sum_mdat_size = 0;

  for (const auto& item : m_items) {
    if (item.construction_method == 0) {
      for (const auto& extent : item.extents) {
        sum_mdat_size += extent.length;
      }
    }
  }

  // --- write mdat box

  if (sum_mdat_size <= 0xFFFFFFFF) {
    writer.write32((uint32_t) (sum_mdat_size + 8));
    writer.write32(fourcc("mdat"));
  }
  else {
    // box size > 4 GB

    writer.write32(1);
    writer.write32(fourcc("mdat"));
    writer.write64(sum_mdat_size+8+8);
  }

  if (m_use_tmpfile) {
    ::lseek(m_tmpfile_fd, 0, SEEK_SET);
  }

  for (auto& item : m_items) {
    if (item.construction_method == 0) {
      item.base_offset = writer.get_position();

      for (auto& extent : item.extents) {
        extent.offset = writer.get_position() - item.base_offset;
        //extent.length = extent.data.size();

        if (m_use_tmpfile) {
          std::vector<uint8_t> data(extent.length);
#if !defined(_WIN32)
          ssize_t cnt = ::read(m_tmpfile_fd, data.data(), extent.length);
#else
          // TODO Currently unused code. Implement when needed.
          assert(false);
# if 0
          int cnt = _read(m_tmpfile_fd, data.data(), extent.length);
# else
          int cnt = -1;
# endif
#endif
          if (cnt<0) {
            std::stringstream sstr;
            sstr << "Cannot read tmp data file, error " << errno;
            return {heif_error_Encoding_error,
                    heif_suberror_Unspecified,
                    sstr.str()};
          }
          else if ((uint64_t)cnt != extent.length) {
            return {heif_error_Encoding_error,
                    heif_suberror_Unspecified,
                    "Tmp data could not be read completely"};
          }
          writer.write(data);
        }
        else {
          writer.write(extent.data);
        }
      }
    }
  }


  // --- patch iloc box

  patch_iloc_header(writer);

  return Error::Ok;
}


void Box_iloc::patch_iloc_header(StreamWriter& writer) const
{
  size_t old_pos = writer.get_position();
  writer.set_position(m_iloc_box_start);

  writer.write8((uint8_t) ((m_offset_size << 4) | (m_length_size)));
  writer.write8((uint8_t) ((m_base_offset_size << 4) | (m_index_size)));

  if (get_version() < 2) {
    writer.write16((uint16_t) m_items.size());
  }
  else {
    writer.write32((uint32_t) m_items.size());
  }

  for (const auto& item : m_items) {
    if (get_version() < 2) {
      writer.write16((uint16_t) item.item_ID);
    }
    else {
      writer.write32((uint32_t) item.item_ID);
    }

    if (get_version() >= 1) {
      writer.write16(item.construction_method);
    }

    writer.write16(item.data_reference_index);
    if (m_base_offset_size > 0) {
      writer.write(m_base_offset_size, item.base_offset);
    }
    else {
      assert(item.base_offset == 0);
    }
    writer.write16((uint16_t) item.extents.size());

    for (const auto& extent : item.extents) {
      if (get_version() >= 1 && m_index_size > 0) {
        writer.write(m_index_size, extent.index);
      }

      writer.write(m_offset_size, extent.offset);
      writer.write(m_length_size, extent.length);
    }
  }

  writer.set_position(old_pos);
}


/*
 *                     version <= 1    version 2   version > 2    mime     uri
 * -----------------------------------------------------------------------------------------------
 * item id               16               16           32          16/32   16/32
 * protection index      16               16           16          16      16
 * item type             -                yes          yes         yes     yes
 * item name             yes              yes          yes         yes     yes
 * content type          yes              -            -           yes     -
 * content encoding      yes              -            -           yes     -
 * hidden item           -                yes          yes         yes     yes
 * item uri type         -                -            -           -       yes
 *
 * Note: HEIF does not allow version 0 and version 1 boxes ! (see 23008-12, 10.2.1)
 */

Error Box_infe::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  parse_full_box_header(range);

  // only versions 2,3 are required by HEIF
  if (get_version() > 3) {
    return unsupported_version_error("infe");
  }

  if (get_version() <= 1) {
    m_item_ID = range.read16();
    m_item_protection_index = range.read16();

    m_item_name = range.read_string();
    m_content_type = range.read_string();
    m_content_encoding = range.read_string();
  }

  m_item_type_4cc = 0;

  if (get_version() >= 2) {
    m_hidden_item = (get_flags() & 1);

    if (get_version() == 2) {
      m_item_ID = range.read16();
    }
    else {
      m_item_ID = range.read32();
    }

    m_item_protection_index = range.read16();
    m_item_type_4cc = range.read32();

    m_item_name = range.read_string();
    if (m_item_type_4cc == fourcc("mime")) {
      m_content_type = range.read_string();
      m_content_encoding = range.read_string();
    }
    else if (m_item_type_4cc == fourcc("uri ")) {
      m_item_uri_type = range.read_string();
    }
  }

  return range.get_error();
}


void Box_infe::derive_box_version()
{
  int min_version = 0;

  if (m_hidden_item) {
    min_version = std::max(min_version, 2);
  }

  if (m_item_ID > 0xFFFF) {
    min_version = std::max(min_version, 3);
  }


  if (m_item_type_4cc != 0) {
    min_version = std::max(min_version, 2);
  }

  set_version((uint8_t) min_version);
}


void Box_infe::set_hidden_item(bool hidden)
{
  m_hidden_item = hidden;

  if (m_hidden_item) {
    set_flags(get_flags() | 1U);
  }
  else {
    set_flags(get_flags() & ~1U);
  }
}

Error Box_infe::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  if (get_version() <= 1) {
    writer.write16((uint16_t) m_item_ID);
    writer.write16(m_item_protection_index);

    writer.write(m_item_name);
    writer.write(m_content_type);
    writer.write(m_content_encoding);
  }

  if (get_version() >= 2) {
    if (get_version() == 2) {
      writer.write16((uint16_t) m_item_ID);
    }
    else if (get_version() == 3) {
      writer.write32(m_item_ID);
    }

    writer.write16(m_item_protection_index);

    writer.write32(m_item_type_4cc);

    writer.write(m_item_name);
    if (m_item_type_4cc == fourcc("mime")) {
      writer.write(m_content_type);
      writer.write(m_content_encoding);
    }
    else if (m_item_type_4cc == fourcc("uri ")) {
      writer.write(m_item_uri_type);
    }
  }

  prepend_header(writer, box_start);

  return Error::Ok;
}


std::string Box_infe::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);

  sstr << indent << "item_ID: " << m_item_ID << "\n"
       << indent << "item_protection_index: " << m_item_protection_index << "\n"
       << indent << "item_type: " << fourcc_to_string(m_item_type_4cc) << "\n"
       << indent << "item_name: " << m_item_name << "\n";

  if (m_item_type_4cc == fourcc("mime")) {
    sstr << indent << "content_type: " << m_content_type << "\n"
         << indent << "content_encoding: " << m_content_encoding << "\n";
  }

  if (m_item_type_4cc == fourcc("uri ")) {
    sstr << indent << "item uri type: " << m_item_uri_type << "\n";
  }

  sstr << indent << "hidden item: " << std::boolalpha << m_hidden_item << "\n";

  return sstr.str();
}


Error Box_iinf::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  parse_full_box_header(range);

  // TODO: there are several images in circulation that have an iinf version=2. We should not enforce this with a hard error.
  if (false && get_version() > 1) {
    return unsupported_version_error("iinf");
  }

  int nEntries_size = (get_version() > 0) ? 4 : 2;

  uint32_t item_count;
  if (nEntries_size == 2) {
    item_count = range.read16();
  }
  else {
    item_count = range.read32();
  }

  if (item_count == 0) {
    return Error::Ok;
  }

  return read_children(range, item_count, limits);
}


std::string Box_iinf::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);

  sstr << dump_children(indent);

  return sstr.str();
}


Error Box_iprp::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  //parse_full_box_header(range);

  return read_children(range, READ_CHILDREN_ALL, limits);
}


void Box_iinf::derive_box_version()
{
  if (m_children.size() > 0xFFFF) {
    set_version(1);
  }
  else {
    set_version(0);
  }
}


Error Box_iinf::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  int nEntries_size = (get_version() > 0) ? 4 : 2;

  writer.write(nEntries_size, m_children.size());


  Error err = write_children(writer);

  prepend_header(writer, box_start);

  return err;
}


std::string Box_iprp::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);

  sstr << dump_children(indent);

  return sstr.str();
}


uint32_t Box_ipco::find_or_append_child_box(const std::shared_ptr<Box>& box)
{
  for (uint32_t i = 0; i < (uint32_t) m_children.size(); i++) {
    if (Box::equal(m_children[i], box)) {
      return i;
    }
  }
  return append_child_box(box);
}


