bufferHelper("no newlines at all", "no newlines at all");
    bufferHelper("two lines\nbut no newline at end", "two lines\n", "but no newline at end");
    bufferHelper(
        "\nempty first line\nno newline at end", "\n", "empty first line\n", "no newline at end");
    bufferHelper("three\rlines\rno newline at end", "three\r", "lines\r", "no newline at end");

    bufferHelper("no newlines at all", "no newlines at all");
    bufferHelper("two lines\nbut no newline at end", "two lines\n", "but no newline at end");
    bufferHelper(
        "\nempty first line\nno newline at end", "\n", "empty first line\n", "no newline at end");
    bufferHelper("three\rlines\rno newline at end", "three\r", "lines\r", "no newline at end");

		n++
	} else {
		n, err = rr.reader.Read(p)
	}

	if err != nil {
		return n, err
	}

	// Do nothing if record-delimiter is already newline.
	if string(rr.recordDelimiter) == "\n" {
		return n, nil
	}

	// Change record delimiters to newline.
	if len(rr.recordDelimiter) == 1 {
		for idx := 0; idx < len(p); {
			i := bytes.Index(p[idx:], rr.recordDelimiter)
			if i < 0 {
				break
			}

        }

        -1 -> {
          val lineEnd = source.indexOfElement(CRLF)
          if (lineEnd != -1L) {
            // Skip the line and newline
            source.skip(lineEnd)
            source.select(options)
          } else {
            return false // No more newlines.
          }
        }

        else -> throw AssertionError()
      }
    }
  }

  @Throws(IOException::class)

import (
	"iter"
	"unicode"
	"unicode/utf8"
)

// Lines returns an iterator over the newline-terminated lines in the byte slice s.
// The lines yielded by the iterator include their terminating newlines.
// If s is empty, the iterator yields no lines at all.
// If s does not end in a newline, the final yielded line will not end in a newline.
// It returns a single-use iterator.
func Lines(s []byte) iter.Seq[[]byte] {

  private static final ImmutableMap<Character, String> NO_REPLACEMENTS = ImmutableMap.of();
  private static final ImmutableMap<Character, String> SIMPLE_REPLACEMENTS =
      ImmutableMap.of(
          '\n', "<newline>",
          '\t', "<tab>",
          '&', "<and>");

  public void testSafeRange() throws IOException {
    // Basic escaping of unsafe chars (wrap them in {,}'s)
    CharEscaper wrappingEscaper =

      val length = logMessage.length
      while (i < length) {
        var newline = logMessage.indexOf('\n', i)
        newline = if (newline != -1) newline else length
        do {
          val end = minOf(newline, i + MAX_LOG_LENGTH)
          Log.println(logLevel, tag, logMessage.substring(i, end))
          i = end
        } while (i < newline)
        i++
      }
    }
  }

}

func NewTokenizer(name string, r io.Reader, file *os.File) *Tokenizer {
	var s scanner.Scanner
	s.Init(r)
	// Newline is like a semicolon; other space characters are fine.
	s.Whitespace = 1<<'\t' | 1<<'\r' | 1<<' '
	// Don't skip comments: we need to count newlines.
	s.Mode = scanner.ScanChars |
		scanner.ScanFloats |
		scanner.ScanIdents |
		scanner.ScanInts |
		scanner.ScanStrings |

  while (!exhausted()) {
    if (buffer[0] != ' '.code.toByte()) return
    skip(1L)
  }
}

private fun BufferedSource.skipRestOfLine() {
  when (val newline = indexOf('\n'.code.toByte())) {
    -1L -> skip(buffer.size) // Exhaust this source.
    else -> skip(newline + 1)
  }
}

/**
 * Reads lines from `IdnaMappingTable.txt`.
 *

The [bytes] package adds several functions that work with iterators:
- [Lines] returns an iterator over the
  newline-terminated lines in the byte slice s.
- [SplitSeq] returns an iterator over
  all substrings of s separated by sep.
- [SplitAfterSeq] returns an iterator
  over substrings of s split after each instance of sep.
- [FieldsSeq] returns an iterator over
  substrings of s split around runs of whitespace characters,
  as defined by unicode.IsSpace.