// Copyright (c) the JPEG XL Project Authors. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

#include <brotli/encode.h>
#include <jxl/cms.h>
#include <jxl/codestream_header.h>
#include <jxl/encode.h>
#include <jxl/memory_manager.h>
#include <jxl/types.h>
#include <jxl/version.h>

#include <algorithm>
#include <atomic>
#include <cstddef>
#include <cstdint>
#include <cstring>
#include <utility>

#include "lib/jxl/base/byte_order.h"
#include "lib/jxl/base/common.h"
#include "lib/jxl/base/compiler_specific.h"
#include "lib/jxl/base/data_parallel.h"
#include "lib/jxl/base/exif.h"
#include "lib/jxl/base/printf_macros.h"
#include "lib/jxl/base/sanitizers.h"
#include "lib/jxl/base/span.h"
#include "lib/jxl/base/status.h"
#include "lib/jxl/codec_in_out.h"
#include "lib/jxl/enc_aux_out.h"
#include "lib/jxl/enc_bit_writer.h"
#include "lib/jxl/enc_cache.h"
#include "lib/jxl/enc_fast_lossless.h"
#include "lib/jxl/enc_fields.h"
#include "lib/jxl/enc_frame.h"
#include "lib/jxl/enc_icc_codec.h"
#include "lib/jxl/enc_params.h"
#include "lib/jxl/encode_internal.h"
#include "lib/jxl/jpeg/enc_jpeg_data.h"
#include "lib/jxl/luminance.h"
#include "lib/jxl/memory_manager_internal.h"
#include "lib/jxl/padded_bytes.h"

struct JxlErrorOrStatus {
  // NOLINTNEXTLINE(google-explicit-constructor)
  operator jxl::Status() const {
    switch (error_) {
      case JXL_ENC_SUCCESS:
        return jxl::OkStatus();
      case JXL_ENC_NEED_MORE_OUTPUT:
        return jxl::StatusCode::kNotEnoughBytes;
      default:
        return jxl::StatusCode::kGenericError;
    }
  }
  // NOLINTNEXTLINE(google-explicit-constructor)
  operator JxlEncoderStatus() const { return error_; }

  static JxlErrorOrStatus Success() {
    return JxlErrorOrStatus(JXL_ENC_SUCCESS);
  }

  static JxlErrorOrStatus MoreOutput() {
    return JxlErrorOrStatus(JXL_ENC_NEED_MORE_OUTPUT);
  }

  static JxlErrorOrStatus Error() { return JxlErrorOrStatus(JXL_ENC_ERROR); }

 private:
  explicit JxlErrorOrStatus(JxlEncoderStatus error) : error_(error) {}
  JxlEncoderStatus error_;
};

// Debug-printing failure macro similar to JXL_FAILURE, but for the status code
// JXL_ENC_ERROR
#if (JXL_CRASH_ON_ERROR)
#define JXL_API_ERROR(enc, error_code, format, ...)                          \
  (enc->error = error_code,                                                  \
   ::jxl::Debug(("%s:%d: " format "\n"), __FILE__, __LINE__, ##__VA_ARGS__), \
   ::jxl::Abort(), JxlErrorOrStatus::Error())
#define JXL_API_ERROR_NOSET(format, ...)                                     \
  (::jxl::Debug(("%s:%d: " format "\n"), __FILE__, __LINE__, ##__VA_ARGS__), \
   ::jxl::Abort(), JxlErrorOrStatus::Error())
#else  // JXL_CRASH_ON_ERROR
#define JXL_API_ERROR(enc, error_code, format, ...)                            \
  (enc->error = error_code,                                                    \
   ((JXL_IS_DEBUG_BUILD) &&                                                    \
    ::jxl::Debug(("%s:%d: " format "\n"), __FILE__, __LINE__, ##__VA_ARGS__)), \
   JxlErrorOrStatus::Error())
#define JXL_API_ERROR_NOSET(format, ...)                                     \
  (::jxl::Debug(("%s:%d: " format "\n"), __FILE__, __LINE__, ##__VA_ARGS__), \
   JxlErrorOrStatus::Error())
#endif  // JXL_CRASH_ON_ERROR

jxl::StatusOr<JxlOutputProcessorBuffer>
JxlEncoderOutputProcessorWrapper::GetBuffer(size_t min_size,
                                            size_t requested_size) {
  JXL_ENSURE(min_size > 0);
  JXL_ENSURE(!has_buffer_);
  if (stop_requested_) return jxl::StatusCode::kNotEnoughBytes;
  requested_size = std::max(min_size, requested_size);

  // If we support seeking, output_position_ == position_.
  if (external_output_processor_ && external_output_processor_->seek) {
    JXL_ENSURE(output_position_ == position_);
  }
  // Otherwise, output_position_ <= position_.
  JXL_ENSURE(output_position_ <= position_);
  size_t additional_size = position_ - output_position_;
  JXL_ENSURE(memory_manager_ != nullptr);

  if (external_output_processor_) {
    // TODO(veluca): here, we cannot just ask for a larger buffer, as it will be
    // released with a prefix of the buffer that has not been written yet.
    // Figure out if there is a good way to do this more efficiently.
    if (additional_size == 0) {
      size_t size = requested_size;
      uint8_t* user_buffer =
          static_cast<uint8_t*>(external_output_processor_->get_buffer(
              external_output_processor_->opaque, &size));
      if (size == 0 || user_buffer == nullptr) {
        stop_requested_ = true;
        return jxl::StatusCode::kNotEnoughBytes;
      }
      if (size < min_size) {
        external_output_processor_->release_buffer(
            external_output_processor_->opaque, 0);
      } else {
        internal_buffers_.emplace(position_, InternalBuffer(memory_manager_));
        has_buffer_ = true;
        return JxlOutputProcessorBuffer(user_buffer, size, 0, this);
      }
    }
  } else {
    if (min_size + additional_size < *avail_out_) {
      internal_buffers_.emplace(position_, InternalBuffer(memory_manager_));
      has_buffer_ = true;
      return JxlOutputProcessorBuffer(*next_out_ + additional_size,
                                      *avail_out_ - additional_size, 0, this);
    }
  }

  // Otherwise, we need to allocate our own buffer.
  auto it =
      internal_buffers_.emplace(position_, InternalBuffer(memory_manager_))
          .first;
  InternalBuffer& buffer = it->second;
  size_t alloc_size = requested_size;
  it++;
  if (it != internal_buffers_.end()) {
    alloc_size = std::min(alloc_size, it->first - position_);
    JXL_ENSURE(alloc_size >= min_size);
  }
  JXL_RETURN_IF_ERROR(buffer.owned_data.resize(alloc_size));
  has_buffer_ = true;
  return JxlOutputProcessorBuffer(buffer.owned_data.data(), alloc_size, 0,
                                  this);
}

jxl::Status JxlEncoderOutputProcessorWrapper::Seek(size_t pos) {
  JXL_ENSURE(!has_buffer_);
  if (external_output_processor_ && external_output_processor_->seek) {
    external_output_processor_->seek(external_output_processor_->opaque, pos);
    output_position_ = pos;
  }
  JXL_ENSURE(pos >= finalized_position_);
  position_ = pos;
  return true;
}

jxl::Status JxlEncoderOutputProcessorWrapper::SetFinalizedPosition() {
  JXL_ENSURE(!has_buffer_);
  if (external_output_processor_ && external_output_processor_->seek) {
    external_output_processor_->set_finalized_position(
        external_output_processor_->opaque, position_);
  }
  finalized_position_ = position_;
  JXL_RETURN_IF_ERROR(FlushOutput());
  return true;
}

jxl::Status JxlEncoderOutputProcessorWrapper::SetAvailOut(uint8_t** next_out,
                                                          size_t* avail_out) {
  JXL_ENSURE(!external_output_processor_);
  avail_out_ = avail_out;
  next_out_ = next_out;
  JXL_RETURN_IF_ERROR(FlushOutput());
  return true;
}

jxl::Status JxlEncoderOutputProcessorWrapper::CopyOutput(
    std::vector<uint8_t>& output, uint8_t* next_out, size_t& avail_out) {
  while (HasOutputToWrite()) {
    JXL_RETURN_IF_ERROR(SetAvailOut(&next_out, &avail_out));
    if (avail_out == 0) {
      size_t offset = next_out - output.data();
      output.resize(output.size() * 2);
      next_out = output.data() + offset;
      avail_out = output.size() - offset;
    }
  }
  output.resize(output.size() - avail_out);
  return true;
}

jxl::Status JxlEncoderOutputProcessorWrapper::ReleaseBuffer(size_t bytes_used) {
  JXL_ENSURE(has_buffer_);
  has_buffer_ = false;
  auto it = internal_buffers_.find(position_);
  JXL_ENSURE(it != internal_buffers_.end());
  if (bytes_used == 0) {
    if (external_output_processor_) {
      external_output_processor_->release_buffer(
          external_output_processor_->opaque, bytes_used);
    }
    internal_buffers_.erase(it);
    return true;
  }
  it->second.written_bytes = bytes_used;
  position_ += bytes_used;

  auto it_to_next = it;
  it_to_next++;
  if (it_to_next != internal_buffers_.end()) {
    JXL_ENSURE(it_to_next->first >= position_);
  }

  if (external_output_processor_) {
    // If the buffer was given by the user, tell the user it is not needed
    // anymore.
    if (it->second.owned_data.empty()) {
      external_output_processor_->release_buffer(
          external_output_processor_->opaque, bytes_used);
      // If we don't support seeking, this implies we will never modify again
      // the bytes that were written so far. Advance the finalized position and
      // flush the output to clean up the internal buffers.
      if (!external_output_processor_->seek) {
        JXL_RETURN_IF_ERROR(SetFinalizedPosition());
        JXL_ENSURE(output_position_ == finalized_position_);
        JXL_ENSURE(output_position_ == position_);
      } else {
        // Otherwise, advance the output position accordingly.
        output_position_ += bytes_used;
        JXL_ENSURE(output_position_ >= finalized_position_);
        JXL_ENSURE(output_position_ == position_);
      }
    } else if (external_output_processor_->seek) {
      // If we had buffered the data internally, flush it out to the external
      // processor if we can.
      external_output_processor_->seek(external_output_processor_->opaque,
                                       position_ - bytes_used);
      output_position_ = position_ - bytes_used;
      while (output_position_ < position_) {
        size_t num_to_write = position_ - output_position_;
        if (!AppendBufferToExternalProcessor(it->second.owned_data.data() +
                                                 output_position_ - position_ +
                                                 bytes_used,
                                             num_to_write)) {
          return true;
        }
      }
      it->second.owned_data.clear();
    }
  }
  return true;
}

// Tries to write all the bytes up to the finalized position.
jxl::Status JxlEncoderOutputProcessorWrapper::FlushOutput() {
  JXL_ENSURE(!has_buffer_);
  while (output_position_ < finalized_position_ &&
         (avail_out_ == nullptr || *avail_out_ > 0)) {
    JXL_ENSURE(!internal_buffers_.empty());
    auto it = internal_buffers_.begin();
    // If this fails, we are trying to move the finalized position past data
    // that was not written yet. This is a library programming error.
    JXL_ENSURE(output_position_ >= it->first);
    JXL_ENSURE(it->second.written_bytes != 0);
    size_t buffer_last_byte = it->first + it->second.written_bytes;
    if (!it->second.owned_data.empty()) {
      size_t start_in_buffer = output_position_ - it->first;
      // Guaranteed by the invariant on `internal_buffers_`.
      JXL_ENSURE(buffer_last_byte > output_position_);
      size_t num_to_write =
          std::min(buffer_last_byte, finalized_position_) - output_position_;
      if (avail_out_ != nullptr) {
        size_t n = std::min(num_to_write, *avail_out_);
        memcpy(*next_out_, it->second.owned_data.data() + start_in_buffer, n);
        *avail_out_ -= n;
        *next_out_ += n;
        output_position_ += n;
      } else {
        JXL_ENSURE(external_output_processor_);
        if (!AppendBufferToExternalProcessor(
                it->second.owned_data.data() + start_in_buffer, num_to_write)) {
          return true;
        }
      }
    } else {
      size_t advance =
          std::min(buffer_last_byte, finalized_position_) - output_position_;
      output_position_ += advance;
      if (avail_out_ != nullptr) {
        *next_out_ += advance;
        *avail_out_ -= advance;
      }
    }
    if (buffer_last_byte == output_position_) {
      internal_buffers_.erase(it);
    }
    if (external_output_processor_ && !external_output_processor_->seek) {
      external_output_processor_->set_finalized_position(
          external_output_processor_->opaque, output_position_);
    }
  }
  return true;
}

bool JxlEncoderOutputProcessorWrapper::AppendBufferToExternalProcessor(
    void* data, size_t count) {
  JXL_DASSERT(external_output_processor_);
  size_t n = count;
  void* user_buffer = external_output_processor_->get_buffer(
      external_output_processor_->opaque, &n);
  if (user_buffer == nullptr || n == 0) {
    stop_requested_ = true;
    return false;
  }
  n = std::min(n, count);
  memcpy(user_buffer, data, n);
  external_output_processor_->release_buffer(external_output_processor_->opaque,
                                             n);
  output_position_ += n;
  return true;
}

namespace jxl {

size_t WriteBoxHeader(const jxl::BoxType& type, size_t size, bool unbounded,
                      bool force_large_box, uint8_t* output) {
  uint64_t box_size = 0;
  bool large_size = false;
  if (!unbounded) {
    if (box_size >= kLargeBoxContentSizeThreshold || force_large_box) {
      large_size = true;
      // TODO(firsching): send a separate CL for this (+ test),
      // quick fix in the old code: box_size += 8
      box_size = size + kLargeBoxHeaderSize;
    } else {
      box_size = size + kSmallBoxHeaderSize;
    }
  }

  size_t idx = 0;
  {
    const uint64_t store = large_size ? 1 : box_size;
    for (size_t i = 0; i < 4; i++) {
      output[idx++] = store >> (8 * (3 - i)) & 0xff;
    }
  }
  for (size_t i = 0; i < 4; i++) {
    output[idx++] = type[i];
  }

  if (large_size) {
    for (size_t i = 0; i < 8; i++) {
      output[idx++] = box_size >> (8 * (7 - i)) & 0xff;
    }
  }
  return idx;
}
}  // namespace jxl

