mdw@git.distorted.org.uk Git - anag/blob - longest.c

   1 /* -*-c-*-
   2  *
   3  * Remember the longest word seen so far
   4  *
   5  * (c) 2005 Mark Wooding
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   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.
  16  *
  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.
  21  *
  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
  33 typedef struct link {
  34   struct link *next;
  35   char *p;
  36 } link;
  37
  38 typedef struct node_longest {
  39   node n;
  40   size_t len;
  41   link *l, **lt;
  42 } node_longest;
  43
  44 /*----- Main code ---------------------------------------------------------*/
  45
  46 static 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
  59 static 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
  72 static 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
  83 static 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
  94 static 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
 105 static 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
 117 node *longest(const char *const *av)
 118   { return mklongest(n_longest, aa_output); }
 119 node *shortest(const char *const *av)
 120   { return mklongest(n_shortest, aa_output); }
 121
 122 /*----- That's all, folks -------------------------------------------------*/