Abstract subanagram code from rack into new bag.c

[wordgame] / subanagram.c

diff --git a/subanagram.c b/subanagram.c
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+/*
+ * Copyright © 2006 Carl Worth
+ *
+ * This program is free software; you can redistribute it and\/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA."
+ */
+
+#include "word-game.h"
+
+#include <string.h>
+
+static const char *subanagram_letters;
+static char subanagram_enumerate_word[WORD_GAME_MAX_WORD_LENGTH];
+static dict_t *subanagram_enumerate_answers;
+
+static void
+subanagram_enumerate (dict_cursor_t     cursor,
+                     uint8_t            seen)
+{
+    char c;
+    unsigned int i, last;
+    uint8_t next_seen;
+
+    if (cursor == DICT_CURSOR_NIL)
+       return;
+
+    if (DICT_ENTRY_IS_WORD (dict_cursor_resolve (cursor)))
+       dict_add_word (subanagram_enumerate_answers, subanagram_enumerate_word);
+
+    last = strlen (subanagram_enumerate_word);
+
+    for (i = 0; i < strlen (subanagram_letters); i++) {
+       if (seen & (1 << i))
+           continue;
+       next_seen = seen | (1 << i);
+       c = subanagram_letters[i];
+       if (c == '?' || c == '_') {
+           for (c = 'a'; c <= 'z'; c++) {
+               subanagram_enumerate_word[last] = c;
+               subanagram_enumerate (dict_cursor_next (cursor, c), next_seen);
+           }
+       } else {
+           subanagram_enumerate_word[last] = c;
+           subanagram_enumerate (dict_cursor_next (cursor, c), next_seen);
+       }
+       subanagram_enumerate_word[last] = '\0';
+    }
+}
+
+void
+subanagram_expand (const char *letters, dict_t *dict, dict_t *answers)
+{
+    subanagram_letters = letters;
+    memset (subanagram_enumerate_word, '\0', WORD_GAME_MAX_WORD_LENGTH);
+    subanagram_enumerate_answers = answers;
+
+    subanagram_enumerate (dict_root (dict), 0);
+}