template <typename WriteBox>
jxl::Status JxlEncoderStruct::AppendBox(const jxl::BoxType& type,
                                        bool unbounded, size_t box_max_size,
                                        const WriteBox& write_box) {
  size_t current_position = output_processor.CurrentPosition();
  bool large_box = false;
  size_t box_header_size = 0;
  if (box_max_size >= jxl::kLargeBoxContentSizeThreshold && !unbounded) {
    box_header_size = jxl::kLargeBoxHeaderSize;
    large_box = true;
  } else {
    box_header_size = jxl::kSmallBoxHeaderSize;
  }
  JXL_RETURN_IF_ERROR(
      output_processor.Seek(current_position + box_header_size));
  size_t box_contents_start = output_processor.CurrentPosition();
  JXL_RETURN_IF_ERROR(write_box());
  size_t box_contents_end = output_processor.CurrentPosition();
  JXL_RETURN_IF_ERROR(output_processor.Seek(current_position));
  JXL_ENSURE(box_contents_end >= box_contents_start);
  if (box_contents_end - box_contents_start > box_max_size) {
    return JXL_API_ERROR(this, JXL_ENC_ERR_GENERIC,
                         "Internal error: upper bound on box size was "
                         "violated, upper bound: %" PRIuS ", actual: %" PRIuS,
                         box_max_size, box_contents_end - box_contents_start);
  }
  // We need to release the buffer before Seek.
  {
    JXL_ASSIGN_OR_RETURN(
        auto buffer,
        output_processor.GetBuffer(box_contents_start - current_position));
    const size_t n =
        jxl::WriteBoxHeader(type, box_contents_end - box_contents_start,
                            unbounded, large_box, buffer.data());
    JXL_ENSURE(n == box_header_size);
    JXL_RETURN_IF_ERROR(buffer.advance(n));
  }
  JXL_RETURN_IF_ERROR(output_processor.Seek(box_contents_end));
  JXL_RETURN_IF_ERROR(output_processor.SetFinalizedPosition());
  return jxl::OkStatus();
}

template <typename BoxContents>
jxl::Status JxlEncoderStruct::AppendBoxWithContents(
    const jxl::BoxType& type, const BoxContents& contents) {
  size_t size = std::end(contents) - std::begin(contents);
  return AppendBox(type, /*unbounded=*/false, size,
                   [&]() { return AppendData(output_processor, contents); });
}

uint32_t JxlEncoderVersion(void) {
  return JPEGXL_MAJOR_VERSION * 1000000 + JPEGXL_MINOR_VERSION * 1000 +
         JPEGXL_PATCH_VERSION;
}

namespace {

void WriteJxlpBoxCounter(uint32_t counter, bool last, uint8_t* buffer) {
  if (last) counter |= 0x80000000;
  for (size_t i = 0; i < 4; i++) {
    buffer[i] = counter >> (8 * (3 - i)) & 0xff;
  }
}

jxl::Status WriteJxlpBoxCounter(uint32_t counter, bool last,
                                JxlOutputProcessorBuffer& buffer) {
  uint8_t buf[4];
  WriteJxlpBoxCounter(counter, last, buf);
  JXL_RETURN_IF_ERROR(buffer.append(buf, 4));
  return true;
}

void QueueFrame(
    const JxlEncoderFrameSettings* frame_settings,
    jxl::MemoryManagerUniquePtr<jxl::JxlEncoderQueuedFrame>& frame) {
  if (frame_settings->values.lossless) {
    frame->option_values.cparams.SetLossless();
  }

  jxl::JxlEncoderQueuedInput queued_input(frame_settings->enc->memory_manager);
  queued_input.frame = std::move(frame);
  frame_settings->enc->input_queue.emplace_back(std::move(queued_input));
  frame_settings->enc->num_queued_frames++;
}

void QueueFastLosslessFrame(const JxlEncoderFrameSettings* frame_settings,
                            JxlFastLosslessFrameState* fast_lossless_frame) {
  jxl::JxlEncoderQueuedInput queued_input(frame_settings->enc->memory_manager);
  queued_input.fast_lossless_frame.reset(fast_lossless_frame);
  frame_settings->enc->input_queue.emplace_back(std::move(queued_input));
  frame_settings->enc->num_queued_frames++;
}

void QueueBox(JxlEncoder* enc,
              jxl::MemoryManagerUniquePtr<jxl::JxlEncoderQueuedBox>& box) {
  jxl::JxlEncoderQueuedInput queued_input(enc->memory_manager);
  queued_input.box = std::move(box);
  enc->input_queue.emplace_back(std::move(queued_input));
  enc->num_queued_boxes++;
}

// TODO(lode): share this code and the Brotli compression code in enc_jpeg_data
JxlEncoderStatus BrotliCompress(int quality, const uint8_t* in, size_t in_size,
                                jxl::PaddedBytes* out) {
  JxlMemoryManager* memory_manager = out->memory_manager();
  std::unique_ptr<BrotliEncoderState, decltype(BrotliEncoderDestroyInstance)*>
      enc(BrotliEncoderCreateInstance(nullptr, nullptr, nullptr),
          BrotliEncoderDestroyInstance);
  if (!enc) return JXL_API_ERROR_NOSET("BrotliEncoderCreateInstance failed");

  BrotliEncoderSetParameter(enc.get(), BROTLI_PARAM_QUALITY, quality);
  BrotliEncoderSetParameter(enc.get(), BROTLI_PARAM_SIZE_HINT, in_size);

  constexpr size_t kBufferSize = 128 * 1024;
#define QUIT(message) return JXL_API_ERROR_NOSET(message)
  JXL_ASSIGN_OR_QUIT(
      jxl::PaddedBytes temp_buffer,
      jxl::PaddedBytes::WithInitialSpace(memory_manager, kBufferSize),
      "Initialization of PaddedBytes failed");
#undef QUIT

  size_t avail_in = in_size;
  const uint8_t* next_in = in;

  size_t total_out = 0;

  for (;;) {
    size_t avail_out = kBufferSize;
    uint8_t* next_out = temp_buffer.data();
    jxl::msan::MemoryIsInitialized(next_in, avail_in);
    if (!BrotliEncoderCompressStream(enc.get(), BROTLI_OPERATION_FINISH,
                                     &avail_in, &next_in, &avail_out, &next_out,
                                     &total_out)) {
      return JXL_API_ERROR_NOSET("Brotli compression failed");
    }
    size_t out_size = next_out - temp_buffer.data();
    jxl::msan::UnpoisonMemory(next_out - out_size, out_size);
    if (!out->resize(out->size() + out_size)) {
      return JXL_API_ERROR_NOSET("resizing of PaddedBytes failed");
    }

    memcpy(out->data() + out->size() - out_size, temp_buffer.data(), out_size);
    if (BrotliEncoderIsFinished(enc.get())) break;
  }

  return JxlErrorOrStatus::Success();
}

// The JXL codestream can have level 5 or level 10. Levels have certain
// restrictions such as max allowed image dimensions. This function checks the
// level required to support the current encoder settings. The debug_string is
// intended to be used for developer API error messages, and may be set to
// nullptr.
int VerifyLevelSettings(const JxlEncoder* enc, std::string* debug_string) {
  const auto& m = enc->metadata.m;

  uint64_t xsize = enc->metadata.size.xsize();
  uint64_t ysize = enc->metadata.size.ysize();
  // The uncompressed ICC size, if it is used.
  size_t icc_size = 0;
  if (m.color_encoding.WantICC()) {
    icc_size = m.color_encoding.ICC().size();
  }

  // Level 10 checks

  if (xsize > (1ull << 30ull) || ysize > (1ull << 30ull) ||
      xsize * ysize > (1ull << 40ull)) {
    if (debug_string) *debug_string = "Too large image dimensions";
    return -1;
  }
  if (icc_size > (1ull << 28)) {
    if (debug_string) *debug_string = "Too large ICC profile size";
    return -1;
  }
  if (m.num_extra_channels > 256) {
    if (debug_string) *debug_string = "Too many extra channels";
    return -1;
  }

  // Level 5 checks

  if (!m.modular_16_bit_buffer_sufficient) {
    if (debug_string) *debug_string = "Too high modular bit depth";
    return 10;
  }
  if (xsize > (1ull << 18ull) || ysize > (1ull << 18ull) ||
      xsize * ysize > (1ull << 28ull)) {
    if (debug_string) *debug_string = "Too large image dimensions";
    return 10;
  }
  if (icc_size > (1ull << 22)) {
    if (debug_string) *debug_string = "Too large ICC profile";
    return 10;
  }
  if (m.num_extra_channels > 4) {
    if (debug_string) *debug_string = "Too many extra channels";
    return 10;
  }
  for (const auto& eci : m.extra_channel_info) {
    if (eci.type == jxl::ExtraChannel::kBlack) {
      if (debug_string) *debug_string = "CMYK channel not allowed";
      return 10;
    }
  }

  // TODO(lode): also need to check if consecutive composite-still frames total
  // pixel amount doesn't exceed 2**28 in the case of level 5. This should be
  // done when adding frame and requires ability to add composite still frames
  // to be added first.

  // TODO(lode): also need to check animation duration of a frame. This should
  // be done when adding frame, but first requires implementing setting the
  // JxlFrameHeader for a frame.

  // TODO(lode): also need to check properties such as num_splines, num_patches,
  // modular_16bit_buffers and multiple properties of modular trees. However
  // these are not user-set properties so cannot be checked here, but decisions
  // the C++ encoder should be able to make based on the level.

  // All level 5 checks passes, so can return the more compatible level 5
  return 5;
}

JxlEncoderStatus CheckValidBitdepth(uint32_t bits_per_sample,
                                    uint32_t exponent_bits_per_sample) {
  if (!exponent_bits_per_sample) {
    // The spec allows up to 31 for bits_per_sample here, but
    // the code does not (yet) support it.
    if (!(bits_per_sample > 0 && bits_per_sample <= 24)) {
      return JXL_API_ERROR_NOSET("Invalid value for bits_per_sample");
    }
  } else if ((exponent_bits_per_sample > 8) ||
             (bits_per_sample > 24 + exponent_bits_per_sample) ||
             (bits_per_sample < 3 + exponent_bits_per_sample)) {
    return JXL_API_ERROR_NOSET(
        "Invalid float description: bits per sample = %u, exp bits = %u",
        bits_per_sample, exponent_bits_per_sample);
  }
  return JxlErrorOrStatus::Success();
}

JxlEncoderStatus VerifyInputBitDepth(JxlBitDepth bit_depth,
                                     JxlPixelFormat format) {
  return JxlErrorOrStatus::Success();
}

inline bool EncodeVarInt(uint64_t value, size_t output_size, size_t* output_pos,
                         uint8_t* output) {
  // While more than 7 bits of data are left,
  // store 7 bits and set the next byte flag
  while (value > 127) {
    // TODO(eustas): should it be `>=` ?
    if (*output_pos > output_size) return false;
    // |128: Set the next byte flag
    output[(*output_pos)++] = (static_cast<uint8_t>(value & 127)) | 128;
    // Remove the seven bits we just wrote
    value >>= 7;
  }
  // TODO(eustas): should it be `>=` ?
  if (*output_pos > output_size) return false;
  output[(*output_pos)++] = static_cast<uint8_t>(value & 127);
  return true;
}

bool EncodeFrameIndexBox(const jxl::JxlEncoderFrameIndexBox& frame_index_box,
                         std::vector<uint8_t>& buffer_vec) {
  bool ok = true;
  int NF = 0;
  for (size_t i = 0; i < frame_index_box.entries.size(); ++i) {
    if (i == 0 || frame_index_box.entries[i].to_be_indexed) {
      ++NF;
    }
  }
  // Frame index box contents varint + 8 bytes
  // continue with NF * 3 * varint
  // varint max length is 10 for 64 bit numbers, and these numbers
  // are limited to 63 bits.
  static const int kVarintMaxLength = 10;
  static const int kFrameIndexBoxHeaderLength = kVarintMaxLength + 8;
  static const int kFrameIndexBoxElementLength = 3 * kVarintMaxLength;
  const int buffer_size =
      kFrameIndexBoxHeaderLength + NF * kFrameIndexBoxElementLength;
  buffer_vec.resize(buffer_size);
  uint8_t* buffer = buffer_vec.data();
  size_t output_pos = 0;
  ok &= EncodeVarInt(NF, buffer_vec.size(), &output_pos, buffer);
  StoreBE32(frame_index_box.TNUM, &buffer[output_pos]);
  output_pos += 4;
  StoreBE32(frame_index_box.TDEN, &buffer[output_pos]);
  output_pos += 4;
  // When we record a frame in the index, the record needs to know
  // how many frames until the next indexed frame. That is why
  // we store the 'prev' record. That 'prev' record needs to store
  // the offset byte position to previously recorded indexed frame,
  // that's why we also trace previous to the previous frame.
  int prev_prev_ix = -1;  // For position offset (OFFi) delta coding.
  int prev_ix = 0;
  int T_prev = 0;
  int T = 0;
  for (size_t i = 1; i < frame_index_box.entries.size(); ++i) {
    if (frame_index_box.entries[i].to_be_indexed) {
      // Now we can record the previous entry, since we need to store
      // there how many frames until the next one.
      int64_t OFFi = frame_index_box.entries[prev_ix].OFFi;
      if (prev_prev_ix != -1) {
        // Offi needs to be offset of start byte of this frame compared to start
        // byte of previous frame from this index in the JPEG XL codestream. For
        // the first frame, this is the offset from the first byte of the JPEG
        // XL codestream.
        OFFi -= frame_index_box.entries[prev_prev_ix].OFFi;
      }
      int32_t Ti = T_prev;
      int32_t Fi = i - prev_ix;
      ok &= EncodeVarInt(OFFi, buffer_vec.size(), &output_pos, buffer);
      ok &= EncodeVarInt(Ti, buffer_vec.size(), &output_pos, buffer);
      ok &= EncodeVarInt(Fi, buffer_vec.size(), &output_pos, buffer);
      prev_prev_ix = prev_ix;
      prev_ix = i;
      T_prev = T;
      T += frame_index_box.entries[i].duration;
    }
  }
  {
    // Last frame.
    size_t i = frame_index_box.entries.size();
    int64_t OFFi = frame_index_box.entries[prev_ix].OFFi;
    if (prev_prev_ix != -1) {
      OFFi -= frame_index_box.entries[prev_prev_ix].OFFi;
    }
    int32_t Ti = T_prev;
    int32_t Fi = i - prev_ix;
    ok &= EncodeVarInt(OFFi, buffer_vec.size(), &output_pos, buffer);
    ok &= EncodeVarInt(Ti, buffer_vec.size(), &output_pos, buffer);
    ok &= EncodeVarInt(Fi, buffer_vec.size(), &output_pos, buffer);
  }
  if (ok) buffer_vec.resize(output_pos);
  return ok;
}

struct RunnerTicket {
  explicit RunnerTicket(jxl::ThreadPool* pool) : pool(pool) {}
  jxl::ThreadPool* pool;
  std::atomic<bool> has_error{false};
};

void FastLosslessRunnerAdapter(void* void_ticket, void* opaque,
                               void fun(void*, size_t), size_t count) {
  auto* ticket = reinterpret_cast<RunnerTicket*>(void_ticket);
  if (!jxl::RunOnPool(
          ticket->pool, 0, count, jxl::ThreadPool::NoInit,
          [&](size_t i, size_t) -> jxl::Status {
            fun(opaque, i);
            return true;
          },
          "Encode fast lossless")) {
    ticket->has_error = true;
  }
}

}  // namespace

jxl::Status JxlEncoderStruct::ProcessOneEnqueuedInput() {
  jxl::PaddedBytes header_bytes{&memory_manager};

  jxl::JxlEncoderQueuedInput& input = input_queue[0];

  // TODO(lode): split this into 3 functions: for adding the signature and other
  // initial headers (jbrd, ...), one for adding frame, and one for adding user
  // box.

