}

    /**
     * Strips invalid XML characters from the input string.
     *
     * This method removes characters that are not allowed in XML documents
     * according to the XML 1.0 specification. Valid characters include:
     * - Tab (0x9)
     * - Line feed (0xA)
     * - Carriage return (0xD)
     * - Any character between 0x20 and 0xD7FF
     * - Any character between 0xE000 and 0xFFFD

   *
   * @param seq the sequence of characters from which to decode the code point
   * @param index the index of the first character to decode
   * @param end the index beyond the last valid character to decode
   * @return the Unicode code point for the given index or the negated value of the trailing high
   *     surrogate character at the end of the sequence
   */
  protected static int codePointAt(CharSequence seq, int index, int end) {

/**
 * Represents a single character mapping rule that defines how input characters are mapped to output characters
 * for text analysis and search processing. This class is used in character mapping dictionaries to transform
 * text during indexing and search operations.
 *
 * <p>Each mapping item consists of one or more input character sequences that are mapped to a single output

   * generalized escaping for characters.
   *
   * <p>Note that arrays returned by this method must not be modified once they have been returned.
   * However it is acceptable to return the same array multiple times (even for different input
   * characters).
   *
   * @param c the character to escape
   * @return the replacement characters, or {@code null} if no escaping was required
   */

import static com.google.common.truth.Truth.assertThat;
import static java.lang.Character.MAX_CODE_POINT;
import static java.lang.Character.MAX_HIGH_SURROGATE;
import static java.lang.Character.MAX_LOW_SURROGATE;
import static java.lang.Character.MIN_HIGH_SURROGATE;
import static java.lang.Character.MIN_LOW_SURROGATE;
import static java.lang.Character.MIN_SUPPLEMENTARY_CODE_POINT;
import static java.nio.charset.StandardCharsets.UTF_8;

        }
        return c;
    }

    /**
     * Merges two characters, handling voiced and semi-voiced sound marks.
     * @param c1 The first character.
     * @param c2 The second character.
     * @return The merged character.
     */
    public static char mergeChar(final char c1, final char c2) {
        if (c2 == 'ﾞ') {

    @Required
    @Size(max = 100)
    public String username;

    /** The password for file authentication (maximum 100 characters). */
    @Size(max = 100)
    public String password;

    /** Additional parameters for file authentication (maximum 1000 characters). */
    @Size(max = 1000)
    public String parameters;

        // Test toString with buffer containing non-printable characters or special unicode
        String unicodeChars = "你好世界"; // "Hello World" in Chinese
        UnicodeString unicodeStringChinese = new UnicodeString(unicodeChars, false);
        assertEquals(unicodeChars, unicodeStringChinese.toString(), "toString should handle unicode characters correctly");

     * The name of the access token.
     * This is a required field with a maximum length of 1000 characters.
     */
    @Required
    @Size(max = 1000)
    public String name;

    /**
     * The actual access token string.
     * This is the token value that will be used for authentication.
     * Maximum length is 10000 characters.
     */
    @Size(max = 10000)
    public String token;

    /**

 * <td>bytes</td>
 * <td>characters</td>
 * <td>bytes, characters</td>
 * <td>characters</td>
 * </tr>
 * <tr>
 * <th>{@link Reader}</th>
 * <td>characters</td>
 * <td>characters</td>
 * <td>characters</td>
 * <td>characters</td>
 * </tr>
 * <tr>
 * <th>{@link File}</th>
 * <td>bytes</td>
 * <td>characters</td>
 * <td>bytes, characters</td>
 * <td>characters</td>
 * </tr>
 * <tr>