Error Box_ipco::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  //parse_full_box_header(range);

  return read_children(range, READ_CHILDREN_ALL, limits);
}


std::string Box_ipco::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);

  sstr << dump_children(indent, true);

  return sstr.str();
}


Error Box_pixi::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  parse_full_box_header(range);

  if (get_version() != 0) {
    return unsupported_version_error("pixi");
  }

  StreamReader::grow_status status;
  uint8_t num_channels = range.read8();
  status = range.wait_for_available_bytes(num_channels);
  if (status != StreamReader::grow_status::size_reached) {
    // TODO: return recoverable error at timeout
    return Error(heif_error_Invalid_input,
                 heif_suberror_End_of_data);
  }

  m_bits_per_channel.resize(num_channels);
  for (int i = 0; i < num_channels; i++) {
    m_bits_per_channel[i] = range.read8();
  }

  return range.get_error();
}


std::string Box_pixi::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);

  sstr << indent << "bits_per_channel: ";

  for (size_t i = 0; i < m_bits_per_channel.size(); i++) {
    if (i > 0) sstr << ",";
    sstr << ((int) m_bits_per_channel[i]);
  }

  sstr << "\n";

  return sstr.str();
}


Error Box_pixi::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  if (m_bits_per_channel.size() > 255 ||
      m_bits_per_channel.empty()) {
    // TODO: error
    assert(false);
  }

  writer.write8((uint8_t) (m_bits_per_channel.size()));
  for (size_t i = 0; i < m_bits_per_channel.size(); i++) {
    writer.write8(m_bits_per_channel[i]);
  }

  prepend_header(writer, box_start);

  return Error::Ok;
}


Error Box_pasp::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  //parse_full_box_header(range);

  hSpacing = range.read32();
  vSpacing = range.read32();

  return range.get_error();
}


std::string Box_pasp::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);

  sstr << indent << "hSpacing: " << hSpacing << "\n";
  sstr << indent << "vSpacing: " << vSpacing << "\n";

  return sstr.str();
}


Error Box_pasp::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  writer.write32(hSpacing);
  writer.write32(vSpacing);

  prepend_header(writer, box_start);

  return Error::Ok;
}


Error Box_lsel::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  layer_id = range.read16();

  return range.get_error();
}


std::string Box_lsel::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);

  sstr << indent << "layer_id: " << layer_id << "\n";

  return sstr.str();
}


Error Box_lsel::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  writer.write16(layer_id);

  prepend_header(writer, box_start);

  return Error::Ok;
}


Error Box_clli::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  //parse_full_box_header(range);

  clli.max_content_light_level = range.read16();
  clli.max_pic_average_light_level = range.read16();

  return range.get_error();
}


std::string Box_clli::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);

  sstr << indent << "max_content_light_level: " << clli.max_content_light_level << "\n";
  sstr << indent << "max_pic_average_light_level: " << clli.max_pic_average_light_level << "\n";

  return sstr.str();
}


Error Box_clli::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  writer.write16(clli.max_content_light_level);
  writer.write16(clli.max_pic_average_light_level);

  prepend_header(writer, box_start);

  return Error::Ok;
}


Box_mdcv::Box_mdcv()
{
  set_short_type(fourcc("mdcv"));

  memset(&mdcv, 0, sizeof(heif_mastering_display_colour_volume));
}


Error Box_mdcv::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  //parse_full_box_header(range);

  for (int c = 0; c < 3; c++) {
    mdcv.display_primaries_x[c] = range.read16();
    mdcv.display_primaries_y[c] = range.read16();
  }

  mdcv.white_point_x = range.read16();
  mdcv.white_point_y = range.read16();
  mdcv.max_display_mastering_luminance = range.read32();
  mdcv.min_display_mastering_luminance = range.read32();

  return range.get_error();
}


std::string Box_mdcv::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);

  sstr << indent << "display_primaries (x,y): ";
  sstr << "(" << mdcv.display_primaries_x[0] << ";" << mdcv.display_primaries_y[0] << "), ";
  sstr << "(" << mdcv.display_primaries_x[1] << ";" << mdcv.display_primaries_y[1] << "), ";
  sstr << "(" << mdcv.display_primaries_x[2] << ";" << mdcv.display_primaries_y[2] << ")\n";

  sstr << indent << "white point (x,y): (" << mdcv.white_point_x << ";" << mdcv.white_point_y << ")\n";
  sstr << indent << "max display mastering luminance: " << mdcv.max_display_mastering_luminance << "\n";
  sstr << indent << "min display mastering luminance: " << mdcv.min_display_mastering_luminance << "\n";

  return sstr.str();
}


Error Box_mdcv::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  for (int c = 0; c < 3; c++) {
    writer.write16(mdcv.display_primaries_x[c]);
    writer.write16(mdcv.display_primaries_y[c]);
  }

  writer.write16(mdcv.white_point_x);
  writer.write16(mdcv.white_point_y);

  writer.write32(mdcv.max_display_mastering_luminance);
  writer.write32(mdcv.min_display_mastering_luminance);

  prepend_header(writer, box_start);

  return Error::Ok;
}

Box_amve::Box_amve()
{
  set_short_type(fourcc("amve"));

  // These values are not valid.
  amve.ambient_illumination = 0;
  amve.ambient_light_x = 0;
  amve.ambient_light_y = 0;
}

Error Box_amve::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  amve.ambient_illumination = range.read32();
  amve.ambient_light_x = range.read16();
  amve.ambient_light_y = range.read16();

  return range.get_error();
}


std::string Box_amve::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);

  sstr << indent << "ambient_illumination: " << amve.ambient_illumination << "\n";
  sstr << indent << "ambient_light_x: " << amve.ambient_light_x << "\n";
  sstr << indent << "ambient_light_y: " << amve.ambient_light_y << "\n";

  return sstr.str();
}


Error Box_amve::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  writer.write32(amve.ambient_illumination);
  writer.write16(amve.ambient_light_x);
  writer.write16(amve.ambient_light_y);

  prepend_header(writer, box_start);

  return Error::Ok;
}


Error Box_ndwt::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  parse_full_box_header(range);

  if (get_version() != 0) {
    return unsupported_version_error("ndwt");
  }

  m_diffuse_white_luminance = range.read32();

  return range.get_error();
}


std::string Box_ndwt::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);

  sstr << indent << "diffuse_white_luminance: " << m_diffuse_white_luminance << "\n";

  return sstr.str();
}


Error Box_ndwt::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  writer.write32(m_diffuse_white_luminance);

  prepend_header(writer, box_start);

  return Error::Ok;
}


Box_cclv::Box_cclv()
{
  set_short_type(fourcc("cclv"));

  m_ccv_primaries_valid = false;
}


void Box_cclv::set_primaries(int32_t x0, int32_t y0, int32_t x1, int32_t y1, int32_t x2, int32_t y2)
{
  m_ccv_primaries_valid = true;
  m_ccv_primaries_x[0] = x0;
  m_ccv_primaries_y[0] = y0;
  m_ccv_primaries_x[1] = x1;
  m_ccv_primaries_y[1] = y1;
  m_ccv_primaries_x[2] = x2;
  m_ccv_primaries_y[2] = y2;
}


Error Box_cclv::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  uint8_t flags = range.read8();

  m_ccv_primaries_valid = (flags & 0b00100000);
  bool ccv_min_luminance_valid = (flags & 0b00010000);
  bool ccv_max_luminance_valid = (flags & 0b00001000);
  bool ccv_avg_luminance_valid = (flags & 0b00000100);

  if (m_ccv_primaries_valid) {
    for (int c = 0; c < 3; c++) {
      m_ccv_primaries_x[c] = range.read32s();
      m_ccv_primaries_y[c] = range.read32s();
    }
  }

  if (ccv_min_luminance_valid) {
    m_ccv_min_luminance_value = range.read32();
  }

  if (ccv_max_luminance_valid) {
    m_ccv_max_luminance_value = range.read32();
  }

  if (ccv_avg_luminance_valid) {
    m_ccv_avg_luminance_value = range.read32();
  }

  return range.get_error();
}


template <typename T> std::ostream& operator<<(std::ostream& ostr, const std::optional<T>& value)
{
  if (value) {
    ostr << *value;
  }
  else {
    ostr << "-";
  }

  return ostr;
}


std::string Box_cclv::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);

  sstr << indent << "ccv_primaries_present_flag: " << m_ccv_primaries_valid << "\n";
  if (m_ccv_primaries_valid) {
    sstr << indent << "ccv_primaries (x,y): ";
    sstr << "(" << m_ccv_primaries_x[0] << ";" << m_ccv_primaries_y[0] << "), ";
    sstr << "(" << m_ccv_primaries_x[1] << ";" << m_ccv_primaries_y[1] << "), ";
    sstr << "(" << m_ccv_primaries_x[2] << ";" << m_ccv_primaries_y[2] << ")\n";
  }

  sstr << indent << "ccv_min_luminance_value: " << m_ccv_min_luminance_value << "\n";
  sstr << indent << "ccv_max_luminance_value: " << m_ccv_max_luminance_value << "\n";
  sstr << indent << "ccv_avg_luminance_value: " << m_ccv_avg_luminance_value << "\n";

  return sstr.str();
}


Error Box_cclv::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  uint8_t flags = 0;
  flags |= m_ccv_primaries_valid     ? uint8_t{0b00100000} : uint8_t{0};
  flags |= m_ccv_min_luminance_value ? uint8_t{0b00010000} : uint8_t{0};
  flags |= m_ccv_max_luminance_value ? uint8_t{0b00001000} : uint8_t{0};
  flags |= m_ccv_avg_luminance_value ? uint8_t{0b00000100} : uint8_t{0};
  writer.write8(flags);

  if (m_ccv_primaries_valid) {
    for (int c = 0; c < 3; c++) {
      writer.write32s(m_ccv_primaries_x[c]);
      writer.write32s(m_ccv_primaries_y[c]);
    }
  }

  if (m_ccv_min_luminance_value) {
    writer.write32(*m_ccv_min_luminance_value);
  }

  if (m_ccv_max_luminance_value) {
    writer.write32(*m_ccv_max_luminance_value);
  }

  if (m_ccv_avg_luminance_value) {
    writer.write32(*m_ccv_avg_luminance_value);
  }

  prepend_header(writer, box_start);

  return Error::Ok;
}


Error Box_ipco::get_properties_for_item_ID(uint32_t itemID,
                                           const std::shared_ptr<class Box_ipma>& ipma,
                                           std::vector<std::shared_ptr<Box>>& out_properties) const
{
  const std::vector<Box_ipma::PropertyAssociation>* property_assoc = ipma->get_properties_for_item_ID(itemID);
  if (property_assoc == nullptr) {
    std::stringstream sstr;
    sstr << "Item (ID=" << itemID << ") has no properties assigned to it in ipma box";

    return Error(heif_error_Invalid_input,
                 heif_suberror_No_properties_assigned_to_item,
                 sstr.str());
  }

  const auto& allProperties = get_all_child_boxes();
  for (const Box_ipma::PropertyAssociation& assoc : *property_assoc) {
    if (assoc.property_index > allProperties.size()) {
      std::stringstream sstr;
      sstr << "Nonexisting property (index=" << assoc.property_index << ") for item "
           << " ID=" << itemID << " referenced in ipma box";

      return Error(heif_error_Invalid_input,
                   heif_suberror_Ipma_box_references_nonexisting_property,
                   sstr.str());
    }

    if (assoc.property_index > 0) {
      out_properties.push_back(allProperties[assoc.property_index - 1]);
    }
  }

