| 1 | /* |
| 2 | * loopgen.h: interface file for loop generation functions for grid.[ch]. |
| 3 | */ |
| 4 | |
| 5 | #ifndef _LOOPGEN_H |
| 6 | #define _LOOPGEN_H |
| 7 | |
| 8 | #include "puzzles.h" |
| 9 | #include "grid.h" |
| 10 | |
| 11 | enum face_colour { FACE_WHITE, FACE_GREY, FACE_BLACK }; |
| 12 | |
| 13 | /* face should be of type grid_face* here. */ |
| 14 | #define FACE_COLOUR(face) \ |
| 15 | ( (face) == NULL ? FACE_BLACK : \ |
| 16 | board[(face) - g->faces] ) |
| 17 | |
| 18 | typedef int (*loopgen_bias_fn_t)(void *ctx, char *board, int face); |
| 19 | |
| 20 | /* 'board' should be a char array whose length is the same as |
| 21 | * g->num_faces: this will be filled in with FACE_WHITE or FACE_BLACK |
| 22 | * after loop generation. |
| 23 | * |
| 24 | * If 'bias' is non-null, it should be a user-provided function which |
| 25 | * rates a half-finished board (i.e. may include some FACE_GREYs) for |
| 26 | * desirability; this will cause the loop generator to bias in favour |
| 27 | * of loops with a high return value from that function. The 'face' |
| 28 | * parameter to the bias function indicates which face of the grid has |
| 29 | * been modified since the last call; it is guaranteed that only one |
| 30 | * will have been (so that bias functions can work incrementally |
| 31 | * rather than re-scanning the whole grid on every call). */ |
| 32 | extern void generate_loop(grid *g, char *board, random_state *rs, |
| 33 | loopgen_bias_fn_t bias, void *biasctx); |
| 34 | |
| 35 | #endif |