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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: mono.c,v 1.2 2004/04/08 01:36:19 mdw Exp $ |
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4 | * |
5 | * Monoalphabetic matcher |
6 | * |
7 | * (c) 2003 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 | |
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29 | /*----- Header files ------------------------------------------------------*/ |
30 | |
31 | #include "anag.h" |
32 | |
33 | /*----- Data structures ---------------------------------------------------*/ |
34 | |
35 | typedef struct node_mono { |
36 | node n; |
37 | unsigned len; |
38 | unsigned char *p; |
39 | } node_mono; |
40 | |
41 | /*----- Main code ---------------------------------------------------------*/ |
42 | |
43 | /* --- Matching --- */ |
44 | |
45 | static int n_mono(node *nn, const char *p, size_t sz) |
46 | { |
47 | node_mono *n = (node_mono *)nn; |
48 | unsigned map[UCHAR_MAX], imap[UCHAR_MAX]; |
49 | const unsigned char *q = n->p; |
50 | int ch, i; |
51 | |
52 | if (sz != n->len) |
53 | return (0); |
54 | memset(map, 0, sizeof(map)); |
55 | memset(imap, 0, sizeof(imap)); |
56 | while (*p) { |
57 | ch = *p++; |
58 | i = *q++; |
59 | if (!map[i]) { |
60 | if (imap[ch]) |
61 | return (0); |
62 | map[i] = ch; |
63 | imap[ch] = 1; |
64 | } else if (map[i] != ch) |
65 | return (0); |
66 | } |
67 | return (1); |
68 | } |
69 | |
70 | /* --- Node creation --- */ |
71 | |
72 | node *mono(const char *const *av) |
73 | { |
74 | unsigned char map[UCHAR_MAX]; |
75 | unsigned max; |
76 | int ch; |
77 | const char *p; |
78 | unsigned char *q; |
79 | |
80 | node_mono *n = xmalloc(sizeof(*n)); |
81 | n->n.func = n_mono; |
82 | memset(map, UCHAR_MAX, sizeof(map)); |
83 | max = 0; |
84 | p = av[0]; |
85 | n->len = strlen(p); |
86 | q = xmalloc(n->len); |
87 | n->p = q; |
88 | while (*p) { |
89 | ch = *p++; |
90 | if (map[ch] >= max) |
91 | map[ch] = max++; |
92 | *q++ = map[ch]; |
93 | } |
94 | return (&n->n); |
95 | } |
96 | |
97 | /*----- That's all, folks -------------------------------------------------*/ |