func (b *block) toGNU() *headerGNU     { return (*headerGNU)(b) }
func (b *block) toSTAR() *headerSTAR   { return (*headerSTAR)(b) }
func (b *block) toUSTAR() *headerUSTAR { return (*headerUSTAR)(b) }
func (b *block) toSparse() sparseArray { return sparseArray(b[:]) }

// getFormat checks that the block is a valid tar header based on the checksum.
// It then attempts to guess the specific format based on magic values.

		if format != FormatUnknown {
			blk.setFormat(format)
		}
		out = append(out, blk[:]...)

		// Write extended sparse blocks.
		for len(sps) > 0 {
			var blk block
			sps = populateSparseMap(blk.toSparse(), sps)
			out = append(out, blk[:]...)
		}
		return out
	}

	makeSparseStrings := func(sp []sparseEntry) (out []string) {
		var f formatter
		for _, s := range sp {
			var b [24]byte

    tryParseAndAssertEquals(LEAST, Integer.toString(LEAST));
    assertThat(Ints.tryParse("")).isNull();
    assertThat(Ints.tryParse("-")).isNull();
    assertThat(Ints.tryParse("+1")).isNull();
    assertThat(Ints.tryParse("9999999999999999")).isNull();
    assertWithMessage("Max integer + 1")
        .that(Ints.tryParse(Long.toString(((long) GREATEST) + 1)))
        .isNull();
    assertWithMessage("Max integer * 10")

      return Double.valueOf(input);
    } catch (NumberFormatException e) {
      return null;
    }
  }

  @GwtIncompatible // Doubles.tryParse
  private static void checkTryParse(String input) {
    Double expected = referenceTryParse(input);
    assertThat(Doubles.tryParse(input)).isEqualTo(expected);
    if (expected != null && !Doubles.FLOATING_POINT_PATTERN.matcher(input).matches()) {

	for i, test := range tests {
		arch, ctxt := setArch(goarch)
		tokenizer := lex.NewTokenizer("", strings.NewReader(test.input+"\n"), nil)
		parser := NewParser(ctxt, arch, tokenizer)

		err := tryParse(t, func() {
			parser.Parse()
		})

		switch {
		case err == nil:
			t.Errorf("#%d: %q: want error %q; have none", i, test.input, test.error)
		case !strings.Contains(err.Error(), test.error):

	}
}

func runBadTest(i int, test badExprTest, t *testing.T) (err error) {
	p := NewParser(nil, nil, nil) // Expression evaluation uses none of these fields of the parser.
	p.start(lex.Tokenize(test.input))
	return tryParse(t, func() {
		p.expr()
	})

   *     a length of zero or cannot be parsed as an integer value
   * @throws NullPointerException if {@code string} is {@code null}
   * @since 11.0
   */
  public static @Nullable Integer tryParse(String string) {
    return tryParse(string, 10);
  }

  /**
   * Parses the specified string as a signed integer value using the specified radix. The ASCII

	architecture, ctxt := setArch(goarch)
	return NewParser(ctxt, architecture, nil)
}

// tryParse executes parse func in panicOnError=true context.
// parse is expected to call any parsing methods that may panic.
// Returns error gathered from recover; nil if no parse errors occurred.
//
// For unexpected panics, calls t.Fatal.
func tryParse(t *testing.T, parse func()) (err error) {
	panicOnError = true
	defer func() {

   *     length of zero or cannot be parsed as a long value
   * @throws NullPointerException if {@code string} is {@code null}
   * @since 14.0
   */
  public static @Nullable Long tryParse(String string) {
    return tryParse(string, 10);
  }

  /**
   * Parses the specified string as a signed long value using the specified radix. The ASCII

   * @throws NullPointerException if {@code string} is {@code null}
   * @since 14.0
   */
  @GwtIncompatible // regular expressions
  public static @Nullable Float tryParse(String string) {
    if (Doubles.FLOATING_POINT_PATTERN.matcher(string).matches()) {
      // TODO(lowasser): could be potentially optimized, but only with
      // extensive testing
      try {