Method detectXRefFormat

src/parser/xref-parser.ts:117–133

* Detect the XRef format at a given offset without fully parsing. * * @returns true if XRef stream, false if table, null if cannot detect

(offset: number)

   * @returns true if XRef stream, false if table, null if cannot detect
   */
  detectXRefFormat(offset: number): boolean | null {
    this.scanner.moveTo(offset);

    const firstByte = this.scanner.peek();

    // 'x' = 0x78 starts "xref" (table format)
    if (firstByte === 0x78) {
      return false;
    }

    // Digit starts "N M obj" (stream format)
    if (firstByte >= DIGIT_0 && firstByte <= DIGIT_9) {
      return true;
    }

    return null;
  }

  /**
   * Parse traditional xref table format.