checkArgument(!token.isEmpty());
    return Ascii.toLowerCase(token);
  }

  private static String normalizeParameterValue(String attribute, String value) {
    checkNotNull(value); // for GWT
    checkArgument(ascii().matchesAllOf(value), "parameter values must be ASCII: %s", value);
    return attribute.equals(CHARSET_ATTRIBUTE) ? Ascii.toLowerCase(value) : value;
  }

  /**

        buf.enc_ndr_small(0); /* minor version */
        buf.enc_ndr_small(this.ptype);
        buf.enc_ndr_small(this.flags);
        buf.enc_ndr_long(0x00000010); /* Little-endian / ASCII / IEEE */
        buf.enc_ndr_short(this.length);
        buf.enc_ndr_short(0); /* length of auth_value */
        buf.enc_ndr_long(this.call_id);
    }

        // Verify subcommand
        assertEquals(SmbComTransaction.NET_SERVER_ENUM2 & 0xFF, (dst[0] & 0xFF) | ((dst[1] & 0xFF) << 8));

        // Verify description
        byte[] descr = NetServerEnum2.DESCR[0].getBytes("ASCII");
        byte[] writtenDescr = new byte[descr.length];
        System.arraycopy(dst, 2, writtenDescr, 0, descr.length);
        assertArrayEquals(descr, writtenDescr);

        int currentIndex = 2 + descr.length;

      try {
        return Integer.decode(userFriendly);
      } catch (NumberFormatException ignored) {
        if (userFriendly.matches("(?i)(?:American|English|ASCII)")) {
          // 1-byte UTF-8 sequences - "American" ASCII text
          return 0x80;
        } else if (userFriendly.matches("(?i)(?:French|Latin|Western.*European)")) {
          // Mostly 1-byte UTF-8 sequences, mixed with occasional 2-byte

        int state, t, x, i, off;
        byte ch;
        final byte[] type = new byte[128];
        final byte[] buf = new byte[16];
        final byte[] ext = extension.toLowerCase().getBytes("ASCII");

        state = ST_START;
        t = x = i = 0;
        for (off = 0; off < inLen; off++) {
            ch = in[off];
            switch (state) {
            case ST_START:

 *
 *  * In queries, ' ' is encoded to '+' and '+' is encoded to "%2B".
 *
 *  * Characters in `encodeSet` are percent-encoded.
 *
 *  * Control characters and non-ASCII characters are percent-encoded.
 *
 *  * All other characters are copied without transformation.
 *
 * @param alreadyEncoded true to leave '%' as-is; false to convert it to '%25'.

        try {
            this.service = new String(buffer, bufferIndex, len, "ASCII");
        } catch (final UnsupportedEncodingException uee) {
            return 0;
        }
        bufferIndex += len + 1;
        // win98 observed not returning nativeFileSystem
        // Problems here with iSeries returning ASCII even though useUnicode = true
        // Fortunately we don't really need nativeFileSystem for anything.

import static com.google.common.collect.Lists.charactersOf;
import static com.google.common.truth.Truth.assertThat;

import com.google.common.annotations.GwtCompatible;
import com.google.common.base.Ascii;
import com.google.common.collect.testing.SpliteratorTester;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Spliterator;
import java.util.stream.DoubleStream;

        try {
            service = new String(buffer, bufferIndex, len, "ASCII");
        } catch (final UnsupportedEncodingException uee) {
            return 0;
        }
        bufferIndex += len + 1;
        // win98 observed not returning nativeFileSystem
        /* Problems here with iSeries returning ASCII even though useUnicode = true
         * Fortunately we don't really need nativeFileSystem for anything.

   *
   * <p>This method accepts non-ASCII digits, for example {@code "１９２.１６８.０.１"} (those are fullwidth
   * characters). That is consistent with {@link InetAddress}, but not with various RFCs. If you
   * want to accept ASCII digits only, you can use something like {@code
   * CharMatcher.ascii().matchesAllOf(ipString)}.
   *