  if (!wrote_bytes) {
    // First time encoding any data, verify the level 5 vs level 10 settings
    std::string level_message;
    int required_level = VerifyLevelSettings(this, &level_message);
    // Only level 5 and 10 are defined, and the function can return -1 to
    // indicate full incompatibility.
    JXL_ENSURE(required_level == -1 || required_level == 5 ||
               required_level == 10);
    // codestream_level == -1 means auto-set to the required level
    if (codestream_level == -1) codestream_level = required_level;
    if (codestream_level == 5 && required_level != 5) {
      // If the required level is 10, return error rather than automatically
      // setting the level to 10, to avoid inadvertently creating a level 10
      // JXL file while intending to target a level 5 decoder.
      return JXL_API_ERROR(
          this, JXL_ENC_ERR_API_USAGE, "%s",
          ("Codestream level verification for level 5 failed: " + level_message)
              .c_str());
    }
    if (required_level == -1) {
      return JXL_API_ERROR(
          this, JXL_ENC_ERR_API_USAGE, "%s",
          ("Codestream level verification for level 10 failed: " +
           level_message)
              .c_str());
    }
    jxl::AuxOut* aux_out =
        input.frame ? input.frame->option_values.aux_out : nullptr;
    jxl::BitWriter writer{&memory_manager};
    if (!WriteCodestreamHeaders(&metadata, &writer, aux_out)) {
      return JXL_API_ERROR(this, JXL_ENC_ERR_GENERIC,
                           "Failed to write codestream header");
    }
    // Only send ICC (at least several hundred bytes) if fields aren't enough.
    if (metadata.m.color_encoding.WantICC()) {
      if (!jxl::WriteICC(
              jxl::Span<const uint8_t>(metadata.m.color_encoding.ICC()),
              &writer, jxl::LayerType::Header, aux_out)) {
        return JXL_API_ERROR(this, JXL_ENC_ERR_GENERIC,
                             "Failed to write ICC profile");
      }
    }
    // TODO(lode): preview should be added here if a preview image is added

    JXL_RETURN_IF_ERROR(
        writer.WithMaxBits(8, jxl::LayerType::Header, aux_out, [&] {
          writer.ZeroPadToByte();
          return true;
        }));

    header_bytes = std::move(writer).TakeBytes();

    // Not actually the end of frame, but the end of metadata/ICC, but helps
    // the next frame to start here for indexing purposes.
    codestream_bytes_written_end_of_frame += header_bytes.size();

    if (MustUseContainer()) {
      // Add "JXL " and ftyp box.
      {
        JXL_ASSIGN_OR_RETURN(auto buffer, output_processor.GetBuffer(
                                              jxl::kContainerHeader.size()));
        JXL_RETURN_IF_ERROR(buffer.append(jxl::kContainerHeader));
      }
      if (codestream_level != 5) {
        // Add jxll box directly after the ftyp box to indicate the codestream
        // level.
        JXL_ASSIGN_OR_RETURN(auto buffer, output_processor.GetBuffer(
                                              jxl::kLevelBoxHeader.size() + 1));
        JXL_RETURN_IF_ERROR(buffer.append(jxl::kLevelBoxHeader));
        uint8_t cl = codestream_level;
        JXL_RETURN_IF_ERROR(buffer.append(&cl, 1));
      }

      // Whether to write the basic info and color profile header of the
      // codestream into an early separate jxlp box, so that it comes before
      // metadata or jpeg reconstruction boxes. In theory this could simply
      // always be done, but there's no reason to add an extra box with box
      // header overhead if the codestream will already come immediately after
      // the signature and level boxes.
      bool partial_header =
          store_jpeg_metadata ||
          (use_boxes && (!input.frame && !input.fast_lossless_frame));

      if (partial_header) {
        auto write_box = [&]() -> jxl::Status {
          JXL_ASSIGN_OR_RETURN(
              auto buffer, output_processor.GetBuffer(header_bytes.size() + 4));
          JXL_RETURN_IF_ERROR(
              WriteJxlpBoxCounter(jxlp_counter++, /*last=*/false, buffer));
          JXL_RETURN_IF_ERROR(buffer.append(header_bytes));
          return jxl::OkStatus();
        };
        JXL_RETURN_IF_ERROR(AppendBox(jxl::MakeBoxType("jxlp"),
                                      /*unbounded=*/false,
                                      header_bytes.size() + 4, write_box));
        header_bytes.clear();
      }

      if (store_jpeg_metadata && !jpeg_metadata.empty()) {
        JXL_RETURN_IF_ERROR(
            AppendBoxWithContents(jxl::MakeBoxType("jbrd"), jpeg_metadata));
      }
    }
    wrote_bytes = true;
  }

  JXL_RETURN_IF_ERROR(output_processor.SetFinalizedPosition());

  // Choose frame or box processing: exactly one of the two unique pointers (box
  // or frame) in the input queue item is non-null.
  if (input.frame || input.fast_lossless_frame) {
    jxl::MemoryManagerUniquePtr<jxl::JxlEncoderQueuedFrame> input_frame =
        std::move(input.frame);
    jxl::FJXLFrameUniquePtr fast_lossless_frame =
        std::move(input.fast_lossless_frame);
    input_queue.erase(input_queue.begin());
    num_queued_frames--;
    if (input_frame) {
      for (unsigned idx = 0; idx < input_frame->ec_initialized.size(); idx++) {
        if (!input_frame->ec_initialized[idx]) {
          return JXL_API_ERROR(this, JXL_ENC_ERR_API_USAGE,
                               "Extra channel %u is not initialized", idx);
        }
      }

      // TODO(zond): If the input queue is empty and the frames_closed is true,
      // then mark this frame as the last.

      // TODO(zond): Handle progressive mode like EncodeFile does it.
      // TODO(zond): Handle animation like EncodeFile does it, by checking if
      //             JxlEncoderCloseFrames has been called and if the frame
      //             queue is empty (to see if it's the last animation frame).

      if (metadata.m.xyb_encoded) {
        input_frame->option_values.cparams.color_transform =
            jxl::ColorTransform::kXYB;
      } else {
        // TODO(zond): Figure out when to use kYCbCr instead.
        input_frame->option_values.cparams.color_transform =
            jxl::ColorTransform::kNone;
      }
    }

    uint32_t duration;
    uint32_t timecode;
    if (input_frame && metadata.m.have_animation) {
      duration = input_frame->option_values.header.duration;
      timecode = input_frame->option_values.header.timecode;
    } else {
      // If have_animation is false, the encoder should ignore the duration and
      // timecode values. However, assigning them to ib will cause the encoder
      // to write an invalid frame header that can't be decoded so ensure
      // they're the default value of 0 here.
      duration = 0;
      timecode = 0;
    }

    const bool last_frame = frames_closed && (num_queued_frames == 0);

    uint32_t max_bits_per_sample = metadata.m.bit_depth.bits_per_sample;
    for (const auto& info : metadata.m.extra_channel_info) {
      max_bits_per_sample =
          std::max(max_bits_per_sample, info.bit_depth.bits_per_sample);
    }
    // Heuristic upper bound on how many bits a single pixel in a single channel
    // can use.
    uint32_t bits_per_channels_estimate =
        std::max(24u, max_bits_per_sample + 3);
    size_t upper_bound_on_compressed_size_bits =
        metadata.xsize() * metadata.ysize() *
        (metadata.m.color_encoding.Channels() + metadata.m.num_extra_channels) *
        bits_per_channels_estimate;
    // Add a 1MB = 0x100000 for an heuristic upper bound on small sizes.
    size_t upper_bound_on_compressed_size_bytes =
        0x100000 + (upper_bound_on_compressed_size_bits >> 3);
    bool use_large_box = upper_bound_on_compressed_size_bytes >=
                         jxl::kLargeBoxContentSizeThreshold;
    size_t box_header_size =
        use_large_box ? jxl::kLargeBoxHeaderSize : jxl::kSmallBoxHeaderSize;

    const size_t frame_start_pos = output_processor.CurrentPosition();
    if (MustUseContainer()) {
      if (!last_frame || jxlp_counter > 0) {
        // If this is the last frame and no jxlp boxes were used yet, it's
        // slightly more efficient to write a jxlc box since it has 4 bytes
        // less overhead.
        box_header_size += 4;  // jxlp_counter field
      }
      JXL_RETURN_IF_ERROR(
          output_processor.Seek(frame_start_pos + box_header_size));
    }
    const size_t frame_codestream_start = output_processor.CurrentPosition();

    JXL_RETURN_IF_ERROR(AppendData(output_processor, header_bytes));

    if (input_frame) {
      frame_index_box.AddFrame(codestream_bytes_written_end_of_frame, duration,
                               input_frame->option_values.frame_index_box);

      size_t save_as_reference =
          input_frame->option_values.header.layer_info.save_as_reference;
      if (save_as_reference >= 3) {
        return JXL_API_ERROR(
            this, JXL_ENC_ERR_API_USAGE,
            "Cannot use save_as_reference values >=3 (found: %d)",
            static_cast<int>(save_as_reference));
      }

      jxl::FrameInfo frame_info;
      frame_info.is_last = last_frame;
      frame_info.save_as_reference = save_as_reference;
      frame_info.source =
          input_frame->option_values.header.layer_info.blend_info.source;
      frame_info.clamp = FROM_JXL_BOOL(
          input_frame->option_values.header.layer_info.blend_info.clamp);
      frame_info.alpha_channel =
          input_frame->option_values.header.layer_info.blend_info.alpha;
      frame_info.extra_channel_blending_info.resize(
          metadata.m.num_extra_channels);
      // If extra channel blend info has not been set, use the blend mode from
      // the layer_info.
      JxlBlendInfo default_blend_info =
          input_frame->option_values.header.layer_info.blend_info;
      for (size_t i = 0; i < metadata.m.num_extra_channels; ++i) {
        auto& to = frame_info.extra_channel_blending_info[i];
        const auto& from =
            i < input_frame->option_values.extra_channel_blend_info.size()
                ? input_frame->option_values.extra_channel_blend_info[i]
                : default_blend_info;
        to.mode = static_cast<jxl::BlendMode>(from.blendmode);
        to.source = from.source;
        to.alpha_channel = from.alpha;
        to.clamp = (from.clamp != 0);
      }
      frame_info.origin.x0 =
          input_frame->option_values.header.layer_info.crop_x0;
      frame_info.origin.y0 =
          input_frame->option_values.header.layer_info.crop_y0;
      frame_info.blendmode = static_cast<jxl::BlendMode>(
          input_frame->option_values.header.layer_info.blend_info.blendmode);
      frame_info.blend =
          input_frame->option_values.header.layer_info.blend_info.blendmode !=
          JXL_BLEND_REPLACE;
      frame_info.image_bit_depth = input_frame->option_values.image_bit_depth;
      frame_info.duration = duration;
      frame_info.timecode = timecode;
      frame_info.name = input_frame->option_values.frame_name;

      if (!jxl::EncodeFrame(&memory_manager, input_frame->option_values.cparams,
                            frame_info, &metadata, input_frame->frame_data, cms,
                            thread_pool.get(), &output_processor,
                            input_frame->option_values.aux_out)) {
        return JXL_API_ERROR(this, JXL_ENC_ERR_GENERIC,
                             "Failed to encode frame");
      }
    } else {
      JXL_ENSURE(fast_lossless_frame);
      RunnerTicket ticket{thread_pool.get()};
      bool ok = JxlFastLosslessProcessFrame(
          fast_lossless_frame.get(), last_frame, &ticket,
          &FastLosslessRunnerAdapter, &output_processor);
      if (!ok || ticket.has_error) {
        return JXL_API_ERROR(this, JXL_ENC_ERR_GENERIC,
                             "Internal: JxlFastLosslessProcessFrame failed");
      }
    }

    const size_t frame_codestream_end = output_processor.CurrentPosition();
    const size_t frame_codestream_size =
        frame_codestream_end - frame_codestream_start;

    codestream_bytes_written_end_of_frame +=
        frame_codestream_size - header_bytes.size();

    if (MustUseContainer()) {
      JXL_RETURN_IF_ERROR(output_processor.Seek(frame_start_pos));
      std::vector<uint8_t> box_header(box_header_size);
      if (!use_large_box &&
          frame_codestream_size >= jxl::kLargeBoxContentSizeThreshold) {
        // Assuming our upper bound estimate is correct, this should never
        // happen.
        return JXL_API_ERROR(
            this, JXL_ENC_ERR_GENERIC,
            "Box size was estimated to be small, but turned out to be large. "
            "Please file this error in size estimation as a bug.");
      }
      if (last_frame && jxlp_counter == 0) {
        size_t n = jxl::WriteBoxHeader(
            jxl::MakeBoxType("jxlc"), frame_codestream_size,
            /*unbounded=*/false, use_large_box, box_header.data());
        JXL_ENSURE(n == box_header_size);
      } else {
        size_t n = jxl::WriteBoxHeader(
            jxl::MakeBoxType("jxlp"), frame_codestream_size + 4,
            /*unbounded=*/false, use_large_box, box_header.data());
        JXL_ENSURE(n == box_header_size - 4);
        WriteJxlpBoxCounter(jxlp_counter++, last_frame,
                            &box_header[box_header_size - 4]);
      }
      JXL_RETURN_IF_ERROR(AppendData(output_processor, box_header));
      JXL_ENSURE(output_processor.CurrentPosition() == frame_codestream_start);
      JXL_RETURN_IF_ERROR(output_processor.Seek(frame_codestream_end));
    }
    JXL_RETURN_IF_ERROR(output_processor.SetFinalizedPosition());
    if (input_frame) {
      last_used_cparams = input_frame->option_values.cparams;
    }
    if (last_frame && frame_index_box.StoreFrameIndexBox()) {
      std::vector<uint8_t> index_box_content;
      // Enough buffer has been allocated, this function should never fail in
      // writing.
      JXL_ENSURE(EncodeFrameIndexBox(frame_index_box, index_box_content));
      JXL_RETURN_IF_ERROR(AppendBoxWithContents(jxl::MakeBoxType("jxli"),
                                                jxl::Bytes(index_box_content)));
    }
  } else {
    // Not a frame, so is a box instead
    jxl::MemoryManagerUniquePtr<jxl::JxlEncoderQueuedBox> box =
        std::move(input.box);
    input_queue.erase(input_queue.begin());
    num_queued_boxes--;

    if (box->compress_box) {
      jxl::PaddedBytes compressed(&memory_manager);
      // Prepend the original box type in the brob box contents
      JXL_RETURN_IF_ERROR(compressed.append(box->type));
      if (JXL_ENC_SUCCESS !=
          BrotliCompress((brotli_effort >= 0 ? brotli_effort : 4),
                         box->contents.data(), box->contents.size(),
                         &compressed)) {
        return JXL_API_ERROR(this, JXL_ENC_ERR_GENERIC,
                             "Brotli compression for brob box failed");
      }

