formats/jpeg/reader.h

// Copyright 2026 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//

#ifndef THIRD_PARTY_CREDENTIO_FORMATS_JPEG_READER_H_
#define THIRD_PARTY_CREDENTIO_FORMATS_JPEG_READER_H_

#include <cstdint>
#include <iosfwd>
#include <optional>
#include <string>

#include "absl/functional/function_ref.h"
#include "absl/status/status.h"
#include "absl/status/statusor.h"
#include "riegeli/bytes/reader.h"

namespace credentio {

struct JpegJumbfData {
  // Offset for this data is contained within
  // `JpegApp11Segment::payload_offset`.
  uint32_t lbox;
  uint32_t tbox;
  uint64_t xlbox;

  // Offset and length of the data contained in the JUMBF segment.
  uint64_t payload_offset;
  uint64_t payload_length;

  friend bool operator==(const JpegJumbfData&, const JpegJumbfData&) = default;
};

void PrintTo(const JpegJumbfData& x, ::std::ostream* os);

struct JpegApp11Segment {
  uint16_t extension_type;
  uint16_t segment_id;
  uint32_t sequence_number;

  // Offset and length of the data contained in the APP11 segment.
  uint64_t payload_offset;
  uint64_t payload_length;

  std::optional<JpegJumbfData> jumbf_data;

  friend bool operator==(const JpegApp11Segment&,
                         const JpegApp11Segment&) = default;
};

void PrintTo(const JpegApp11Segment& x, ::std::ostream* os);

struct JpegSegment {
  uint64_t offset;
  uint16_t marker;           // Marker code for the segment.
  std::string marker_label;  // Human-readable label for the marker.
  uint64_t length;

  // Offset and length of the data contained in the segment.
  uint64_t payload_offset;
  uint64_t payload_length;

  std::optional<JpegApp11Segment> app11_info;

  friend bool operator==(const JpegSegment&, const JpegSegment&) = default;
};

void PrintTo(const JpegSegment& x, ::std::ostream* os);

using JpegSegmentProcessor =
    absl::FunctionRef<absl::StatusOr<bool>(const JpegSegment&)>;

// Iterates over all JPEG segments in the given reader, calling the given
// function for each segment. The method will NOT seek to position 0 in the
// reader before iterating, it will start from the current position.
absl::Status IterateOverJpegSegments(riegeli::Reader& reader,
                                     JpegSegmentProcessor processor,
                                     int64_t end_offset = -1);

}  // namespace credentio

#endif  // THIRD_PARTY_CREDENTIO_FORMATS_JPEG_READER_H_