185 lines
5.5 KiB
C
185 lines
5.5 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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/*
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* A* definitions.
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*
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* @(#)as.h 1.9 11/13/90
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*/
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/*
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* 11/09/98 - Steve McClure
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* Added path list caching structures
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*/
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#include <stdio.h> /* for FILE */
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#include "misc.h" /* for s_char */
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/*
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* Coordinate.
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*/
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struct as_coord {
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int x, y;
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};
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/*
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* Path, made up of a linked list of coordinates.
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*/
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struct as_path {
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struct as_coord c;
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struct as_path *next;
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};
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/*
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* Basic node, used internally by A* algorithm.
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*/
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struct as_node {
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struct as_coord c; /* our coordinate */
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double knowncost; /* cost so far */
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double lbcost; /* lower bound on cost to dest */
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double inclbcost; /* incremental lower bound cost */
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double seccost; /* used to break ties */
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int step;
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int flags;
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struct as_node *back;
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};
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#define AS_TRIED 1 /* we've tried this node before */
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/*
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* Linked list of nodes, used internally by A* algorithm.
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*/
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struct as_queue {
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struct as_node *np;
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struct as_queue *next;
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struct as_queue *prev;
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};
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/*
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* Hash table entry, used to determine if we've seen a particular
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* coordinate before.
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*/
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struct as_hash {
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struct as_coord c;
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struct as_queue *qp;
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struct as_hash *next;
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};
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/*
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* User's handle on A*, returned by as_init(). Some of the data here is
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* used by A* internals.
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*/
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struct as_data {
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int maxneighbors; /* max # of neighbors a cell can have */
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int hashsize; /* size of internal hash table */
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int (*hash) (struct as_coord); /* hash function (coord -> int) */
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int (*neighbor) (struct as_coord, struct as_coord *, s_char *); /* function to find neighbors */
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double (*lbcost) (struct as_coord, struct as_coord, s_char *); /* function to give lower bound cost */
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double (*realcost) (struct as_coord, struct as_coord, s_char *); /* function to give real cost */
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double (*seccost) (struct as_coord, struct as_coord, s_char *); /* function to secondary cost */
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char *userdata; /* user's data, passed to callbacks */
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struct as_coord from; /* from coordinate */
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struct as_coord to; /* to coordinate */
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struct as_path *path; /* solution */
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/* below are "private" to as_ routines */
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struct as_queue *head;
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struct as_queue *tried;
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struct as_hash **hashtab;
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struct as_queue *subsumed;
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struct as_coord *neighbor_coords;
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struct as_node **neighbor_nodes;
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};
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/*
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* Added these for caching of paths as we stumble across them
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*/
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struct as_topath {
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coord x;
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struct as_path *path; /* Path from holder of this list to here */
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struct as_topath *next;
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};
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struct as_frompath {
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coord x;
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struct as_topath **tolist; /* List of nodes we have a path to */
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struct as_frompath *next;
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};
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/*
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* Some cheezy allocation macros.
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*/
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#define AS_NEW_ARRAY(p, type, n, err) \
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(p) = (type *)calloc((n), sizeof (*(p))); \
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if ((p) == NULL) \
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return err; \
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#define AS_NEW(p, type, err) \
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AS_NEW_ARRAY((p), type, 1, err);
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#define AS_NEW_MALLOC(p, type, err) \
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(p) = (type *)malloc(sizeof(type)); \
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if ((p) == NULL) \
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return err; \
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/* Functions that the user can call. */
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extern struct as_data *as_init(int maxneighbors, int hashsize,
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int (*hashfunc) (struct as_coord),
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int (*neighborfunc) (struct as_coord,
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struct as_coord *,
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s_char *),
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double (*lbcostfunc) (struct as_coord,
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struct as_coord,
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s_char *),
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double (*realcostfunc) (struct as_coord,
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struct as_coord,
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s_char *),
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double (*seccostfunc) (struct as_coord,
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struct as_coord,
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s_char *),
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s_char *userdata);
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extern int as_search(struct as_data *adp);
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extern void as_delete(struct as_data *adp);
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extern void as_reset(struct as_data *adp);
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extern void as_stats(struct as_data *adp, FILE * fp);
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extern struct as_path *as_find_cachepath(coord fx,
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coord fy, coord tx, coord ty);
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/* Functions that are "private" to algorithm */
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extern void as_add_cachepath(struct as_data *adp);
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extern void as_clear_cachepath(void);
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extern void as_enable_cachepath(void);
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extern void as_disable_cachepath(void);
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extern void as_makepath(struct as_data *adp);
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extern void as_free_path(struct as_path *pp);
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extern int as_costcomp(const void *, const void *);
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extern struct as_queue *as_extend(struct as_data *adp);
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extern struct as_queue *as_merge(struct as_data *adp,
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struct as_queue *head,
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struct as_node **neighbors);
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extern struct as_queue *as_iscinq(struct as_data *adp, struct as_coord c);
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extern void as_setcinq(struct as_data *adp,
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struct as_coord c, struct as_queue *qp);
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extern void as_free_hashtab(struct as_data *adp);
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extern int as_winnow(struct as_data *adp,
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struct as_coord *coords, int ncoords);
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