/*
 * Copyright (C) 2009 Archie L. Cobbs. All rights reserved.
 *
 * $Id: InputStream.java 2 2009-12-17 02:39:56Z archie.cobbs $
 */

package java.io;

public abstract class InputStream {

    public abstract int read() throws IOException;

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

    public int read(byte[] buf, int off, int len) throws IOException {
        if (off < 0 || len < 0 || off + len < 0 || off + len > buf.length)
            throw new IndexOutOfBoundsException();
        if (len == 0)
            return 0;
        int x = read();
        if (x == -1)
            return -1;
        buf[off] = (byte)x;
        int total = 1;
        while (total < len) {
            try {
                x = read();
            } catch (IOException e) {
                break;
            }
            if (x == -1)
                break;
            buf[off + total++] = (byte)x;
        }
        return total;
    }

    public long skip(long n) throws IOException {
        byte[] buf = new byte[1024];
        long total = 0;
        while (n > 0) {
            int r = read(buf, 0, Math.min((int)n, buf.length));
            if (r <= 0)
                break;
            total += r;
            n -= r;
        }
        return total;
    }

    public int available() throws IOException {
        return 0;
    }

    public void close() throws IOException {
    }

    public void mark(int readlimit) {
    }

    public void reset() throws IOException {
        throw new IOException();
    }

    public boolean markSupported() {
        return false;
    }
}