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transposition.h
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transposition.h
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/*-
* Copyright (c) 2017 Robert Clausecker. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef TRANSPOSITION_H
#define TRANSPOSITION_H
#include <stdalign.h>
#include "tileset.h"
#include "puzzle.h"
enum {
/*
* The number of ways the tray can be rotated and transposed.
*/
AUTOMORPHISM_COUNT = 2 * 4,
};
extern alignas(64) const unsigned char automorphisms[AUTOMORPHISM_COUNT][2][32];
/* transposition of the tray along the main diagonal */
#define transpositions (automorphisms[0][1])
extern void transpose(struct puzzle *);
extern void morph(struct puzzle *, unsigned);
extern tileset tileset_morph(tileset, unsigned);
extern int is_admissible_morphism(tileset, unsigned);
extern unsigned canonical_automorphism(tileset);
extern unsigned compose_morphisms(unsigned, unsigned);
/*
* Invert an automorphism. All automorphisms are self-inverse except
* for 1 and 3 which are inverse to each other.
*/
static inline unsigned
inverse_morphism(unsigned a)
{
return ((a | 2) == 3 ? a ^ 2 : a);
}
/*
* Convenience function.
*/
static inline tileset
tileset_transpose(tileset ts)
{
return (tileset_morph(ts, 4));
}
#endif /* TRANSPOSITION_H */