package ranab.io;

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

/**
 * Read ASCII data. It filters out the ASCII data from the 
 * <code>InputStream</code>.
 * 
 * @author <a href="mailto:rana_b@yahoo.com">Rana Bhattacharyya</a>
 */
public
class AsciiInputStream extends InputStream {
    
    private long mlActualByteRead    = 0;
    private boolean mbIgnoreNonAscii = true;
    private InputStream mInputStream;
    
    /**
     * Constructor
     * @param is <code>InputStream</code> to be filtered.
     */
    public AsciiInputStream(InputStream is) {
        mInputStream = is;
    }
     
    /**
     * Read a single character. Change "\r\n" to "\n". 
     */
    public int read() throws IOException {
        int c;
        while ( (c = actualRead()) != -1) {
            if (c == '\r') {
                continue;
            }
            if (mbIgnoreNonAscii && (c > 0x7F) ) {
                continue;
            }
            break;
        }
        return c;
    }
     
    /**
     * Close stream
     */ 
    public void close() throws IOException {
        mInputStream.close();
    }    
        
    /**
     * read actual data from the stream
     */
    private int actualRead() throws IOException {
        int c = mInputStream.read();
        if (c != -1) {
            ++mlActualByteRead;
        }
        return c;
    }
     
    /**
     * Get actual byte read.
     */
    public long getActualByteRead() {
        return mlActualByteRead;
    }
     
    /**
     * Is non ascii character ignored. 
     * If true don't read non-ascii character.
     * Else first convert it to ascii by ANDing with 0x7F. 
     */
    public boolean getIsIgnoreNonAscii() {
        return mbIgnoreNonAscii;
    }
    
    /**
     * Set non-ascii ignore boolean value.
     */
    public void setIsIgnoreNonAscii(boolean ig) {
      mbIgnoreNonAscii = ig;  
    }
}