      JXL_RETURN_IF_ERROR(
          AppendBoxWithContents(jxl::MakeBoxType("brob"), compressed));
    } else {
      JXL_RETURN_IF_ERROR(AppendBoxWithContents(box->type, box->contents));
    }
  }

  return jxl::OkStatus();
}

JxlEncoderStatus JxlEncoderSetColorEncoding(JxlEncoder* enc,
                                            const JxlColorEncoding* color) {
  if (!enc->basic_info_set) {
    return JXL_API_ERROR(enc, JXL_ENC_ERR_API_USAGE, "Basic info not yet set");
  }
  if (enc->color_encoding_set) {
    return JXL_API_ERROR(enc, JXL_ENC_ERR_API_USAGE,
                         "Color encoding is already set");
  }
  if (!enc->metadata.m.color_encoding.FromExternal(*color)) {
    return JXL_API_ERROR(enc, JXL_ENC_ERR_GENERIC, "Error in color conversion");
  }
  if (enc->metadata.m.color_encoding.GetColorSpace() ==
      jxl::ColorSpace::kGray) {
    if (enc->basic_info.num_color_channels != 1) {
      return JXL_API_ERROR(
          enc, JXL_ENC_ERR_API_USAGE,
          "Cannot use grayscale color encoding with num_color_channels != 1");
    }
  } else {
    if (enc->basic_info.num_color_channels != 3) {
      return JXL_API_ERROR(
          enc, JXL_ENC_ERR_API_USAGE,
          "Cannot use RGB color encoding with num_color_channels != 3");
    }
  }
  enc->color_encoding_set = true;
  if (!enc->intensity_target_set) {
    jxl::SetIntensityTarget(&enc->metadata.m);
  }
  return JxlErrorOrStatus::Success();
}

JxlEncoderStatus JxlEncoderSetICCProfile(JxlEncoder* enc,
                                         const uint8_t* icc_profile,
                                         size_t size) {
  if (!enc->basic_info_set) {
    return JXL_API_ERROR(enc, JXL_ENC_ERR_API_USAGE, "Basic info not yet set");
  }
  if (enc->color_encoding_set) {
    return JXL_API_ERROR(enc, JXL_ENC_ERR_API_USAGE,
                         "ICC profile is already set");
  }
  if (size == 0) {
    return JXL_API_ERROR(enc, JXL_ENC_ERR_BAD_INPUT, "Empty ICC profile");
  }
  jxl::IccBytes icc;
  icc.assign(icc_profile, icc_profile + size);
  if (enc->cms_set) {
    if (!enc->metadata.m.color_encoding.SetICC(std::move(icc), &enc->cms)) {
      return JXL_API_ERROR(enc, JXL_ENC_ERR_BAD_INPUT,
                           "ICC profile could not be set");
    }
  } else {
    enc->metadata.m.color_encoding.SetICCRaw(std::move(icc));
  }
  if (enc->metadata.m.color_encoding.GetColorSpace() ==
      jxl::ColorSpace::kGray) {
    if (enc->basic_info.num_color_channels != 1) {
      return JXL_API_ERROR(
          enc, JXL_ENC_ERR_BAD_INPUT,
          "Cannot use grayscale ICC profile with num_color_channels != 1");
    }
  } else {
    if (enc->basic_info.num_color_channels != 3) {
      return JXL_API_ERROR(
          enc, JXL_ENC_ERR_BAD_INPUT,
          "Cannot use RGB ICC profile with num_color_channels != 3");
    }
    // TODO(jon): also check that a kBlack extra channel is provided in the CMYK
    // case
  }
  enc->color_encoding_set = true;
  if (!enc->intensity_target_set) {
    jxl::SetIntensityTarget(&enc->metadata.m);
  }

  if (!enc->basic_info.uses_original_profile && enc->cms_set) {
    enc->metadata.m.color_encoding.DecideIfWantICC(enc->cms);
  }

  return JxlErrorOrStatus::Success();
}

void JxlEncoderInitBasicInfo(JxlBasicInfo* info) {
  info->have_container = JXL_FALSE;
  info->xsize = 0;
  info->ysize = 0;
  info->bits_per_sample = 8;
  info->exponent_bits_per_sample = 0;
  info->intensity_target = 0.f;
  info->min_nits = 0.f;
  info->relative_to_max_display = JXL_FALSE;
  info->linear_below = 0.f;
  info->uses_original_profile = JXL_FALSE;
  info->have_preview = JXL_FALSE;
  info->have_animation = JXL_FALSE;
  info->orientation = JXL_ORIENT_IDENTITY;
  info->num_color_channels = 3;
  info->num_extra_channels = 0;
  info->alpha_bits = 0;
  info->alpha_exponent_bits = 0;
  info->alpha_premultiplied = JXL_FALSE;
  info->preview.xsize = 0;
  info->preview.ysize = 0;
  info->intrinsic_xsize = 0;
  info->intrinsic_ysize = 0;
  info->animation.tps_numerator = 10;
  info->animation.tps_denominator = 1;
  info->animation.num_loops = 0;
  info->animation.have_timecodes = JXL_FALSE;
}

void JxlEncoderInitFrameHeader(JxlFrameHeader* frame_header) {
  // For each field, the default value of the specification is used. Depending
  // on whether an animation frame, or a composite still blending frame,
  // is used, different fields have to be set up by the user after initing
  // the frame header.
  frame_header->duration = 0;
  frame_header->timecode = 0;
  frame_header->name_length = 0;
  // In the specification, the default value of is_last is !frame_type, and the
  // default frame_type is kRegularFrame which has value 0, so is_last is true
  // by default. However, the encoder does not use this value (the field exists
  // for the decoder to set) since last frame is determined by usage of
  // JxlEncoderCloseFrames instead.
  frame_header->is_last = JXL_TRUE;
  frame_header->layer_info.have_crop = JXL_FALSE;
  frame_header->layer_info.crop_x0 = 0;
  frame_header->layer_info.crop_y0 = 0;
  // These must be set if have_crop is enabled, but the default value has
  // have_crop false, and these dimensions 0. The user must set these to the
  // desired size after enabling have_crop (which is not yet implemented).
  frame_header->layer_info.xsize = 0;
  frame_header->layer_info.ysize = 0;
  JxlEncoderInitBlendInfo(&frame_header->layer_info.blend_info);
  frame_header->layer_info.save_as_reference = 0;
}

void JxlEncoderInitBlendInfo(JxlBlendInfo* blend_info) {
  // Default blend mode in the specification is 0. Note that combining
  // blend mode of replace with a duration is not useful, but the user has to
  // manually set duration in case of animation, or manually change the blend
  // mode in case of composite stills, so initing to a combination that is not
  // useful on its own is not an issue.
  blend_info->blendmode = JXL_BLEND_REPLACE;
  blend_info->source = 0;
  blend_info->alpha = 0;
  blend_info->clamp = 0;
}

JxlEncoderStatus JxlEncoderSetBasicInfo(JxlEncoder* enc,
                                        const JxlBasicInfo* info) {
  if (!enc->metadata.size.Set(info->xsize, info->ysize)) {
    return JXL_API_ERROR(enc, JXL_ENC_ERR_API_USAGE, "Invalid dimensions");
  }
  if (JXL_ENC_SUCCESS != CheckValidBitdepth(info->bits_per_sample,
                                            info->exponent_bits_per_sample)) {
    return JXL_API_ERROR(enc, JXL_ENC_ERR_API_USAGE, "Invalid bit depth");
  }

  enc->metadata.m.bit_depth.bits_per_sample = info->bits_per_sample;
  enc->metadata.m.bit_depth.exponent_bits_per_sample =
      info->exponent_bits_per_sample;
  enc->metadata.m.bit_depth.floating_point_sample =
      (info->exponent_bits_per_sample != 0u);
  enc->metadata.m.modular_16_bit_buffer_sufficient =
      (!FROM_JXL_BOOL(info->uses_original_profile) ||
       info->bits_per_sample <= 12) &&
      info->alpha_bits <= 12;
  if ((info->intrinsic_xsize > 0 || info->intrinsic_ysize > 0) &&
      (info->intrinsic_xsize != info->xsize ||
       info->intrinsic_ysize != info->ysize)) {
    if (info->intrinsic_xsize > (1ull << 30ull) ||
        info->intrinsic_ysize > (1ull << 30ull) ||
        !enc->metadata.m.intrinsic_size.Set(info->intrinsic_xsize,
                                            info->intrinsic_ysize)) {
      return JXL_API_ERROR(enc, JXL_ENC_ERR_API_USAGE,
                           "Invalid intrinsic dimensions");
    }
    enc->metadata.m.have_intrinsic_size = true;
  }

  // The number of extra channels includes the alpha channel, so for example and
  // RGBA with no other extra channels, has exactly num_extra_channels == 1
  enc->metadata.m.num_extra_channels = info->num_extra_channels;
  enc->metadata.m.extra_channel_info.resize(enc->metadata.m.num_extra_channels);
  if (info->num_extra_channels == 0 && info->alpha_bits) {
    return JXL_API_ERROR(
        enc, JXL_ENC_ERR_API_USAGE,
        "when alpha_bits is non-zero, the number of channels must be at least "
        "1");
  }
  // If the user provides non-zero alpha_bits, we make the channel info at index
  // zero the appropriate alpha channel.
  if (info->alpha_bits) {
    JxlExtraChannelInfo channel_info;
    JxlEncoderInitExtraChannelInfo(JXL_CHANNEL_ALPHA, &channel_info);
    channel_info.bits_per_sample = info->alpha_bits;
    channel_info.exponent_bits_per_sample = info->alpha_exponent_bits;
    if (JxlEncoderSetExtraChannelInfo(enc, 0, &channel_info)) {
      return JXL_API_ERROR(enc, JXL_ENC_ERR_API_USAGE,
                           "Problem setting extra channel info for alpha");
    }
  }

  enc->metadata.m.xyb_encoded = !FROM_JXL_BOOL(info->uses_original_profile);
  if (info->orientation > 0 && info->orientation <= 8) {
    enc->metadata.m.orientation = info->orientation;
  } else {
    return JXL_API_ERROR(enc, JXL_ENC_ERR_API_USAGE,
                         "Invalid value for orientation field");
  }
  if (info->num_color_channels != 1 && info->num_color_channels != 3) {
    return JXL_API_ERROR(enc, JXL_ENC_ERR_API_USAGE,
                         "Invalid number of color channels");
  }
  if (info->intensity_target != 0) {
    enc->metadata.m.SetIntensityTarget(info->intensity_target);
    enc->intensity_target_set = true;
  } else if (enc->color_encoding_set) {
    // If this is false, JxlEncoderSetColorEncoding will be called later and we
    // will get one more chance to call jxl::SetIntensityTarget, after the color
    // encoding is indeed set.
    jxl::SetIntensityTarget(&enc->metadata.m);
    enc->intensity_target_set = true;
  }
  enc->metadata.m.tone_mapping.min_nits = info->min_nits;
  enc->metadata.m.tone_mapping.relative_to_max_display =
      FROM_JXL_BOOL(info->relative_to_max_display);
  enc->metadata.m.tone_mapping.linear_below = info->linear_below;
  enc->basic_info = *info;
  enc->basic_info_set = true;

  enc->metadata.m.have_animation = FROM_JXL_BOOL(info->have_animation);
  if (info->have_animation) {
    if (info->animation.tps_denominator < 1) {
      return JXL_API_ERROR(
          enc, JXL_ENC_ERR_API_USAGE,
          "If animation is used, tps_denominator must be >= 1");
    }
    if (info->animation.tps_numerator < 1) {
      return JXL_API_ERROR(enc, JXL_ENC_ERR_API_USAGE,
                           "If animation is used, tps_numerator must be >= 1");
    }
    enc->metadata.m.animation.tps_numerator = info->animation.tps_numerator;
    enc->metadata.m.animation.tps_denominator = info->animation.tps_denominator;
    enc->metadata.m.animation.num_loops = info->animation.num_loops;
    enc->metadata.m.animation.have_timecodes =
        FROM_JXL_BOOL(info->animation.have_timecodes);
  }
  std::string level_message;
  int required_level = VerifyLevelSettings(enc, &level_message);
  if (required_level == -1 ||
      (static_cast<int>(enc->codestream_level) < required_level &&
       enc->codestream_level != -1)) {
    return JXL_API_ERROR(
        enc, JXL_ENC_ERR_API_USAGE, "%s",
        ("Codestream level verification for level " +
         std::to_string(enc->codestream_level) + " failed: " + level_message)
            .c_str());
  }
  return JxlErrorOrStatus::Success();
}

void JxlEncoderInitExtraChannelInfo(JxlExtraChannelType type,
                                    JxlExtraChannelInfo* info) {
  info->type = type;
  info->bits_per_sample = 8;
  info->exponent_bits_per_sample = 0;
  info->dim_shift = 0;
  info->name_length = 0;
  info->alpha_premultiplied = JXL_FALSE;
  info->spot_color[0] = 0;
  info->spot_color[1] = 0;
  info->spot_color[2] = 0;
  info->spot_color[3] = 0;
  info->cfa_channel = 0;
}

JXL_EXPORT JxlEncoderStatus JxlEncoderSetUpsamplingMode(JxlEncoder* enc,
                                                        const int64_t factor,
                                                        const int64_t mode) {
  // for convenience, allow calling this with factor 1 and just make it a no-op
  if (factor == 1) return JxlErrorOrStatus::Success();
  if (factor != 2 && factor != 4 && factor != 8) {
    return JXL_API_ERROR(enc, JXL_ENC_ERR_API_USAGE,
                         "Invalid upsampling factor");
  }
  if (mode < -1)
    return JXL_API_ERROR(enc, JXL_ENC_ERR_API_USAGE, "Invalid upsampling mode");
  if (mode > 1) {
    return JXL_API_ERROR(enc, JXL_ENC_ERR_NOT_SUPPORTED,
                         "Unsupported upsampling mode");
  }

  const size_t count = (factor == 2 ? 15 : (factor == 4 ? 55 : 210));
  auto& td = enc->metadata.transform_data;
  float* weights = (factor == 2 ? td.upsampling2_weights
                                : (factor == 4 ? td.upsampling4_weights
                                               : td.upsampling8_weights));
  if (mode == -1) {
    // Default fancy upsampling: don't signal custom weights
    enc->metadata.transform_data.custom_weights_mask &= ~(factor >> 1);
  } else if (mode == 0) {
    // Nearest neighbor upsampling
    enc->metadata.transform_data.custom_weights_mask |= (factor >> 1);
    memset(weights, 0, sizeof(float) * count);
    if (factor == 2) {
      weights[9] = 1.f;
    } else if (factor == 4) {
      for (int i : {19, 24, 49}) weights[i] = 1.f;
    } else if (factor == 8) {
      for (int i : {39, 44, 49, 54, 119, 124, 129, 174, 179, 204}) {
        weights[i] = 1.f;
      }
    }
  } else if (mode == 1) {
    // 'Pixel dots' upsampling (nearest-neighbor with cut corners)
    JxlEncoderSetUpsamplingMode(enc, factor, 0);
    if (factor == 4) {
      weights[19] = 0.f;
      weights[24] = 0.5f;
    } else if (factor == 8) {
      for (int i : {39, 44, 49, 119}) weights[i] = 0.f;
      for (int i : {54, 124}) weights[i] = 0.5f;
    }
  }
  return JxlErrorOrStatus::Success();
}

