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

   1 /* -*-c-*-
   2  *
   3  * $Id$
   4  *
   5  * Remember the longest word seen so far
   6  *
   7  * (c) 2005 Mark Wooding
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of Anag: a simple wordgame helper.
  13  *
  14  * Anag is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * Anag is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with Anag; if not, write to the Free Software Foundation,
  26  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  27  */
  28
  29 /*----- Header files ------------------------------------------------------*/
  30
  31 #include "anag.h"
  32
  33 /*----- Data structures ---------------------------------------------------*/
  34
  35 typedef struct link {
  36   struct link *next;
  37   char *p;
  38 } link;
  39
  40 typedef struct node_longest {
  41   node n;
  42   size_t len;
  43   link *l, **lt;
  44 } node_longest;
  45
  46 /*----- Main code ---------------------------------------------------------*/
  47
  48 static void empty(node_longest *n)
  49 {
  50   link *l, *ll;
  51
  52   for (l = n->l; l; l = ll) {
  53     ll = l->next;
  54     free(l->p);
  55     free(l);
  56   }
  57   n->l = 0;
  58   n->lt = &n->l;
  59 }
  60
  61 static void insert(node_longest *n, const char *p, size_t sz)
  62 {
  63   link *l;
  64
  65   n->len = sz;
  66   l = xmalloc(sizeof(*l));
  67   l->p = xmalloc(sz + 1);
  68   memcpy(l->p, p, sz + 1);
  69   l->next = 0;
  70   *n->lt = l;
  71   n->lt = &l->next;
  72 }
  73
  74 static int aa_output(void *p)
  75 {
  76   node_longest *n = p;
  77   link *l;
  78
  79   if (!n->l) return (0);
  80   for (l = n->l; l; l = l->next)
  81     puts(l->p);
  82   return (1);
  83 }
  84
  85 static int n_longest(node *nn, const char *p, size_t sz)
  86 {
  87   node_longest *n = (node_longest *)nn;
  88   if (sz < n->len)
  89     return (0);
  90   if (sz > n->len)
  91     empty(n);
  92   insert(n, p, sz);
  93   return (0);
  94 }
  95
  96 static int n_shortest(node *nn, const char *p, size_t sz)
  97 {
  98   node_longest *n = (node_longest *)nn;
  99   if (n->len && sz > n->len)
 100     return (0);
 101   if (!n->len || sz < n->len)
 102     empty(n);
 103   insert(n, p, sz);
 104   return (0);
 105 }
 106
 107 static node *mklongest(int (*nf)(node *, const char *, size_t),
 108                        int (*aa)(void *))
 109 {
 110   node_longest *n = xmalloc(sizeof(*n));
 111   n->n.func = nf;
 112   n->len = 0;
 113   n->l = 0;
 114   n->lt = &n->l;
 115   atend_register(aa, n);
 116   return (&n->n);
 117 }
 118
 119 node *longest(const char *const *av)
 120   { return mklongest(n_longest, aa_output); }
 121 node *shortest(const char *const *av)
 122   { return mklongest(n_shortest, aa_output); }
 123
 124 /*----- That's all, folks -------------------------------------------------*/