////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2017-2023 The Octave Project Developers
//
// See the file COPYRIGHT.md in the top-level directory of this
// distribution or <https://octave.org/copyright/>.
//
// This file is part of Octave.
//
// Octave is free software: you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Octave is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Octave; see the file COPYING.  If not, see
// <https://www.gnu.org/licenses/>.
//
////////////////////////////////////////////////////////////////////////

// Extracted from urlwrite.cc.

#if defined (HAVE_CONFIG_H)
#  include "config.h"
#endif

#include <cmath>

#include "url-handle-manager.h"

OCTAVE_BEGIN_NAMESPACE(octave)

static double
make_handle_fraction ()
{
  static double maxrand = RAND_MAX + 2.0;

  return (rand () + 1.0) / maxrand;
}

url_handle
url_handle_manager::get_handle ()
{
  url_handle retval;

  // Curl handles are negative integers plus some random fractional
  // part.  To avoid running out of integers, we recycle the integer
  // part but tack on a new random part each time.

  auto p = m_handle_free_list.begin ();

  if (p != m_handle_free_list.end ())
    {
      retval = *p;
      m_handle_free_list.erase (p);
    }
  else
    {
      retval = url_handle (m_next_handle);

      m_next_handle = std::ceil (m_next_handle) - 1.0 - make_handle_fraction ();
    }

  return retval;
}

void
url_handle_manager::free (const url_handle& h)
{
  if (h.ok ())
    {
      auto p = m_handle_map.find (h);

      if (p == m_handle_map.end ())
        error ("url_handle_manager::free: invalid object %g", h.value ());

      // Curl handles are negative integers plus some random
      // fractional part.  To avoid running out of integers, we
      // recycle the integer part but tack on a new random part
      // each time.

      m_handle_map.erase (p);

      if (h.value () < 0)
        m_handle_free_list.insert
        (std::ceil (h.value ()) - make_handle_fraction ());
    }
}

OCTAVE_END_NAMESPACE(octave)