  return Error::Ok;
}


std::shared_ptr<Box> Box_ipco::get_property_for_item_ID(heif_item_id itemID,
                                                        const std::shared_ptr<class Box_ipma>& ipma,
                                                        uint32_t box_type) const
{
  const std::vector<Box_ipma::PropertyAssociation>* property_assoc = ipma->get_properties_for_item_ID(itemID);
  if (property_assoc == nullptr) {
    return nullptr;
  }

  const auto& allProperties = get_all_child_boxes();
  for (const Box_ipma::PropertyAssociation& assoc : *property_assoc) {
    if (assoc.property_index > allProperties.size() ||
        assoc.property_index == 0) {
      return nullptr;
    }

    const auto& property = allProperties[assoc.property_index - 1];
    if (property->get_short_type() == box_type) {
      return property;
    }
  }

  return nullptr;
}


bool Box_ipco::is_property_essential_for_item(heif_item_id itemId,
                                              const std::shared_ptr<const class Box>& property,
                                              const std::shared_ptr<class Box_ipma>& ipma) const
{
  // find property index

  for (int i = 0; i < (int) m_children.size(); i++) {
    if (m_children[i] == property) {
      return ipma->is_property_essential_for_item(itemId, i + 1);
    }
  }

  assert(false); // non-existing property
  return false;
}


Error Box_ispe::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  parse_full_box_header(range);

  if (get_version() != 0) {
    return unsupported_version_error("ispe");
  }

  m_image_width = range.read32();
  m_image_height = range.read32();

  return range.get_error();
}


std::string Box_ispe::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);

  sstr << indent << "image width: " << m_image_width << "\n"
       << indent << "image height: " << m_image_height << "\n";

  return sstr.str();
}


Error Box_ispe::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  writer.write32(m_image_width);
  writer.write32(m_image_height);

  prepend_header(writer, box_start);

  return Error::Ok;
}


bool Box_ispe::operator==(const Box& other) const
{
  const auto* other_ispe = dynamic_cast<const Box_ispe*>(&other);
  if (other_ispe == nullptr) {
    return false;
  }

  return (m_image_width == other_ispe->m_image_width &&
          m_image_height == other_ispe->m_image_height);
}


Error Box_ipma::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  parse_full_box_header(range);

  // TODO: is there any specification of allowed values for the ipma version in the HEIF standards?

  if (get_version() > 1) {
    return unsupported_version_error("ipma");
  }

  uint32_t entry_cnt = range.read32();

  if (limits->max_items && entry_cnt > limits->max_items) {
    std::stringstream sstr;
    sstr << "ipma box wants to define properties for " << entry_cnt
         << " items, but the security limit has been set to " << limits->max_items << " items";
    return {heif_error_Invalid_input,
            heif_suberror_Security_limit_exceeded,
            sstr.str()};
  }

  for (uint32_t i = 0; i < entry_cnt && !range.error() && !range.eof(); i++) {
    Entry entry;
    if (get_version() < 1) {
      entry.item_ID = range.read16();
    }
    else {
      entry.item_ID = range.read32();
    }

    int assoc_cnt = range.read8();
    for (int k = 0; k < assoc_cnt; k++) {
      PropertyAssociation association{};

      uint16_t index;
      if (get_flags() & 1) {
        index = range.read16();
        association.essential = !!(index & 0x8000);
        association.property_index = (index & 0x7fff);
      }
      else {
        index = range.read8();
        association.essential = !!(index & 0x80);
        association.property_index = (index & 0x7f);
      }

      entry.associations.push_back(association);
    }

    m_entries.push_back(entry);
  }

  return range.get_error();
}


const std::vector<Box_ipma::PropertyAssociation>* Box_ipma::get_properties_for_item_ID(uint32_t itemID) const
{
  for (const auto& entry : m_entries) {
    if (entry.item_ID == itemID) {
      return &entry.associations;
    }
  }

  return nullptr;
}


bool Box_ipma::is_property_essential_for_item(heif_item_id itemId, int propertyIndex) const
{
  for (const auto& entry : m_entries) {
    if (entry.item_ID == itemId) {
      for (const auto& assoc : entry.associations) {
        if (assoc.property_index == propertyIndex) {
          return assoc.essential;
        }
      }
    }
  }

  assert(false);
  return false;
}


void Box_ipma::add_property_for_item_ID(heif_item_id itemID,
                                        PropertyAssociation assoc)
{
  size_t idx;
  for (idx = 0; idx < m_entries.size(); idx++) {
    if (m_entries[idx].item_ID == itemID) {
      break;
    }
  }

  // if itemID does not exist, add a new entry
  if (idx == m_entries.size()) {
    Entry entry;
    entry.item_ID = itemID;
    m_entries.push_back(entry);
  }

  // If the property is already associated with the item, skip.
  for (auto const& a : m_entries[idx].associations) {
    if (a.property_index == assoc.property_index) {
      return;
    }

    // TODO: should we check that the essential flag matches and return an internal error if not?
  }

  // add the property association
  m_entries[idx].associations.push_back(assoc);
}


std::string Box_ipma::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);

  for (const Entry& entry : m_entries) {
    sstr << indent << "associations for item ID: " << entry.item_ID << "\n";
    indent++;
    for (const auto& assoc : entry.associations) {
      sstr << indent << "property index: " << assoc.property_index
           << " (essential: " << std::boolalpha << assoc.essential << ")\n";
    }
    indent--;
  }

  return sstr.str();
}


void Box_ipma::derive_box_version()
{
  int version = 0;
  bool large_property_indices = false;

  for (const Entry& entry : m_entries) {
    if (entry.item_ID > 0xFFFF) {
      version = 1;
    }

    for (const auto& assoc : entry.associations) {
      if (assoc.property_index > 0x7F) {
        large_property_indices = true;
      }
    }
  }

  set_version((uint8_t) version);
  set_flags(large_property_indices ? 1 : 0);
}


Error Box_ipma::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  size_t entry_cnt = m_entries.size();
  writer.write32((uint32_t) entry_cnt);

  for (const Entry& entry : m_entries) {

    if (get_version() < 1) {
      writer.write16((uint16_t) entry.item_ID);
    }
    else {
      writer.write32(entry.item_ID);
    }

    size_t assoc_cnt = entry.associations.size();
    if (assoc_cnt > 0xFF) {
      // TODO: error, too many associations
    }

    writer.write8((uint8_t) assoc_cnt);

    for (const PropertyAssociation& association : entry.associations) {

      if (get_flags() & 1) {
        writer.write16((uint16_t) ((association.essential ? 0x8000 : 0) |
                                   (association.property_index & 0x7FFF)));
      }
      else {
        writer.write8((uint8_t) ((association.essential ? 0x80 : 0) |
                                 (association.property_index & 0x7F)));
      }
    }
  }

  prepend_header(writer, box_start);

  return Error::Ok;
}


void Box_ipma::insert_entries_from_other_ipma_box(const Box_ipma& b)
{
  m_entries.insert(m_entries.end(),
                   b.m_entries.begin(),
                   b.m_entries.end());
}


void Box_ipma::sort_properties(const std::shared_ptr<Box_ipco>& ipco)
{
  auto properties = ipco->get_all_child_boxes();

  // Stable-partition: all descriptive properties before all transformative properties.
  // The order within each group is preserved (spec requires it for transformative properties).

  for (auto& item : m_entries) {
    std::stable_partition(item.associations.begin(), item.associations.end(),
                          [&properties](const PropertyAssociation& assoc) {
                            if (assoc.property_index == 0 || assoc.property_index > properties.size()) {
                              return true; // keep invalid/unset entries in the descriptive group
                            }
                            return !properties[assoc.property_index - 1]->is_transformative_property();
                          });
  }
}


Error Box_auxC::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  parse_full_box_header(range);

  if (get_version() != 0) {
    return unsupported_version_error("auxC");
  }

  m_aux_type = range.read_string();

  while (!range.eof()) {
    m_aux_subtypes.push_back(range.read8());
  }

  return range.get_error();
}


Error Box_auxC::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  writer.write(m_aux_type);

  for (uint8_t subtype : m_aux_subtypes) {
    writer.write8(subtype);
  }

  prepend_header(writer, box_start);

  return Error::Ok;
}


std::string Box_auxC::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);

  sstr << indent << "aux type: " << m_aux_type << "\n"
       << indent << "aux subtypes: ";
  for (uint8_t subtype : m_aux_subtypes) {
    sstr << std::hex << std::setw(2) << std::setfill('0') << ((int) subtype) << " ";
  }

  sstr << "\n";

  return sstr.str();
}


Error Box_irot::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  //parse_full_box_header(range);

  uint16_t rotation = range.read8();
  rotation &= 0x03;

  m_rotation = rotation * 90;

  return range.get_error();
}


Error Box_irot::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  writer.write8((uint8_t) (m_rotation / 90));

  prepend_header(writer, box_start);

  return Error::Ok;
}


std::string Box_irot::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);

  sstr << indent << "rotation: " << m_rotation << " degrees (CCW)\n";

  return sstr.str();
}


Error Box_imir::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  //parse_full_box_header(range);

  uint8_t axis = range.read8();
  if (axis & 1) {
    m_axis = heif_transform_mirror_direction_horizontal;
  }
  else {
    m_axis = heif_transform_mirror_direction_vertical;
  }

  return range.get_error();
}


Error Box_imir::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  writer.write8(m_axis);

  prepend_header(writer, box_start);

  return Error::Ok;
}


std::string Box_imir::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);

  sstr << indent << "mirror direction: ";
  switch (m_axis) {
    case heif_transform_mirror_direction_vertical:
      sstr << "vertical\n";
      break;
    case heif_transform_mirror_direction_horizontal:
      sstr << "horizontal\n";
      break;
    case heif_transform_mirror_direction_invalid:
      sstr << "invalid\n";
      break;
  }

  return sstr.str();
}


Error Box_iscl::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  parse_full_box_header(range);

  if (get_version() != 0) {
    return unsupported_version_error("iscl");
  }

  m_target_width_numerator = range.read16();
  m_target_width_denominator = range.read16();
  m_target_height_numerator = range.read16();
  m_target_height_denominator = range.read16();

  if (m_target_width_numerator == 0 || m_target_width_denominator == 0 ||
      m_target_height_numerator == 0 || m_target_height_denominator == 0) {
    return {heif_error_Invalid_input,
            heif_suberror_Invalid_fractional_number,
            "iscl property has zero numerator or denominator"};
  }

  return range.get_error();
}


Error Box_iscl::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  writer.write16(m_target_width_numerator);
  writer.write16(m_target_width_denominator);
  writer.write16(m_target_height_numerator);
  writer.write16(m_target_height_denominator);

  prepend_header(writer, box_start);

  return Error::Ok;
}


std::string Box_iscl::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << FullBox::dump(indent);

  sstr << indent << "horizontal scaling factor: " << m_target_width_numerator << " / " << m_target_width_denominator << "\n";
  sstr << indent << "vertical scaling factor:   " << m_target_height_numerator << " / " << m_target_height_denominator << "\n";

  return sstr.str();
}


Error Box_clap::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  //parse_full_box_header(range);

  uint32_t clean_aperture_width_num = range.read32();
  uint32_t clean_aperture_width_den = range.read32();
  uint32_t clean_aperture_height_num = range.read32();
  uint32_t clean_aperture_height_den = range.read32();

