diff options
Diffstat (limited to 'usr.bin/tsort')
| -rw-r--r-- | usr.bin/tsort/CVS/Entries | 4 | ||||
| -rw-r--r-- | usr.bin/tsort/CVS/Repository | 1 | ||||
| -rw-r--r-- | usr.bin/tsort/CVS/Root | 1 | ||||
| -rw-r--r-- | usr.bin/tsort/Makefile | 9 | ||||
| -rw-r--r-- | usr.bin/tsort/tsort.1 | 167 | ||||
| -rw-r--r-- | usr.bin/tsort/tsort.c | 1014 |
6 files changed, 0 insertions, 1196 deletions
diff --git a/usr.bin/tsort/CVS/Entries b/usr.bin/tsort/CVS/Entries deleted file mode 100644 index 528f3f2..0000000 --- a/usr.bin/tsort/CVS/Entries +++ /dev/null @@ -1,4 +0,0 @@ -/Makefile/1.7/Thu Sep 23 13:56:23 2021// -/tsort.1/1.24/Thu Sep 23 13:56:23 2021// -/tsort.c/1.37/Thu Sep 23 13:56:23 2021// -D diff --git a/usr.bin/tsort/CVS/Repository b/usr.bin/tsort/CVS/Repository deleted file mode 100644 index 3079881..0000000 --- a/usr.bin/tsort/CVS/Repository +++ /dev/null @@ -1 +0,0 @@ -src/usr.bin/tsort diff --git a/usr.bin/tsort/CVS/Root b/usr.bin/tsort/CVS/Root deleted file mode 100644 index 3811072..0000000 --- a/usr.bin/tsort/CVS/Root +++ /dev/null @@ -1 +0,0 @@ -/cvs diff --git a/usr.bin/tsort/Makefile b/usr.bin/tsort/Makefile deleted file mode 100644 index 0c57770..0000000 --- a/usr.bin/tsort/Makefile +++ /dev/null @@ -1,9 +0,0 @@ -# $OpenBSD: Makefile,v 1.7 2017/07/09 21:23:19 espie Exp $ - -PROG = tsort - -CDIAGFLAGS = -Wall -Wno-char-subscripts -Wstrict-prototypes -pedantic -W -DPADD += ${LIBUTIL} -LDADD += -lutil - -.include <bsd.prog.mk> diff --git a/usr.bin/tsort/tsort.1 b/usr.bin/tsort/tsort.1 deleted file mode 100644 index 56f5fc3..0000000 --- a/usr.bin/tsort/tsort.1 +++ /dev/null @@ -1,167 +0,0 @@ -.\" $OpenBSD: tsort.1,v 1.24 2019/04/23 18:13:11 schwarze Exp $ -.\" $NetBSD: tsort.1,v 1.6 1996/01/17 20:37:49 mycroft Exp $ -.\" -.\" Copyright (c) 1990, 1993, 1994 -.\" The Regents of the University of California. All rights reserved. -.\" -.\" This manual is derived from one 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. 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. -.\" -.\" @(#)tsort.1 8.3 (Berkeley) 4/1/94 -.\" -.Dd $Mdocdate: April 23 2019 $ -.Dt TSORT 1 -.Os -.Sh NAME -.Nm tsort -.Nd topological sort of a directed graph -.Sh SYNOPSIS -.Nm tsort -.Op Fl flqrvw -.Op Fl h Ar file -.Op Ar file -.Sh DESCRIPTION -.Nm tsort -takes a list of pairs of node names representing directed arcs in -a graph and prints the nodes in topological order on standard output. -That is, the input describes a partial ordering relation, from which -.Nm -computes a total order compatible with this partial ordering. -.Pp -Input is taken from the named -.Ar file , -or from standard input if no file -is given. -.Pp -Node names in the input are separated by white space and there must -be an even number of node names. -.Pp -Presence of a node in a graph can be represented by an arc from the node -to itself. -This is useful when a node is not connected to any other nodes. -.Pp -If the graph contains a cycle (and therefore cannot be properly sorted), -one of the arcs in the cycle is ignored and the sort continues. -Cycles are reported on standard error. -.Pp -The options are as follows: -.Bl -tag -width Ds -.It Fl f -Resolve ambiguities by selecting nodes based on the order of appearance -of the first component of the pairs. -.It Fl h Ar file -Use -.Ar file , -which holds an ordered list of nodes, to resolve ambiguities. -In case of duplicates, the first entry is chosen. -.It Fl l -Search for and display the longest