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//==========================================================================

//

//      ./lib/current/src/mt_support.c

//

//

//==========================================================================

// ####ECOSGPLCOPYRIGHTBEGIN####                                            

// -------------------------------------------                              

// This file is part of eCos, the Embedded Configurable Operating System.   

// Copyright (C) 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.

//

// eCos 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 or (at your option) any later      

// version.                                                                 

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// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License    

// for more details.                                                        

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// You should have received a copy of the GNU General Public License        

// along with eCos; if not, write to the Free Software Foundation, Inc.,    

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//

// As a special exception, if other files instantiate templates or use      

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// this file does not by itself cause the resulting work to be covered by   

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// General Public License v2.                                               

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// ####ECOSGPLCOPYRIGHTEND####                                              

//####UCDSNMPCOPYRIGHTBEGIN####

//

// -------------------------------------------

//

// Portions of this software may have been derived from the UCD-SNMP

// project,  <http://ucd-snmp.ucdavis.edu/>  from the University of

// California at Davis, which was originally based on the Carnegie Mellon

// University SNMP implementation.  Portions of this software are therefore

// covered by the appropriate copyright disclaimers included herein.

//

// The release used was version 4.1.2 of May 2000.  "ucd-snmp-4.1.2"

// -------------------------------------------

//

//####UCDSNMPCOPYRIGHTEND####

//==========================================================================

//#####DESCRIPTIONBEGIN####

//

// Author(s):    hmt

// Contributors: hmt

// Date:         2000-05-30

// Purpose:      Port of UCD-SNMP distribution to eCos.

// Description:  

//              

//

//####DESCRIPTIONEND####

//

//==========================================================================

/********************************************************************

       Copyright 1989, 1991, 1992 by Carnegie Mellon University

                          Derivative Work -

Copyright 1996, 1998, 1999, 2000 The Regents of the University of California

                         All Rights Reserved

Permission to use, copy, modify and distribute this software and its

documentation for any purpose and without fee is hereby granted,

provided that the above copyright notice appears in all copies and

that both that copyright notice and this permission notice appear in

supporting documentation, and that the name of CMU and The Regents of

the University of California not be used in advertising or publicity

pertaining to distribution of the software without specific written

permission.

CMU AND THE REGENTS OF THE UNIVERSITY OF CALIFORNIA DISCLAIM ALL

WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED

WARRANTIES OF MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL CMU OR

THE REGENTS OF THE UNIVERSITY OF CALIFORNIA BE LIABLE FOR ANY SPECIAL,

INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING

FROM THE LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF

CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN

CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

*********************************************************************/

/* mt_support.c - multi-thread resource locking support */

/*

 * Author: Markku Laukkanen

 * Created: 6-Sep-1999

 * History:

 *  8-Sep-1999 M. Slifcak method names changed;

 *                        use array of resource locking structures.

 */

#include <config.h>

#include <errno.h>

#include "mt_support.h"

#ifdef __cplusplus

extern "C" {

#endif

#ifdef _REENTRANT

static

mutex_type s_res[MT_MAX_IDS][MT_LIB_MAXIMUM];  /* locking structures */

static mutex_type * _mt_res(int groupID, int resourceID)

{

    if (groupID < 1) return 0;

    if (groupID >= MT_MAX_IDS) return 0;

    if (resourceID < 1) return 0;

    if (resourceID >= MT_LIB_MAXIMUM) return 0;

    return (&s_res[groupID][resourceID]);

}

static

int snmp_res_init_mutex(mutex_type * mutex)

{

    int rc = 0;

#if HAVE_PTHREAD_H

    rc = pthread_mutex_init(mutex, MT_MUTEX_INIT_DEFAULT);

#elif defined(WIN32)

    InitializeCriticalSection(mutex);

#endif

    return rc;

}

int snmp_res_init(void)

{

    int ii, jj;

    int rc = 0;

    mutex_type *mutex;

  for (jj = 0; (0 == rc) && (jj < MT_MAX_IDS); jj++)

  for (ii = 0; (0 == rc) && (ii < MT_LIB_MAXIMUM); ii++)

  {

    mutex = _mt_res(jj, ii);

    if (!mutex) continue;

    rc = snmp_res_init_mutex( mutex );

  }

    return rc;

}

int snmp_res_destroy_mutex(int groupID, int resourceID)

{

    int rc = 0;

    mutex_type *mutex = _mt_res(groupID, resourceID);

    if (!mutex) return EFAULT;

#if HAVE_PTHREAD_H

    rc = pthread_mutex_destroy(mutex);

#elif defined(WIN32)

    DeleteCriticalSection(mutex);

#endif

    return rc;

}

int snmp_res_lock(int groupID, int resourceID)

{

    int rc = 0;

    mutex_type *mutex = _mt_res(groupID, resourceID);

    if (!mutex) return EFAULT;

#if HAVE_PTHREAD_H

    rc = pthread_mutex_lock(mutex);

#elif defined(WIN32)

    EnterCriticalSection(mutex);

#endif

    return rc;

}

int snmp_res_unlock(int groupID, int resourceID)

{

    int rc = 0;

    mutex_type *mutex = _mt_res(groupID, resourceID);

    if (!mutex) return EFAULT;

#if HAVE_PTHREAD_H

    rc = pthread_mutex_unlock(mutex);

#elif defined(WIN32)

    LeaveCriticalSection(mutex);

#endif

    return rc;

}

#else  /* !_REENTRANT */

#ifdef WIN32

/* Provide "do nothing" targets for Release (.DLL) builds. */

#undef snmp_res_init

#undef snmp_res_lock

#undef snmp_res_unlock

#undef snmp_res_destroy_mutex

int snmp_res_init(void) { return 0; }

int snmp_res_lock(int groupID, int resourceID) { return 0; }

int snmp_res_unlock(int groupID, int resourceID) { return 0; }

int snmp_res_destroy_mutex(int groupID, int resourceID) { return 0; }

#endif /* !WIN32 */

#endif /* !_REENTRANT */

#ifdef __cplusplus

};

#endif