  // Note: in the standard document 14496-12(2015), it says that the offset values should also be unsigned integers,
  // but this is obviously an error. Even the accompanying standard text says that offsets may be negative.
  int32_t horizontal_offset_num = (int32_t) range.read32();
  uint32_t horizontal_offset_den = (uint32_t) range.read32();
  int32_t vertical_offset_num = (int32_t) range.read32();
  uint32_t vertical_offset_den = (uint32_t) range.read32();

  if (clean_aperture_width_num > (uint32_t) std::numeric_limits<int32_t>::max() ||
      clean_aperture_width_den > (uint32_t) std::numeric_limits<int32_t>::max() ||
      clean_aperture_height_num > (uint32_t) std::numeric_limits<int32_t>::max() ||
      clean_aperture_height_den > (uint32_t) std::numeric_limits<int32_t>::max() ||
      horizontal_offset_den > (uint32_t) std::numeric_limits<int32_t>::max() ||
      vertical_offset_den > (uint32_t) std::numeric_limits<int32_t>::max()) {
    return Error(heif_error_Invalid_input,
                 heif_suberror_Invalid_fractional_number,
                 "Exceeded supported value range.");
  }

  m_clean_aperture_width = Fraction(clean_aperture_width_num,
                                    clean_aperture_width_den);
  m_clean_aperture_height = Fraction(clean_aperture_height_num,
                                     clean_aperture_height_den);
  m_horizontal_offset = Fraction(horizontal_offset_num, (int32_t) horizontal_offset_den);
  m_vertical_offset = Fraction(vertical_offset_num, (int32_t) vertical_offset_den);
  if (!m_clean_aperture_width.is_valid() || !m_clean_aperture_height.is_valid() ||
      !m_horizontal_offset.is_valid() || !m_vertical_offset.is_valid()) {
    return Error(heif_error_Invalid_input,
                 heif_suberror_Invalid_fractional_number);
  }

  return range.get_error();
}


Error Box_clap::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  writer.write32(m_clean_aperture_width.numerator);
  writer.write32(m_clean_aperture_width.denominator);
  writer.write32(m_clean_aperture_height.numerator);
  writer.write32(m_clean_aperture_height.denominator);
  writer.write32s(m_horizontal_offset.numerator);
  writer.write32(m_horizontal_offset.denominator);
  writer.write32s(m_vertical_offset.numerator);
  writer.write32(m_vertical_offset.denominator);

  prepend_header(writer, box_start);

  return Error::Ok;
}


std::string Box_clap::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);

  sstr << indent << "clean_aperture: " << m_clean_aperture_width.numerator
       << "/" << m_clean_aperture_width.denominator << " x "
       << m_clean_aperture_height.numerator << "/"
       << m_clean_aperture_height.denominator << "\n";
  sstr << indent << "offset: " << m_horizontal_offset.numerator << "/"
       << m_horizontal_offset.denominator << " ; "
       << m_vertical_offset.numerator << "/"
       << m_vertical_offset.denominator << "\n";

  return sstr.str();
}


double Box_clap::left(int image_width) const
{
  Fraction pcX = m_horizontal_offset + Fraction(image_width - 1, 2);
  Fraction left = pcX - (m_clean_aperture_width - 1) / 2;
  return left.to_double();
}

double Box_clap::top(int image_height) const
{
  Fraction pcY = m_vertical_offset + Fraction(image_height - 1, 2);
  Fraction top = pcY - (m_clean_aperture_height - 1) / 2;
  return top.to_double();
}


int Box_clap::left_rounded(uint32_t image_width) const
{
  // pcX = horizOff + (width  - 1)/2
  // pcX ± (cleanApertureWidth - 1)/2

  // left = horizOff + (width-1)/2 - (clapWidth-1)/2

  // Guard against image_width==0: `image_width - 1U` would underflow to
  // UINT32_MAX and overflow the Fraction (GHSA-jc8f-p23p-5hjg).
  if (image_width == 0) {
    return 0;
  }

  Fraction pcX = m_horizontal_offset + Fraction(image_width - 1U, 2U);
  Fraction left = pcX - (m_clean_aperture_width - 1) / 2;

  return left.round_down();
}

int Box_clap::right_rounded(uint32_t image_width) const
{
  Fraction right = m_clean_aperture_width - 1 + left_rounded(image_width);

  return right.round();
}

int Box_clap::top_rounded(uint32_t image_height) const
{
  // Guard against image_height==0 underflowing the Fraction (see left_rounded).
  if (image_height == 0) {
    return 0;
  }

  Fraction pcY = m_vertical_offset + Fraction(image_height - 1U, 2U);
  Fraction top = pcY - (m_clean_aperture_height - 1) / 2;

  return top.round();
}

int Box_clap::bottom_rounded(uint32_t image_height) const
{
  Fraction bottom = m_clean_aperture_height - 1 + top_rounded(image_height);

  return bottom.round();
}

int Box_clap::get_width_rounded() const
{
  return m_clean_aperture_width.round();
}

int Box_clap::get_height_rounded() const
{
  return m_clean_aperture_height.round();
}

void Box_clap::set(uint32_t clap_width, uint32_t clap_height,
                   uint32_t image_width, uint32_t image_height)
{
  assert(image_width >= clap_width);
  assert(image_height >= clap_height);

  m_clean_aperture_width = Fraction(clap_width, 1U);
  m_clean_aperture_height = Fraction(clap_height, 1U);

  m_horizontal_offset = Fraction(-(int32_t) (image_width - clap_width), 2);
  m_vertical_offset = Fraction(-(int32_t) (image_height - clap_height), 2);
}


Error Box_iref::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  parse_full_box_header(range);

  if (get_version() > 1) {
    return unsupported_version_error("iref");
  }

  while (!range.eof()) {
    Reference ref;

    Error err = ref.header.parse_header(range);
    if (err != Error::Ok) {
      return err;
    }

    int read_len = (get_version() == 0) ? 16 : 32;

    ref.from_item_ID = static_cast<uint32_t>(range.read_uint(read_len));
    uint16_t nRefs = range.read16();

    if (nRefs==0) {
      return {heif_error_Invalid_input,
              heif_suberror_Unspecified,
              "Input file has an 'iref' box with no references."};
    }

    if (limits->max_items && nRefs > limits->max_items) {
      std::stringstream sstr;
      sstr << "Number of references in iref box (" << nRefs << ") exceeds the security limits of " << limits->max_items << " references.";

      return {heif_error_Invalid_input,
              heif_suberror_Security_limit_exceeded,
              sstr.str()};
    }

    for (int i = 0; i < nRefs; i++) {
      if (range.eof()) {
        std::stringstream sstr;
        sstr << "iref box should contain " << nRefs << " references, but we can only read " << i << " references.";

        return {heif_error_Invalid_input,
                heif_suberror_End_of_data,
                sstr.str()};
      }

      ref.to_item_ID.push_back(static_cast<uint32_t>(range.read_uint(read_len)));
    }

    m_references.push_back(ref);
  }


  // --- check for duplicate references

  if (auto error = check_for_double_references()) {
    return error;
  }


#if 0
  // Note: This input sanity check first did not work as expected.
  // Its idea was to prevent infinite recursions while decoding when the input file
  // contains cyclic references. However, apparently there are cases where cyclic
  // references are actually allowed, like with images that have premultiplied alpha channels:
  // | Box: iref -----
  // | size: 40   (header size: 12)
  // | reference with type 'auxl' from ID: 2 to IDs: 1
  // | reference with type 'prem' from ID: 1 to IDs: 2
  //
  // We now test for cyclic references during the image decoding.
  // We pass down the item IDs that have already been seen during the decoding process.
  // If we try to decode an image IDs that has already been seen previously, we throw an error.
  // The advantage is that the error only occurs when we are trying to decode the faulty image.

