b2e3074c1bdfae043c95dd2dd60322270e36997f
5 * (c) 2001 Mark Wooding
8 /*----- Licensing notice --------------------------------------------------*
10 * This file is part of Anag: a simple wordgame helper.
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.
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.
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.
27 /*----- Header files ------------------------------------------------------*/
31 /*----- Data structures ---------------------------------------------------*/
35 typedef struct tcell
{
36 struct tcell
*hop
[NDIR
];
41 typedef struct node_track
{
48 /*----- Utility functions -------------------------------------------------*/
52 * Arguments: @long a@ = the target value
54 * Returns: %$\lfloor \sqrt{a} \rfloor$%
56 * Use: Computes an integer square root. This algorithm is
57 * Newton-Raphson with integers. I've stolen this more-or-less
58 * wholesale fom the multiprecision integer square-root function
66 /* --- Initial guess is half the input length --- */
68 for (i
= q
= a
; q
; q
>>= 2)
71 /* --- Do the main series iteration --- */
75 if (!q
|| (q
< 0 && -q
<= 2 * i
))
85 /*----- Main code ---------------------------------------------------------*/
89 * Arguments: @tcell *c@ = pointer to start cell
90 * @const char *p@ = string to match
92 * Returns: Nonzero for a match, zero if no match was found.
94 * Use: Searches for a match in a trackword.
97 static int track(tcell
*c
, const char *p
)
107 for (cc
= c
->hop
; *cc
; cc
++) {
119 /* --- Node matcher --- */
121 static int n_track(node
*nn
, const char *p
, size_t sz
)
123 node_track
*n
= (node_track
*)nn
;
128 for (c
= n
->c
; c
->ch
; c
++) {
135 /* --- Node creation --- */
137 node
*trackword(const char *const *av
)
142 const char *p
= av
[0], *q
, *l
;
143 size_t sz
= strlen(p
);
144 tcell
*c
, **cc
, **ccc
;
146 /* --- Work out the dimensions --- */
152 die("bad trackword `%s': not square, and no line markers", p
);
157 die("bad trackword `%s': no columns", p
);
168 die("bad trackword `%s': inconsistent line lengths", p
);
174 die("bad trackword `%s': no rows", p
);
176 /* --- Build the match node --- */
178 n
= xmalloc(sizeof(*n
));
181 n
->c
= xmalloc((x
* y
+ 1) * sizeof(tcell
));
185 for (j
= 0; j
< y
; j
++) {
188 for (i
= 0; i
< x
; i
++) {
194 #define SOK (j < y - 1)
196 #define EOK (i < x - 1)
198 if (NOK
) *cc
++ = c
- x
;
199 if (SOK
) *cc
++ = c
+ x
;
200 if (WOK
) *cc
++ = c
- 1;
201 if (EOK
) *cc
++ = c
+ 1;
203 if (NOK
&& WOK
) *cc
++ = c
- x
- 1;
204 if (NOK
&& EOK
) *cc
++ = c
- x
+ 1;
205 if (SOK
&& WOK
) *cc
++ = c
+ x
- 1;
206 if (SOK
&& EOK
) *cc
++ = c
+ x
+ 1;
219 /* --- Now prune out bogus links --- */
221 for (c
= n
->c
; c
->ch
; c
++) {
223 for (cc
= c
->hop
; *cc
; cc
++) {
224 if (isalpha((unsigned char)(*cc
)->ch
)) {
236 /*----- That's all, folks -------------------------------------------------*/