/*******************************************************************************
 * Copyright (c) 2000, 2011 QNX Software Systems and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *******************************************************************************/
package org.eclipse.cdt.utils.spawner;

import java.io.*;

import com.google.eclipse.cdt.core.CCorePlugin;

class SpawnerInputStream extends InputStream {
  private int fd;

  /**
   * From a Unix valid file descriptor set a Reader.
   * @param fd file descriptor.
   */
  public SpawnerInputStream(int fd) {
    this.fd = fd;
  }

  @Override public int read() throws IOException {
    byte b[] = new byte[1];
    if (1 != read(b, 0, 1)) {
      return -1;
    }
    return b[0];
  }

  @Override public int read(byte[] buf, int off, int len) throws IOException {
    if (buf == null) {
      throw new NullPointerException();
    } else if ((off < 0) || (off > buf.length) || (len < 0) || ((off + len) > buf.length) || ((off + len) < 0)) {
      throw new IndexOutOfBoundsException();
    } else if (len == 0) {
      return 0;
    }
    byte[] tmpBuf = off > 0 ? new byte[len] : buf;

    len = read0(fd, tmpBuf, len);
    if (len <= 0) {
      return -1;
    }

    if (tmpBuf != buf) {
      System.arraycopy(tmpBuf, 0, buf, off, len);
    }
    return len;
  }

  @Override public void close() throws IOException {
    if (fd == -1) {
      return;
    }
    int status = close0(fd);
    if (status == -1) {
      throw new IOException(CCorePlugin.getResourceString("Util.exception.closeError"));
    }
    fd = -1;
  }

  @Override public int available() throws IOException {
    try {
      return available0(fd);
    } catch (UnsatisfiedLinkError e) {
      // for those platforms that do not implement available0
      return super.available();
    }
  }

  @Override protected void finalize() throws IOException {
    close();
  }

  private native int read0(int fileDesc, byte[] buf, int len) throws IOException;

  private native int close0(int fileDesc) throws IOException;

  private native int available0(int fileDesc) throws IOException;

  static {
    System.loadLibrary(Spawner.LIBRARY_NAME);
  }
}