cycle. -Can take a very long time, as it may need to solve an NP-complete problem. -.It Fl q -Do not display informational messages about cycles. -This is primarily intended for building libraries, where optimal ordering -is not critical, and cycles occur often. -.It Fl r -Reverse the ordering relation. -.It Fl v -Inform on the exact number of edges broken while breaking cycles. -If a hints file was used, inform on seen nodes absent from that file. -.It Fl w -Exit with exit code the number of cycles -.Nm -had to break. -.El -.Sh EXIT STATUS -.Ex -std tsort -.Sh EXAMPLES -Faced with the input: -.Bd -literal -offset indent -a b -b c -b d -d f -c e -.Ed -.Pp -.Nm -outputs: -.Bd -literal -offset indent -a -b -c -e -d -f -.Ed -.Pp -which is one total ordering compatible with the individual relations. -There is no unicity, another compatible total ordering would be: -.Bd -literal -offset indent -a -b -c -d -e -f -.Ed -.Pp -.Nm -is commonly used to analyze dependencies and find a correct build order -in a static way, whereas -.Xr make 1 -accomplishes the same task in a dynamic way. -.Sh SEE ALSO -.Xr ar 1 , -.Xr lorder 1 , -.Xr make 1 -.Rs -.%A Donald E. Knuth -.%B The Art of Computer Programming -.%V Vol. 1 -.%P pp. 258\(en268 -.%D 1973 -.Re -.Sh STANDARDS -The -.Nm -utility is compliant with the -.St -p1003.1-2008 -specification. -.Pp -The flags -.Op Fl fhlqrvw -are extensions to that specification. -.Sh HISTORY -A -.Nm -command appeared in -.At v7 . -This -.Nm tsort -command was completely rewritten by Marc Espie for -.Ox , -to finally use the well-known optimal algorithms for topological sorting. diff --git a/usr.bin/tsort/tsort.c b/usr.bin/tsort/tsort.c deleted file mode 100644 index 3e0e1ab..0000000 --- a/usr.bin/tsort/tsort.c +++ /dev/null @@ -1,1014 +0,0 @@ -/* $OpenBSD: tsort.c,v 1.37 2019/07/11 17:28:32 mestre Exp $ */ -/* ex:ts=8 sw=4: - * - * Copyright (c) 1999-2004 Marc Espie <espie@openbsd.org> - * - * Permission to use, copy, modify, and distribute this software for any - * purpose with or without fee is hereby granted, provided that the above - * copyright notice and this permission notice appear in all copies. - * - * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES - * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF - * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR - * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES - * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN - * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF - * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. - */ - -#include <assert.h> -#include <ctype.h> -#include <err.h> -#include <limits.h> -#include <stddef.h> -#include <stdio.h> -#include <stdint.h> -#include <stdlib.h> -#include <string.h> -#include <unistd.h> -#include <ohash.h> - -/* The complexity of topological sorting is O(e), where e is the - * size of input. While reading input, vertices have to be identified, - * thus add the complexity of e keys retrieval among v keys using - * an appropriate data structure. This program uses open double hashing - * for that purpose. See Knuth for the expected complexity of double - * hashing (Brent variation should probably be used if v << e, as a user - * option). - * - * The algorithm used for longest cycle reporting is accurate, but somewhat - * expensive. It may need to build all free paths of the graph (a free - * path is a path that never goes twice through the same node), whose - * number