Method getPageForParagraphIndex

lib/Epub/Epub/Section.cpp:400–437

}

std::optional<uint16_t> Section::getPageForParagraphIndex(const uint16_t pIndex) 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) {
    return std::nullopt;
  }

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

  uint16_t resultPage = count - 1;
  for (uint16_t i = 0; i < count; i++) {
    uint16_t pagePIdx;
    serialization::readPod(f, pagePIdx);
    if (pagePIdx >= pIndex) {
      resultPage = i;
      break;
    }
  }

  return resultPage;
}

std::optional<uint16_t> Section::getParagraphIndexForPage(const uint16_t page) const {
  HalFile f;