// Warning to maintainers: this implementation is highly optimized.
    int utf16Length = sequence.length();
    int utf8Length = utf16Length;
    int i = 0;

    // This loop optimizes for pure ASCII.
    while (i < utf16Length && sequence.charAt(i) < 0x80) {
      i++;
    }

    // This loop optimizes for chars less than 0x800.
    for (; i < utf16Length; i++) {
      char c = sequence.charAt(i);

      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

      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

        try {
            service = new String( buffer, bufferIndex, len, "ASCII" );
        } catch( 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.

 *
 * @author Mike Bostock
 * @since 1.0
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public final class Charsets {
  private Charsets() {}

  /**
   * US-ASCII: seven-bit ASCII, the Basic Latin block of the Unicode character set (ISO646-US).
   *
   * <p><b>Note:</b> this constant is now unnecessary and should be treated as deprecated; use
   * {@link StandardCharsets#US_ASCII} instead.
   *

    assertEquals("&lt;tab&gt;", xmlEscaper.escape("<tab>"));

    // Test all non-escaped ASCII characters.
    String s =
        "!@#$%^*()_+=-/?\\|]}[{,.;:"
            + "abcdefghijklmnopqrstuvwxyz"
            + "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
            + "1234567890";
    assertEquals(s, xmlEscaper.escape(s));

    // Test ASCII control characters.
    for (char ch = 0; ch < 0x20; ch++) {

    assert response.json() == {"detail": "Invalid authentication credentials"}


def test_security_http_basic_non_basic_credentials():
    payload = b64encode(b"johnsecret").decode("ascii")
    auth_header = f"Basic {payload}"
    response = client.get("/users/me", headers={"Authorization": auth_header})
    assert response.status_code == 401, response.text
    assert response.headers["WWW-Authenticate"] == "Basic"

 * lookups.
 *
 * <p>During construction, names are normalized in two ways:
 *
 * <ol>
 *   <li>ASCII uppercase characters are converted to lowercase.
 *   <li>Unicode dot separators other than the ASCII period ({@code '.'}) are converted to the ASCII
 *       period.
 * </ol>
 *
 * <p>The normalized values will be returned from {@link #toString()} and {@link #parts()}, and will

      return "CharMatcher.breakingWhitespace()";
    }
  }

  /** Implementation of {@link #ascii()}. */
  private static final class Ascii extends NamedFastMatcher {

    static final CharMatcher INSTANCE = new Ascii();

    Ascii() {
      super("CharMatcher.ascii()");
    }

    @Override
    public boolean matches(char c) {
      return c <= '\u007f';
    }
  }

 * library.
 *
 * <h2>Contents</h2>
 *
 * The classes in this package that are most commonly useful are:
 *
 * <h3>String utilities</h3>
 *
 * <ul>
 *   <li>{@link Ascii}
 *   <li>{@link CaseFormat}
 *   <li>{@link CharMatcher}
 *   <li>{@link Splitter}
 *   <li>{@link Strings}
 * </ul>
 *
 * <h3>Function types</h3>
 *
 * <ul>
 *   <li>{@link Converter}