event_gen_release.c

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/*
** Copyright (C) 2005 by Kevin L. Mitchell <klmitch@mit.edu>
**
** This program 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 2 of the License, or
** (at your option) any later version.
**
** This program 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 this program; if not, write to the Free Software
** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
**
** @(#)$Id: event_gen_release.c,v 1.2 2005/10/26 12:53:59 klmitch Exp $
*/
#include "event_int.h"

#include <stdlib.h>

RCSTAG("@(#)$Id: event_gen_release.c,v 1.2 2005/10/26 12:53:59 klmitch Exp $");

ev_err_t
event_gen_release(ev_ctx_t *ctx, ev_genhdr_t *gen)
{
  ev_err_t err;
  ev_gendesc_t *gd;

  ev_init(); /* make sure library is initialized... */

  if (!ec_verify(ctx) || !gen) /* sanity-check arguments */
    ev_return(EINVAL);
  if (gen->eg_flags & EV_GEN_ACTIVE)
    ev_return(EBUSY);

  /* OK, first, let's look up the descriptor for the generator... */
  if ((err = _ev_gen_lookup(ctx, gen->eg_type, &gd)))
    ev_return(err);

  /* One final check--is this a valid generator? */
  if (!eg_verify(gen, gd->gd_magic))
    ev_return(EINVAL);

  /* Let's remove it from the active list... */
  if (gen->eg_next)
    gen->eg_next->eg_prev = gen->eg_prev;
  if (gen->eg_prev)
    gen->eg_prev->eg_next = gen->eg_next;
  else
    gd->gd_active.gl_list = gen->eg_next;

  gd->gd_active.gl_count--; /* decrement the active list count... */

  /* OK, stick it on the free list */
  gen->eg_next = gd->gd_free.gl_list;
  if (gen->eg_next)
    gen->eg_next->eg_prev = gen;
  gd->gd_free.gl_list = gen;

  gd->gd_free.gl_count++; /* and increment the free list count */

  ev_return(0); /* all done! */
}

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