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/* $OpenBSD: alloc.c,v 1.5 2002/03/01 13:06:18 espie 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"
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 *)(((char *)(p)) - sizeof(struct link)) )
void *
alloc(size_t size, Area *ap)
{
struct link *l;
l = malloc(size + sizeof(struct link));
if (!l)
return NULL;
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;
l2 = realloc(l, size+sizeof(struct link));
if (l2) {
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;
if (!ptr)
return;
l = P2L(ptr);
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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