Java BufferedReader for zero-terminated strings

Question

I need to read zero-terminated strings from InputStream in Java.

Is there similar to BufferedReader.readLine() method for reading zero-termianted strings?

Answer 1

No. Java doesn't recognise a zero-terminated string as such. You'll have to read the InputStream and look for a 0 byte.

Note that this doesn't address the issue of character-encoding. The InputStream will give you the stream of bytes, and you'll then have to encode to characters via a Reader. If you have a multi-byte character encoding then the issue becomes more complex.

Answer 2

You could enter create a method similar to the one bellow. Creating a BufferedReader from an InputStream. BufferedReader passed by reference so will retain state. Could be easily stored as an instance variable either.

public String readLine(BufferedReader buff) throws IOException{
 int c = buff.read();
 // if EOF
 if (c == -1){
  return null;
 }
 StringBuilder builder = new StringBuilder("");
 // Check if new line or EOF
 while (c != -1 && c != 0){
  builder.append((char) c);
  c = buff.read();
 }
 return builder.toString();
}

....

String line = reader.readLine(buff);
while (line != null)
{
System.out.println(line);
line = reader.readLine(someBufferedReader);

}

Answer 3

you will also need to understand what is that "zero" means . input/output streams deal with bytes whereas readers/writers deal with characters. if you want to match against a zero character then byte to char conversion encoding will come into play.

Answer 4

package com;

import java.io.*;
import java.util.Scanner;

public class AAA {

    private static final String ENCODING = "UTF-8";

    public static void main(String[] args) throws Exception {
        ByteArrayOutputStream bOut = new ByteArrayOutputStream();
        bOut.write("the first line".getBytes(ENCODING));
        bOut.write(0);
        bOut.write("the second line\r\n (long one)".getBytes(ENCODING));
        bOut.write(0);
        bOut.write("the third line".getBytes(ENCODING));
        printLines(new ByteArrayInputStream(bOut.toByteArray()));
    }

    public static void printLines(InputStream in) {
        Scanner scanner = new Scanner(in, ENCODING);
        scanner.useDelimiter("\u0000");
        while (scanner.hasNext()) {
            System.out.println(scanner.next());
            System.out.println("--------------------------------");
        }
    }
}