Minimal InputStream subclass to fetch bytes form a String : InputStream « File « Java Tutorial

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import java.io.IOException;
import java.io.InputStream;

/**
 * minimal InputStream subclass to fetch bytes form a String
 *
 * @author Fred Toussi (fredt@users dot sourceforge.net)
 * @version 1.7.0
 */
public class StringInputStream extends InputStream {

    protected int    strOffset  = 0;
    protected int    charOffset = 0;
    protected int    available;
    protected String str;

    public StringInputStream(String s) {
        str       = s;
        available = s.length() * 2;
    }

    public int read() throws java.io.IOException {

        if (available == 0) {
            return -1;
        }

        available--;

        char c = str.charAt(strOffset);

        if (charOffset == 0) {
            charOffset = 1;

            return (c & 0x0000ff00) >> 8;
        } else {
            charOffset = 0;

            strOffset++;

            return c & 0x000000ff;
        }
    }

    public int available() throws IOException {
        return available;
    }
}