chiark / gitweb /
Quick lick of paint before we really get started.
[anag] / longest.c
CommitLineData
94ed9b30 1/* -*-c-*-
2 *
94ed9b30 3 * Remember the longest word seen so far
4 *
5 * (c) 2005 Mark Wooding
6 */
7
0279756e 8/*----- Licensing notice --------------------------------------------------*
94ed9b30 9 *
10 * This file is part of Anag: a simple wordgame helper.
11 *
12 * Anag is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
0279756e 16 *
94ed9b30 17 * Anag is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
0279756e 21 *
94ed9b30 22 * You should have received a copy of the GNU General Public License
23 * along with Anag; if not, write to the Free Software Foundation,
24 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
25 */
26
27/*----- Header files ------------------------------------------------------*/
28
29#include "anag.h"
30
31/*----- Data structures ---------------------------------------------------*/
32
33typedef struct link {
34 struct link *next;
35 char *p;
36} link;
37
38typedef struct node_longest {
39 node n;
40 size_t len;
41 link *l, **lt;
42} node_longest;
43
44/*----- Main code ---------------------------------------------------------*/
45
46static void empty(node_longest *n)
47{
48 link *l, *ll;
49
50 for (l = n->l; l; l = ll) {
51 ll = l->next;
52 free(l->p);
53 free(l);
54 }
55 n->l = 0;
56 n->lt = &n->l;
57}
58
59static void insert(node_longest *n, const char *p, size_t sz)
60{
61 link *l;
62
63 n->len = sz;
64 l = xmalloc(sizeof(*l));
65 l->p = xmalloc(sz + 1);
66 memcpy(l->p, p, sz + 1);
67 l->next = 0;
68 *n->lt = l;
69 n->lt = &l->next;
70}
71
72static int aa_output(void *p)
73{
74 node_longest *n = p;
75 link *l;
76
77 if (!n->l) return (0);
78 for (l = n->l; l; l = l->next)
79 puts(l->p);
80 return (1);
81}
82
83static int n_longest(node *nn, const char *p, size_t sz)
84{
85 node_longest *n = (node_longest *)nn;
86 if (sz < n->len)
87 return (0);
88 if (sz > n->len)
89 empty(n);
90 insert(n, p, sz);
91 return (0);
92}
93
94static int n_shortest(node *nn, const char *p, size_t sz)
95{
96 node_longest *n = (node_longest *)nn;
97 if (n->len && sz > n->len)
98 return (0);
99 if (!n->len || sz < n->len)
100 empty(n);
101 insert(n, p, sz);
102 return (0);
103}
104
105static node *mklongest(int (*nf)(node *, const char *, size_t),
106 int (*aa)(void *))
107{
108 node_longest *n = xmalloc(sizeof(*n));
109 n->n.func = nf;
110 n->len = 0;
111 n->l = 0;
112 n->lt = &n->l;
113 atend_register(aa, n);
114 return (&n->n);
115}
116
117node *longest(const char *const *av)
118 { return mklongest(n_longest, aa_output); }
119node *shortest(const char *const *av)
120 { return mklongest(n_shortest, aa_output); }
121
122/*----- That's all, folks -------------------------------------------------*/