ref: f279c5eba035d018a8805a65a8a245b8b8d2ea2e
dir: /loopgen.h/
/*
* loopgen.h: interface file for loop generation functions for grid.[ch].
*/
#ifndef PUZZLES_LOOPGEN_H
#define PUZZLES_LOOPGEN_H
#include "puzzles.h"
#include "grid.h"
enum face_colour { FACE_WHITE, FACE_GREY, FACE_BLACK };
/* face should be of type grid_face* here. */
#define FACE_COLOUR(face) \
( (face) == NULL ? FACE_BLACK : \
board[(face)->index] )
typedef int (*loopgen_bias_fn_t)(void *ctx, char *board, int face);
/* 'board' should be a char array whose length is the same as
* g->num_faces: this will be filled in with FACE_WHITE or FACE_BLACK
* after loop generation.
*
* If 'bias' is non-null, it should be a user-provided function which
* rates a half-finished board (i.e. may include some FACE_GREYs) for
* desirability; this will cause the loop generator to bias in favour
* of loops with a high return value from that function. The 'face'
* parameter to the bias function indicates which face of the grid has
* been modified since the last call; it is guaranteed that only one
* will have been (so that bias functions can work incrementally
* rather than re-scanning the whole grid on every call). */
extern void generate_loop(grid *g, char *board, random_state *rs,
loopgen_bias_fn_t bias, void *biasctx);
#endif