JXL_EXPORT JxlEncoderStatus JxlEncoderSetExtraChannelInfo(
    JxlEncoder* enc, size_t index, const JxlExtraChannelInfo* info) {
  if (index >= enc->metadata.m.num_extra_channels) {
    return JXL_API_ERROR(enc, JXL_ENC_ERR_API_USAGE,
                         "Invalid value for the index of extra channel");
  }
  if (JXL_ENC_SUCCESS != CheckValidBitdepth(info->bits_per_sample,
                                            info->exponent_bits_per_sample)) {
    return JXL_API_ERROR(enc, JXL_ENC_ERR_API_USAGE, "Invalid bit depth");
  }

  jxl::ExtraChannelInfo& channel = enc->metadata.m.extra_channel_info[index];
  channel.type = static_cast<jxl::ExtraChannel>(info->type);
  channel.bit_depth.bits_per_sample = info->bits_per_sample;
  enc->metadata.m.modular_16_bit_buffer_sufficient &=
      info->bits_per_sample <= 12;
  channel.bit_depth.exponent_bits_per_sample = info->exponent_bits_per_sample;
  channel.bit_depth.floating_point_sample = info->exponent_bits_per_sample != 0;
  channel.dim_shift = info->dim_shift;
  channel.name = "";
  channel.alpha_associated = (info->alpha_premultiplied != 0);
  channel.cfa_channel = info->cfa_channel;
  channel.spot_color[0] = info->spot_color[0];
  channel.spot_color[1] = info->spot_color[1];
  channel.spot_color[2] = info->spot_color[2];
  channel.spot_color[3] = info->spot_color[3];
  std::string level_message;
  int required_level = VerifyLevelSettings(enc, &level_message);
  if (required_level == -1 ||
      (static_cast<int>(enc->codestream_level) < required_level &&
       enc->codestream_level != -1)) {
    return JXL_API_ERROR(
        enc, JXL_ENC_ERR_API_USAGE, "%s",
        ("Codestream level verification for level " +
         std::to_string(enc->codestream_level) + " failed: " + level_message)
            .c_str());
  }
  return JxlErrorOrStatus::Success();
}

JXL_EXPORT JxlEncoderStatus JxlEncoderSetExtraChannelName(JxlEncoder* enc,
                                                          size_t index,
                                                          const char* name,
                                                          size_t size) {
  if (index >= enc->metadata.m.num_extra_channels) {
    return JXL_API_ERROR(enc, JXL_ENC_ERR_API_USAGE,
                         "Invalid value for the index of extra channel");
  }
  enc->metadata.m.extra_channel_info[index].name =
      std::string(name, name + size);
  return JxlErrorOrStatus::Success();
}

JxlEncoderFrameSettings* JxlEncoderFrameSettingsCreate(
    JxlEncoder* enc, const JxlEncoderFrameSettings* source) {
  auto opts = jxl::MemoryManagerMakeUnique<JxlEncoderFrameSettings>(
      &enc->memory_manager);
  if (!opts) return nullptr;
  opts->enc = enc;
  if (source != nullptr) {
    opts->values = source->values;
  } else {
    opts->values.lossless = false;
  }
  opts->values.cparams.level = enc->codestream_level;
  opts->values.cparams.ec_distance.resize(enc->metadata.m.num_extra_channels,
                                          0);

  JxlEncoderFrameSettings* ret = opts.get();
  enc->encoder_options.emplace_back(std::move(opts));
  return ret;
}

JxlEncoderStatus JxlEncoderSetFrameLossless(
    JxlEncoderFrameSettings* frame_settings, const JXL_BOOL lossless) {
  if (lossless && frame_settings->enc->basic_info_set &&
      frame_settings->enc->metadata.m.xyb_encoded) {
    return JXL_API_ERROR(
        frame_settings->enc, JXL_ENC_ERR_API_USAGE,
        "Set uses_original_profile=true for lossless encoding");
  }
  frame_settings->values.lossless = FROM_JXL_BOOL(lossless);
  return JxlErrorOrStatus::Success();
}

JxlEncoderStatus JxlEncoderSetFrameDistance(
    JxlEncoderFrameSettings* frame_settings, float distance) {
  if (distance < 0.f || distance > 25.f) {
    return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                         "Distance has to be in [0.0..25.0] (corresponding to "
                         "quality in [0.0..100.0])");
  }
  if (distance > 0.f && distance < 0.01f) {
    distance = 0.01f;
  }
  frame_settings->values.cparams.butteraugli_distance = distance;
  return JxlErrorOrStatus::Success();
}

JxlEncoderStatus JxlEncoderSetExtraChannelDistance(
    JxlEncoderFrameSettings* frame_settings, size_t index, float distance) {
  if (index >= frame_settings->enc->metadata.m.num_extra_channels) {
    return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                         "Invalid value for the index of extra channel");
  }
  if (distance != -1.f && (distance < 0.f || distance > 25.f)) {
    return JXL_API_ERROR(
        frame_settings->enc, JXL_ENC_ERR_API_USAGE,
        "Distance has to be -1 or in [0.0..25.0] (corresponding to "
        "quality in [0.0..100.0])");
  }
  if (distance > 0.f && distance < 0.01f) {
    distance = 0.01f;
  }

  if (index >= frame_settings->values.cparams.ec_distance.size()) {
    // This can only happen if JxlEncoderFrameSettingsCreate() was called before
    // JxlEncoderSetBasicInfo().
    frame_settings->values.cparams.ec_distance.resize(
        frame_settings->enc->metadata.m.num_extra_channels, 0);
  }

  frame_settings->values.cparams.ec_distance[index] = distance;
  return JxlErrorOrStatus::Success();
}

float JxlEncoderDistanceFromQuality(float quality) {
  return quality >= 100.0 ? 0.0
         : quality >= 30
             ? 0.1 + (100 - quality) * 0.09
             : 53.0 / 3000.0 * quality * quality - 23.0 / 20.0 * quality + 25.0;
}

JxlEncoderStatus JxlEncoderFrameSettingsSetOption(
    JxlEncoderFrameSettings* frame_settings, JxlEncoderFrameSettingId option,
    int64_t value) {
  // Tri-state to bool convertors.
  const auto default_to_true = [](int64_t v) { return v != 0; };
  const auto default_to_false = [](int64_t v) { return v == 1; };

  // check if value is -1, 0 or 1 for Override-type options
  switch (option) {
    case JXL_ENC_FRAME_SETTING_NOISE:
    case JXL_ENC_FRAME_SETTING_DOTS:
    case JXL_ENC_FRAME_SETTING_PATCHES:
    case JXL_ENC_FRAME_SETTING_GABORISH:
    case JXL_ENC_FRAME_SETTING_MODULAR:
    case JXL_ENC_FRAME_SETTING_KEEP_INVISIBLE:
    case JXL_ENC_FRAME_SETTING_GROUP_ORDER:
    case JXL_ENC_FRAME_SETTING_RESPONSIVE:
    case JXL_ENC_FRAME_SETTING_PROGRESSIVE_AC:
    case JXL_ENC_FRAME_SETTING_QPROGRESSIVE_AC:
    case JXL_ENC_FRAME_SETTING_LOSSY_PALETTE:
    case JXL_ENC_FRAME_SETTING_JPEG_RECON_CFL:
    case JXL_ENC_FRAME_SETTING_JPEG_COMPRESS_BOXES:
    case JXL_ENC_FRAME_SETTING_JPEG_KEEP_EXIF:
    case JXL_ENC_FRAME_SETTING_JPEG_KEEP_XMP:
    case JXL_ENC_FRAME_SETTING_JPEG_KEEP_JUMBF:
      if (value < -1 || value > 1) {
        return JXL_API_ERROR(
            frame_settings->enc, JXL_ENC_ERR_API_USAGE,
            "Option value has to be -1 (default), 0 (off) or 1 (on)");
      }
      break;
    default:
      break;
  }

  switch (option) {
    case JXL_ENC_FRAME_SETTING_EFFORT:
      if (frame_settings->enc->allow_expert_options) {
        if (value < 1 || value > 11) {
          return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_NOT_SUPPORTED,
                               "Encode effort has to be in [1..11]");
        }
      } else {
        if (value < 1 || value > 10) {
          return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_NOT_SUPPORTED,
                               "Encode effort has to be in [1..10]");
        }
      }
      frame_settings->values.cparams.speed_tier =
          static_cast<jxl::SpeedTier>(10 - value);
      break;
    case JXL_ENC_FRAME_SETTING_BROTLI_EFFORT:
      if (value < -1 || value > 11) {
        return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                             "Brotli effort has to be in [-1..11]");
      }
      // set cparams for brotli use in JPEG frames
      frame_settings->values.cparams.brotli_effort = value;
      // set enc option for brotli use in brob boxes
      frame_settings->enc->brotli_effort = value;
      break;
    case JXL_ENC_FRAME_SETTING_DECODING_SPEED:
      if (value < 0 || value > 4) {
        return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_NOT_SUPPORTED,
                             "Decoding speed has to be in [0..4]");
      }
      frame_settings->values.cparams.decoding_speed_tier = value;
      break;
    case JXL_ENC_FRAME_SETTING_RESAMPLING:
      if (value != -1 && value != 1 && value != 2 && value != 4 && value != 8) {
        return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                             "Resampling factor has to be 1, 2, 4 or 8");
      }
      frame_settings->values.cparams.resampling = value;
      break;
    case JXL_ENC_FRAME_SETTING_EXTRA_CHANNEL_RESAMPLING:
      // TODO(lode): the jxl codestream allows choosing a different resampling
      // factor for each extra channel, independently per frame. Move this
      // option to a JxlEncoderFrameSettings-option that can be set per extra
      // channel, so needs its own function rather than
      // JxlEncoderFrameSettingsSetOption due to the extra channel index
      // argument required.
      if (value != -1 && value != 1 && value != 2 && value != 4 && value != 8) {
        return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                             "Resampling factor has to be 1, 2, 4 or 8");
      }
      frame_settings->values.cparams.ec_resampling = value;
      break;
    case JXL_ENC_FRAME_SETTING_ALREADY_DOWNSAMPLED:
      if (value < 0 || value > 1) {
        return JxlErrorOrStatus::Error();
      }
      frame_settings->values.cparams.already_downsampled = (value == 1);
      break;
    case JXL_ENC_FRAME_SETTING_NOISE:
      frame_settings->values.cparams.noise = static_cast<jxl::Override>(value);
      break;
    case JXL_ENC_FRAME_SETTING_DOTS:
      frame_settings->values.cparams.dots = static_cast<jxl::Override>(value);
      break;
    case JXL_ENC_FRAME_SETTING_PATCHES:
      frame_settings->values.cparams.patches =
          static_cast<jxl::Override>(value);
      break;
    case JXL_ENC_FRAME_SETTING_EPF:
      if (value < -1 || value > 3) {
        return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                             "EPF value has to be in [-1..3]");
      }
      frame_settings->values.cparams.epf = static_cast<int>(value);
      break;
    case JXL_ENC_FRAME_SETTING_GABORISH:
      frame_settings->values.cparams.gaborish =
          static_cast<jxl::Override>(value);
      break;
    case JXL_ENC_FRAME_SETTING_MODULAR:
      frame_settings->values.cparams.modular_mode = (value == 1);
      break;
    case JXL_ENC_FRAME_SETTING_KEEP_INVISIBLE:
      frame_settings->values.cparams.keep_invisible =
          static_cast<jxl::Override>(value);
      break;
    case JXL_ENC_FRAME_SETTING_GROUP_ORDER:
      frame_settings->values.cparams.centerfirst = (value == 1);
      break;
    case JXL_ENC_FRAME_SETTING_GROUP_ORDER_CENTER_X:
      if (value < -1) {
        return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                             "Center x coordinate has to be -1 or positive");
      }
      frame_settings->values.cparams.center_x = static_cast<size_t>(value);
      break;
    case JXL_ENC_FRAME_SETTING_GROUP_ORDER_CENTER_Y:
      if (value < -1) {
        return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                             "Center y coordinate has to be -1 or positive");
      }
      frame_settings->values.cparams.center_y = static_cast<size_t>(value);
      break;
    case JXL_ENC_FRAME_SETTING_RESPONSIVE:
      frame_settings->values.cparams.responsive = value;
      break;
    case JXL_ENC_FRAME_SETTING_PROGRESSIVE_AC:
      frame_settings->values.cparams.progressive_mode =
          static_cast<jxl::Override>(value);
      break;
    case JXL_ENC_FRAME_SETTING_QPROGRESSIVE_AC:
      frame_settings->values.cparams.qprogressive_mode =
          static_cast<jxl::Override>(value);
      break;
    case JXL_ENC_FRAME_SETTING_PROGRESSIVE_DC:
      if (value < -1 || value > 2) {
        return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                             "Progressive DC has to be in [-1..2]");
      }
      frame_settings->values.cparams.progressive_dc = value;
      break;
    case JXL_ENC_FRAME_SETTING_PALETTE_COLORS:
      if (value < -1 || value > 70913) {
        return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                             "Option value has to be in [-1..70913]");
      }
      if (value == -1) {
        frame_settings->values.cparams.palette_colors = 1 << 10;
      } else {
        frame_settings->values.cparams.palette_colors = value;
      }
      break;
    case JXL_ENC_FRAME_SETTING_LOSSY_PALETTE:
      // TODO(lode): the defaults of some palette settings depend on others.
      // See the logic in cjxl. Similar for other settings. This should be
      // handled in the encoder during JxlEncoderProcessOutput (or,
      // alternatively, in the cjxl binary like now)
      frame_settings->values.cparams.lossy_palette = default_to_false(value);
      break;
    case JXL_ENC_FRAME_SETTING_COLOR_TRANSFORM:
      if (value < -1 || value > 2) {
        return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                             "Option value has to be in [-1..2]");
      }
      if (value == -1) {
        frame_settings->values.cparams.color_transform =
            jxl::ColorTransform::kXYB;
      } else {
        frame_settings->values.cparams.color_transform =
            static_cast<jxl::ColorTransform>(value);
      }
      break;
    case JXL_ENC_FRAME_SETTING_MODULAR_COLOR_SPACE:
      if (value < -1 || value > 41) {
        return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                             "Option value has to be in [-1..41]");
      }
      frame_settings->values.cparams.colorspace = value;
      break;
    case JXL_ENC_FRAME_SETTING_MODULAR_GROUP_SIZE:
      if (value < -1 || value > 3) {
        return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                             "Option value has to be in [-1..3]");
      }
      frame_settings->values.cparams.modular_group_size_shift = value;
      break;
    case JXL_ENC_FRAME_SETTING_MODULAR_PREDICTOR:
      if (value < -1 || value > 15) {
        return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                             "Option value has to be in [-1..15]");
      }
      frame_settings->values.cparams.options.predictor =
          static_cast<jxl::Predictor>(value);
      break;
    case JXL_ENC_FRAME_SETTING_MODULAR_NB_PREV_CHANNELS:
      // The max allowed value can in theory be higher. However, it depends on
      // the effort setting. 11 is the highest safe value that doesn't cause
      // tree_samples to be >= 64 in the encoder. The specification may allow
      // more than this. With more fine tuning higher values could be allowed.
      // For N-channel images, the largest useful value is N-1.
      if (value < -1 || value > 11) {
        return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                             "Option value has to be in [-1..11]");
      }
      if (value == -1) {
        frame_settings->values.cparams.options.max_properties = 0;
      } else {
        frame_settings->values.cparams.options.max_properties = value;
      }
      break;
    case JXL_ENC_FRAME_SETTING_JPEG_RECON_CFL:
      frame_settings->values.cparams.force_cfl_jpeg_recompression =
          default_to_true(value);
      break;
    case JXL_ENC_FRAME_INDEX_BOX:
      if (value < 0 || value > 1) {
        return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_NOT_SUPPORTED,
                             "Option value has to be 0 or 1");
      }
      frame_settings->values.frame_index_box = true;
      break;
    case JXL_ENC_FRAME_SETTING_PHOTON_NOISE:
      return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_NOT_SUPPORTED,
                           "Float option, try setting it with "
                           "JxlEncoderFrameSettingsSetFloatOption");
    case JXL_ENC_FRAME_SETTING_JPEG_COMPRESS_BOXES:
      frame_settings->values.cparams.jpeg_compress_boxes =
          default_to_true(value);
      break;
    case JXL_ENC_FRAME_SETTING_BUFFERING:
      if (value < -1 || value > 3) {
        return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_NOT_SUPPORTED,
                             "Buffering has to be in [-1..3]");
      }
      frame_settings->values.cparams.buffering = value;
      break;
    case JXL_ENC_FRAME_SETTING_JPEG_KEEP_EXIF:
      frame_settings->values.cparams.jpeg_keep_exif = default_to_true(value);
      break;
    case JXL_ENC_FRAME_SETTING_JPEG_KEEP_XMP:
      frame_settings->values.cparams.jpeg_keep_xmp = default_to_true(value);
      break;
    case JXL_ENC_FRAME_SETTING_JPEG_KEEP_JUMBF:
      frame_settings->values.cparams.jpeg_keep_jumbf = default_to_true(value);
      break;
    case JXL_ENC_FRAME_SETTING_USE_FULL_IMAGE_HEURISTICS:
      if (value < 0 || value > 1) {
        return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_NOT_SUPPORTED,
                             "Option value has to be 0 or 1");
      }
      frame_settings->values.cparams.use_full_image_heuristics =
          default_to_false(value);
      break;
    case JXL_ENC_FRAME_SETTING_DISABLE_PERCEPTUAL_HEURISTICS:
      if (value < 0 || value > 1) {
        return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_NOT_SUPPORTED,
                             "Option value has to be 0 or 1");
      }
      frame_settings->values.cparams.disable_perceptual_optimizations =
          default_to_false(value);
      if (frame_settings->values.cparams.disable_perceptual_optimizations &&
          frame_settings->enc->basic_info_set &&
          frame_settings->enc->metadata.m.xyb_encoded) {
        return JXL_API_ERROR(
            frame_settings->enc, JXL_ENC_ERR_API_USAGE,
            "Set uses_original_profile=true for non-perceptual encoding");
      }
      break;

