433 lines
10 KiB
C
433 lines
10 KiB
C
/* $NetBSD: tsort.c,v 1.23 2011/09/06 18:34:37 joerg Exp $ */
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/*
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* Copyright (c) 1989, 1993, 1994
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Michael Rendell of Memorial University of Newfoundland.
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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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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#if HAVE_NBTOOL_CONFIG_H
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#include "nbtool_config.h"
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#endif
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#include <sys/cdefs.h>
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#if !defined(lint)
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__COPYRIGHT("@(#) Copyright (c) 1989, 1993, 1994\
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The Regents of the University of California. All rights reserved.");
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#if 0
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static char sccsid[] = "@(#)tsort.c 8.3 (Berkeley) 5/4/95";
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#endif
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__RCSID("$NetBSD: tsort.c,v 1.23 2011/09/06 18:34:37 joerg Exp $");
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#endif /* not lint */
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#include <sys/types.h>
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#include <ctype.h>
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#include <db.h>
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#include <err.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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/*
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* Topological sort. Input is a list of pairs of strings separated by
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* white space (spaces, tabs, and/or newlines); strings are written to
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* standard output in sorted order, one per line.
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*
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* usage:
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* tsort [-l] [inputfile]
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* If no input file is specified, standard input is read.
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*
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* Should be compatible with AT&T tsort HOWEVER the output is not identical
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* (i.e. for most graphs there is more than one sorted order, and this tsort
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* usually generates a different one then the AT&T tsort). Also, cycle
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* reporting seems to be more accurate in this version (the AT&T tsort
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* sometimes says a node is in a cycle when it isn't).
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*
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* Michael Rendell, michael@stretch.cs.mun.ca - Feb 26, '90
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*/
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#define HASHSIZE 53 /* doesn't need to be big */
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#define NF_MARK 0x1 /* marker for cycle detection */
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#define NF_ACYCLIC 0x2 /* this node is cycle free */
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#define NF_NODEST 0x4 /* Unreachable */
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typedef struct node_str NODE;
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struct node_str {
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NODE **n_prevp; /* pointer to previous node's n_next */
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NODE *n_next; /* next node in graph */
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NODE **n_arcs; /* array of arcs to other nodes */
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int n_narcs; /* number of arcs in n_arcs[] */
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int n_arcsize; /* size of n_arcs[] array */
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int n_refcnt; /* # of arcs pointing to this node */
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int n_flags; /* NF_* */
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char n_name[1]; /* name of this node */
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};
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typedef struct _buf {
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char *b_buf;
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int b_bsize;
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} BUF;
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static DB *db;
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static NODE *graph, **cycle_buf, **longest_cycle;
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static int debug, longest, quiet;
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static void add_arc(char *, char *);
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static void clear_cycle(void);
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static int find_cycle(NODE *, NODE *, int, int);
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static NODE *get_node(char *);
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static void *grow_buf(void *, int);
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static void remove_node(NODE *);
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static void tsort(void);
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__dead static void usage(void);
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int
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main(int argc, char *argv[])
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{
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BUF *b;
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int c, n;
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FILE *fp;
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int bsize, ch, nused;
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BUF bufs[2];
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setprogname(argv[0]);
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fp = NULL;
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while ((ch = getopt(argc, argv, "dlq")) != -1)
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switch (ch) {
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case 'd':
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debug = 1;
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break;
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case 'l':
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longest = 1;
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break;
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case 'q':
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quiet = 1;
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break;
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case '?':
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default:
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usage();
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}
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argc -= optind;
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argv += optind;
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switch (argc) {
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case 0:
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fp = stdin;
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break;
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case 1:
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if ((fp = fopen(*argv, "r")) == NULL)
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err(1, "%s", *argv);
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break;
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default:
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usage();
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}
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for (b = bufs, n = 2; --n >= 0; b++)
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b->b_buf = grow_buf(NULL, b->b_bsize = 1024);
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/* parse input and build the graph */
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for (n = 0, c = getc(fp);;) {
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while (c != EOF && isspace(c))
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c = getc(fp);
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if (c == EOF)
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break;
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nused = 0;
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b = &bufs[n];
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bsize = b->b_bsize;
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do {
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b->b_buf[nused++] = c;
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if (nused == bsize)
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b->b_buf = grow_buf(b->b_buf, bsize *= 2);
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c = getc(fp);
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} while (c != EOF && !isspace(c));
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b->b_buf[nused] = '\0';
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b->b_bsize = bsize;
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if (n)
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add_arc(bufs[0].b_buf, bufs[1].b_buf);
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n = !n;
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}
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(void)fclose(fp);
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if (n)
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errx(1, "odd data count");
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/* do the sort */
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tsort();
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return(0);
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}
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/* double the size of oldbuf and return a pointer to the new buffer. */
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static void *
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grow_buf(void *bp, int size)
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{
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void *n;
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if ((n = realloc(bp, (u_int)size)) == NULL)
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err(1, "realloc");
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bp = n;
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return (bp);
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}
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/*
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* add an arc from node s1 to node s2 in the graph. If s1 or s2 are not in
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* the graph, then add them.
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*/
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static void
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add_arc(char *s1, char *s2)
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{
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NODE *n1;
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NODE *n2;
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int bsize, i;
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n1 = get_node(s1);
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if (!strcmp(s1, s2))
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return;
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n2 = get_node(s2);
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/*
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* Check if this arc is already here.
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*/
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for (i = 0; i < n1->n_narcs; i++)
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if (n1->n_arcs[i] == n2)
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return;
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/*
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* Add it.
