Binary and ASCII

[mac]

Guys, how can I check if a file I am about to open is binary or ASCII

[quad64bit]

well... ASCII is binary too :D I don't know of a way to auto-detect, since many plain binary sequences do represent real ascii characters, it'd be hard to tell just by looking at the file (with java, not your eyes).

[pbrockway2]

Now posted at New To Java - Binary or ASCII (Sun forums)

@OP: It would be good to actually tell the rest of us (and link) when the discussion is going on at other places.

[JosAH]

well... ASCII is binary too :D I don't know of a way to auto-detect, since many plain binary sequences do represent real ascii characters, it'd be hard to tell just by looking at the file (with java, not your eyes).

Not that it matters much but there are filing systems that keep a 'type' word with every file: text, binary, executable, script etc. Os Z comes to mind but I don't think Java is implemented for those beasts.

kind regards,

Jos

[FON]

I encountered this issue, while working with files
that contained words from foreign alphabets so I used this code:

import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CharacterCodingException;

/**
	Test if char is ASCII or not
*/


public class TestAscii {

	public static void main (String args[])
	throws Exception {
		// this String throws an Exception, it contains an accented letter
		String test = "Réal";
		// this String is OK
		//String test = "Real";

		byte bytearray []  = test.getBytes();
		System.out.println("Test string : " + test);

		CharsetDecoder d = Charset.forName("US-ASCII").newDecoder();
		try {
			CharBuffer r = d.decode(ByteBuffer.wrap(bytearray));
			r.toString();
		}
		catch(CharacterCodingException e) {
			System.out.println("only regular ASCII characters please!");
			// interrupt the processing
			throw new Exception(e);
		}
		System.out.println("Ok, it's ASCII only!");
	}
}