  // --- check for cyclic references

  for (const auto& ref : m_references) {
    if (ref.header.get_short_type() != fourcc("dimg") &&
        ref.header.get_short_type() != fourcc("auxl")) {
      continue;
    }

    std::set<heif_item_id> reached_ids; // IDs that we have already reached in the DAG
    std::set<heif_item_id> todo;    // IDs that still need to be followed

    bool reverse = (ref.header.get_short_type() != fourcc("auxl"));

    if (!reverse) {
      todo.insert(ref.from_item_ID);  // start at base item
    }
    else {
      if (ref.to_item_ID.empty()) {
        continue;
      }

      // TODO: what if aux image is assigned to multiple images?
      todo.insert(ref.to_item_ID[0]);  // start at base item
    }

    while (!todo.empty()) {
      // transfer ID into set of reached IDs
      auto id = *todo.begin();
      todo.erase(id);
      reached_ids.insert(id);

      // if this ID refers to another 'iref', follow it

      for (const auto& succ_ref : m_references) {
        if (succ_ref.header.get_short_type() != fourcc("dimg") &&
            succ_ref.header.get_short_type() != fourcc("auxl")) {
          continue;
        }

        heif_item_id from;
        std::vector<heif_item_id> to;

        if (succ_ref.header.get_short_type() == fourcc("auxl")) {
          if (succ_ref.to_item_ID.empty()) {
            continue;
          }

          from = succ_ref.to_item_ID[0];
          to = {succ_ref.from_item_ID};
        }
        else {
          from = succ_ref.from_item_ID;
          to = succ_ref.to_item_ID;
        }

        if (from == id) {

          // Check whether any successor IDs has been visited yet, which would be an error.
          // Otherwise, put that ID into the 'todo' set.

          for (const auto& succ_ref_id : to) {
            if (reached_ids.find(succ_ref_id) != reached_ids.end()) {
              return Error(heif_error_Invalid_input,
                           heif_suberror_Unspecified,
                           "'iref' has cyclic references");
            }

            todo.insert(succ_ref_id);
          }
        }
      }
    }
  }
#endif

  return range.get_error();
}


Error Box_iref::check_for_double_references() const
{
  for (const auto& ref : m_references) {
    std::set<heif_item_id> to_ids;
    for (const auto to_id : ref.to_item_ID) {
      if (to_ids.find(to_id) == to_ids.end()) {
        to_ids.insert(to_id);
      }
      else {
        return {heif_error_Invalid_input,
                heif_suberror_Unspecified,
                "'iref' has double references"};
      }
    }
  }

  return Error::Ok;
}


void Box_iref::derive_box_version()
{
  uint8_t version = 0;

  for (const auto& ref : m_references) {
    if (ref.from_item_ID > 0xFFFF) {
      version = 1;
      break;
    }

    for (uint32_t r : ref.to_item_ID) {
      if (r > 0xFFFF) {
        version = 1;
        break;
      }
    }
  }

  set_version(version);
}


Error Box_iref::write(StreamWriter& writer) const
{
  if (auto error = check_for_double_references()) {
    return error;
  }

  size_t box_start = reserve_box_header_space(writer);

  int id_size = ((get_version() == 0) ? 2 : 4);

  for (const auto& ref : m_references) {
    uint32_t box_size = uint32_t(4 + 4 + 2 + id_size * (1 + ref.to_item_ID.size()));

    // we write the BoxHeader ourselves since it is very simple
    writer.write32(box_size);
    writer.write32(ref.header.get_short_type());

    writer.write(id_size, ref.from_item_ID);
    writer.write16((uint16_t) ref.to_item_ID.size());

    for (uint32_t r : ref.to_item_ID) {
      writer.write(id_size, r);
    }
  }

  prepend_header(writer, box_start);

  return Error::Ok;
}


std::string Box_iref::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);

  for (const auto& ref : m_references) {
    sstr << indent << "reference with type '" << ref.header.get_type_string() << "'"
         << " from ID: " << ref.from_item_ID
         << " to IDs: ";
    for (uint32_t id : ref.to_item_ID) {
      sstr << id << " ";
    }
    sstr << "\n";
  }

  return sstr.str();
}


bool Box_iref::has_references(uint32_t itemID) const
{
  for (const Reference& ref : m_references) {
    if (ref.from_item_ID == itemID) {
      return true;
    }
  }

  return false;
}


std::vector<Box_iref::Reference> Box_iref::get_references_from(heif_item_id itemID) const
{
  std::vector<Reference> references;

  for (const Reference& ref : m_references) {
    if (ref.from_item_ID == itemID) {
      references.push_back(ref);
    }
  }

  return references;
}


std::vector<uint32_t> Box_iref::get_references(uint32_t itemID, uint32_t ref_type) const
{
  for (const Reference& ref : m_references) {
    if (ref.from_item_ID == itemID &&
        ref.header.get_short_type() == ref_type) {
      return ref.to_item_ID;
    }
  }

  return std::vector<uint32_t>();
}


void Box_iref::add_references(heif_item_id from_id, uint32_t type, const std::vector<heif_item_id>& to_ids)
{
  Reference ref;
  ref.header.set_short_type(type);
  ref.from_item_ID = from_id;
  ref.to_item_ID = to_ids;

  assert(to_ids.size() <= 0xFFFF);

  m_references.push_back(ref);
}


void Box_iref::overwrite_reference(heif_item_id from_id, uint32_t type, uint32_t reference_idx, heif_item_id to_item)
{
  for (auto& ref : m_references) {
    if (ref.from_item_ID == from_id && ref.header.get_short_type() == type) {
      assert(reference_idx < ref.to_item_ID.size());

      ref.to_item_ID[reference_idx] = to_item;
      return;
    }
  }

  assert(false); // reference was not found
}


Error Box_rref::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  parse_full_box_header(range);

  if (get_version() > 1) {
    return unsupported_version_error("rref");
  }

  size_t remainingBytes = range.get_remaining_bytes();

  // The number of reference types should be stored in uint(8), but the
  // common test images C043, C044 store them as uint(32).
  // Let us detect this case by the number of data bytes in this box.
  bool cnt_as_uint32 = (remainingBytes > 0 && remainingBytes % 4 == 0);

  uint8_t nRefTypes;
  if (cnt_as_uint32) {
    // fix broken C043, C044 files
    // TODO: remove me when the files have been corrected as the above check can misfire when there is extra padding
    nRefTypes = (uint8_t)range.read32();
  }
  else {
    nRefTypes = range.read8();
  }

  for (uint8_t i = 0; i < nRefTypes; i++) {
    uint32_t refType = range.read32();

    if (range.error()) {
      std::stringstream sstr;
      sstr << "rref box should contain " << ((int)nRefTypes) << " reference types, but we can only read " << m_reference_types.size() << " reference types.";

      return {
        heif_error_Invalid_input,
        heif_suberror_End_of_data,
        sstr.str()
      };
    }

    m_reference_types.push_back(refType);
  }

  return range.get_error();
}


static constexpr std::array supported_reference_types{
  fourcc("thmb"),
  fourcc("base"),
  fourcc("cdsc"),
  fourcc("dimg"),
  fourcc("auxl"),
  fourcc("prem")
};


bool Box_rref::all_reference_types_supported() const
{
  // TODO: replace with std::ranges variant once it is widely supported (e.g. on older clang/libc++):
  //   return std::ranges::all_of(m_reference_types, [](uint32_t t) {
  //     return std::ranges::find(supported_reference_types, t) != supported_reference_types.end();
  //   });
  return std::all_of(m_reference_types.begin(), m_reference_types.end(), [](uint32_t t) {
    return std::find(supported_reference_types.begin(), supported_reference_types.end(), t)
           != supported_reference_types.end();
  });
}


Error Box_rref::reference_types_supported_error() const
{
  std::vector<uint32_t> unsupported_types;

  for (uint32_t refType : m_reference_types) {
    // TODO: replace with std::ranges variant once it is widely supported (e.g. on older clang/libc++):
    //   if (std::ranges::find(supported_reference_types, refType) == supported_reference_types.end()) {
    if (std::find(supported_reference_types.begin(), supported_reference_types.end(), refType) == supported_reference_types.end()) {
      unsupported_types.push_back(refType);
    }
  }

  if (unsupported_types.empty()) {
    return Error::Ok;
  }

  std::stringstream sstr;

  sstr << "Unsupported reference types: ";
  for (size_t i = 0; i < unsupported_types.size(); i++) {
    if (i > 0) {
      sstr << ", ";
    }
    sstr << fourcc_to_string(unsupported_types[i]);
  }

  return {
    heif_error_Unsupported_feature,
    heif_suberror_Unspecified,
    sstr.str()
  };
}


Error Box_rref::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  if (m_reference_types.size() > std::numeric_limits<uint8_t>::max()) {
    return {
      heif_error_Usage_error,
      heif_suberror_Unspecified,
      "Too many rref reference types."
    };
  }

  writer.write8(static_cast<uint8_t>(m_reference_types.size()));

  for (uint32_t refType : m_reference_types) {
    writer.write32(refType);
  }

  prepend_header(writer, box_start);

  return Error::Ok;
}


std::string Box_rref::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);

  sstr << indent << "reference types: ";
  for (size_t i = 0; i < m_reference_types.size(); i++) {
    if (i > 0) sstr << ", ";
    sstr << fourcc_to_string(m_reference_types[i]);
  }
  sstr << "\n";

  return sstr.str();
}


Error Box_idat::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  //parse_full_box_header(range);

  m_data_start_pos = range.get_istream()->get_position();

  return range.get_error();
}


Error Box_idat::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  writer.write(m_data_for_writing);

  prepend_header(writer, box_start);

  return Error::Ok;
}


std::string Box_idat::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);

  if (get_box_size() >= get_header_size()) {
    sstr << indent << "number of data bytes: " << get_box_size() - get_header_size() << "\n";
  } else {
     sstr << indent << "number of data bytes is invalid\n";
  }

  return sstr.str();
}


Error Box_idat::read_data(const std::shared_ptr<StreamReader>& istr,
                          uint64_t start, uint64_t length,
                          std::vector<uint8_t>& out_data,
                          const heif_security_limits* limits) const
{
  // --- security check that we do not allocate too much data

  auto curr_size = out_data.size();

  auto max_memory_block_size = limits->max_memory_block_size;
  if (max_memory_block_size && max_memory_block_size - curr_size < length) {
    std::stringstream sstr;
    sstr << "idat box contained " << length << " bytes, total memory size would be "
         << (curr_size + length) << " bytes, exceeding the security limit of "
         << max_memory_block_size << " bytes";

    return Error(heif_error_Memory_allocation_error,
                 heif_suberror_Security_limit_exceeded,
                 sstr.str());
  }


  // move to start of data
  if (start > (uint64_t) m_data_start_pos + get_box_size()) {
    return Error(heif_error_Invalid_input,
                 heif_suberror_End_of_data);
  }
  else if (length > get_box_size() || start + length > get_box_size()) {
    return Error(heif_error_Invalid_input,
                 heif_suberror_End_of_data);
  }

  StreamReader::grow_status status = istr->wait_for_file_size((int64_t) m_data_start_pos + start + length);
  if (status == StreamReader::grow_status::size_beyond_eof ||
      status == StreamReader::grow_status::timeout) {
    // TODO: maybe we should introduce some 'Recoverable error' instead of 'Invalid input'
    return Error(heif_error_Invalid_input,
                 heif_suberror_End_of_data);
  }

  bool success;
  success = istr->seek(m_data_start_pos + (std::streampos) start);
  assert(success);
  (void) success;

  if (length > 0) {
    // reserve space for the data in the output array
    out_data.resize(static_cast<size_t>(curr_size + length));
    uint8_t* data = &out_data[curr_size];

    success = istr->read((char*) data, static_cast<size_t>(length));
    assert(success);
    (void) success;
  }

  return Error::Ok;
}


Error Box_grpl::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  //parse_full_box_header(range);

  return read_children(range, READ_CHILDREN_ALL, limits); // should we pass the parsing context 'grpl' or are the box types unique?
}


std::string Box_grpl::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);
  sstr << dump_children(indent);
  return sstr.str();
}


