Method copyStreamRef

src/document/object-copier.ts:248–321

* Copy a stream reference, handling circular references and encryption.

(key: string, srcStream: PdfStream)

   * Copy a stream reference, handling circular references and encryption.
   */
  private copyStreamRef(key: string, srcStream: PdfStream): PdfRef {
    const sourceWasEncrypted = this.source.isEncrypted;

    // Clone the stream's dictionary
    const clonedDict = srcStream.clone();

    // Get stream data based on encryption state
    let streamData: Uint8Array;

    if (!sourceWasEncrypted) {
      // Source wasn't encrypted - copy raw encoded bytes directly
      streamData = srcStream.data;
    } else {
      // Source was encrypted - decode and re-encode
      // Wrap in try/catch since decoding may fail for corrupt streams
      try {
        const decodedData = srcStream.getDecodedData();
        const filterEntry = srcStream.get("Filter");

        if (filterEntry) {
          try {
            const filterSpecs = this.buildFilterSpecs(srcStream);

            streamData = FilterPipeline.encode(decodedData, filterSpecs);

            clonedDict.set("Length", PdfNumber.of(streamData.length));
          } catch (error) {
            console.warn(`Could not re-encode stream ${key}, will use uncompressed data`);
            console.warn(error);

            // If re-encoding fails, store uncompressed
            clonedDict.delete("Filter");
            clonedDict.delete("DecodeParms");

            streamData = decodedData;

            clonedDict.set("Length", PdfNumber.of(streamData.length));
          }
        } else {
          streamData = decodedData;
          clonedDict.set("Length", PdfNumber.of(streamData.length));
        }
      } catch (error) {
        console.warn(`Could not decode stream ${key}, will use raw data`);
        console.warn(error);

        // If decoding fails entirely, try to copy raw bytes as fallback
        // Clear filters since we can't guarantee the data is properly encoded
        clonedDict.delete("Filter");
        clonedDict.delete("DecodeParms");

        streamData = srcStream.data;

        clonedDict.set("Length", PdfNumber.of(streamData.length));
      }
    }

    // Create the stream with data