81 lines
2.1 KiB
C
81 lines
2.1 KiB
C
/*
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* A* Search - A search library used in Empire to determine paths between
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* objects.
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* Copyright (C) 1990-1998 Phil Lapsley
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include "as.h"
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/*
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* Return a pointer to the as_queue structure associated with
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* this coordinate if the coordinate is in the queue.
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*/
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struct as_queue *
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as_iscinq(struct as_data *adp, struct as_coord c)
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{
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int hashval;
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struct as_hash *hp;
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hashval = (*adp->hash) (c) % adp->hashsize;
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for (hp = adp->hashtab[hashval]; hp; hp = hp->next)
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if (hp->c.x == c.x && hp->c.y == c.y)
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return (hp->qp);
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return (NULL);
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}
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/*
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* Set the queue structure associated with this coordinate.
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*/
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void
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as_setcinq(struct as_data *adp, struct as_coord c, struct as_queue *qp)
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{
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int hashval;
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struct as_hash *hp;
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struct as_hash *new;
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new = (struct as_hash *)malloc(sizeof(struct as_hash));
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new->c = c;
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new->qp = qp;
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hashval = (*adp->hash) (c) % adp->hashsize;
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hp = adp->hashtab[hashval];
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new->next = (hp) ? hp : NULL;
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adp->hashtab[hashval] = new;
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}
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/*
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* Walk down the hash table array, freeing the chains and zeroing
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* the chain pointers.
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*/
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void
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as_free_hashtab(struct as_data *adp)
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{
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int i;
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struct as_hash *hp, *hp2;
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for (i = 0; i < adp->hashsize; i++) {
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for (hp = adp->hashtab[i]; hp; hp = hp2) {
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hp2 = hp->next;
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free(hp);
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}
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adp->hashtab[i] = NULL;
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}
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}
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