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LineInputStream.javaAPI DocJavaMail 1.4.34201Tue Nov 17 10:38:12 GMT 2009com.sun.mail.util

LineInputStream

public class LineInputStream extends FilterInputStream
This class is to support reading CRLF terminated lines that contain only US-ASCII characters from an input stream. Provides functionality that is similar to the deprecated DataInputStream.readLine(). Expected use is to read lines as String objects from a RFC822 stream. It is implemented as a FilterInputStream, so one can just wrap this class around any input stream and read bytes from this filter.
author
John Mani

Fields Summary
private char[]
lineBuffer
Constructors Summary
public LineInputStream(InputStream in)

 // reusable byte buffer

       
	super(in);
    
Methods Summary
public java.lang.StringreadLine()
Read a line containing only ASCII characters from the input stream. A line is terminated by a CR or NL or CR-NL sequence. A common error is a CR-CR-NL sequence, which will also terminate a line. The line terminator is not returned as part of the returned String. Returns null if no data is available.

This class is similar to the deprecated DataInputStream.readLine()

	InputStream in = this.in;
	char[] buf = lineBuffer;

	if (buf == null)
	    buf = lineBuffer = new char[128];

	int c1;
	int room = buf.length;
	int offset = 0;

	while ((c1 = in.read()) != -1) {
	    if (c1 == '\n") // Got NL, outa here.
		break;
	    else if (c1 == '\r") {
		// Got CR, is the next char NL ?
		int c2 = in.read();
		if (c2 == '\r")		// discard extraneous CR
		    c2 = in.read();
		if (c2 != '\n") {
		    // If not NL, push it back
		    if (!(in instanceof PushbackInputStream))
			in = this.in = new PushbackInputStream(in);
		    ((PushbackInputStream)in).unread(c2);
		}
		break; // outa here.
	    }

	    // Not CR, NL or CR-NL ...
	    // .. Insert the byte into our byte buffer
	    if (--room < 0) { // No room, need to grow.
		buf = new char[offset + 128];
		room = buf.length - offset - 1;
		System.arraycopy(lineBuffer, 0, buf, 0, offset);
		lineBuffer = buf;
	    }
	    buf[offset++] = (char)c1;
	}

	if ((c1 == -1) && (offset == 0))
	    return null;
	
	return String.copyValueOf(buf, 0, offset);