/*
 * $Id: zmalloc.c,v 1.14 1998/07/08 13:41:37 ceder Exp $
 * Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995  Lysator Academic Computer Association.
 *
 * This file is part of the LysKOM server.
 * 
 * LysKOM 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 1, or (at your option) 
 * any later version.
 * 
 * LysKOM 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 LysKOM; see the file COPYING.  If not, write to
 * Lysator, c/o ISY, Linkoping University, S-581 83 Linkoping, SWEDEN,
 * or the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, 
 * MA 02139, USA.
 *
 * Please mail bug reports to bug-lyskom@lysator.liu.se. 
 */
/*
 *  zmalloc.c
 *		
 *
 *
 *  Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995	Lysator Computer Club,
 *			Linkoping University,  Sweden
 *
 *  Everyone is granted permission to copy, modify and redistribute
 *  this code, provided the people they give it to can.
 *
 *
 *  Author:	Thomas Bellman
 *		Lysator Computer Club
 *		Linkoping University
 *		Sweden
 *
 *  email:	Bellman@Lysator.LiU.SE
 *
 *
 *  Any opinions expressed in this code are the author's PERSONAL opinions,
 *  and does NOT, repeat NOT, represent any official standpoint of Lysator,
 *  even if so stated.
 */


static const char *
rcsid = "$Id: zmalloc.c,v 1.14 1998/07/08 13:41:37 ceder Exp $";

#include <sys/types.h>
#ifdef HAVE_STDDEF_H
#  include <stddef.h>
#endif
#ifdef HAVE_STDLIB_H
#  include <stdlib.h>
#endif

#if STDC_HEADERS || HAVE_STRING_H
#  include <string.h>
#  if !STDC_HEADERS && HAVE_MEMORY_H
#    include <memory.h>
#  endif
#else /* not STDC_HEADERS and not HAVE_STRING_H */
#  include <strings.h>
   /* memory.h and strings.h conflict on some systems.  */
#endif /* not STDC_HEADERS and not HAVE_STRING_H */
#ifndef NULL
#  include <stdio.h>
#endif

#include "compiler.h"
#include "zmalloc.h"
#include "rcs.h"
USE(rcsid);


#define EXPORT


typedef	struct	{
	int		refcount;
	size_t		size;
}  z_info;



#define	REFCOUNT(pointer)	\
	(((z_info *) ((char *) pointer - sizeof (z_info)))->refcount)

#define	AREA_SIZE(pointer)	\
	(((z_info *) ((char *) pointer - sizeof (z_info)))->size)


#define MIN(n1, n2)		(((n1) < (n2)) ? (n1) : (n2))



EXPORT  void *
zmalloc (size_t	   size)
{
    void		* memory;

    memory = malloc (size + sizeof (z_info));
    if (memory == NULL)
	return  NULL;
    ((z_info *) memory)->size = size;
    ((z_info *) memory)->refcount = 1;
    return  (char *) memory + sizeof (z_info);
}



EXPORT  void *
zcalloc (size_t	   n,
	 size_t	   size)

{
    void		* memory;

    memory = malloc (n * size + sizeof (z_info));
    if (memory == NULL)
	return  NULL;
    ((z_info *) memory)->size = n * size;
    ((z_info *) memory)->refcount = 1;
    memset ((char *) memory + sizeof (z_info),
	    0, n * size);

    return  (char *) memory + sizeof (z_info);
}



EXPORT  void *
zrealloc (void	  * ptr,
	  size_t    size)

{
    void		* memory;

    if (ptr == NULL)
	return  zmalloc (size);
    if (REFCOUNT (ptr) > 1)
    {
	memory = zmalloc (size);
	if (memory == NULL)
	    return  NULL;
	memcpy (memory, ptr, MIN (size, AREA_SIZE (ptr)));
	--REFCOUNT (ptr);
	return  memory;
    }
    else
    {
	memory = realloc ((char *) ptr - sizeof (z_info),
			  size + sizeof (z_info));
	return  (char *) memory + sizeof (z_info);
    }
}



EXPORT  void
zfree (void	* ptr)
{
    if (ptr != NULL && --REFCOUNT (ptr) <= 0)
    {
	free ((char *) ptr - sizeof (z_info));
    }
}



EXPORT  void
zdestruct (void	  * ptr)
{
    if (ptr != NULL)
	free ((char *) ptr - sizeof (z_info));
}



EXPORT  void *
zuse (void	* ptr)
{
    if (ptr != NULL)
    {
	++REFCOUNT (ptr);
    }
    return  ptr;
}



EXPORT  void *
zown (void	* ptr)
{
    void	* memory;

    if (ptr == NULL)
	return  NULL;
    if (REFCOUNT (ptr) == 1)
	return  ptr;
    else
    {
	if ((memory = malloc (AREA_SIZE (ptr))) == NULL)
	    return  NULL;
	memcpy (memory, ptr, AREA_SIZE (ptr));
	zfree (ptr);

	return  memory;
    }
}