Error Box_EntityToGroup::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  Error err = parse_full_box_header(range);
  if (err != Error::Ok) {
    return err;
  }

  group_id = range.read32();
  uint32_t nEntities = range.read32();

  if (nEntities > range.get_remaining_bytes() / 4) {
    std::stringstream sstr;
    size_t maxEntries = range.get_remaining_bytes() / 4;
    sstr << "entity group box should contain " << nEntities << " entities, but we can only read " << maxEntries << " entities.";

    return {heif_error_Invalid_input,
            heif_suberror_End_of_data,
            sstr.str()};
  }

  if (limits->max_size_entity_group && nEntities > limits->max_size_entity_group) {
    std::stringstream sstr;
    sstr << "entity group box contains " << nEntities << " entities, but the security limit is set to " << limits->max_size_entity_group << " entities.";

    return {heif_error_Invalid_input,
            heif_suberror_Security_limit_exceeded,
            sstr.str()};
  }

  entity_ids.resize(nEntities);
  for (uint32_t i = 0; i < nEntities; i++) {
    entity_ids[i] = range.read32();
  }

  return Error::Ok;
}


Error Box_EntityToGroup::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  write_entity_group_ids(writer);

  prepend_header(writer, box_start);

  return Error::Ok;
}


void Box_EntityToGroup::write_entity_group_ids(StreamWriter& writer) const
{
  assert(entity_ids.size() <= 0xFFFFFFFF);

  writer.write32(group_id);
  writer.write32(static_cast<uint32_t>(entity_ids.size()));

  for (uint32_t id : entity_ids) {
    writer.write32(id);
  }
}


std::string Box_EntityToGroup::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);

  sstr << indent << "group id: " << group_id << "\n"
       << indent << "entity IDs: ";

  bool first = true;
  for (uint32_t id : entity_ids) {
    if (first) {
      first = false;
    }
    else {
      sstr << ' ';
    }

    sstr << id;
  }

  sstr << "\n";

  return sstr.str();
}


Error Box_ster::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  Error err = Box_EntityToGroup::parse(range, limits);
  if (err) {
    return err;
  }

  if (entity_ids.size() != 2) {
    return {heif_error_Invalid_input,
            heif_suberror_Invalid_box_size,
            "'ster' entity group does not exists of exactly two images"};
  }

  return Error::Ok;
}


std::string Box_ster::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);

  sstr << indent << "group id: " << group_id << "\n"
       << indent << "left image ID: " << entity_ids[0] << "\n"
       << indent << "right image ID: " << entity_ids[1] << "\n";

  return sstr.str();
}



Error Box_pymd::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  Error err = Box_EntityToGroup::parse(range, limits);
  if (err) {
    return err;
  }

  tile_size_x = range.read16();
  tile_size_y = range.read16();

  for (size_t i = 0; i < entity_ids.size(); i++) {
    LayerInfo layer{};
    layer.layer_binning = range.read16();
    layer.tiles_in_layer_row_minus1 = range.read16();
    layer.tiles_in_layer_column_minus1 = range.read16();

    m_layer_infos.push_back(layer);
  }

  return Error::Ok;
}


Error Box_pymd::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  Box_EntityToGroup::write_entity_group_ids(writer);

  writer.write16(tile_size_x);
  writer.write16(tile_size_y);

  for (size_t i = 0; i < entity_ids.size(); i++) {
    const LayerInfo& layer = m_layer_infos[i];

    writer.write16(layer.layer_binning);
    writer.write16(layer.tiles_in_layer_row_minus1);
    writer.write16(layer.tiles_in_layer_column_minus1);
  }

  prepend_header(writer, box_start);

  return Error::Ok;
}


std::string Box_pymd::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box_EntityToGroup::dump(indent);

  sstr << indent << "tile size: " << tile_size_x << "x" << tile_size_y << "\n";

  int layerNr = 0;
  for (const auto& layer : m_layer_infos) {
    sstr << indent << "layer " << layerNr << ":\n"
         << indent << "| binning: " << layer.layer_binning << "\n"
         << indent << "| tiles: " << (layer.tiles_in_layer_row_minus1 + 1) << "x" << (layer.tiles_in_layer_column_minus1 + 1) << "\n";

    layerNr++;
  }

  return sstr.str();
}


Error Box_dinf::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  //parse_full_box_header(range);

  return read_children(range, READ_CHILDREN_ALL, limits);
}


std::string Box_dinf::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);
  sstr << dump_children(indent);

  return sstr.str();
}


Error Box_dref::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  parse_full_box_header(range);

  if (get_version() != 0) {
    return unsupported_version_error("dref");
  }

  uint32_t nEntities = range.read32();

  /*
  for (int i=0;i<nEntities;i++) {
    if (range.eof()) {
      break;
    }
  }
  */

  if (nEntities > (uint32_t)std::numeric_limits<int>::max()) {
    return Error(heif_error_Memory_allocation_error,
                 heif_suberror_Security_limit_exceeded,
                 "Too many entities in dref box.");
  }

  Error err = read_children(range, (int)nEntities, limits);
  if (err) {
    return err;
  }

  if (m_children.size() != nEntities) {
    // TODO return Error(
  }

  return err;
}


Error Box_dref::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  if (m_children.size() > 0xFFFF) {
    return {
      heif_error_Usage_error,
      heif_suberror_Unspecified,
      "Too many dref children boxes."
    };
  }

  writer.write32(static_cast<uint32_t>(m_children.size()));
  write_children(writer);

  prepend_header(writer, box_start);
  return Error::Ok;
}


std::string Box_dref::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);
  sstr << dump_children(indent);

  return sstr.str();
}


Error Box_url::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  parse_full_box_header(range);

  if (get_version() > 0) {
    return unsupported_version_error("url");
  }

  if (get_flags() & 1) {
    // data in same file
    m_location.clear();
  }
  else {
    m_location = range.read_string();
  }

  return range.get_error();
}


Error Box_url::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  if (m_location.empty()) {
    assert(get_flags() == 1);
  }
  else {
    assert(get_flags() == 0);
    writer.write(m_location);
  }

  prepend_header(writer, box_start);
  return Error::Ok;
}


std::string Box_url::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);
  //sstr << dump_children(indent);

  sstr << indent << "location: " << m_location << "\n";

  return sstr.str();
}


Error Box_udes::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  parse_full_box_header(range);

  if (get_version() > 0) {
    return unsupported_version_error("udes");
  }

  m_lang = range.read_string();
  m_name = range.read_string();
  m_description = range.read_string();
  m_tags = range.read_string();
  return range.get_error();
}

std::string Box_udes::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);
  sstr << indent << "lang: " << m_lang << "\n";
  sstr << indent << "name: " << m_name << "\n";
  sstr << indent << "description: " << m_description << "\n";
  sstr << indent << "tags: " << m_lang << "\n";
  return sstr.str();
}

Error Box_udes::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);
  writer.write(m_lang);
  writer.write(m_name);
  writer.write(m_description);
  writer.write(m_tags);
  prepend_header(writer, box_start);
  return Error::Ok;
}


void Box_cmin::RelativeIntrinsicMatrix::compute_focal_length(int image_width, int image_height,
                                                             double& out_focal_length_x, double& out_focal_length_y) const
{
  out_focal_length_x = focal_length_x * image_width;

  if (is_anisotropic) {
    out_focal_length_y = focal_length_y * image_height;
  }
  else {
    out_focal_length_y = out_focal_length_x;
  }
}


void Box_cmin::RelativeIntrinsicMatrix::compute_principal_point(int image_width, int image_height,
                                                                double& out_principal_point_x, double& out_principal_point_y) const
{
  out_principal_point_x = principal_point_x * image_width;
  out_principal_point_y = principal_point_y * image_height;
}


Box_cmin::AbsoluteIntrinsicMatrix Box_cmin::RelativeIntrinsicMatrix::to_absolute(int image_width, int image_height) const
{
  AbsoluteIntrinsicMatrix m{};
  compute_focal_length(image_width, image_height, m.focal_length_x, m.focal_length_y);
  compute_principal_point(image_width, image_height, m.principal_point_x, m.principal_point_y);
  m.skew = skew;

  return m;
}


std::string Box_cmin::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);
  sstr << indent << "principal-point: " << m_matrix.principal_point_x << ", " << m_matrix.principal_point_y << "\n";
  if (m_matrix.is_anisotropic) {
    sstr << indent << "focal-length: " << m_matrix.focal_length_x << ", " << m_matrix.focal_length_y << "\n";
    sstr << indent << "skew: " << m_matrix.skew << "\n";
  }
  else {
    sstr << indent << "focal-length: " << m_matrix.focal_length_x << "\n";
    sstr << indent << "no skew\n";
  }

  return sstr.str();
}


Error Box_cmin::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  parse_full_box_header(range);

  if (get_version() > 0) {
    return unsupported_version_error("cmin");
  }

  m_denominatorShift = (get_flags() & 0x1F00) >> 8;
  uint32_t denominator = (1U << m_denominatorShift);

  m_matrix.focal_length_x = range.read32s() / (double)denominator;
  m_matrix.principal_point_x = range.read32s() / (double)denominator;
  m_matrix.principal_point_y = range.read32s() / (double)denominator;

  if (get_flags() & 1) {
    m_skewDenominatorShift = ((get_flags()) & 0x1F0000) >> 16;
    uint32_t skewDenominator = (1U << m_skewDenominatorShift);

    m_matrix.focal_length_y = range.read32s() / (double)denominator;
    m_matrix.skew = range.read32s() / (double)skewDenominator;

    m_matrix.is_anisotropic = true;
  }
  else {
    m_matrix.is_anisotropic = false;
    m_matrix.focal_length_y = 0;
    m_matrix.skew = 0;
  }
  return range.get_error();
}


