// natSelectorImplPosix.cc

/* Copyright (C) 2002, 2003  Free Software Foundation

   This file is part of libgcj.

This software is copyrighted work licensed under the terms of the
Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
details.  */

#include <config.h>
#include <platform.h>

#include <errno.h>
#include <string.h>

#include <gnu/java/nio/SelectorImpl.h>
#include <java/io/IOException.h>

static void
helper_put_filedescriptors (jintArray fdArray, fd_set& fds, int& max_fd)
{
  jint* tmpFDArray = elements (fdArray);

  for (int index = 0; index < JvGetArrayLength (fdArray); index++)
    {
      FD_SET (tmpFDArray [index], &fds);

      if (tmpFDArray [index] > max_fd)
        max_fd = tmpFDArray [index];
    }
}

static void
helper_get_filedescriptors (jintArray& fdArray, fd_set fds)
{
  jint* tmpFDArray = elements (fdArray);
  
  for (int index = 0; index < JvGetArrayLength (fdArray); index++)
    if (!FD_ISSET (tmpFDArray [index], &fds))
      tmpFDArray [index] = 0;
}

jint
gnu::java::nio::SelectorImpl::implSelect (jintArray read, jintArray write,
                                          jintArray except, jlong timeout)
{
  jint result;
  int max_fd = 0;
  fd_set read_fds;
  fd_set write_fds;
  fd_set except_fds;
  struct timeval real_time_data;
  struct timeval *time_data = NULL;

  real_time_data.tv_sec = 0;
  real_time_data.tv_usec = timeout;

  // If not legal timeout value is given, use NULL.
  // This means an infinite timeout. The specification
  // also says that a zero timeout should be treated
  // as infinite.
  if (timeout > 0)
    {
      time_data = &real_time_data;
    }

  // Reset all fd_set structures
  FD_ZERO (&read_fds);
  FD_ZERO (&write_fds);
  FD_ZERO (&except_fds);

  // Fill the fd_set data structures for the _Jv_select() call.
  helper_put_filedescriptors (read, read_fds, max_fd);
  helper_put_filedescriptors (write, write_fds, max_fd);
  helper_put_filedescriptors (except, except_fds, max_fd);

  // Actually do the select
  result = _Jv_select (max_fd + 1, &read_fds, &write_fds, &except_fds, time_data);

  if (result < 0)
    {
      char* strerr = strerror (errno);
      throw new ::java::io::IOException (JvNewStringUTF (strerr));
    }

  // Set the file descriptors according to the values returned from select().
  helper_get_filedescriptors (read, read_fds);
  helper_get_filedescriptors (write, write_fds);
  helper_get_filedescriptors (except, except_fds);

  return result;
}