Function parseDTDInternalSubset

xml/_parse_sync.ts:203–284

* Parse DTD internal subset with validation. * Validates whitespace requirements per XML 1.0 spec.

()

   * Validates whitespace requirements per XML 1.0 spec.
   */
  function parseDTDInternalSubset(): void {
    while (pos < len) {
      const code = input.charCodeAt(pos);

      if (code === CC_RBRACKET) {
        pos++;
        return; // End of internal subset
      }

      if (isWhitespace(code)) {
        // Batch-skip whitespace for better performance
        skipWhitespace();
        continue;
      }

      if (code === CC_LT) {
        pos++;
        if (pos >= len) {
          error("Unexpected end of input in DTD");
        }

        const nextCode = input.charCodeAt(pos);
        if (nextCode === CC_BANG) {
          pos++;
          parseDTDMarkupDeclaration();
        } else if (nextCode === CC_QUESTION) {
          pos++;
          // Processing instruction in DTD
          while (pos < len) {
            if (
              input.charCodeAt(pos) === CC_QUESTION &&
              pos + 1 < len &&
              input.charCodeAt(pos + 1) === CC_GT
            ) {
              pos += 2;
              break;
            }
            pos++;
          }
        } else {
          error(`Unexpected character '${input[pos]}' after '<' in DTD`);
        }
        continue;
      }

      if (code === CC_LBRACKET) {
        // Conditional sections are not allowed in internal subset
        error(
          "Conditional sections (INCLUDE/IGNORE) are not allowed in internal DTD subset",
        );
      }

      // Parameter entity reference: %name;
      // These are valid in internal subset and must be skipped
      if (code === CC_PERCENT) {
        pos++;
        while (pos < len) {
          const c = input.charCodeAt(pos);