Parser and printer.

.gitignore

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+cdok
+.*.swp
+*~
+*.o

LICENSE

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+cdok -- Calcudoku solver/generator
+Copyright (C) 2012 Daniel Beer <[email protected]>
+
+Permission to use, copy, modify, and/or distribute this software for
+any purpose with or without fee is hereby granted, provided that the
+above copyright notice and this permission notice appear in all
+copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
+WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
+AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
+DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
+PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+PERFORMANCE OF THIS SOFTWARE.

Makefile

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+# cdok -- Calcudoku solver/generator
+# Copyright (C) 2012 Daniel Beer <[email protected]>
+#
+# Permission to use, copy, modify, and/or distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+CC ?= gcc
+CDOK_CFLAGS = -O2 -Wall
+
+all: cdok
+
+cdok: main.o cdok.o parser.o printer.o
+	$(CC) -o $@ $^
+
+clean:
+	rm -f cdok
+	rm -f *.o
+
+%.o: %.c
+	$(CC) $(CFLAGS) $(CDOK_CFLAGS) -o $*.o -c $*.c

cdok.c

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+/* cdok -- Calcudoku solver/generator
+ * Copyright (C) 2012 Daniel Beer <[email protected]>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <string.h>
+
+#include "cdok.h"
+
+/* Map a character to a group ID */
+uint8_t cdok_char_to_group(uint8_t ch)
+{
+	if (ch >= 'A' && ch <= 'Z')
+		return ch - 'A';
+
+	if (ch >= 'a' && ch <= 'z')
+		return ch - 'a' + 26;
+
+	return CDOK_GROUP_NONE;
+}
+
+/* Map a group ID to a character */
+uint8_t cdok_group_to_char(uint8_t g)
+{
+	if (g < 26)
+		return g + 'A';
+
+	return g - 26 + 'a';
+}
+
+void cdok_init_puzzle(struct cdok_puzzle *puz, int size)
+{
+	int i;
+
+	memset(puz, 0, sizeof(*puz));
+
+	for (i = 0; i < CDOK_GROUPS; i++)
+		puz->groups[i].target = -1;
+
+	puz->size = size;
+	memset(puz->group_map, CDOK_GROUP_NONE, sizeof(puz->group_map));
+}
+
+/* Flood fill from the src value to 0 on the given map. */
+void cdok_flood_fill(uint8_t *map, uint8_t src, int x, int y)
+{
+	int start_x = x;
+	int end_x = x;
+	int i;
+
+	if (map[CDOK_POS(x, y)] != src)
+		return;
+
+	while (start_x > 0 && map[CDOK_POS(start_x - 1, y)] == src)
+		start_x--;
+
+	while (end_x + 1 < CDOK_SIZE && map[CDOK_POS(end_x + 1, y)] == src)
+		end_x++;
+
+	for (i = start_x; i <= end_x; i++)
+		map[CDOK_POS(i, y)] = CDOK_GROUP_NONE;
+
+	if (y > 0)
+		for (i = start_x; i <= end_x; i++)
+			cdok_flood_fill(map, src, i, y - 1);
+
+	if (y + 1 < CDOK_SIZE)
+		for (i = start_x; i <= end_x; i++)
+			cdok_flood_fill(map, src, i, y + 1);
+}

cdok.h

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+/* cdok -- Calcudoku solver/generator
+ * Copyright (C) 2012 Daniel Beer <[email protected]>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef CDOK_H_
+#define CDOK_H_
+
+/* This header file defines basic data structures and utilities for
+ * representing puzzles and grids. A grid is represented using a flat
+ * array of size CDOK_CELLS. Coordinates are converted to and from
+ * array indices (cdok_pos_t) via the CDOK_POS* macros.
+ */
+
+#include <stdint.h>
+
+/* Limits on puzzle and group sizes. */
+#define	CDOK_SIZE		16
+#define CDOK_GROUPS		52
+#define CDOK_CELLS		256
+#define CDOK_GROUP_SIZE		8
+
+/* Position reference. This is an index into a grid. */
+typedef int cdok_pos_t;
+
+#define CDOK_POS(x, y)	(((y) << 4) | (x))
+#define CDOK_POS_X(c)	((c) & 0xf)
+#define CDOK_POS_Y(c)	((c) >> 4)
+
+/* Group types. */
+typedef enum {
+	CDOK_SUM = '+',
+	CDOK_DIFFERENCE = '-',
+	CDOK_PRODUCT = '*',
+	CDOK_RATIO = '/'
+} cdok_gtype_t;
+
+/* Clue group. This consists of a type, clue value (target), and a list
+ * of member cells, specified as position references.
+ *
+ * A size of 0 indicates that the group is unused/unallocated.
+ */
+struct cdok_group {
+	cdok_gtype_t	type;
+	int		target;
+	unsigned int	size;
+	cdok_pos_t	members[CDOK_GROUP_SIZE];
+};
+
+#define CDOK_GROUP_NONE		0xff
+
+/* Puzzle representation. This consists of:
+ *
+ *   size:      the dimensions of the puzzle (<= CDOK_SIZE)
+ *   values:    given clues, indexed by cdok_pos_t. A value of zero
+ *              indicates that there is no given value for this cell.
+ *   groups:    a list of grouped cells and their clues.
+ *   group_map: a mapping from cells to the groups to which they belong,
+ *              if any (indexed by cdok_pos_t). A value of CDOK_GROUP_NONE
+ *              indicates that the cell does not belong to a group.
+ *
+ * The following basic invariants should hold:
+ *
+ *    * 1 <= size <= CDOK_SIZE
+ *    * The size of any valid group is >= 2.
+ *    * If group_map[c] == g for every cell c in group g.
+ *    * Cells are a member of one group only, at most.
+ *    * Groups are composed of contiguous cells -- you can trace a route
+ *      from any cell in a group to any other, travelling only
+ *      up/down/left/right.
+ */
+struct cdok_puzzle {
+	unsigned int		size;
+	struct cdok_group	groups[CDOK_GROUPS];
+	uint8_t			values[CDOK_CELLS];
+	uint8_t			group_map[CDOK_CELLS];
+};
+
+/* This data type is used to represent sets of values. It's guaranteed
+ * to have at least CDOK_SIZE bits.
+ */
+typedef uint16_t cdok_set_t;
+
+#define CDOK_SET_SINGLE(c)		(1 << ((c) - 1))
+#define CDOK_SET_ONES(s)		((1 << (s)) - 1)
+#define CDOK_SET_RANGE(min, max)	\
+	(CDOK_SET_ONES(max - min + 1) << (min - 1))
+
+/* Initialize a new, empty grid */
+void cdok_init_puzzle(struct cdok_puzzle *puz, int size);
+
+/* Flood-fill a group map, setting cells from the source value to
+ * CDOK_GROUP_NONE. This function is used to check for valid geometry.
+ */
+void cdok_flood_fill(uint8_t *map, uint8_t src, int x, int y);
+
+/* Each group is named in a puzzle spec using an alphabetic character.
+ * These functions map group indices to and from characters.
+ */
+uint8_t cdok_group_to_char(uint8_t g);
+uint8_t cdok_char_to_group(uint8_t ch);
+
+#endif