can be as high as O(2^e). Usually, the number of free paths is - * much smaller though. This program's author does not believe that a - * significantly better worst-case complexity algorithm exists. - * - * In case of a hints file, the set of minimal nodes is maintained as a - * heap. The resulting complexity is O(e+v log v) for the worst case. - * The average should actually be near O(e). - * - * If the hints file is incomplete, there is some extra complexity incurred - * by make_transparent, which does propagate order values to unmarked - * nodes. In the worst case, make_transparent is O(e u), - * where u is the number of originally unmarked nodes. - * In practice, it is much faster. - * - * The simple topological sort algorithm detects cycles. This program - * goes further, breaking cycles through the use of simple heuristics. - * Each cycle break checks the whole set of nodes, hence if c cycles break - * are needed, this is an extra cost of O(c v). - * - * Possible heuristics are as follows: - * - break cycle at node with lowest number of predecessors (default case), - * - break longest cycle at node with lowest number of predecessors, - * - break cycle at next node from the hints file. - * - * Except for the hints file case, which sets an explicit constraint on - * which cycle to break, those heuristics locally result in the smallest - * number of broken edges. - * - * Those are admittedly greedy strategies, as is the selection of the next - * node from the hints file amongst equivalent candidates that is used for - * `stable' topological sorting. - */ - -#ifdef __GNUC__ -#define UNUSED __attribute__((unused)) -#else -#define UNUSED -#endif - -struct node; - -/* The set of arcs from a given node is stored as a linked list. */ -struct link { - struct link *next; - struct node *node; -}; - -#define NO_ORDER UINT_MAX - -struct node { - unsigned int refs; /* Number of arcs left, coming into this node. - * Note that nodes with a null count can't - * be part of cycles. */ - unsigned int order; /* Order of nodes according to a hint file. */ - - struct link *arcs; /* List of forward arcs. */ - - /* Cycle detection algorithms build a free path of nodes. */ - struct node *from; /* Previous node in the current path. */ - struct link *traverse; /* Next link to traverse when backtracking. */ - unsigned int mark; /* Mark processed nodes in cycle discovery. */ - - char k[1]; /* Name of this node. */ -}; - -#define HASH_START 9 - -struct array { - unsigned int entries; - struct node **t; -}; - -static void nodes_init(struct ohash *); -static struct node *node_lookup(struct ohash *, const char *, const char *); -static __dead void usage(void); -static struct node *new_node(const char *, const char *); - -static unsigned int read_pairs(FILE *, struct ohash *, int, - const char *, unsigned int, int); -static void split_nodes(struct ohash *, struct array *, struct array *); -static void make_transparent(struct ohash *); -static void insert_arc(struct node *, struct node *); - -#ifdef DEBUG -static void dump_node(struct node *); -static void dump_array(struct array *); -static void dump_hash(struct ohash *); -#endif -static unsigned int read_hints(FILE *, struct ohash *, int, - const char *, unsigned int); -static struct node *find_smallest_node(struct array *); -static struct node *find_good_cycle_break(struct array *); -static void print_cycle(struct array *); -static struct node *find_cycle_from(struct node *, struct