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DSS Model contains the data model representation for DSS
There is a newer version: 6.0.d4j.2
package port.org.bouncycastle.util;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;

public final class Strings {

	public static String fromUTF8ByteArray(byte[] bytes) {
		int i = 0;
		int length = 0;

		while (i < bytes.length) {
			length++;
			if ((bytes[i] & 0xf0) == 0xf0) {
				// surrogate pair
				length++;
				i += 4;
			} else if ((bytes[i] & 0xe0) == 0xe0) {
				i += 3;
			} else if ((bytes[i] & 0xc0) == 0xc0) {
				i += 2;
			} else {
				i += 1;
			}
		}

		char[] cs = new char[length];

		i = 0;
		length = 0;

		while (i < bytes.length) {
			char ch;

			if ((bytes[i] & 0xf0) == 0xf0) {
				int codePoint = ((bytes[i] & 0x03) << 18) | ((bytes[i + 1] & 0x3F) << 12) | ((bytes[i + 2] & 0x3F) << 6) | (bytes[i + 3] & 0x3F);
				int U = codePoint - 0x10000;
				char W1 = (char) (0xD800 | (U >> 10));
				char W2 = (char) (0xDC00 | (U & 0x3FF));
				cs[length++] = W1;
				ch = W2;
				i += 4;
			} else if ((bytes[i] & 0xe0) == 0xe0) {
				ch = (char) (((bytes[i] & 0x0f) << 12) | ((bytes[i + 1] & 0x3f) << 6) | (bytes[i + 2] & 0x3f));
				i += 3;
			} else if ((bytes[i] & 0xd0) == 0xd0) {
				ch = (char) (((bytes[i] & 0x1f) << 6) | (bytes[i + 1] & 0x3f));
				i += 2;
			} else if ((bytes[i] & 0xc0) == 0xc0) {
				ch = (char) (((bytes[i] & 0x1f) << 6) | (bytes[i + 1] & 0x3f));
				i += 2;
			} else {
				ch = (char) (bytes[i] & 0xff);
				i += 1;
			}

			cs[length++] = ch;
		}

		return new String(cs);
	}

	public static byte[] toUTF8ByteArray(String string) {
		return toUTF8ByteArray(string.toCharArray());
	}

	public static byte[] toUTF8ByteArray(char[] string) {
		ByteArrayOutputStream bOut = new ByteArrayOutputStream();

		try {
			toUTF8ByteArray(string, bOut);
		} catch (IOException e) {
			throw new IllegalStateException("cannot encode string to byte array!");
		}

		return bOut.toByteArray();
	}

	public static void toUTF8ByteArray(char[] string, OutputStream sOut) throws IOException {
		char[] c = string;
		int i = 0;

		while (i < c.length) {
			char ch = c[i];

			if (ch < 0x0080) {
				sOut.write(ch);
			} else if (ch < 0x0800) {
				sOut.write(0xc0 | (ch >> 6));
				sOut.write(0x80 | (ch & 0x3f));
			}
			// surrogate pair
			else if ((ch >= 0xD800) && (ch <= 0xDFFF)) {
				// in error - can only happen, if the Java String class has a
				// bug.
				if ((i + 1) >= c.length) {
					throw new IllegalStateException("invalid UTF-16 codepoint");
				}
				char W1 = ch;
				ch = c[++i];
				char W2 = ch;
				// in error - can only happen, if the Java String class has a
				// bug.
				if (W1 > 0xDBFF) {
					throw new IllegalStateException("invalid UTF-16 codepoint");
				}
				int codePoint = (((W1 & 0x03FF) << 10) | (W2 & 0x03FF)) + 0x10000;
				sOut.write(0xf0 | (codePoint >> 18));
				sOut.write(0x80 | ((codePoint >> 12) & 0x3F));
				sOut.write(0x80 | ((codePoint >> 6) & 0x3F));
				sOut.write(0x80 | (codePoint & 0x3F));
			} else {
				sOut.write(0xe0 | (ch >> 12));
				sOut.write(0x80 | ((ch >> 6) & 0x3F));
				sOut.write(0x80 | (ch & 0x3F));
			}

			i++;
		}
	}

	public static byte[] toByteArray(String string) {
		byte[] bytes = new byte[string.length()];

		for (int i = 0; i != bytes.length; i++) {
			char ch = string.charAt(i);

			bytes[i] = (byte) ch;
		}

		return bytes;
	}

	/**
	 * Convert an array of 8 bit characters into a string.
	 *
	 * @param bytes
	 *            8 bit characters.
	 * @return resulting String.
	 */
	public static String fromByteArray(byte[] bytes) {
		return new String(asCharArray(bytes));
	}

	/**
	 * Do a simple conversion of an array of 8 bit characters into a string.
	 *
	 * @param bytes
	 *            8 bit characters.
	 * @return resulting String.
	 */
	public static char[] asCharArray(byte[] bytes) {
		char[] chars = new char[bytes.length];

		for (int i = 0; i != chars.length; i++) {
			chars[i] = (char) (bytes[i] & 0xff);
		}

		return chars;
	}

}