Function assemble

packages/core/src/utils/umd-parser.ts:303–351

(a: AssembleArgs)

}

function assemble(a: AssembleArgs): UmdParsed {
  const titles = parseTitles(a.dataById.get(a.idTitleList));
  const offsets = parseChapterOffsets(a.dataById.get(a.idChapterList));
  const contentBytes = decompressContent(a);

  const chapters: UmdChapter[] = [];
  const effectiveContentLen = a.contentLen > 0 && a.contentLen <= contentBytes.length
    ? a.contentLen
    : contentBytes.length;

  for (let i = 0; i < titles.length; i++) {
    const start = offsets[i] ?? 0;
    const end = i + 1 < offsets.length ? offsets[i + 1]! : effectiveContentLen;
    const clampedStart = Math.min(Math.max(start, 0), effectiveContentLen);
    const clampedEnd = Math.min(Math.max(end, clampedStart), effectiveContentLen);
    const slice = contentBytes.subarray(clampedStart, clampedEnd);
    chapters.push({ title: titles[i]!, content: decodeUtf16LE(slice) });
  }

  // Fallback: no chapters detected but we do have content — emit one chapter.
  if (chapters.length === 0 && effectiveContentLen > 0) {
    chapters.push({
      title: a.bookTitle || "正文",
      content: decodeUtf16LE(contentBytes.subarray(0, effectiveContentLen)),
    });
  }

  let coverBytes: Uint8Array | undefined;
  let coverMime: "image/jpeg" | undefined;
  if (a.idCover) {
    const blob = a.dataById.get(a.idCover);
    if (blob && blob.length > 0) {
      coverBytes = blob;
      coverMime = "image/jpeg";
    }
  }

  return {
    bookTitle: a.bookTitle,
    author: a.author,
    date: a.date,
    bookType: a.bookType,
    publisher: a.publisher,
    retailer: a.retailer,
    chapters,
    coverBytes,
    coverMime,
  };
}

function parseTitles(data: Uint8Array | undefined): string[] {
  if (!data) return [];