    default:
      return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_NOT_SUPPORTED,
                           "Unknown option");
  }
  return JxlErrorOrStatus::Success();
}

JxlEncoderStatus JxlEncoderFrameSettingsSetFloatOption(
    JxlEncoderFrameSettings* frame_settings, JxlEncoderFrameSettingId option,
    float value) {
  switch (option) {
    case JXL_ENC_FRAME_SETTING_PHOTON_NOISE:
      if (value < 0) return JXL_ENC_ERROR;
      // TODO(lode): add encoder setting to set the 8 floating point values of
      // the noise synthesis parameters per frame for more fine grained control.
      frame_settings->values.cparams.photon_noise_iso = value;
      return JxlErrorOrStatus::Success();
    case JXL_ENC_FRAME_SETTING_MODULAR_MA_TREE_LEARNING_PERCENT:
      if (value < -1.f || value > 100.f) {
        return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                             "Option value has to be smaller than 100");
      }
      // This value is called "iterations" or "nb_repeats" in cjxl, but is in
      // fact a fraction in range 0.0-1.0, with the default value 0.5.
      // Convert from floating point percentage to floating point fraction here.
      if (value < -.5f) {
        // TODO(lode): for this and many other settings (also in
        // JxlEncoderFrameSettingsSetOption), avoid duplicating the default
        // values here and in enc_params.h and options.h, have one location
        // where the defaults are specified.
        frame_settings->values.cparams.options.nb_repeats = 0.5f;
      } else {
        frame_settings->values.cparams.options.nb_repeats = value * 0.01f;
      }
      return JxlErrorOrStatus::Success();
    case JXL_ENC_FRAME_SETTING_CHANNEL_COLORS_GLOBAL_PERCENT:
      if (value < -1.f || value > 100.f) {
        return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                             "Option value has to be in [-1..100]");
      }
      if (value < -.5f) {
        frame_settings->values.cparams.channel_colors_pre_transform_percent =
            95.0f;
      } else {
        frame_settings->values.cparams.channel_colors_pre_transform_percent =
            value;
      }
      return JxlErrorOrStatus::Success();
    case JXL_ENC_FRAME_SETTING_CHANNEL_COLORS_GROUP_PERCENT:
      if (value < -1.f || value > 100.f) {
        return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                             "Option value has to be in [-1..100]");
      }
      if (value < -.5f) {
        frame_settings->values.cparams.channel_colors_percent = 80.0f;
      } else {
        frame_settings->values.cparams.channel_colors_percent = value;
      }
      return JxlErrorOrStatus::Success();
    case JXL_ENC_FRAME_SETTING_EFFORT:
    case JXL_ENC_FRAME_SETTING_DECODING_SPEED:
    case JXL_ENC_FRAME_SETTING_RESAMPLING:
    case JXL_ENC_FRAME_SETTING_EXTRA_CHANNEL_RESAMPLING:
    case JXL_ENC_FRAME_SETTING_ALREADY_DOWNSAMPLED:
    case JXL_ENC_FRAME_SETTING_NOISE:
    case JXL_ENC_FRAME_SETTING_DOTS:
    case JXL_ENC_FRAME_SETTING_PATCHES:
    case JXL_ENC_FRAME_SETTING_EPF:
    case JXL_ENC_FRAME_SETTING_GABORISH:
    case JXL_ENC_FRAME_SETTING_MODULAR:
    case JXL_ENC_FRAME_SETTING_KEEP_INVISIBLE:
    case JXL_ENC_FRAME_SETTING_GROUP_ORDER:
    case JXL_ENC_FRAME_SETTING_GROUP_ORDER_CENTER_X:
    case JXL_ENC_FRAME_SETTING_GROUP_ORDER_CENTER_Y:
    case JXL_ENC_FRAME_SETTING_RESPONSIVE:
    case JXL_ENC_FRAME_SETTING_PROGRESSIVE_AC:
    case JXL_ENC_FRAME_SETTING_QPROGRESSIVE_AC:
    case JXL_ENC_FRAME_SETTING_PROGRESSIVE_DC:
    case JXL_ENC_FRAME_SETTING_PALETTE_COLORS:
    case JXL_ENC_FRAME_SETTING_LOSSY_PALETTE:
    case JXL_ENC_FRAME_SETTING_COLOR_TRANSFORM:
    case JXL_ENC_FRAME_SETTING_MODULAR_COLOR_SPACE:
    case JXL_ENC_FRAME_SETTING_MODULAR_GROUP_SIZE:
    case JXL_ENC_FRAME_SETTING_MODULAR_PREDICTOR:
    case JXL_ENC_FRAME_SETTING_MODULAR_NB_PREV_CHANNELS:
    case JXL_ENC_FRAME_SETTING_JPEG_RECON_CFL:
    case JXL_ENC_FRAME_INDEX_BOX:
    case JXL_ENC_FRAME_SETTING_BROTLI_EFFORT:
    case JXL_ENC_FRAME_SETTING_FILL_ENUM:
    case JXL_ENC_FRAME_SETTING_JPEG_COMPRESS_BOXES:
    case JXL_ENC_FRAME_SETTING_BUFFERING:
    case JXL_ENC_FRAME_SETTING_JPEG_KEEP_EXIF:
    case JXL_ENC_FRAME_SETTING_JPEG_KEEP_XMP:
    case JXL_ENC_FRAME_SETTING_JPEG_KEEP_JUMBF:
    case JXL_ENC_FRAME_SETTING_USE_FULL_IMAGE_HEURISTICS:
      return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_NOT_SUPPORTED,
                           "Int option, try setting it with "
                           "JxlEncoderFrameSettingsSetOption");
    default:
      return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_NOT_SUPPORTED,
                           "Unknown option");
  }
}
JxlEncoder* JxlEncoderCreate(const JxlMemoryManager* memory_manager) {
  JxlMemoryManager local_memory_manager;
  if (!jxl::MemoryManagerInit(&local_memory_manager, memory_manager)) {
    return nullptr;
  }

  void* alloc =
      jxl::MemoryManagerAlloc(&local_memory_manager, sizeof(JxlEncoder));
  if (!alloc) return nullptr;
  JxlEncoder* enc = new (alloc) JxlEncoder();
  enc->memory_manager = local_memory_manager;
  // TODO(sboukortt): add an API function to set this.
  enc->cms = *JxlGetDefaultCms();
  enc->cms_set = true;

  // Initialize all the field values.
  JxlEncoderReset(enc);

  return enc;
}

void JxlEncoderReset(JxlEncoder* enc) {
  enc->thread_pool.reset();
  enc->input_queue.clear();
  enc->num_queued_frames = 0;
  enc->num_queued_boxes = 0;
  enc->encoder_options.clear();
  enc->codestream_bytes_written_end_of_frame = 0;
  enc->wrote_bytes = false;
  enc->jxlp_counter = 0;
  enc->metadata = jxl::CodecMetadata();
  enc->last_used_cparams = jxl::CompressParams();
  enc->frames_closed = false;
  enc->boxes_closed = false;
  enc->basic_info_set = false;
  enc->color_encoding_set = false;
  enc->intensity_target_set = false;
  enc->use_container = false;
  enc->use_boxes = false;
  enc->store_jpeg_metadata = false;
  enc->codestream_level = -1;
  enc->output_processor =
      JxlEncoderOutputProcessorWrapper(&enc->memory_manager);
  JxlEncoderInitBasicInfo(&enc->basic_info);

  // jxl::JxlEncoderFrameIndexBox frame_index_box;
  // JxlEncoderError error = JxlEncoderError::JXL_ENC_ERR_OK;
  // bool allow_expert_options = false;
  // int brotli_effort = -1;
}

void JxlEncoderDestroy(JxlEncoder* enc) {
  if (enc) {
    JxlMemoryManager local_memory_manager = enc->memory_manager;
    // Call destructor directly since custom free function is used.
    enc->~JxlEncoder();
    jxl::MemoryManagerFree(&local_memory_manager, enc);
  }
}

JxlEncoderError JxlEncoderGetError(JxlEncoder* enc) { return enc->error; }

JxlEncoderStatus JxlEncoderUseContainer(JxlEncoder* enc,
                                        JXL_BOOL use_container) {
  if (enc->wrote_bytes) {
    return JXL_API_ERROR(enc, JXL_ENC_ERR_API_USAGE,
                         "this setting can only be set at the beginning");
  }
  enc->use_container = FROM_JXL_BOOL(use_container);
  return JxlErrorOrStatus::Success();
}

JxlEncoderStatus JxlEncoderStoreJPEGMetadata(JxlEncoder* enc,
                                             JXL_BOOL store_jpeg_metadata) {
  if (enc->wrote_bytes) {
    return JXL_API_ERROR(enc, JXL_ENC_ERR_API_USAGE,
                         "this setting can only be set at the beginning");
  }
  enc->store_jpeg_metadata = FROM_JXL_BOOL(store_jpeg_metadata);
  return JxlErrorOrStatus::Success();
}

JxlEncoderStatus JxlEncoderSetCodestreamLevel(JxlEncoder* enc, int level) {
  if (level != -1 && level != 5 && level != 10) {
    return JXL_API_ERROR(enc, JXL_ENC_ERR_NOT_SUPPORTED, "invalid level");
  }
  if (enc->wrote_bytes) {
    return JXL_API_ERROR(enc, JXL_ENC_ERR_API_USAGE,
                         "this setting can only be set at the beginning");
  }
  enc->codestream_level = level;
  return JxlErrorOrStatus::Success();
}

int JxlEncoderGetRequiredCodestreamLevel(const JxlEncoder* enc) {
  return VerifyLevelSettings(enc, nullptr);
}

void JxlEncoderSetCms(JxlEncoder* enc, JxlCmsInterface cms) {
  jxl::msan::MemoryIsInitialized(&cms, sizeof(cms));
  enc->cms = cms;
  enc->cms_set = true;
}

JxlEncoderStatus JxlEncoderSetParallelRunner(JxlEncoder* enc,
                                             JxlParallelRunner parallel_runner,
                                             void* parallel_runner_opaque) {
  if (enc->thread_pool) {
    return JXL_API_ERROR(enc, JXL_ENC_ERR_API_USAGE,
                         "parallel runner already set");
  }
  enc->thread_pool = jxl::MemoryManagerMakeUnique<jxl::ThreadPool>(
      &enc->memory_manager, parallel_runner, parallel_runner_opaque);
  if (!enc->thread_pool) {
    return JXL_API_ERROR(enc, JXL_ENC_ERR_GENERIC,
                         "error setting parallel runner");
  }
  return JxlErrorOrStatus::Success();
}

namespace {
JxlEncoderStatus GetCurrentDimensions(
    const JxlEncoderFrameSettings* frame_settings, size_t& xsize,
    size_t& ysize) {
  xsize = frame_settings->enc->metadata.xsize();
  ysize = frame_settings->enc->metadata.ysize();
  if (frame_settings->values.header.layer_info.have_crop) {
    xsize = frame_settings->values.header.layer_info.xsize;
    ysize = frame_settings->values.header.layer_info.ysize;
  }
  if (frame_settings->values.cparams.already_downsampled) {
    size_t factor = frame_settings->values.cparams.resampling;
    xsize = jxl::DivCeil(xsize, factor);
    ysize = jxl::DivCeil(ysize, factor);
  }
  if (xsize == 0 || ysize == 0) {
    return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                         "zero-sized frame is not allowed");
  }
  return JxlErrorOrStatus::Success();
}
}  // namespace

