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diff --git a/misc-utils/tsort.c b/misc-utils/tsort.c
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+/*
+ * Copyright (c) 1989 The Regents of the University of California.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Michael Rendell of Memorial University of Newfoundland.
+ *
+ * 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.
+ * 3. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * This product includes software developed by the University of
+ * California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
+ */
+
+#ifndef lint
+char copyright[] =
+"@(#) Copyright (c) 1989 The Regents of the University of California.\n\
+ All rights reserved.\n";
+#endif /* not lint */
+
+#ifndef lint
+static char sccsid[] = "@(#)tsort.c 5.3 (Berkeley) 6/1/90";
+#endif /* not lint */
+
+#include <sys/types.h>
+#include <errno.h>
+#include <stdio.h>
+#include <ctype.h>
+#include <string.h>
+
+/*
+ * Topological sort. Input is a list of pairs of strings seperated by
+ * white space (spaces, tabs, and/or newlines); strings are written to
+ * standard output in sorted order, one per line.
+ *
+ * usage:
+ * tsort [inputfile]
+ * If no input file is specified, standard input is read.
+ *
+ * Should be compatable with AT&T tsort HOWEVER the output is not identical
+ * (i.e. for most graphs there is more than one sorted order, and this tsort
+ * usually generates a different one then the AT&T tsort). Also, cycle
+ * reporting seems to be more accurate in this version (the AT&T tsort
+ * sometimes says a node is in a cycle when it isn't).
+ *
+ * Michael Rendell, michael@stretch.cs.mun.ca - Feb 26, '90
+ */
+#define HASHSIZE 53 /* doesn't need to be big */
+#define NF_MARK 0x1 /* marker for cycle detection */
+#define NF_ACYCLIC 0x2 /* this node is cycle free */
+
+typedef struct node_str NODE;
+
+struct node_str {
+ char *n_name; /* name of this node */
+ NODE **n_prevp; /* pointer to previous node's n_next */
+ NODE *n_next; /* next node in graph */
+ NODE *n_hash; /* next node in hash table */
+ int n_narcs; /* number of arcs in n_arcs[] */
+ int n_arcsize; /* size of n_arcs[] array */
+ NODE **n_arcs; /* array of arcs to other nodes */
+ int n_refcnt; /* # of arcs pointing to this node */
+ int n_flags; /* NF_* */
+};
+
+typedef struct _buf {
+ char *b_buf;
+ int b_bsize;
+} BUF;
+
+NODE *add_node(), *find_node();
+void add_arc(), no_memory(), remove_node(), tsort();
+char *grow_buf(), *malloc();
+
+extern int errno;
+NODE *graph;
+NODE *hashtable[HASHSIZE];
+NODE **cycle_buf;
+NODE **longest_cycle;
+
+main(argc, argv)
+ int argc;
+ char **argv;
+{
+ register BUF *b;
+ register int c, n;
+ FILE *fp;
+ int bsize, nused;
+ BUF bufs[2];
+
+ if (argc < 2)
+ fp = stdin;
+ /* == becomes > in next line per Volker Meyer_zu_Bexten
+ <vmzb@ims.fhg.de> -- faith@cs.unc.edu, Sat Feb 4 21:25:09 1995 */
+ else if (argc > 2) {
+ (void)fprintf(stderr, "usage: tsort [ inputfile ]\n");
+ exit(1);
+ } else if (!(fp = fopen(argv[1], "r"))) {
+ (void)fprintf(stderr, "tsort: %s.\n", strerror(errno));
+ exit(1);
+ }
+
+ for (b = bufs, n = 2; --n >= 0; b++)
+ b->b_buf = grow_buf((char *)NULL, b->b_bsize = 1024);
+
+ /* parse input and build the graph */
+ for (n = 0, c = getc(fp);;) {
+ while (c != EOF && isspace(c))
+ c = getc(fp);
+ if (c == EOF)
+ break;
+
+ nused = 0;
+ b = &bufs[n];
+ bsize = b->b_bsize;
+ do {
+ b->b_buf[nused++] = c;
+ if (nused == bsize) {
+ bsize *= 2;
+ b->b_buf = grow_buf(b->b_buf, bsize);
+ }
+ c = getc(fp);
+ } while (c != EOF && !isspace(c));
+
+ b->b_buf[nused] = '\0';
+ b->b_bsize = bsize;
+ if (n)
+ add_arc(bufs[0].b_buf, bufs[1].b_buf);
+ n = !n;
+ }
+ (void)fclose(fp);
+ if (n) {
+ (void)fprintf(stderr, "tsort: odd data count.\n");
+ exit(1);
+ }
+
+ /* do the sort */
+ tsort();
+ exit(0);
+}
+
+/* double the size of oldbuf and return a pointer to the new buffer. */
+char *
+grow_buf(bp, size)
+ char *bp;
+ int size;
+{
+ char *realloc();
+
+ if (!(bp = realloc(bp, (u_int)size)))
+ no_memory();
+ return(bp);
+}
+
+/*
+ * add an arc from node s1 to node s2 in the graph. If s1 or s2 are not in
+ * the graph, then add them.
+ */
+void
+add_arc(s1, s2)
+ char *s1, *s2;
+{
+ register NODE *n1;
+ NODE *n2;
+ int bsize;
+
+ n1 = find_node(s1);
+ if (!n1)
+ n1 = add_node(s1);
+
+ if (!strcmp(s1, s2))
+ return;
+
+ n2 = find_node(s2);
+ if (!n2)
+ n2 = add_node(s2);
+
+ /*
+ * could check to see if this arc is here already, but it isn't
+ * worth the bother -- there usually isn't and it doesn't hurt if
+ * there is (I think :-).