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*/
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if (n1->n_narcs == n1->n_arcsize) {
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if (!n1->n_arcsize)
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n1->n_arcsize = 10;
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bsize = n1->n_arcsize * sizeof(*n1->n_arcs) * 2;
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n1->n_arcs = grow_buf(n1->n_arcs, bsize);
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n1->n_arcsize = bsize / sizeof(*n1->n_arcs);
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}
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n1->n_arcs[n1->n_narcs++] = n2;
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++n2->n_refcnt;
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}
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/* Find a node in the graph (insert if not found) and return a pointer to it. */
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static NODE *
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get_node(char *name)
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{
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DBT data, key;
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NODE *n;
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if (db == NULL &&
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(db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == NULL)
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err(1, "db: %s", name);
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key.data = name;
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key.size = strlen(name) + 1;
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switch ((*db->get)(db, &key, &data, 0)) {
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case 0:
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(void)memmove(&n, data.data, sizeof(n));
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return (n);
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case 1:
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break;
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default:
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case -1:
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err(1, "db: %s", name);
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}
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if ((n = malloc(sizeof(NODE) + key.size)) == NULL)
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err(1, "malloc");
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n->n_narcs = 0;
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n->n_arcsize = 0;
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n->n_arcs = NULL;
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n->n_refcnt = 0;
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n->n_flags = 0;
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(void)memmove(n->n_name, name, key.size);
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/* Add to linked list. */
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if ((n->n_next = graph) != NULL)
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graph->n_prevp = &n->n_next;
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n->n_prevp = &graph;
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graph = n;
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/* Add to hash table. */
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data.data = &n;
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data.size = sizeof(n);
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if ((*db->put)(db, &key, &data, 0))
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err(1, "db: %s", name);
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return (n);
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}
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/*
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* Clear the NODEST flag from all nodes.
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*/
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static void
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clear_cycle(void)
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{
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NODE *n;
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for (n = graph; n != NULL; n = n->n_next)
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n->n_flags &= ~NF_NODEST;
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}
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/* do topological sort on graph */
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static void
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tsort(void)
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{
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NODE *n, *next;
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int cnt, i;
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while (graph != NULL) {
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/*
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* Keep getting rid of simple cases until there are none left,
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* if there are any nodes still in the graph, then there is
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* a cycle in it.
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*/
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do {
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for (cnt = 0, n = graph; n != NULL; n = next) {
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next = n->n_next;
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if (n->n_refcnt == 0) {
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remove_node(n);
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++cnt;
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}
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}
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} while (graph != NULL && cnt);
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if (graph == NULL)
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break;
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if (!cycle_buf) {
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/*
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* Allocate space for two cycle logs - one to be used
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* as scratch space, the other to save the longest
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* cycle.
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*/
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for (cnt = 0, n = graph; n != NULL; n = n->n_next)
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++cnt;
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cycle_buf = malloc((u_int)sizeof(NODE *) * cnt);
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longest_cycle = malloc((u_int)sizeof(NODE *) * cnt);
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if (cycle_buf == NULL || longest_cycle == NULL)
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err(1, "malloc");
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}
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for (n = graph; n != NULL; n = n->n_next) {
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if (!(n->n_flags & NF_ACYCLIC)) {
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if ((cnt = find_cycle(n, n, 0, 0)) != 0) {
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if (!quiet) {
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warnx("cycle in data");
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for (i = 0; i < cnt; i++)
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warnx("%s",
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longest_cycle[i]->n_name);
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}
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remove_node(n);
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clear_cycle();
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break;
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} else {
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/* to avoid further checks */
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n->n_flags |= NF_ACYCLIC;
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clear_cycle();
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}
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}
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}
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if (n == NULL)
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errx(1, "internal error -- could not find cycle");
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}
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}
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/* print node and remove from graph (does not actually free node) */
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static void
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remove_node(NODE *n)
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{
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NODE **np;
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int i;
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(void)printf("%s\n", n->n_name);
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for (np = n->n_arcs, i = n->n_narcs; --i >= 0; np++)
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--(*np)->n_refcnt;
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n->n_narcs = 0;
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*n->n_prevp = n->n_next;
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if (n->n_next)
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n->n_next->n_prevp = n->n_prevp;
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}
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/* look for the longest? cycle from node from to node to. */
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static int
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find_cycle(NODE *from, NODE *to, int longest_len, int depth)
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{
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NODE **np;
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int i, len;
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/*
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* avoid infinite loops and ignore portions of the graph known
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* to be acyclic
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*/
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if (from->n_flags & (NF_NODEST|NF_MARK|NF_ACYCLIC))
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return (0);
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from->n_flags |= NF_MARK;
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for (np = from->n_arcs, i = from->n_narcs; --i >= 0; np++) {
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cycle_buf[depth] = *np;
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if (*np == to) {
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if (depth + 1 > longest_len) {
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longest_len = depth + 1;
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(void)memcpy(longest_cycle, cycle_buf,
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longest_len * sizeof(NODE *));
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}
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} else {
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if ((*np)->n_flags & (NF_MARK|NF_ACYCLIC|NF_NODEST))
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continue;
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len = find_cycle(*np, to, longest_len, depth + 1);
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if (debug)
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(void)printf("%*s %s->%s %d\n", depth, "",
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from->n_name, to->n_name, len);
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if (len == 0)
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(*np)->n_flags |= NF_NODEST;
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if (len > longest_len)
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longest_len = len;
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if (len > 0 && !longest)
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break;
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}
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}
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from->n_flags &= ~NF_MARK;
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return (longest_len);
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}
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static void
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usage(void)
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{
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(void)fprintf(stderr, "usage: tsort [-lq] [file]\n");
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exit(1);
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}
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