array *); -static struct node *find_predecessor(struct array *, struct node *); -static unsigned int traverse_node(struct node *, unsigned int, struct array *); -static struct node *find_longest_cycle(struct array *, struct array *); -static struct node *find_normal_cycle(struct array *, struct array *); - -static void heap_down(struct array *, unsigned int); -static void heapify(struct array *, int); -static struct node *dequeue(struct array *); -static void enqueue(struct array *, struct node *); - - - -static void *hash_calloc(size_t, size_t, void *); -static void hash_free(void *, void *); -static void* entry_alloc(size_t, void *); -static void *ereallocarray(void *, size_t, size_t); -static void *emem(void *); -#define DEBUG_TRAVERSE 0 -static struct ohash_info node_info = { - offsetof(struct node, k), NULL, hash_calloc, hash_free, entry_alloc }; -static void parse_args(int, char *[], struct ohash *); -static int tsort(struct ohash *); - -static int quiet_flag, long_flag, - warn_flag, hints_flag, verbose_flag; - - -int main(int, char *[]); - -/*** - *** Memory handling. - ***/ - -static void * -emem(void *p) -{ - if (p) - return p; - else - errx(1, "Memory exhausted"); -} - -static void * -hash_calloc(size_t n, size_t s, void *u UNUSED) -{ - return emem(calloc(n, s)); -} - -static void -hash_free(void *p, void *u UNUSED) -{ - free(p); -} - -static void * -entry_alloc(size_t s, void *u UNUSED) -{ - return ereallocarray(NULL, 1, s); -} - -static void * -ereallocarray(void *p, size_t n, size_t s) -{ - return emem(reallocarray(p, n, s)); -} - - -/*** - *** Hash table. - ***/ - -/* Inserting and finding nodes in the hash structure. - * We handle interval strings for efficiency wrt fgetln. */ -static struct node * -new_node(const char *start, const char *end) -{ - struct node *n; - - n = ohash_create_entry(&node_info, start, &end); - n->from = NULL; - n->arcs = NULL; - n->refs = 0; - n->mark = 0; - n->order = NO_ORDER; - n->traverse = NULL; - return n; -} - - -static void -nodes_init(struct ohash *h) -{ - ohash_init(h, HASH_START, &node_info); -} - -static struct node * -node_lookup(struct ohash *h, const char *start, const char *end) -{ - unsigned int i; - struct node * n; - - i = ohash_qlookupi(h, start, &end); - - n = ohash_find(h, i); - if (n == NULL) - n = ohash_insert(h, i, new_node(start, end)); - return n; -} - -#ifdef DEBUG -static void -dump_node(struct node *n) -{ - struct link *l; - - if (n->refs == 0) - return; - printf("%s (%u/%u): ", n->k, n->order, n->refs); - for (l = n->arcs; l != NULL; l = l->next) - if (n->refs != 0) - printf("%s(%u/%u) ", l->node->k, l->node->order, l->node->refs); - putchar('\n'); -} - -static void -dump_array(struct array *a) -{ - unsigned int i; - - for (i = 0; i < a->entries; i++) - dump_node(a->t[i]); -} - -static void -dump_hash(struct ohash *h) -{ - unsigned int i; - struct node *n; - - for (n = ohash_first(h, &i); n != NULL; n = ohash_next(h, &i)) - dump_node(n); -} -#endif - -/*** - *** Reading data. - ***/ - -static void -insert_arc(struct node *a, struct node *b) -{ - struct link *l; - - /* Check that this arc is not already present. */ - for (l = a->arcs; l != NULL; l = l->next) { - if (l->node == b) - return; - } - b->refs++; - l = ereallocarray(NULL, 1, sizeof(struct link)); - l->node = b; - l->next = a->arcs; - a->arcs = l; -} - -static unsigned int -read_pairs(FILE *f, struct ohash *h, int reverse, const char *name, - unsigned int order, int hint) -{ - int