122 lines
2.7 KiB
C
122 lines
2.7 KiB
C
/* $NetBSD: alloc.c,v 1.6 2004/07/07 19:20:09 mycroft Exp $ */
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/*
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* Copyright (c) 2002 Marc Espie.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE OPENBSD PROJECT AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OPENBSD
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* PROJECT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* area-based allocation built on malloc/free
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*/
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#include "sh.h"
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struct link {
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struct link *prev;
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struct link *next;
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};
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Area *
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ainit(Area *ap)
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{
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ap->freelist = NULL;
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return ap;
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}
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void
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afreeall(Area *ap)
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{
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struct link *l, *l2;
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for (l = ap->freelist; l != NULL; l = l2) {
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l2 = l->next;
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free(l);
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}
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ap->freelist = NULL;
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}
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#define L2P(l) ( (void *)(((char *)(l)) + sizeof(struct link)) )
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#define P2L(p) ( (struct link *)(((char *)(p)) - sizeof(struct link)) )
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void *
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alloc(size_t size, Area *ap)
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{
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struct link *l;
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l = malloc(sizeof(struct link) + size);
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if (l == NULL)
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internal_errorf(1, "unable to allocate memory");
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l->next = ap->freelist;
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l->prev = NULL;
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if (ap->freelist)
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ap->freelist->prev = l;
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ap->freelist = l;
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return L2P(l);
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}
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void *
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aresize(void *ptr, size_t size, Area *ap)
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{
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struct link *l, *l2, *lprev, *lnext;
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if (ptr == NULL)
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return alloc(size, ap);
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l = P2L(ptr);
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lprev = l->prev;
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lnext = l->next;
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l2 = realloc(l, sizeof(struct link) + size);
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if (l2 == NULL)
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internal_errorf(1, "unable to allocate memory");
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if (lprev)
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lprev->next = l2;
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else
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ap->freelist = l2;
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if (lnext)
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lnext->prev = l2;
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return L2P(l2);
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}
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void
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afree(void *ptr, Area *ap)
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{
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struct link *l;
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if (!ptr)
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return;
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l = P2L(ptr);
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if (l->prev)
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l->prev->next = l->next;
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else
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ap->freelist = l->next;
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if (l->next)
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l->next->prev = l->prev;
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free(l);
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}
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