static uint32_t get_signed_fixed_point_shift(double v)
{
  if (v==0) {
    return 31;
  }

  v = std::abs(v);

  uint32_t shift = 0;
  while (v < (1<<30)) {
    v *= 2;
    shift++;

    if (shift==31) {
      return shift;
    }
  }

  return shift;
}


void Box_cmin::set_intrinsic_matrix(RelativeIntrinsicMatrix matrix)
{
  m_matrix = matrix;

  uint32_t flags = 0;
  flags |= matrix.is_anisotropic ? 1 : 0;

  uint32_t shift_fx = get_signed_fixed_point_shift(matrix.focal_length_x);
  uint32_t shift_px = get_signed_fixed_point_shift(matrix.principal_point_x);
  uint32_t shift_py = get_signed_fixed_point_shift(matrix.principal_point_y);
  m_denominatorShift = std::min(std::min(shift_fx, shift_px), shift_py);

  if (matrix.is_anisotropic) {
    uint32_t shift_fy = get_signed_fixed_point_shift(matrix.focal_length_y);
    m_denominatorShift = std::min(m_denominatorShift, shift_fy);

    m_skewDenominatorShift = get_signed_fixed_point_shift(matrix.skew);
  }
  else {
    m_skewDenominatorShift = 0;
  }

  flags |= (m_denominatorShift << 8);
  flags |= (m_skewDenominatorShift << 16);

  set_flags(flags);
}


Error Box_cmin::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  uint32_t denominator = (1U << m_denominatorShift);

  writer.write32s(static_cast<int32_t>(m_matrix.focal_length_x * denominator));
  writer.write32s(static_cast<int32_t>(m_matrix.principal_point_x * denominator));
  writer.write32s(static_cast<int32_t>(m_matrix.principal_point_y * denominator));

  if (get_flags() & 1) {
    writer.write32s(static_cast<int32_t>(m_matrix.focal_length_y * denominator));

    uint32_t skewDenominator = (1U << m_skewDenominatorShift);
    writer.write32s(static_cast<int32_t>(m_matrix.skew * skewDenominator));
  }

  prepend_header(writer, box_start);

  return Error::Ok;
}


static std::array<double,9> mul(const std::array<double,9>& a, const std::array<double,9>& b)
{
  std::array<double, 9> m{};

  m[0] = a[0]*b[0] + a[1]*b[3] + a[2]*b[6];
  m[1] = a[0]*b[1] + a[1]*b[4] + a[2]*b[7];
  m[2] = a[0]*b[2] + a[1]*b[5] + a[2]*b[8];

  m[3] = a[3]*b[0] + a[4]*b[3] + a[5]*b[6];
  m[4] = a[3]*b[1] + a[4]*b[4] + a[5]*b[7];
  m[5] = a[3]*b[2] + a[4]*b[5] + a[5]*b[8];

  m[6] = a[6]*b[0] + a[7]*b[3] + a[8]*b[6];
  m[7] = a[6]*b[1] + a[7]*b[4] + a[8]*b[7];
  m[8] = a[6]*b[2] + a[7]*b[5] + a[8]*b[8];

  return m;
}


std::array<double,9> Box_cmex::ExtrinsicMatrix::calculate_rotation_matrix() const
{
  std::array<double,9> m{};

  if (rotation_as_quaternions) {
    double qx = quaternion_x;
    double qy = quaternion_y;
    double qz = quaternion_z;
    double qw = quaternion_w;

    m[0] = 1-2*(qy*qy+qz*qz);
    m[1] = 2*(qx*qy-qz*qw);
    m[2] = 2*(qx*qz+qy*qw);
    m[3] = 2*(qx*qy+qz*qw);
    m[4] = 1-2*(qx*qx+qz*qz);
    m[5] = 2*(qy*qz-qx*qw);
    m[6] = 2*(qx*qz-qy*qw);
    m[7] = 2*(qy*qz+qx*qw);
    m[8] = 1-2*(qx*qx+qy*qy);
  }
  else {
    // This rotation order fits the conformance data
    // https://github.com/MPEGGroup/FileFormatConformance
    // branch m62054_extrinsics : FileFormatConformance/data/file_features/under_consideration/ex_in_trinsics/extrinsic_rotation

    std::array<double,9> m_yaw{};    // Z
    std::array<double,9> m_pitch{};  // Y
    std::array<double,9> m_roll{};   // X

    const double d2r = M_PI/180;

    double x = d2r * rotation_roll;
    double y = d2r * rotation_pitch;
    double z = d2r * rotation_yaw;

    // X
    m_roll[0] = 1;
    m_roll[4] = m_roll[8] = cos(x);
    m_roll[5] = -sin(x);
    m_roll[7] = sin(x);

    // Y
    m_pitch[4] = 1;
    m_pitch[0] = m_pitch[8] = cos(y);
    m_pitch[6] = -sin(y);
    m_pitch[2] = sin(y);

    // Z
    m_yaw[8] = 1;
    m_yaw[0] = m_yaw[4] = cos(z);
    m_yaw[1] = -sin(z);
    m_yaw[3] = sin(z);

    m = mul(m_yaw, mul(m_pitch, m_roll));
  }

  return m;
}


Error Box_cmex::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  parse_full_box_header(range);

  if (get_version() > 0) {
    return unsupported_version_error("cmex");
  }

  m_matrix = ExtrinsicMatrix{};

  if (get_flags() & pos_x_present) {
    m_has_pos_x = true;
    m_matrix.pos_x = range.read32s();
  }

  if (get_flags() & pos_y_present) {
    m_has_pos_y = true;
    m_matrix.pos_y = range.read32s();
  }

  if (get_flags() & pos_z_present) {
    m_has_pos_z = true;
    m_matrix.pos_z = range.read32s();
  }

  if (get_flags() & orientation_present) {
    m_has_orientation = true;

    if (get_version() == 0) {
      bool use32bit = (get_flags() & rot_large_field_size);
      int32_t quat_x = use32bit ? range.read32s() : range.read16s();
      int32_t quat_y = use32bit ? range.read32s() : range.read16s();
      int32_t quat_z = use32bit ? range.read32s() : range.read16s();

      uint32_t div = 1U << (14 + (use32bit ? 16 : 0));

      m_matrix.rotation_as_quaternions = true;
      m_matrix.quaternion_x = quat_x / (double)div;
      m_matrix.quaternion_y = quat_y / (double)div;
      m_matrix.quaternion_z = quat_z / (double)div;

      double q_sum = (m_matrix.quaternion_x * m_matrix.quaternion_x +
                      m_matrix.quaternion_y * m_matrix.quaternion_y +
                      m_matrix.quaternion_z * m_matrix.quaternion_z);

      if (q_sum > 1.0) {
        return Error(heif_error_Invalid_input,
                     heif_suberror_Unspecified,
                     "Invalid quaternion in extrinsic rotation matrix");
      }

      m_matrix.quaternion_w = sqrt(1 - q_sum);

    } else if (get_version() == 1) {
      uint32_t div = 1<<16;
      m_matrix.rotation_yaw = range.read32s() / (double)div;
      m_matrix.rotation_pitch = range.read32s() / (double)div;
      m_matrix.rotation_roll = range.read32s() / (double)div;
    }
  }

  if (get_flags() & id_present) {
    m_has_world_coordinate_system_id = true;
    m_matrix.world_coordinate_system_id = range.read32();
  }

  return range.get_error();
}


std::string Box_cmex::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);
  sstr << indent << "camera position (um): ";
  sstr << m_matrix.pos_x << " ; ";
  sstr << m_matrix.pos_y << " ; ";
  sstr << m_matrix.pos_z << "\n";

  sstr << indent << "orientation ";
  if (m_matrix.rotation_as_quaternions) {
    sstr << "(quaterion)\n";
    sstr << indent << "  q = ["
         << m_matrix.quaternion_x << ";"
         << m_matrix.quaternion_y << ";"
         << m_matrix.quaternion_z << ";"
         << m_matrix.quaternion_w << "]\n";
  }
  else {
    sstr << "(angles)\n";
    sstr << indent << "  yaw:   " << m_matrix.rotation_yaw << "\n";
    sstr << indent << "  pitch: " << m_matrix.rotation_pitch << "\n";
    sstr << indent << "  roll:  " << m_matrix.rotation_roll << "\n";
  }

  sstr << indent << "world coordinate system id: " << m_matrix.world_coordinate_system_id << "\n";

  return sstr.str();
}




Error Box_cmex::set_extrinsic_matrix(ExtrinsicMatrix matrix)
{
  m_matrix = matrix;

  uint32_t flags = 0;

  m_has_pos_x = (matrix.pos_x != 0);
  m_has_pos_y = (matrix.pos_y != 0);
  m_has_pos_z = (matrix.pos_z != 0);

  if (m_has_pos_x) {
    flags |= pos_x_present;
  }

  if (m_has_pos_y) {
    flags |= pos_y_present;
  }

  if (m_has_pos_z) {
    flags |= pos_z_present;
  }

  if (matrix.rotation_as_quaternions) {
    if (matrix.quaternion_x != 0 ||
        matrix.quaternion_y != 0 ||
        matrix.quaternion_z != 0) {
      flags |= orientation_present;

      double q_sum = (m_matrix.quaternion_x * m_matrix.quaternion_x +
                      m_matrix.quaternion_y * m_matrix.quaternion_y +
                      m_matrix.quaternion_z * m_matrix.quaternion_z);

      if (q_sum > 1.0) {
        return Error(heif_error_Invalid_input,
                     heif_suberror_Unspecified,
                     "Invalid quaternion in extrinsic rotation matrix");
      }

      if (matrix.quaternion_w < 0) {
        matrix.quaternion_x = -matrix.quaternion_x;
        matrix.quaternion_y = -matrix.quaternion_y;
        matrix.quaternion_z = -matrix.quaternion_z;
        matrix.quaternion_w = -matrix.quaternion_w;
      }
    }
  }
  else {
    if (matrix.rotation_yaw != 0 ||
        matrix.rotation_pitch != 0 ||
        matrix.rotation_roll != 0) {
      flags |= orientation_present;

      if (matrix.rotation_yaw < -180.0 || matrix.rotation_yaw >= 180.0) {
        return Error(heif_error_Invalid_input,
                     heif_suberror_Unspecified,
                     "Invalid yaw angle");
      }

