Java UTF from toUtf8Codes(String str)

Description

convert string to utf8 codes

License

Apache License

Parameter

Parameter	Description
str	not null

Declaration

public static int[] toUtf8Codes(String str) 

Method Source Code

//package com.java2s;
/*//from  ww  w. ja  va  2 s  .  c o m
 * Copyright (C) 2014-2015 Nagisa Sekiguchi
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.List;

public class Main {
    public final static Charset DEFAULT_CHARSET = Charset.forName("UTF-8");
    /**
     * for utf8. drop support 5-6 byte character
     */
    private final static byte[] utf8SkipData = { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
            1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
            1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
            1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
            1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
            1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2,
            2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3,
            3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 1, 1, 1, 1, 1, 1, 1, 1 };

    /**
     * convert string to utf8 codes
     *
     * @param str not null
     * @return
     */
    public static int[] toUtf8Codes(String str) {
        byte[] buf = str.getBytes(DEFAULT_CHARSET);
        int startIndex = 0;
        List<Integer> utf8CodeList = new ArrayList<>();

        while (startIndex < buf.length) {
            byte b = buf[startIndex];
            int charLength = getUtf8Length(b);
            utf8CodeList.add(toUtf8Code(buf, startIndex, charLength));
            startIndex += charLength;
        }

        final int size = utf8CodeList.size();
        int[] utf8Codes = new int[size];
        for (int i = 0; i < size; i++) {
            utf8Codes[i] = utf8CodeList.get(i);
        }
        return utf8Codes;
    }

    /**
     * get length of utf8 character
     *
     * @param ch start character.
     * @return
     */
    public static int getUtf8Length(byte ch) {
        return utf8SkipData[Byte.toUnsignedInt(ch)];
    }

    /**
     * convert java character literal to utf8 code
     *
     * @param utf16 java character literal
     * @return utf8 code
     */
    public static int toUtf8Code(char utf16) {
        byte[] buf = Character.toString(utf16).getBytes(DEFAULT_CHARSET);
        return toUtf8Code(buf, 0, buf.length);
    }

    /**
     * convert unicode code point to utf8 code
     *
     * @param codePoint
     * @return utf8 code
     */
    public static int toUtf8Code(int codePoint) {
        byte[] buf = new String(Character.toChars(codePoint)).getBytes(DEFAULT_CHARSET);
        return toUtf8Code(buf, 0, buf.length);
    }

    /**
     * convert byte array to utf8 code
     *
     * @param buf
     * @param startIndex
     * @param charLength 1, 2, 3 or 4
     * @return utf8 code
     */
    public static int toUtf8Code(byte[] buf, int startIndex, int charLength) {
        switch (charLength) {
        case 1:
            return buf[startIndex];
        case 2:
            return (Byte.toUnsignedInt(buf[startIndex]) << 8) | Byte.toUnsignedInt(buf[++startIndex]);
        case 3:
            return (Byte.toUnsignedInt(buf[startIndex]) << 16) | (Byte.toUnsignedInt(buf[++startIndex]) << 8)
                    | Byte.toUnsignedInt(buf[++startIndex]);
        case 4:
            return (Byte.toUnsignedInt(buf[startIndex]) << 24) | (Byte.toUnsignedInt(buf[++startIndex]) << 16)
                    | (Byte.toUnsignedInt(buf[++startIndex]) << 8) | Byte.toUnsignedInt(buf[++startIndex]);
        default:
            throw new RuntimeException("broken string");
        }
    }
}

Related

1. toUTF8(String string)
2. toUtf8(String texto)
3. toUTF8ByteArray(String s)
4. toUtf8ByteArray(String source)
5. toUtf8Code(char utf16)
6. toUTF8FromLatin1(byte[] outputBuffer, String string)
7. toUTF8k(String in)
8. toUtf8Path(String path)
9. toUTF8String(byte[] b, int offset, int length)