formats/tiff/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_TIFF_READER_H_
#define THIRD_PARTY_CREDENTIO_FORMATS_TIFF_READER_H_

#include <stdbool.h>
#include <sys/types.h>

#include <cstdint>
#include <optional>
#include <vector>

#include "absl/container/flat_hash_set.h"
#include "absl/functional/function_ref.h"
#include "absl/status/status.h"
#include "absl/status/statusor.h"
#include "formats/byte_range.h"
#include "formats/tiff/constants.h"
#include "riegeli/bytes/reader.h"

namespace credentio {

enum class TiffEndianness {
  kBigEndian,
  kLittleEndian,
};

struct TiffImageFileDirectoryEntry {
  uint64_t offset;

  uint16_t tag;
  uint16_t type;
  uint32_t count;
  uint32_t value_or_offset;

  uint64_t size() const { return SizeOfTiffType(type) * count; }

  ByteRange RangeOfCount() const;

  ByteRange RangeOfValue() const;
};

struct TiffImageFileDirectory {
  uint32_t offset_of_pointer;

  uint32_t offset;
  std::vector<TiffImageFileDirectoryEntry> entries;
};

using ImageFileDirectoryProcessor = absl::FunctionRef<absl::StatusOr<bool>(
    const TiffImageFileDirectory&, TiffEndianness)>;

absl::Status IterateOverImageFileDirectories(
    riegeli::Reader& source, std::optional<TiffEndianness> known_endianness,
    absl::flat_hash_set<uint32_t>& visited_offsets,
    ImageFileDirectoryProcessor process_ifd);

}  // namespace credentio

#endif  // THIRD_PARTY_CREDENTIO_FORMATS_TIFF_READER_H_