Method getParagraphIndexForPage

lib/Epub/Epub/Section.cpp:439–469

}

std::optional<uint16_t> Section::getParagraphIndexForPage(const uint16_t page) const {
  HalFile f;
  if (!Storage.openFileForRead("SCT", filePath, f)) {
    return std::nullopt;
  }

  const uint32_t fileSize = f.size();
  f.seek(HEADER_SIZE - sizeof(uint32_t) * 2);
  uint32_t paragraphLutOffset;
  serialization::readPod(f, paragraphLutOffset);
  if (paragraphLutOffset == 0 || paragraphLutOffset >= fileSize) {
    return std::nullopt;
  }

  f.seek(paragraphLutOffset);
  uint16_t count;
  serialization::readPod(f, count);
  if (count == 0 || page >= count) {
    return std::nullopt;
  }

  const uint32_t entryEnd = paragraphLutOffset + sizeof(uint16_t) + (page + 1) * sizeof(uint16_t);
  if (entryEnd > fileSize) {
    return std::nullopt;
  }

  f.seek(paragraphLutOffset + sizeof(uint16_t) + page * sizeof(uint16_t));
  uint16_t pIdx;
  serialization::readPod(f, pIdx);
  return pIdx;
}

std::optional<uint16_t> Section::getPageForListItemIndex(const uint16_t liIndex) const {
  HalFile f;