toggle; - struct node *a; - size_t size; - char *str; - - toggle = 1; - a = NULL; - - while ((str = fgetln(f, &size)) != NULL) { - char *sentinel; - - sentinel = str + size; - for (;;) { - char *e; - - while (str < sentinel && - isspace((unsigned char)*str)) - str++; - if (str == sentinel) - break; - for (e = str; - e < sentinel && !isspace((unsigned char)*e); e++) - continue; - if (toggle) { - a = node_lookup(h, str, e); - if (a->order == NO_ORDER && hint) - a->order = order++; - } else { - struct node *b; - - b = node_lookup(h, str, e); - assert(a != NULL); - if (b != a) { - if (reverse) - insert_arc(b, a); - else - insert_arc(a, b); - } - } - toggle = !toggle; - str = e; - } - } - if (toggle == 0) - errx(1, "odd number of node names in %s", name); - if (!feof(f)) - err(1, "error reading %s", name); - return order; -} - -static unsigned int -read_hints(FILE *f, struct ohash *h, int quiet, const char *name, - unsigned int order) -{ - char *str; - size_t size; - - while ((str = fgetln(f, &size)) != NULL) { - char *sentinel; - - sentinel = str + size; - for (;;) { - char *e; - struct node *a; - - while (str < sentinel && isspace((unsigned char)*str)) - str++; - if (str == sentinel) - break; - for (e = str; - e < sentinel && !isspace((unsigned char)*e); e++) - continue; - a = node_lookup(h, str, e); - if (a->order != NO_ORDER) { - if (!quiet) - warnx( - "duplicate node %s in hints file %s", - a->k, name); - } else - a->order = order++; - str = e; - } - } - if (!feof(f)) - err(1, "error reading %s", name); - return order; -} - - -/*** - *** Standard heap handling routines. - ***/ - -static void -heap_down(struct array *h, unsigned int i) -{ - unsigned int j; - struct node *swap; - - for (; (j=2*i+1) < h->entries; i = j) { - if (j+1 < h->entries && h->t[j+1]->order < h->t[j]->order) - j++; - if (h->t[i]->order <= h->t[j]->order) - break; - swap = h->t[i]; - h->t[i] = h->t[j]; - h->t[j] = swap; - } -} - -static void -heapify(struct array *h, int verbose) -{ - unsigned int i; - - for (i = h->entries; i != 0;) { - if (h->t[--i]->order == NO_ORDER && verbose) - warnx("node %s absent from hints file", h->t[i]->k); - heap_down(h, i); - } -} - -#define DEQUEUE(h) ( hints_flag ? dequeue(h) : (h)->t[--(h)->entries] ) - -static struct node * -dequeue(struct array *h) -{ - struct node *n; - - if (h->entries == 0) - n = NULL; - else { - n = h->t[0]; - if (--h->entries != 0) { - h->t[0] = h->t[h->entries]; - heap_down(h, 0); - } - } - return n; -} - -#define ENQUEUE(h, n) do { \ - if (hints_flag) \ - enqueue((h), (n)); \ - else \ - (h)->t[(h)->entries++] = (n); \ - } while(0); - -static void -enqueue(struct array *h, struct node *n) -{ - unsigned int i, j; - struct node *swap; - - h->t[h->entries++] = n; - for (i = h->entries-1; i > 0; i = j) { - j = (i-1)/2; - if (h->t[j]->order < h->t[i]->order) - break; - swap = h->t[j]; - h->t[j] = h->t[i]; - h->t[i] = swap; - } -} - -/* Nodes without order should not hinder direct dependencies. - * Iterate until no nodes are left. - */ -static void -make_transparent(struct ohash *hash) -{ - struct node *n; - unsigned int i; - struct link *l; - int adjusted; - int bad; - unsigned int min; - - /* first try to solve complete nodes */ - do { - adjusted = 0; - bad = 0; - for (n = ohash_first(hash, &i); n != NULL; - n = ohash_next(hash, &i)) { - if (n->order == NO_ORDER) { - min = NO_ORDER; - - for (l = n->arcs; l != NULL; l = l->next) { - /* unsolved node -> delay resolution */ - if (l->node->order == NO_ORDER) { - bad = 1; - break; - } else if (l->node->order < min) - min = l->node->order; - } - if (min < NO_ORDER && l == NULL) { - n->order = min; - adjusted = 1; - } - } - } - - } while (adjusted); - - /* then, if incomplete nodes are left, do them */ - if (bad) do { - adjusted = 0; - for (n = ohash_first(hash, &i); n != NULL; - n = ohash_next(hash, &i)) - if (n->order == NO_ORDER) - for (l = n->arcs; l != NULL; l = l->next) - if (l->node->order < n->order) { - n->order = l->node->order; - adjusted = 1; - } - } while (adjusted); -} - - -/*** - *** Search through hash array for nodes. - ***/ - -/* Split nodes into unrefed nodes/live nodes. */ -static void -split_nodes(struct ohash *hash, struct array *heap, struct array *remaining) -{ - - struct node *n; - unsigned int i; - - heap->t = ereallocarray(NULL, ohash_entries(hash), - sizeof(struct node *)); - remaining->t = ereallocarray(NULL, ohash_entries(hash), - sizeof(struct node *)); - heap->entries = 0; - remaining->entries = 0; - - for (n = ohash_first(hash, &i); n != NULL; n = ohash_next(hash, &i)) { - if (n->refs == 0) - heap->t[heap->entries++] = n; - else - remaining->t[remaining->entries++] = n; - } -} - -/* Good point to break a cycle: live node with as few refs as possible. */ -static struct node * -find_good_cycle_break(struct array *h) -{ - unsigned int i; - unsigned int best; - struct node *u; - - best = UINT_MAX; - u = NULL; - - assert(h->entries != 0); - for (i = 0; i < h->entries; i++) { - struct node *n = h->t[i]; - /* No need to look further. */ - if (n->refs == 1) - return n; - if (n->refs != 0 && n->refs < best) { - best = n->refs; - u = n; - } - } - assert(u != NULL); - return u; -} - -/* Retrieve the node with the smallest order. */ -static struct node * -find_smallest_node(struct array *h) -{ - unsigned int i; - unsigned int best; - struct node *u; - - best = UINT_MAX; - u = NULL; - - assert(h->entries != 0); - for (i = 0; i < h->entries; i++) { - struct node *n = h->t[i]; - if (n->refs != 0 && n->order < best) { - best = n->order; - u = n; - } - } - assert(u != NULL); - return u; -} - - -/*** - *** Graph algorithms. - ***/ - -/* Explore the nodes reachable from i to find a cycle, store it in c. - * This may fail. */ -static struct node * -find_cycle_from(struct node *i, struct array *c) -{ - struct node *n; - - n = i; - /* XXX Previous cycle findings may have left this pointer non-null. */ - i->from = NULL; - - for (;;) { - /* Note that all marks are reversed before this code exits. */ - n->mark = 1; - if (n->traverse) - n->traverse = n->traverse->next; - else - n->traverse = n->arcs; - /* Skip over dead nodes. */ - while (n->traverse && n->traverse->node->refs == 0) - n->traverse = n->traverse->next; - if (n->traverse) { - struct node *go = n->traverse->node; - - if (go->mark) { - c->entries = 0; - for (; n != NULL && n != go; n = n->from) { - c->t[c->entries++] = n; - n->mark = 0; - } - for (; n != NULL; n = n->from) - n->mark = 0; - c->t[c->entries++] = go; - return go; - } else { - go->from = n; - n = go; - } - } else { - n->mark = 0; - n = n->from; - if (n == NULL) - return NULL; - } - } -} - -/* Find a live predecessor of node n. This is a slow routine, as it needs - * to go through the whole array, but it is not needed often. - */ -static struct node * -find_predecessor(struct array *a, struct node *n) -{ - unsigned int i; - - for (i = 0; i < a->entries; i++) { - struct node *m; - - m = a->t[i]; - if (m->refs != 