package com.trilead.ssh2.channel;

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

/**
 * ChannelInputStream.
 *
 * @author Christian Plattner, plattner@trilead.com
 * @version $Id: ChannelInputStream.java,v 1.1 2007/10/15 12:49:56 cplattne Exp $
 */
public final class ChannelInputStream extends InputStream {
    Channel c;

    boolean isClosed = false;
    boolean isEOF = false;
    boolean extendedFlag = false;

    ChannelInputStream(Channel c, boolean isExtended) {
        this.c = c;
        this.extendedFlag = isExtended;
    }

    public int available() throws IOException {
        if (isEOF)
            return 0;

        int avail = c.cm.getAvailable(c, extendedFlag);
        /* We must not return -1 on EOF */
        return (avail > 0) ? avail : 0;
    }

    public void close() throws IOException {
        isClosed = true;
    }

    public int read(byte[] b, int off, int len) throws IOException {
        if (b == null)
            throw new NullPointerException();

        if ((off < 0) || (len < 0) || ((off + len) > b.length) || ((off + len) < 0) || (off > b.length))
            throw new IndexOutOfBoundsException();

        if (len == 0)
            return 0;

        if (isEOF)
            return -1;

        int ret = c.cm.getChannelData(c, extendedFlag, b, off, len);

        if (ret == -1) {
            isEOF = true;
        }

        return ret;
    }

    public int read(byte[] b) throws IOException {
        return read(b, 0, b.length);
    }

    public int read() throws IOException {
        /* Yes, this stream is pure and unbuffered, a single byte read() is slow */
        final byte b[] = new byte[1];
        int ret = read(b, 0, 1);

        if (ret != 1)
            return -1;

        return b[0] & 0xff;
    }
}