Java DataInputStream Read Long readLongString(DataInputStream in)

Description

This is a copy of DataInputStream#readUTF(DataInput) with the main difference that the length is not read as a short but as a long.

License

Apache License

Declaration

@SuppressWarnings("cast")
public final static String readLongString(DataInputStream in) throws IOException 

Method Source Code

//package com.java2s;
/*-------------------------------------------------------------------------+
|                                                                          |
| Copyright 2005-2011 the ConQAT Project                                   |
|                                                                          |
| 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.io.DataInputStream;

import java.io.IOException;
import java.io.UTFDataFormatException;

public class Main {
    /**// w w  w .j a  va 2  s . co  m
     * This is a copy of {@link DataInputStream#readUTF(DataInput)} with the
     * main difference that the length is not read as a short but as a long.
     */
    @SuppressWarnings("cast")
    public final static String readLongString(DataInputStream in) throws IOException {
        int utflen = (int) in.readLong();
        byte[] bytearr = new byte[utflen];
        char[] chararr = new char[utflen];

        int c, char2, char3;
        int count = 0;
        int chararr_count = 0;

        in.readFully(bytearr, 0, utflen);

        while (count < utflen) {
            c = (int) bytearr[count] & 0xff;
            if (c > 127)
                break;
            count++;
            chararr[chararr_count++] = (char) c;
        }

        while (count < utflen) {
            c = (int) bytearr[count] & 0xff;
            switch (c >> 4) {
            case 0:
            case 1:
            case 2:
            case 3:
            case 4:
            case 5:
            case 6:
            case 7:
                /* 0xxxxxxx */
                count++;
                chararr[chararr_count++] = (char) c;
                break;
            case 12:
            case 13:
                /* 110x xxxx 10xx xxxx */
                count += 2;
                if (count > utflen)
                    throw new UTFDataFormatException("malformed input: partial character at end");
                char2 = (int) bytearr[count - 1];
                if ((char2 & 0xC0) != 0x80)
                    throw new UTFDataFormatException("malformed input around byte " + count);
                chararr[chararr_count++] = (char) (((c & 0x1F) << 6) | (char2 & 0x3F));
                break;
            case 14:
                /* 1110 xxxx 10xx xxxx 10xx xxxx */
                count += 3;
                if (count > utflen)
                    throw new UTFDataFormatException("malformed input: partial character at end");
                char2 = (int) bytearr[count - 2];
                char3 = (int) bytearr[count - 1];
                if (((char2 & 0xC0) != 0x80) || ((char3 & 0xC0) != 0x80))
                    throw new UTFDataFormatException("malformed input around byte " + (count - 1));
                chararr[chararr_count++] = (char) (((c & 0x0F) << 12) | ((char2 & 0x3F) << 6)
                        | ((char3 & 0x3F) << 0));
                break;
            default:
                /* 10xx xxxx, 1111 xxxx */
                throw new UTFDataFormatException("malformed input around byte " + count);
            }
        }
        // The number of chars produced may be less than utflen
        return new String(chararr, 0, chararr_count);
    }
}

Related

1. readLong(DataInputStream dataStream)
2. readLong(DataInputStream inputStream)
3. readLong(final DataInputStream in)
4. readLong(final DataInputStream in)