Java ByteBuffer Set validBytesUTF8(ByteBuffer buf, int offset, int limit)

Description

valid Bytes UTF

License

Open Source License

Declaration

public static boolean validBytesUTF8(ByteBuffer buf, int offset, int limit) 

Method Source Code

//package com.java2s;
/**// w ww . j  av a2s .  c o  m
 * Copyright 2007-2015, Kaazing Corporation. All rights reserved.
 *
 * 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 static java.lang.String.format;

import java.nio.ByteBuffer;

public class Main {
    public static boolean validBytesUTF8(byte[] input) {
        for (int index = 0; index < input.length;) {
            byte leadingByte = input[index++];
            if ((leadingByte & 0xc0) == 0x80) {
                return false;
            }
            int remaining = remainingBytesUTF8(leadingByte);
            switch (remaining) {
            case 0:
                break;
            default:
                while (remaining-- > 0) {
                    if ((input[index++] & 0xc0) != 0x80) {
                        return false;
                    }
                }
            }
        }

        return true;
    }

    public static boolean validBytesUTF8(ByteBuffer buf, int offset, int limit) {
        for (int index = offset; index < limit;) {
            byte leadingByte = buf.get(index++);
            if ((leadingByte & 0xc0) == 0x80) {
                return false;
            }
            int remaining = remainingBytesUTF8(leadingByte);
            switch (remaining) {
            case 0:
                break;
            default:
                while (remaining-- > 0) {
                    if ((buf.get(index++) & 0xc0) != 0x80) {
                        return false;
                    }
                }
            }
        }

        return true;
    }

    public static int remainingBytesUTF8(int leadingByte) {
        if ((leadingByte & 0x80) == 0) {
            return 0;
        }

        for (byte i = 0; i < 7; i++) {
            int bitMask = 1 << (7 - i);

            if ((leadingByte & bitMask) != 0) {
                continue;
            } else {
                switch (i) {
                case 0:
                case 7:
                    throw new IllegalStateException(
                            format("Invalid UTF-8 sequence leader byte: 0x%02x", leadingByte));
                default:
                    return i - 1;
                }
            }
        }

        throw new IllegalStateException(String.format("Invalid UTF-8 sequence leader byte: 0x%02x", leadingByte));
    }
}

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