JxlEncoderStatus JxlEncoderAddJPEGFrame(
    const JxlEncoderFrameSettings* frame_settings, const uint8_t* buffer,
    size_t size) {
  if (frame_settings->enc->frames_closed) {
    return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                         "Frame input is already closed");
  }

  jxl::CodecInOut io{&frame_settings->enc->memory_manager};
  if (!jxl::jpeg::DecodeImageJPG(jxl::Bytes(buffer, size), &io)) {
    return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_BAD_INPUT,
                         "Error during decode of input JPEG");
  }

  if (!frame_settings->enc->color_encoding_set) {
    if (!SetColorEncodingFromJpegData(
            *io.Main().jpeg_data,
            &frame_settings->enc->metadata.m.color_encoding)) {
      return JXL_API_ERROR(
          frame_settings->enc, JXL_ENC_ERR_BAD_INPUT,
          "Error decoding the ICC profile embedded in the input JPEG");
    }
    frame_settings->enc->color_encoding_set = true;
  }

  if (!frame_settings->enc->basic_info_set) {
    JxlBasicInfo basic_info;
    JxlEncoderInitBasicInfo(&basic_info);
    basic_info.xsize = io.Main().jpeg_data->width;
    basic_info.ysize = io.Main().jpeg_data->height;
    basic_info.uses_original_profile = JXL_TRUE;
    if (JxlEncoderSetBasicInfo(frame_settings->enc, &basic_info) !=
        JXL_ENC_SUCCESS) {
      return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_GENERIC,
                           "Error setting basic info");
    }
  }

  size_t xsize;
  size_t ysize;
  if (GetCurrentDimensions(frame_settings, xsize, ysize) != JXL_ENC_SUCCESS) {
    return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_GENERIC,
                         "bad dimensions");
  }
  if (xsize != static_cast<size_t>(io.Main().jpeg_data->width) ||
      ysize != static_cast<size_t>(io.Main().jpeg_data->height)) {
    return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_GENERIC,
                         "JPEG dimensions don't match frame dimensions");
  }

  if (frame_settings->enc->metadata.m.xyb_encoded) {
    return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                         "Can't XYB encode a lossless JPEG");
  }
  if (!io.blobs.exif.empty()) {
    JxlOrientation orientation = static_cast<JxlOrientation>(
        frame_settings->enc->metadata.m.orientation);
    jxl::InterpretExif(io.blobs.exif, &orientation);
    frame_settings->enc->metadata.m.orientation = orientation;
  }
  if (!io.blobs.exif.empty() && frame_settings->values.cparams.jpeg_keep_exif) {
    size_t exif_size = io.blobs.exif.size();
    // Exif data in JPEG is limited to 64k
    if (exif_size > 0xFFFF) {
      return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_GENERIC,
                           "Exif larger than possible in JPEG?");
    }
    exif_size += 4;  // prefix 4 zero bytes for tiff offset
    std::vector<uint8_t> exif(exif_size);
    memcpy(exif.data() + 4, io.blobs.exif.data(), io.blobs.exif.size());
    JxlEncoderUseBoxes(frame_settings->enc);
    JxlEncoderAddBox(
        frame_settings->enc, "Exif", exif.data(), exif_size,
        TO_JXL_BOOL(frame_settings->values.cparams.jpeg_compress_boxes));
  }
  if (!io.blobs.xmp.empty() && frame_settings->values.cparams.jpeg_keep_xmp) {
    JxlEncoderUseBoxes(frame_settings->enc);
    JxlEncoderAddBox(
        frame_settings->enc, "xml ", io.blobs.xmp.data(), io.blobs.xmp.size(),
        TO_JXL_BOOL(frame_settings->values.cparams.jpeg_compress_boxes));
  }
  if (!io.blobs.jumbf.empty() &&
      frame_settings->values.cparams.jpeg_keep_jumbf) {
    JxlEncoderUseBoxes(frame_settings->enc);
    JxlEncoderAddBox(
        frame_settings->enc, "jumb", io.blobs.jumbf.data(),
        io.blobs.jumbf.size(),
        TO_JXL_BOOL(frame_settings->values.cparams.jpeg_compress_boxes));
  }
  if (frame_settings->enc->store_jpeg_metadata) {
    if (!frame_settings->values.cparams.jpeg_keep_exif ||
        !frame_settings->values.cparams.jpeg_keep_xmp) {
      return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                           "Need to preserve EXIF and XMP to allow JPEG "
                           "bitstream reconstruction");
    }
    jxl::jpeg::JPEGData data_in = *io.Main().jpeg_data;
    std::vector<uint8_t> jpeg_data;
    if (!jxl::jpeg::EncodeJPEGData(&frame_settings->enc->memory_manager,
                                   data_in, &jpeg_data,
                                   frame_settings->values.cparams)) {
      return JXL_API_ERROR(
          frame_settings->enc, JXL_ENC_ERR_JBRD,
          "JPEG bitstream reconstruction data cannot be encoded");
    }
    frame_settings->enc->jpeg_metadata = jpeg_data;
  }

  jxl::JxlEncoderChunkedFrameAdapter frame_data(
      xsize, ysize, frame_settings->enc->metadata.m.num_extra_channels);
  frame_data.SetJPEGData(std::move(io.Main().jpeg_data));

  auto queued_frame = jxl::MemoryManagerMakeUnique<jxl::JxlEncoderQueuedFrame>(
      &frame_settings->enc->memory_manager,
      // JxlEncoderQueuedFrame is a struct with no constructors, so we use the
      // default move constructor there.
      jxl::JxlEncoderQueuedFrame{
          frame_settings->values, std::move(frame_data), {}});
  if (!queued_frame) {
    // TODO(jon): when can this happen? is this an API usage error?
    return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_GENERIC,
                         "No frame queued?");
  }
  queued_frame->ec_initialized.resize(
      frame_settings->enc->metadata.m.num_extra_channels);

  QueueFrame(frame_settings, queued_frame);
  return JxlErrorOrStatus::Success();
}

static bool CanDoFastLossless(const JxlEncoderFrameSettings* frame_settings,
                              const JxlPixelFormat* pixel_format,
                              bool has_alpha) {
  if (!frame_settings->values.lossless) {
    return false;
  }
  // TODO(veluca): many of the following options could be made to work, but are
  // just not implemented in FJXL's frame header handling yet.
  if (frame_settings->values.frame_index_box) {
    return false;
  }
  if (frame_settings->values.header.layer_info.have_crop) {
    return false;
  }
  if (frame_settings->enc->metadata.m.have_animation) {
    return false;
  }
  if (frame_settings->values.cparams.speed_tier != jxl::SpeedTier::kLightning) {
    return false;
  }
  if (frame_settings->values.image_bit_depth.type ==
          JxlBitDepthType::JXL_BIT_DEPTH_CUSTOM &&
      frame_settings->values.image_bit_depth.bits_per_sample !=
          frame_settings->enc->metadata.m.bit_depth.bits_per_sample) {
    return false;
  }
  // TODO(veluca): implement support for LSB-padded input in fast_lossless.
  if (frame_settings->values.image_bit_depth.type ==
          JxlBitDepthType::JXL_BIT_DEPTH_FROM_PIXEL_FORMAT &&
      frame_settings->enc->metadata.m.bit_depth.bits_per_sample % 8 != 0) {
    return false;
  }
  if (!frame_settings->values.frame_name.empty()) {
    return false;
  }
  // No extra channels other than alpha.
  if (!(has_alpha && frame_settings->enc->metadata.m.num_extra_channels == 1) &&
      frame_settings->enc->metadata.m.num_extra_channels != 0) {
    return false;
  }
  if (frame_settings->enc->metadata.m.bit_depth.bits_per_sample > 16) {
    return false;
  }
  if (pixel_format->data_type != JxlDataType::JXL_TYPE_FLOAT16 &&
      pixel_format->data_type != JxlDataType::JXL_TYPE_UINT16 &&
      pixel_format->data_type != JxlDataType::JXL_TYPE_UINT8) {
    return false;
  }
  if ((frame_settings->enc->metadata.m.bit_depth.bits_per_sample > 8) !=
      (pixel_format->data_type == JxlDataType::JXL_TYPE_UINT16 ||
       pixel_format->data_type == JxlDataType::JXL_TYPE_FLOAT16)) {
    return false;
  }
  if (!((pixel_format->num_channels == 1 || pixel_format->num_channels == 3) &&
        !has_alpha) &&
      !((pixel_format->num_channels == 2 || pixel_format->num_channels == 4) &&
        has_alpha)) {
    return false;
  }

  return true;
}

namespace {
JxlEncoderStatus JxlEncoderAddImageFrameInternal(
    const JxlEncoderFrameSettings* frame_settings, size_t xsize, size_t ysize,
    bool streaming, jxl::JxlEncoderChunkedFrameAdapter&& frame_data) {
  JxlPixelFormat pixel_format = {4, JXL_TYPE_UINT8, JXL_NATIVE_ENDIAN, 0};
  {
    JxlChunkedFrameInputSource input = frame_data.GetInputSource();
    input.get_color_channels_pixel_format(input.opaque, &pixel_format);
  }
  uint32_t num_channels = pixel_format.num_channels;
  size_t has_interleaved_alpha =
      static_cast<size_t>(num_channels == 2 || num_channels == 4);

  if (!frame_settings->enc->basic_info_set) {
    // Basic Info must be set. Otherwise, this is an API misuse.
    return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                         "Basic info or color encoding not set yet");
  }
  if (frame_settings->enc->frames_closed) {
    return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                         "Frame input already closed");
  }
  if (num_channels < 3) {
    if (frame_settings->enc->basic_info.num_color_channels != 1) {
      return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                           "Grayscale pixel format input for an RGB image");
    }
  } else {
    if (frame_settings->enc->basic_info.num_color_channels != 3) {
      return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                           "RGB pixel format input for a grayscale image");
    }
  }
  if (frame_settings->values.lossless &&
      frame_settings->enc->metadata.m.xyb_encoded) {
    return JXL_API_ERROR(
        frame_settings->enc, JXL_ENC_ERR_API_USAGE,
        "Set uses_original_profile=true for lossless encoding");
  }
  if (frame_settings->values.cparams.disable_perceptual_optimizations &&
      frame_settings->enc->metadata.m.xyb_encoded) {
    return JXL_API_ERROR(
        frame_settings->enc, JXL_ENC_ERR_API_USAGE,
        "Set uses_original_profile=true for non-perceptual encoding");
  }
  if (JXL_ENC_SUCCESS !=
      VerifyInputBitDepth(frame_settings->values.image_bit_depth,
                          pixel_format)) {
    return JXL_API_ERROR_NOSET("Invalid input bit depth");
  }
  if (has_interleaved_alpha >
      frame_settings->enc->metadata.m.num_extra_channels) {
    return JXL_API_ERROR(
        frame_settings->enc, JXL_ENC_ERR_API_USAGE,
        "number of extra channels mismatch (need 1 extra channel for alpha)");
  }

  bool has_alpha = frame_settings->enc->metadata.m.HasAlpha();

  // All required conditions to do fast-lossless.
  if (CanDoFastLossless(frame_settings, &pixel_format, has_alpha)) {
    const bool big_endian =
        pixel_format.endianness == JXL_BIG_ENDIAN ||
        (pixel_format.endianness == JXL_NATIVE_ENDIAN && !IsLittleEndian());

    RunnerTicket ticket{frame_settings->enc->thread_pool.get()};
    JXL_BOOL oneshot = TO_JXL_BOOL(!frame_data.StreamingInput());
    auto* frame_state = JxlFastLosslessPrepareFrame(
        frame_data.GetInputSource(), xsize, ysize, num_channels,
        frame_settings->enc->metadata.m.bit_depth.bits_per_sample, big_endian,
        /*effort=*/2, oneshot);
    if (!streaming) {
      bool ok =
          JxlFastLosslessProcessFrame(frame_state, /*is_last=*/false, &ticket,
                                      &FastLosslessRunnerAdapter, nullptr);
      if (!ok || ticket.has_error) {
        return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_GENERIC,
                             "Internal: JxlFastLosslessProcessFrame failed");
      }
    }
    QueueFastLosslessFrame(frame_settings, frame_state);
    return JxlErrorOrStatus::Success();
  }

  if (!streaming) {
    // The input callbacks are only guaranteed to be available during frame
    // encoding when both the input and the output is streaming. In all other
    // cases we need to create an internal copy of the frame data.
    if (!frame_data.CopyBuffers()) {
      return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                           "Invalid chunked frame input source");
    }
  }

  if (!frame_settings->enc->color_encoding_set) {
    jxl::ColorEncoding c_current;
    if ((pixel_format.data_type == JXL_TYPE_FLOAT) ||
        (pixel_format.data_type == JXL_TYPE_FLOAT16)) {
      c_current = jxl::ColorEncoding::LinearSRGB(num_channels < 3);
    } else {
      c_current = jxl::ColorEncoding::SRGB(num_channels < 3);
    }
    frame_settings->enc->metadata.m.color_encoding = c_current;
  }

  auto queued_frame = jxl::MemoryManagerMakeUnique<jxl::JxlEncoderQueuedFrame>(
      &frame_settings->enc->memory_manager,
      // JxlEncoderQueuedFrame is a struct with no constructors, so we use the
      // default move constructor there.
      jxl::JxlEncoderQueuedFrame{
          frame_settings->values, std::move(frame_data), {}});

  if (!queued_frame) {
    // TODO(jon): when can this happen? is this an API usage error?
    return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_GENERIC,
                         "No frame queued?");
  }

  for (auto& ec_info : frame_settings->enc->metadata.m.extra_channel_info) {
    if (has_interleaved_alpha && ec_info.type == jxl::ExtraChannel::kAlpha) {
      queued_frame->ec_initialized.push_back(1);
      has_interleaved_alpha = 0;  // only first Alpha is initialized
    } else {
      queued_frame->ec_initialized.push_back(0);
    }
  }
  queued_frame->option_values.cparams.level =
      frame_settings->enc->codestream_level;

  QueueFrame(frame_settings, queued_frame);
  return JxlErrorOrStatus::Success();
}
}  // namespace

JxlEncoderStatus JxlEncoderAddImageFrame(
    const JxlEncoderFrameSettings* frame_settings,
    const JxlPixelFormat* pixel_format, const void* buffer, size_t size) {
  size_t xsize;
  size_t ysize;
  if (GetCurrentDimensions(frame_settings, xsize, ysize) != JXL_ENC_SUCCESS) {
    return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_GENERIC,
                         "bad dimensions");
  }
  jxl::JxlEncoderChunkedFrameAdapter frame_data(
      xsize, ysize, frame_settings->enc->metadata.m.num_extra_channels);
  if (!frame_data.SetFromBuffer(0, reinterpret_cast<const uint8_t*>(buffer),
                                size, *pixel_format)) {
    return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                         "provided image buffer too small");
  }
  return JxlEncoderAddImageFrameInternal(frame_settings, xsize, ysize,
                                         /*streaming=*/false,
                                         std::move(frame_data));
}

JxlEncoderStatus JxlEncoderAddChunkedFrame(
    const JxlEncoderFrameSettings* frame_settings, JXL_BOOL is_last_frame,
    JxlChunkedFrameInputSource chunked_frame_input) {
  size_t xsize;
  size_t ysize;
  if (GetCurrentDimensions(frame_settings, xsize, ysize) != JXL_ENC_SUCCESS) {
    return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_GENERIC,
                         "bad dimensions");
  }
  bool streaming = frame_settings->enc->output_processor.OutputProcessorSet();
  jxl::JxlEncoderChunkedFrameAdapter frame_data(
      xsize, ysize, frame_settings->enc->metadata.m.num_extra_channels);
  frame_data.SetInputSource(chunked_frame_input);
  auto status = JxlEncoderAddImageFrameInternal(
      frame_settings, xsize, ysize, streaming, std::move(frame_data));
  if (status != JXL_ENC_SUCCESS) return status;

  auto& queued_frame = frame_settings->enc->input_queue.back();
  if (queued_frame.frame) {
    for (auto& val : queued_frame.frame->ec_initialized) val = 1;
  }

  if (is_last_frame) {
    JxlEncoderCloseInput(frame_settings->enc);
  }
  if (streaming) {
    return JxlEncoderFlushInput(frame_settings->enc);
  }
  return JxlErrorOrStatus::Success();
}