0) { - struct link *l; - - for (l = m->arcs; l != NULL; l = l->next) - if (l->node == n) - return m; - } - } - assert(1 == 0); - return NULL; -} - -/* Traverse all strongly connected components reachable from node n. - Start numbering them at o. Return the maximum order reached. - Update the largest cycle found so far. - */ -static unsigned int -traverse_node(struct node *n, unsigned int o, struct array *c) -{ - unsigned int min, max; - - n->from = NULL; - min = o; - max = ++o; - - for (;;) { - n->mark = o; - if (DEBUG_TRAVERSE) - printf("%s(%u) ", n->k, n->mark); - /* Find next arc to explore. */ - if (n->traverse) - n->traverse = n->traverse->next; - else - n->traverse = n->arcs; - /* Skip over dead nodes. */ - while (n->traverse && n->traverse->node->refs == 0) - n->traverse = n->traverse->next; - /* If arc left. */ - if (n->traverse) { - struct node *go; - - go = n->traverse->node; - /* Optimisation: if go->mark < min, we already - * visited this strongly-connected component in - * a previous pass. Hence, this can yield no new - * cycle. */ - - /* Not part of the current path: go for it. */ - if (go->mark == 0 || go->mark == min) { - go->from = n; - n = go; - o++; - if (o > max) - max = o; - /* Part of the current path: check cycle length. */ - } else if (go->mark > min) { - if (DEBUG_TRAVERSE) - printf("%d\n", o - go->mark + 1); - if (o - go->mark + 1 > c->entries) { - struct node *t; - unsigned int i; - - c->entries = o - go->mark + 1; - i = 0; - c->t[i++] = go; - for (t = n; t != go; t = t->from) - c->t[i++] = t; - } - } - - /* No arc left: backtrack. */ - } else { - n->mark = min; - n = n->from; - if (!n) - return max; - o--; - } - } -} - -static void -print_cycle(struct array *c) -{ - unsigned int i; - - /* Printing in reverse order, since cycle discoveries finds reverse - * edges. */ - for (i = c->entries; i != 0;) { - i--; - warnx("%s", c->t[i]->k); - } -} - -static struct node * -find_longest_cycle(struct array *h, struct array *c) -{ - unsigned int i; - unsigned int o; - unsigned int best; - struct node *n; - static int notfirst = 0; - - assert(h->entries != 0); - - /* No cycle found yet. */ - c->entries = 0; - - /* Reset the set of marks, except the first time around. */ - if (notfirst) { - for (i = 0; i < h->entries; i++) - h->t[i]->mark = 0; - } else - notfirst = 1; - - o = 0; - - /* Traverse the array. Each unmarked, live node heralds a - * new set of strongly connected components. */ - for (i = 0; i < h->entries; i++) { - n = h->t[i]; - if (n->refs != 0 && n->mark == 0) { - /* Each call to traverse_node uses a separate - * interval of numbers to mark nodes. */ - o++; - o = traverse_node(n, o, c); - } - } - - assert(c->entries != 0); - n = c->t[0]; - best = n->refs; - for (i = 0; i < c->entries; i++) { - if (c->t[i]->refs < best) { - n = c->t[i]; - best = n->refs; - } - } - return n; -} - -static struct node * -find_normal_cycle(struct array *h, struct array *c) -{ - struct node *b, *n; - - if (hints_flag) - n = find_smallest_node(h); - else - n = find_good_cycle_break(h); - while ((b = find_cycle_from(n, c)) == NULL) - n = find_predecessor(h, n); - return b; -} - - -#define plural(n) ((n) > 1 ? "s" : "") - -static void -parse_args(int argc, char *argv[], struct ohash *pairs) -{ - int c; - unsigned int order; - int reverse_flag; - const char **files; - int i, j; - - i = 0; - - reverse_flag = quiet_flag = long_flag = - warn_flag = hints_flag = verbose_flag = 0; - /* argc is good enough, as we