Set<Character> positive = Sets.newHashSetWithExpectedSize(chars.length);
    for (char c : chars) {
      positive.add(c);
    }
    for (int c = 0; c <= Character.MAX_VALUE; c++) {
      assertFalse(positive.contains(Character.valueOf((char) c)) ^ m.matches((char) c));
    }
  }

  static char[] randomChars(Random rand, int size) {
    Set<Character> chars = new HashSet<>(size);

namespace tensorflow {
namespace {

TFE_MonitoringCounter0* CreateCounter0(const char* counter_name);
TFE_MonitoringCounter1* CreateCounter1(const char* counter_name,
                                       const char* label);
void IncrementCounter0(TFE_MonitoringCounter0* counter, int64_t delta = 1);
void IncrementCounter1(TFE_MonitoringCounter1* counter, const char* label,
                       int64_t delta = 1);

TF_Function* TF_GraphToFunctionWithControlOutputs(
    const TF_Graph* fn_body, const char* fn_name,
    unsigned char append_hash_to_fn_name, int num_opers,
    const TF_Operation* const* opers, int ninputs, const TF_Output* inputs,
    int noutputs, const TF_Output* outputs, const char* const* output_names,
    int ncontrol_outputs, const TF_Operation* const* control_outputs,
    const char* const* control_output_names, const TF_FunctionOptions* opts,

   */
  @Override
  protected final char @Nullable [] escape(char c) {
    if (c < replacementsLength) {
      char[] chars = replacements[c];
      if (chars != null) {
        return chars;
      }
    }
    if (c >= safeMin && c <= safeMax) {
      return null;
    }
    return escapeUnsafe(c);
  }

  /**

      chars.add(randomAlpha());
    }
    for (int i = 0; i < nonAlpha; i++) {
      chars.add(randomNonAlpha());
    }
    Collections.shuffle(chars, random);
    char[] array = Chars.toArray(chars);
    this.testString = new String(array);
  }

  private char randomAlpha() {
    return ALPHA.charAt(random.nextInt(ALPHA.length()));
  }

  private char randomNonAlpha() {

      while (i + 4 <= utf16Length) {
        char c0 = input.charAt(i);
        char c1 = input.charAt(i + 1);
        char c2 = input.charAt(i + 2);
        char c3 = input.charAt(i + 3);
        if (c0 < 0x80 && c1 < 0x80 && c2 < 0x80 && c3 < 0x80) {
          int k1 = c0 | (c1 << 8) | (c2 << 16) | (c3 << 24);
          k1 = mixK1(k1);
          h1 = mixH1(h1, k1);
          i += 4;

        << "Mismatch in expected values at (zero-based) index " << i;
  }
}

void CheckRemoteMatMulExecutesOK(TFE_Context* ctx,
                                 const char* remote_device_name,
                                 const char* local_device_name) {
  TF_Status* status = TF_NewStatus();
  TFE_TensorHandle* h0_task0 = TestMatrixTensorHandle(ctx);

  TFE_Op* matmul = MatMulOp(ctx, h0_task0, h0_task0);

    if (chars instanceof String) {
      return toLowerCase((String) chars);
    }
    char[] newChars = new char[chars.length()];
    for (int i = 0; i < newChars.length; i++) {
      newChars[i] = toLowerCase(chars.charAt(i));
    }
    return String.valueOf(newChars);
  }

  /**
   * If the argument is an {@linkplain #isUpperCase(char) uppercase ASCII character}, returns the

  static long copyReaderToBuilder(Reader from, StringBuilder to) throws IOException {
    checkNotNull(from);
    checkNotNull(to);
    char[] buf = new char[DEFAULT_BUF_SIZE];
    int nRead;
    long total = 0;
    while ((nRead = from.read(buf)) != -1) {
      to.append(buf, 0, nRead);
      total += nRead;
    }
    return total;
  }

  /**

     * @return a hexadecimal string representation of the value, padded to the specified size
     */
    public static String toHexString(final int val, final int size) {
        final char[] c = new char[size];
        toHexChars(val, c, 0, size);
        return new String(c);
    }

    /**
     * Converts a long value to a hexadecimal string representation with specified padding.
     *