JxlEncoderStatus JxlEncoderUseBoxes(JxlEncoder* enc) {
  if (enc->wrote_bytes) {
    return JXL_API_ERROR(enc, JXL_ENC_ERR_API_USAGE,
                         "this setting can only be set at the beginning");
  }
  enc->use_boxes = true;
  return JxlErrorOrStatus::Success();
}

JxlEncoderStatus JxlEncoderAddBox(JxlEncoder* enc, const JxlBoxType type,
                                  const uint8_t* contents, size_t size,
                                  JXL_BOOL compress_box) {
  if (!enc->use_boxes) {
    return JXL_API_ERROR(
        enc, JXL_ENC_ERR_API_USAGE,
        "must set JxlEncoderUseBoxes at the beginning to add boxes");
  }
  if (enc->boxes_closed) {
    return JXL_API_ERROR(enc, JXL_ENC_ERR_API_USAGE,
                         "Box input already closed");
  }
  if (compress_box) {
    if (memcmp("jxl", type, 3) == 0) {
      return JXL_API_ERROR(
          enc, JXL_ENC_ERR_API_USAGE,
          "brob box may not contain a type starting with \"jxl\"");
    }
    if (memcmp("jbrd", type, 4) == 0) {
      return JXL_API_ERROR(enc, JXL_ENC_ERR_API_USAGE,
                           "jbrd box may not be brob compressed");
    }
    if (memcmp("brob", type, 4) == 0) {
      // The compress_box will compress an existing non-brob box into a brob
      // box. If already giving a valid brotli-compressed brob box, set
      // compress_box to false since it is already compressed.
      return JXL_API_ERROR(enc, JXL_ENC_ERR_API_USAGE,
                           "a brob box cannot contain another brob box");
    }
  }

  auto box = jxl::MemoryManagerMakeUnique<jxl::JxlEncoderQueuedBox>(
      &enc->memory_manager);

  box->type = jxl::MakeBoxType(type);
  box->contents.assign(contents, contents + size);
  box->compress_box = FROM_JXL_BOOL(compress_box);
  QueueBox(enc, box);
  return JxlErrorOrStatus::Success();
}

JXL_EXPORT JxlEncoderStatus JxlEncoderSetExtraChannelBuffer(
    const JxlEncoderFrameSettings* frame_settings,
    const JxlPixelFormat* pixel_format, const void* buffer, size_t size,
    uint32_t index) {
  if (index >= frame_settings->enc->metadata.m.num_extra_channels) {
    return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                         "Invalid value for the index of extra channel");
  }
  if (!frame_settings->enc->basic_info_set ||
      !frame_settings->enc->color_encoding_set) {
    return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                         "Basic info has to be set first");
  }
  if (frame_settings->enc->input_queue.empty()) {
    return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                         "First add image frame, then extra channels");
  }
  if (frame_settings->enc->frames_closed) {
    return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                         "Frame input already closed");
  }
  JxlPixelFormat ec_format = *pixel_format;
  ec_format.num_channels = 1;
  if (JXL_ENC_SUCCESS !=
      VerifyInputBitDepth(frame_settings->values.image_bit_depth, ec_format)) {
    return JXL_API_ERROR_NOSET("Invalid input bit depth");
  }
  const uint8_t* uint8_buffer = reinterpret_cast<const uint8_t*>(buffer);
  auto* queued_frame = frame_settings->enc->input_queue.back().frame.get();
  if (!queued_frame->frame_data.SetFromBuffer(1 + index, uint8_buffer, size,
                                              ec_format)) {
    return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                         "provided image buffer too small");
  }
  queued_frame->ec_initialized[index] = 1;

  return JxlErrorOrStatus::Success();
}

void JxlEncoderCloseFrames(JxlEncoder* enc) { enc->frames_closed = true; }

void JxlEncoderCloseBoxes(JxlEncoder* enc) { enc->boxes_closed = true; }

void JxlEncoderCloseInput(JxlEncoder* enc) {
  JxlEncoderCloseFrames(enc);
  JxlEncoderCloseBoxes(enc);
}

JXL_EXPORT JxlEncoderStatus JxlEncoderFlushInput(JxlEncoder* enc) {
  if (!enc->output_processor.OutputProcessorSet()) {
    return JXL_API_ERROR(enc, JXL_ENC_ERR_API_USAGE,
                         "Cannot flush input without setting output "
                         "processor with JxlEncoderSetOutputProcessor");
  }
  while (!enc->input_queue.empty()) {
    if (!enc->ProcessOneEnqueuedInput()) {
      return JxlErrorOrStatus::Error();
    }
  }
  return JxlErrorOrStatus::Success();
}

JXL_EXPORT JxlEncoderStatus JxlEncoderSetOutputProcessor(
    JxlEncoder* enc, JxlEncoderOutputProcessor output_processor) {
  if (enc->output_processor.HasAvailOut()) {
    return JXL_API_ERROR(
        enc, JXL_ENC_ERR_API_USAGE,
        "Cannot set an output processor when some output was already produced");
  }
  if (!output_processor.set_finalized_position ||
      !output_processor.get_buffer || !output_processor.release_buffer) {
    return JXL_API_ERROR(enc, JXL_ENC_ERR_API_USAGE,
                         "Missing output processor functions");
  }
  enc->output_processor =
      JxlEncoderOutputProcessorWrapper(&enc->memory_manager, output_processor);
  return JxlErrorOrStatus::Success();
}

JxlEncoderStatus JxlEncoderProcessOutput(JxlEncoder* enc, uint8_t** next_out,
                                         size_t* avail_out) {
  if (enc->output_processor.OutputProcessorSet()) {
    return JXL_API_ERROR(enc, JXL_ENC_ERR_API_USAGE,
                         "Cannot call JxlEncoderProcessOutput after calling "
                         "JxlEncoderSetOutputProcessor");
  }
  if (!enc->output_processor.SetAvailOut(next_out, avail_out)) {
    return JxlErrorOrStatus::Error();
  }
  while (*avail_out != 0 && !enc->input_queue.empty()) {
    if (!enc->ProcessOneEnqueuedInput()) {
      return JxlErrorOrStatus::Error();
    }
  }

  if (!enc->input_queue.empty() || enc->output_processor.HasOutputToWrite()) {
    return JxlErrorOrStatus::MoreOutput();
  }
  return JxlErrorOrStatus::Success();
}

JxlEncoderStatus JxlEncoderSetFrameHeader(
    JxlEncoderFrameSettings* frame_settings,
    const JxlFrameHeader* frame_header) {
  if (frame_header->layer_info.blend_info.source > 3) {
    return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                         "invalid blending source index");
  }
  // If there are no extra channels, it's ok for the value to be 0.
  if (frame_header->layer_info.blend_info.alpha != 0 &&
      frame_header->layer_info.blend_info.alpha >=
          frame_settings->enc->metadata.m.extra_channel_info.size()) {
    return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                         "alpha blend channel index out of bounds");
  }

  frame_settings->values.header = *frame_header;
  // Setting the frame header resets the frame name, it must be set again with
  // JxlEncoderSetFrameName if desired.
  frame_settings->values.frame_name = "";

  return JxlErrorOrStatus::Success();
}

JxlEncoderStatus JxlEncoderSetExtraChannelBlendInfo(
    JxlEncoderFrameSettings* frame_settings, size_t index,
    const JxlBlendInfo* blend_info) {
  if (index >= frame_settings->enc->metadata.m.num_extra_channels) {
    return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                         "Invalid value for the index of extra channel");
  }

  if (frame_settings->values.extra_channel_blend_info.size() !=
      frame_settings->enc->metadata.m.num_extra_channels) {
    JxlBlendInfo default_blend_info;
    JxlEncoderInitBlendInfo(&default_blend_info);
    frame_settings->values.extra_channel_blend_info.resize(
        frame_settings->enc->metadata.m.num_extra_channels, default_blend_info);
  }
  frame_settings->values.extra_channel_blend_info[index] = *blend_info;
  return JxlErrorOrStatus::Success();
}

JxlEncoderStatus JxlEncoderSetFrameName(JxlEncoderFrameSettings* frame_settings,
                                        const char* frame_name) {
  std::string str = frame_name ? frame_name : "";
  if (str.size() > 1071) {
    return JXL_API_ERROR(frame_settings->enc, JXL_ENC_ERR_API_USAGE,
                         "frame name can be max 1071 bytes long");
  }
  frame_settings->values.frame_name = str;
  frame_settings->values.header.name_length = str.size();
  return JxlErrorOrStatus::Success();
}

JxlEncoderStatus JxlEncoderSetFrameBitDepth(
    JxlEncoderFrameSettings* frame_settings, const JxlBitDepth* bit_depth) {
  if (bit_depth->type != JXL_BIT_DEPTH_FROM_PIXEL_FORMAT &&
      bit_depth->type != JXL_BIT_DEPTH_FROM_CODESTREAM) {
    return JXL_API_ERROR_NOSET(
        "Only JXL_BIT_DEPTH_FROM_PIXEL_FORMAT and "
        "JXL_BIT_DEPTH_FROM_CODESTREAM is implemented "
        "for input buffers.");
  }
  frame_settings->values.image_bit_depth = *bit_depth;
  return JxlErrorOrStatus::Success();
}

void JxlColorEncodingSetToSRGB(JxlColorEncoding* color_encoding,
                               JXL_BOOL is_gray) {
  *color_encoding =
      jxl::ColorEncoding::SRGB(FROM_JXL_BOOL(is_gray)).ToExternal();
}

void JxlColorEncodingSetToLinearSRGB(JxlColorEncoding* color_encoding,
                                     JXL_BOOL is_gray) {
  *color_encoding =
      jxl::ColorEncoding::LinearSRGB(FROM_JXL_BOOL(is_gray)).ToExternal();
}

void JxlEncoderAllowExpertOptions(JxlEncoder* enc) {
  enc->allow_expert_options = true;
}

JXL_EXPORT void JxlEncoderSetDebugImageCallback(
    JxlEncoderFrameSettings* frame_settings, JxlDebugImageCallback callback,
    void* opaque) {
  frame_settings->values.cparams.debug_image = callback;
  frame_settings->values.cparams.debug_image_opaque = opaque;
}

JXL_EXPORT JxlEncoderStats* JxlEncoderStatsCreate() {
  JxlEncoderStats* result = new JxlEncoderStats();
  result->aux_out = jxl::make_unique<jxl::AuxOut>();
  return result;
}

JXL_EXPORT void JxlEncoderStatsDestroy(JxlEncoderStats* stats) { delete stats; }

JXL_EXPORT void JxlEncoderCollectStats(JxlEncoderFrameSettings* frame_settings,
                                       JxlEncoderStats* stats) {
  if (!stats) return;
  frame_settings->values.aux_out = stats->aux_out.get();
}

JXL_EXPORT size_t JxlEncoderStatsGet(const JxlEncoderStats* stats,
                                     JxlEncoderStatsKey key) {
  if (!stats) return 0;
  const jxl::AuxOut& aux_out = *stats->aux_out;
  switch (key) {
    case JXL_ENC_STAT_HEADER_BITS:
      return aux_out.layer(jxl::LayerType::Header).total_bits;
    case JXL_ENC_STAT_TOC_BITS:
      return aux_out.layer(jxl::LayerType::Toc).total_bits;
    case JXL_ENC_STAT_DICTIONARY_BITS:
      return aux_out.layer(jxl::LayerType::Dictionary).total_bits;
    case JXL_ENC_STAT_SPLINES_BITS:
      return aux_out.layer(jxl::LayerType::Splines).total_bits;
    case JXL_ENC_STAT_NOISE_BITS:
      return aux_out.layer(jxl::LayerType::Noise).total_bits;
    case JXL_ENC_STAT_QUANT_BITS:
      return aux_out.layer(jxl::LayerType::Quant).total_bits;
    case JXL_ENC_STAT_MODULAR_TREE_BITS:
      return aux_out.layer(jxl::LayerType::ModularTree).total_bits;
    case JXL_ENC_STAT_MODULAR_GLOBAL_BITS:
      return aux_out.layer(jxl::LayerType::ModularGlobal).total_bits;
    case JXL_ENC_STAT_DC_BITS:
      return aux_out.layer(jxl::LayerType::Dc).total_bits;
    case JXL_ENC_STAT_MODULAR_DC_GROUP_BITS:
      return aux_out.layer(jxl::LayerType::ModularDcGroup).total_bits;
    case JXL_ENC_STAT_CONTROL_FIELDS_BITS:
      return aux_out.layer(jxl::LayerType::ControlFields).total_bits;
    case JXL_ENC_STAT_COEF_ORDER_BITS:
      return aux_out.layer(jxl::LayerType::Order).total_bits;
    case JXL_ENC_STAT_AC_HISTOGRAM_BITS:
      return aux_out.layer(jxl::LayerType::Ac).total_bits;
    case JXL_ENC_STAT_AC_BITS:
      return aux_out.layer(jxl::LayerType::AcTokens).total_bits;
    case JXL_ENC_STAT_MODULAR_AC_GROUP_BITS:
      return aux_out.layer(jxl::LayerType::ModularAcGroup).total_bits;
    case JXL_ENC_STAT_NUM_SMALL_BLOCKS:
      return aux_out.num_small_blocks;
    case JXL_ENC_STAT_NUM_DCT4X8_BLOCKS:
      return aux_out.num_dct4x8_blocks;
    case JXL_ENC_STAT_NUM_AFV_BLOCKS:
      return aux_out.num_afv_blocks;
    case JXL_ENC_STAT_NUM_DCT8_BLOCKS:
      return aux_out.num_dct8_blocks;
    case JXL_ENC_STAT_NUM_DCT8X32_BLOCKS:
      return aux_out.num_dct16_blocks;
    case JXL_ENC_STAT_NUM_DCT16_BLOCKS:
      return aux_out.num_dct16x32_blocks;
    case JXL_ENC_STAT_NUM_DCT16X32_BLOCKS:
      return aux_out.num_dct32_blocks;
    case JXL_ENC_STAT_NUM_DCT32_BLOCKS:
      return aux_out.num_dct32x64_blocks;
    case JXL_ENC_STAT_NUM_DCT32X64_BLOCKS:
      return aux_out.num_dct32x64_blocks;
    case JXL_ENC_STAT_NUM_DCT64_BLOCKS:
      return aux_out.num_dct64_blocks;
    case JXL_ENC_STAT_NUM_BUTTERAUGLI_ITERS:
      return aux_out.num_butteraugli_iters;
    default:
      return 0;
  }
}

JXL_EXPORT void JxlEncoderStatsMerge(JxlEncoderStats* stats,
                                     const JxlEncoderStats* other) {
  if (!stats || !other) return;
  stats->aux_out->Assimilate(*other->aux_out);
}