Function parseLinearizationDict

src/document/linearization.ts:67–102

(dict: PdfDict)

 * @returns The parsed parameters, or null if invalid
 */
export function parseLinearizationDict(dict: PdfDict): LinearizationParams | null {
  // Required fields
  const version = dict.getNumber("Linearized")?.value;
  const fileLength = dict.getNumber("L")?.value;
  const firstPage = dict.getNumber("O")?.value;
  const endOfFirstPage = dict.getNumber("E")?.value;
  const pageCount = dict.getNumber("N")?.value;
  const mainXRefOffset = dict.getNumber("T")?.value;

  // Hint stream info (in /H array)
  const hintArray = dict.getArray("H");
  const hintOffset = hintArray?.at(0);
  const hintLength = hintArray?.at(1);

  if (
    version === undefined ||
    fileLength === undefined ||
    firstPage === undefined ||
    endOfFirstPage === undefined ||
    pageCount === undefined ||
    mainXRefOffset === undefined
  ) {
    return null;
  }

  return {
    version,
    fileLength,
    hintOffset: hintOffset && hintOffset instanceof PdfNumber ? hintOffset.value : 0,
    hintLength: hintLength && hintLength instanceof PdfNumber ? hintLength.value : 0,
    firstPage,
    endOfFirstPage,
    pageCount,
    mainXRefOffset,
  };
}