+ */
+ if (n1->n_narcs == n1->n_arcsize) {
+ if (!n1->n_arcsize)
+ n1->n_arcsize = 10;
+ bsize = n1->n_arcsize * sizeof(*n1->n_arcs) * 2;
+ n1->n_arcs = (NODE **)grow_buf((char *)n1->n_arcs, bsize);
+ n1->n_arcsize = bsize / sizeof(*n1->n_arcs);
+ }
+ n1->n_arcs[n1->n_narcs++] = n2;
+ ++n2->n_refcnt;
+}
+
+hash_string(s)
+ char *s;
+{
+ register int hash, i;
+
+ for (hash = 0, i = 1; *s; s++, i++)
+ hash += *s * i;
+ return(hash % HASHSIZE);
+}
+
+/*
+ * find a node in the graph and return a pointer to it - returns null if not
+ * found.
+ */
+NODE *
+find_node(name)
+ char *name;
+{
+ register NODE *n;
+
+ for (n = hashtable[hash_string(name)]; n; n = n->n_hash)
+ if (!strcmp(n->n_name, name))
+ return(n);
+ return((NODE *)NULL);
+}
+
+/* Add a node to the graph and return a pointer to it. */
+NODE *
+add_node(name)
+ char *name;
+{
+ register NODE *n;
+ int hash;
+
+ if (!(n = (NODE *)malloc(sizeof(NODE))) || !(n->n_name = strdup(name)))
+ no_memory();
+
+ n->n_narcs = 0;
+ n->n_arcsize = 0;
+ n->n_arcs = (NODE **)NULL;
+ n->n_refcnt = 0;
+ n->n_flags = 0;
+
+ /* add to linked list */
+ if (n->n_next = graph)
+ graph->n_prevp = &n->n_next;
+ n->n_prevp = &graph;
+ graph = n;
+
+ /* add to hash table */
+ hash = hash_string(name);
+ n->n_hash = hashtable[hash];
+ hashtable[hash] = n;
+ return(n);
+}
+
+/* do topological sort on graph */
+void
+tsort()
+{
+ register NODE *n, *next;
+ register int cnt;
+
+ while (graph) {
+ /*
+ * keep getting rid of simple cases until there are none left,
+ * if there are any nodes still in the graph, then there is
+ * a cycle in it.
+ */
+ do {
+ for (cnt = 0, n = graph; n; n = next) {
+ next = n->n_next;
+ if (n->n_refcnt == 0) {
+ remove_node(n);
+ ++cnt;
+ }
+ }
+ } while (graph && cnt);
+
+ if (!graph)
+ break;
+
+ if (!cycle_buf) {
+ /*
+ * allocate space for two cycle logs - one to be used
+ * as scratch space, the other to save the longest
+ * cycle.
+ */
+ for (cnt = 0, n = graph; n; n = n->n_next)
+ ++cnt;
+ cycle_buf =
+ (NODE **)malloc((u_int)sizeof(NODE *) * cnt);
+ longest_cycle =
+ (NODE **)malloc((u_int)sizeof(NODE *) * cnt);
+ if (!cycle_buf || !longest_cycle)
+ no_memory();
+ }
+ for (n = graph; n; n = n->n_next)
+ if (!(n->n_flags & NF_ACYCLIC)) {
+ if (cnt = find_cycle(n, n, 0, 0)) {
+ register int i;
+
+ (void)fprintf(stderr,
+ "tsort: cycle in data.\n");
+ for (i = 0; i < cnt; i++)
+ (void)fprintf(stderr,
+ "tsort: %s.\n", longest_cycle[i]->n_name);
+ remove_node(n);
+ break;
+ } else
+ /* to avoid further checks */
+ n->n_flags = NF_ACYCLIC;
+ }
+
+ if (!n) {
+ (void)fprintf(stderr,
+ "tsort: internal error -- could not find cycle.\n");
+ exit(1);
+ }
+ }
+}
+
+/* print node and remove from graph (does not actually free node) */
+void
+remove_node(n)
+ register NODE *n;
+{
+ register NODE **np;
+ register int i;
+
+ (void)printf("%s\n", n->n_name);
+ for (np = n->n_arcs, i = n->n_narcs; --i >= 0; np++)
+ --(*np)->n_refcnt;
+ n->n_narcs = 0;
+ *n->n_prevp = n->n_next;
+ if (n->n_next)
+ n->n_next->n_prevp = n->n_prevp;
+}
+
+/* look for the longest cycle from node from to node to. */
+find_cycle(from, to, longest_len, depth)
+ NODE *from, *to;
+ int depth, longest_len;
+{
+ register NODE **np;
+ register int i, len;
+
+ /*
+ * avoid infinite loops and ignore portions of the graph known
+ * to be acyclic
+ */
+ if (from->n_flags & (NF_MARK|NF_ACYCLIC))
+ return(0);
+ from->n_flags = NF_MARK;
+
+ for (np = from->n_arcs, i = from->n_narcs; --i >= 0; np++) {
+ cycle_buf[depth] = *np;
+ if (*np == to) {
+ if (depth + 1 > longest_len) {
+ longest_len = depth + 1;
+ (void)memcpy((char *)longest_cycle,
+ (char *)cycle_buf,
+ longest_len * sizeof(NODE *));
+ }
+ } else {
+ len = find_cycle(*np, to, longest_len, depth + 1);
+ if (len > longest_len)
+ longest_len = len;
+ }
+ }
+ from->n_flags &= ~NF_MARK;
+ return(longest_len);
+}
+
+void
+no_memory()
+{
+ (void)fprintf(stderr, "tsort: %s.\n", strerror(ENOMEM));
+ exit(1);
+}
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