      if (matrix.rotation_pitch < -90.0 || matrix.rotation_pitch > 90.0) {
        return Error(heif_error_Invalid_input,
                     heif_suberror_Unspecified,
                     "Invalid pitch angle");
      }

      if (matrix.rotation_roll < -180.0 || matrix.rotation_roll >= 180.0) {
        return Error(heif_error_Invalid_input,
                     heif_suberror_Unspecified,
                     "Invalid roll angle");
      }
    }
  }

  if (matrix.orientation_is_32bit) {
    flags |= rot_large_field_size;
  }

  if (matrix.world_coordinate_system_id != 0) {
    flags |= id_present;
  }

  set_flags(flags);
  set_version(m_matrix.rotation_as_quaternions ? 0 : 1);

  return Error::Ok;
}


Error Box_cmex::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  if (m_has_pos_x) {
    writer.write32s(m_matrix.pos_x);
  }

  if (m_has_pos_y) {
    writer.write32s(m_matrix.pos_y);
  }

  if (m_has_pos_z) {
    writer.write32s(m_matrix.pos_z);
  }

  if (m_has_orientation) {
    if (m_matrix.rotation_as_quaternions) {
      if (m_matrix.orientation_is_32bit) {
        writer.write32s(static_cast<int32_t>(m_matrix.quaternion_x * (1<<30)));
        writer.write32s(static_cast<int32_t>(m_matrix.quaternion_y * (1<<30)));
        writer.write32s(static_cast<int32_t>(m_matrix.quaternion_z * (1<<30)));
      }
      else {
        writer.write16s(static_cast<int16_t>(m_matrix.quaternion_x * (1<<14)));
        writer.write16s(static_cast<int16_t>(m_matrix.quaternion_y * (1<<14)));
        writer.write16s(static_cast<int16_t>(m_matrix.quaternion_z * (1<<14)));
      }
    }
    else {
      writer.write32s(static_cast<int32_t>(m_matrix.rotation_yaw * (1<<16)));
      writer.write32s(static_cast<int32_t>(m_matrix.rotation_pitch * (1<<16)));
      writer.write32s(static_cast<int32_t>(m_matrix.rotation_roll * (1<<16)));
    }
  }

  if (m_has_world_coordinate_system_id) {
    writer.write32(m_matrix.world_coordinate_system_id);
  }


  prepend_header(writer, box_start);

  return Error::Ok;
}


std::string Box_taic::dump(const heif_tai_clock_info& info, Indent& indent)
{
  std::ostringstream sstr;
  sstr << indent << "time_uncertainty: ";
  if (info.time_uncertainty == heif_tai_clock_info_time_uncertainty_unknown) {
    sstr << "unknown\n";
  }
  else {
    sstr << info.time_uncertainty << "\n";
  }
  sstr << indent << "clock_resolution: " << info.clock_resolution << "\n";
  sstr << indent << "clock_drift_rate: ";
  if (info.clock_drift_rate == heif_tai_clock_info_clock_drift_rate_unknown) {
    sstr << "undefined\n";
  }
  else {
    sstr << info.clock_drift_rate << "\n";
  }

  sstr << indent << "clock_type: " << int(info.clock_type) << " ";
  switch (info.clock_type) {
    case heif_tai_clock_info_clock_type_unknown: sstr << "(unknown)\n"; break;
    case heif_tai_clock_info_clock_type_synchronized_to_atomic_source: sstr << "(synchronized to atomic source)\n"; break;
    case heif_tai_clock_info_clock_type_not_synchronized_to_atomic_source: sstr << "(not synchronized to atomic source)\n"; break;
    default: sstr << "(illegal value)\n"; break;;
  }
  return sstr.str();
}


std::string Box_taic::dump(Indent& indent) const {
  std::ostringstream sstr;
  sstr << Box::dump(indent);
  sstr << dump(m_info, indent);

  return sstr.str();
}

Error Box_taic::write(StreamWriter& writer) const {
  size_t box_start = reserve_box_header_space(writer);
  writer.write64(m_info.time_uncertainty);
  writer.write32(m_info.clock_resolution);
  writer.write32(m_info.clock_drift_rate);
  writer.write8(static_cast<uint8_t>(m_info.clock_type << 6));

  prepend_header(writer, box_start);

  return Error::Ok;
}

Error Box_taic::parse(BitstreamRange& range, const heif_security_limits*) {
  parse_full_box_header(range);

  m_info.time_uncertainty = range.read64();
  m_info.clock_resolution = range.read32();

  m_info.clock_drift_rate = range.read32s();
  m_info.clock_type = range.read8() >> 6;
  return range.get_error();
}


bool operator==(const heif_tai_clock_info& a,
                const heif_tai_clock_info& b)
{
  return a.version == b.version &&
         a.time_uncertainty == b.time_uncertainty &&
         a.clock_resolution == b.clock_resolution &&
         a.clock_drift_rate == b.clock_drift_rate &&
         a.clock_type == b.clock_type;
}

bool Box_taic::operator==(const Box& other) const
{
  const auto* other_taic = dynamic_cast<const Box_taic*>(&other);
  if (other_taic == nullptr) {
    return false;
  }

  return m_info == other_taic->m_info;
}


std::string Box_itai::dump(Indent& indent) const {
  std::ostringstream sstr;
  sstr << Box::dump(indent);
  sstr << indent << "tai_timestamp: " << m_timestamp.tai_timestamp << "\n";
  sstr << indent << "synchronization_state: " << int(m_timestamp.synchronization_state) << "\n";
  sstr << indent << "timestamp_generation_failure: " << int(m_timestamp.timestamp_generation_failure) << "\n";
  sstr << indent << "timestamp_is_modified: " << int(m_timestamp.timestamp_is_modified) << "\n";
  return sstr.str();
}


std::vector<uint8_t> Box_itai::encode_tai_to_bitstream(const heif_tai_timestamp_packet* tai)
{
  StreamWriter writer;
  writer.write64(tai->tai_timestamp);

  uint8_t status_bits = 0;
  status_bits |= tai->synchronization_state ? (1 << 7) : 0;
  status_bits |= tai->timestamp_generation_failure ? (1 << 6) : 0;
  status_bits |= tai->timestamp_is_modified ? (1 << 5) : 0;

  writer.write8(status_bits);

  return writer.get_data();
}

bool operator==(const heif_tai_timestamp_packet& a,
                const heif_tai_timestamp_packet& b)
{
  return a.version == b.version &&
         a.tai_timestamp == b.tai_timestamp &&
         a.synchronization_state == b.synchronization_state &&
         a.timestamp_generation_failure == b.timestamp_generation_failure &&
         a.timestamp_is_modified == b.timestamp_is_modified;
}

bool Box_itai::operator==(const Box& other) const
{
  const auto* other_itai = dynamic_cast<const Box_itai*>(&other);
  if (other_itai == nullptr) {
    return false;
  }

  return m_timestamp == other_itai->m_timestamp;
}



uint64_t uint8_vector_to_uint64_BE(const uint8_t* data)
{
  uint64_t value = ((static_cast<uint64_t>(data[0]) << 56) |
                    (static_cast<uint64_t>(data[1]) << 48) |
                    (static_cast<uint64_t>(data[2]) << 40) |
                    (static_cast<uint64_t>(data[3]) << 32) |
                    (static_cast<uint64_t>(data[4]) << 24) |
                    (static_cast<uint64_t>(data[5]) << 16) |
                    (static_cast<uint64_t>(data[6]) << 8) |
                    (static_cast<uint64_t>(data[7]) << 0));

  return value;
}


Result<heif_tai_timestamp_packet> Box_itai::decode_tai_from_vector(const std::vector<uint8_t>& data)
{
  if (data.size() != 9) {
    return Error{heif_error_Invalid_input,
                 heif_suberror_Unspecified,
                 "Wrong size of TAI timestamp data"};
  }

  uint8_t status_bits = data[8];

  heif_tai_timestamp_packet tai;
  tai.version = 1;
  tai.tai_timestamp = uint8_vector_to_uint64_BE(data.data());
  tai.synchronization_state = !!(status_bits & 0x80);
  tai.timestamp_generation_failure = !!(status_bits & 0x40);
  tai.timestamp_is_modified = !!(status_bits & 0x20);

  return tai;
}


Error Box_itai::write(StreamWriter& writer) const {
  size_t box_start = reserve_box_header_space(writer);

  std::vector<uint8_t> tai_data = encode_tai_to_bitstream(&m_timestamp);

  writer.write(tai_data);

  prepend_header(writer, box_start);
  return Error::Ok;
}

Error Box_itai::parse(BitstreamRange& range, const heif_security_limits*) {
  parse_full_box_header(range);

  m_timestamp.version = 1;
  m_timestamp.tai_timestamp = range.read64();

  uint8_t status_bits = range.read8();

  m_timestamp.synchronization_state = !!(status_bits & 0x80);
  m_timestamp.timestamp_generation_failure = !!(status_bits & 0x40);
  m_timestamp.timestamp_is_modified = !!(status_bits & 0x20);

  return range.get_error();
}

Error Box_elng::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  parse_full_box_header(range);

  if (get_version() > 0) {
    return unsupported_version_error("elng");
  }

  m_lang = range.read_string();
  return range.get_error();
}

std::string Box_elng::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);
  sstr << indent << "extended_language: " << m_lang << "\n";
  return sstr.str();
}

Error Box_elng::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);
  writer.write(m_lang);
  prepend_header(writer, box_start);
  return Error::Ok;
}


Error Box_gimi_content_id::parse(BitstreamRange& range, const heif_security_limits* limits)
{
  m_content_id = range.read_string_until_eof();

  return range.get_error();
}


Error Box_gimi_content_id::write(StreamWriter& writer) const
{
  size_t box_start = reserve_box_header_space(writer);

  writer.write(m_content_id, false);

  prepend_header(writer, box_start);

  return Error::Ok;
}


std::string Box_gimi_content_id::dump(Indent& indent) const
{
  std::ostringstream sstr;
  sstr << Box::dump(indent);

  sstr << indent << "content ID: " << m_content_id << "\n";

  return sstr.str();
}

Coverage Report

Created: 2026-07-20 07:19