/* fmtno.c: NULL OBJECT FORMAT IMPLEMENTATION
 *
 *  $Id: //info.ravenbrook.com/project/mps/version/1.113/code/fmtno.c#1 $
 *  Copyright (c) 2001 Ravenbrook Limited.  See end of file for license.
 *
 * .readership: MPS developers
 */


#include "fmtno.h"
#include "mps.h"
#include <assert.h>
#include <string.h>
#include <stdlib.h>


#define notreached()    assert(0)
#define unused(param)   ((void)param)

#ifdef MPS_BUILD_MV

/* MSVC 2.0 generates a warning for unused(). */
#ifdef _MSC_VER
#if _MSC_VER < 1000
#pragma warning(disable: 4705)
#endif
#else /* _MSC_VER */
#error "Expected _MSC_VER to be defined for builder.mv"
#endif /* _MSC_VER */

/* windows.h causes warnings about "unreferenced inline function */
/* has been removed". */
#pragma warning(disable: 4514)

#endif /* MPS_BUILD_MV */

#define ALIGN           sizeof(mps_word_t)

/* Functions for the null format. */

mps_res_t no_scan(mps_ss_t mps_ss,
                  mps_addr_t base,
                  mps_addr_t limit)
{
    unused(mps_ss); unused(base); unused(limit);
    notreached();
    return 0;
}

mps_addr_t no_skip(mps_addr_t object)
{
    unused(object);
    notreached();
    return 0;
}

void no_copy(mps_addr_t old,
             mps_addr_t new)
{
    unused(old); unused(new);
    notreached();
}

void no_fwd(mps_addr_t old,
            mps_addr_t new)
{
    unused(old); unused(new);
    notreached();
}

mps_addr_t no_isfwd(mps_addr_t object)
{
    unused(object);
    notreached();
    return 0;
}

void no_pad(mps_addr_t addr,
            size_t size)
{
    unused(addr); unused(size);
    notreached();
}

mps_addr_t no_class(mps_addr_t obj)
{
    unused(obj);
    notreached();
    return 0;
}

/* The null format structures */

static struct mps_fmt_A_s no_fmt_A_s =
{
    ALIGN,
    no_scan,
    no_skip,
    no_copy,
    no_fwd,
    no_isfwd,
    no_pad
};

static struct mps_fmt_B_s no_fmt_B_s =
{
    ALIGN,
    no_scan,
    no_skip,
    no_copy,
    no_fwd,
    no_isfwd,
    no_pad,
    no_class
};

/* Functions returning the null format structures. */

mps_fmt_A_s *no_fmt_A(void)
{
    return &no_fmt_A_s;
}

mps_fmt_B_s *no_fmt_B(void)
{
    return &no_fmt_B_s;
}

/* Format variety-independent version that picks the right format
 * variety and creates it.  */

mps_res_t no_fmt(mps_fmt_t *mps_fmt_o, mps_arena_t arena)
{
    return mps_fmt_create_B(mps_fmt_o, arena, no_fmt_B());
}


/* C. COPYRIGHT AND LICENSE
 *
 * Copyright (C) 2001-2002 Ravenbrook Limited <http://www.ravenbrook.com/>.
 * All rights reserved.  This is an open source license.  Contact
 * Ravenbrook for commercial licensing options.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 * 
 * 1. Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * 
 * 2. Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 * 
 * 3. Redistributions in any form must be accompanied by information on how
 * to obtain complete source code for this software and any accompanying
 * software that uses this software.  The source code must either be
 * included in the distribution or be available for no more than the cost
 * of distribution plus a nominal fee, and must be freely redistributable
 * under reasonable conditions.  For an executable file, complete source
 * code means the source code for all modules it contains. It does not
 * include source code for modules or files that typically accompany the
 * major components of the operating system on which the executable file
 * runs.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
 * PURPOSE, OR NON-INFRINGEMENT, ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT HOLDERS AND CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
