Method BuildHeader

contrib/libs/flatbuffers/src/binary_annotator.cpp:159–235

}

uint64_t BinaryAnnotator::BuildHeader(const uint64_t header_offset) {
  uint64_t offset = header_offset;
  std::vector<BinaryRegion> regions;

  // If this binary is a size prefixed one, attempt to parse the size.
  if (is_size_prefixed_) {
    BinaryRegionComment prefix_length_comment;
    prefix_length_comment.type = BinaryRegionCommentType::SizePrefix;

    bool has_prefix_value = false;
    const auto prefix_length = ReadScalar<uoffset64_t>(offset);
    if (*prefix_length <= binary_length_) {
      regions.push_back(MakeBinaryRegion(offset, sizeof(uoffset64_t),
                                         BinaryRegionType::Uint64, 0, 0,
                                         prefix_length_comment));
      offset += sizeof(uoffset64_t);
      has_prefix_value = true;
    }

    if (!has_prefix_value) {
      const auto prefix_length = ReadScalar<uoffset_t>(offset);
      if (*prefix_length <= binary_length_) {
        regions.push_back(MakeBinaryRegion(offset, sizeof(uoffset_t),
                                           BinaryRegionType::Uint32, 0, 0,
                                           prefix_length_comment));
        offset += sizeof(uoffset_t);
        has_prefix_value = true;
      }
    }

    if (!has_prefix_value) {
      SetError(prefix_length_comment, BinaryRegionStatus::ERROR);
    }
  }

  const auto root_table_offset = ReadScalar<uint32_t>(offset);

  if (!root_table_offset.has_value()) {
    // This shouldn't occur, since we validate the min size of the buffer
    // before. But for completion sake, we shouldn't read passed the binary end.
    return std::numeric_limits<uint64_t>::max();
  }

  const auto root_table_loc = offset + *root_table_offset;

  BinaryRegionComment root_offset_comment;
  root_offset_comment.type = BinaryRegionCommentType::RootTableOffset;
  root_offset_comment.name = schema_->root_table()->name()->str();

  if (!IsValidOffset(root_table_loc)) {
    SetError(root_offset_comment,
             BinaryRegionStatus::ERROR_OFFSET_OUT_OF_BINARY);
  }

  regions.push_back(MakeBinaryRegion(offset, sizeof(uint32_t),
                                     BinaryRegionType::UOffset, 0,
                                     root_table_loc, root_offset_comment));
  offset += sizeof(uint32_t);