start at argv[1] */ - files = ereallocarray(NULL, argc, sizeof (char *)); - while ((c = getopt(argc, argv, "h:flqrvw")) != -1) { - switch(c) { - case 'h': - files[i++] = optarg; - hints_flag = 1; - break; - /*FALLTHRU*/ - case 'f': - hints_flag = 2; - break; - case 'l': - long_flag = 1; - break; - case 'q': - quiet_flag = 1; - break; - case 'r': - reverse_flag = 1; - break; - case 'v': - verbose_flag = 1; - break; - case 'w': - warn_flag = 1; - break; - default: - usage(); - } - } - - argc -= optind; - argv += optind; - - switch(argc) { - case 1: - files[i++] = argv[0]; - break; - case 0: - break; - default: - usage(); - } - - files[i] = NULL; - - nodes_init(pairs); - order = 0; - - for (j = 0; j != i-argc; j++) { - FILE *f; - - f = fopen(files[j], "r"); - if (f == NULL) - err(1, "Can't open hint file %s", files[i]); - order = read_hints(f, pairs, quiet_flag, files[i], order); - fclose(f); - } - free(files); - - if (argc == 1) { - FILE *f; - - f = fopen(argv[0], "r"); - if (f == NULL) - err(1, "Can't open file %s", argv[0]); - order = read_pairs(f, pairs, reverse_flag, argv[0], order, - hints_flag == 2); - fclose(f); - } else { - order = read_pairs(stdin, pairs, reverse_flag, "stdin", - order, hints_flag == 2); - } -} - -static int -tsort(struct ohash *pairs) -{ - struct array aux; /* Unrefed nodes/cycle reporting. */ - struct array remaining; - unsigned int broken_arcs, broken_cycles; - unsigned int left; - - broken_arcs = 0; - broken_cycles = 0; - - if (hints_flag) - make_transparent(pairs); - split_nodes(pairs, &aux, &remaining); - ohash_delete(pairs); - - if (hints_flag) - heapify(&aux, verbose_flag); - - left = remaining.entries + aux.entries; - while (left != 0) { - - /* Standard topological sort. */ - while (aux.entries) { - struct link *l; - struct node *n; - - n = DEQUEUE(&aux); - printf("%s\n", n->k); - left--; - /* We can't free nodes, as we don't know which - * entry we can remove in the hash table. We - * rely on refs == 0 to recognize live nodes. - * Decrease ref count of live nodes, enter new - * candidates into the unrefed list. */ - for (l = n->arcs; l != NULL; l = l->next) - if (l->node->refs != 0 && - --l->node->refs == 0) { - ENQUEUE(&aux, l->node); - } - } - /* There are still cycles to break. */ - if (left != 0) { - struct node *n; - - broken_cycles++; - /* XXX Simple cycle detection and long cycle - * detection are mutually exclusive. */ - - if (long_flag) - n = find_longest_cycle(&remaining, &aux); - else - n = find_normal_cycle(&remaining, &aux); - - if (!quiet_flag) { - warnx("cycle in data"); - print_cycle(&aux); - } - - if (verbose_flag) - warnx("%u edge%s broken", n->refs, - plural(n->refs)); - broken_arcs += n->refs; - n->refs = 0; - /* Reinitialization, cycle reporting uses aux. */ - aux.t[0] = n; - aux.entries = 1; - } - } - if (verbose_flag && broken_cycles != 0) - warnx("%u cycle%s broken, for a total of %u edge%s", - broken_cycles, plural(broken_cycles), - broken_arcs, plural(broken_arcs)); - if (warn_flag) - return (broken_cycles < 256 ? broken_cycles : 255); - else - return (0); -} - -int -main(int argc, char *argv[]) -{ - struct ohash pairs; - - if (pledge("stdio rpath", NULL) == -1) - err(1, "pledge"); - - parse_args(argc, argv, &pairs); - - if (pledge("stdio", NULL) == -1) - err(1, "pledge"); - - return tsort(&pairs); -} - - -extern char *__progname; - -static void -usage(void) -{ - fprintf(stderr, "Usage: %s [-flqrvw] [-h file] [file]\n", __progname); - exit(1); -} |