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/* $OpenBSD: alloc.c,v 1.7 2004/02/19 18:51:17 deraadt Exp $ */
/*-
* Copyright (c) 2002 Marc Espie.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE OPENBSD PROJECT AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OPENBSD
* PROJECT OR 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.
*-
* area-based allocation built on malloc/free
*/
#include "sh.h"
__RCSID("$MirOS: src/bin/mksh/alloc.c,v 1.7 2008/07/13 16:43:55 tg Exp $");
struct link {
struct link *prev;
struct link *next;
};
Area *
ainit(Area *ap)
{
ap->freelist = NULL;
return (ap);
}
void
afreeall(Area *ap)
{
struct link *l, *l2;
for (l = ap->freelist; l != NULL; l = l2) {
l2 = l->next;
free(l);
}
ap->freelist = NULL;
}
#define L2P(l) ( (void *)(((char *)(l)) + sizeof (struct link)) )
#define P2L(p) ( (struct link *)(((ptrdiff_t)(p)) - sizeof (struct link)) )
void *
alloc(size_t size, Area *ap)
{
struct link *l;
if ((l = malloc(sizeof (struct link) + size)) == NULL)
internal_errorf("unable to allocate memory");
l->next = ap->freelist;
l->prev = NULL;
if (ap->freelist)
ap->freelist->prev = l;
ap->freelist = l;
return (L2P(l));
}
void *
aresize(void *ptr, size_t size, Area *ap)
{
struct link *l, *l2, *lprev, *lnext;
if (ptr == NULL)
return (alloc(size, ap));
l = P2L(ptr);
lprev = l->prev;
lnext = l->next;
if ((l2 = realloc(l, sizeof (struct link) + size)) == NULL)
internal_errorf("unable to allocate memory");
if (lprev)
lprev->next = l2;
else
ap->freelist = l2;
if (lnext)
lnext->prev = l2;
return (L2P(l2));
}
void
afree(void *ptr, Area *ap)
{
struct link *l;
#ifdef MKSH_AFREE_DEBUG
struct link *lp;
#endif
if (!ptr)
return;
l = P2L(ptr);
#ifdef MKSH_AFREE_DEBUG
for (lp = ap->freelist; lp != NULL; lp = lp->next)
if (l == lp)
break;
if (lp == NULL) {
internal_warningf("afree: pointer %p not allocated", ptr);
exit(255);
}
#endif
if (l->prev)
l->prev->next = l->next;
else
ap->freelist = l->next;
if (l->next)
l->next->prev = l->prev;
free(l);
}
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