diff --git a/misc.c b/misc.c index 025083d..17ec48c 100644 --- a/misc.c +++ b/misc.c @@ -196,4 +196,20 @@ void game_mkhighlight(frontend *fe, float *ret, } } +void shuffle(void *array, int nelts, int eltsize, random_state *rs) +{ + char *tmp = smalloc(eltsize); + char *carray = (char *)array; + int i; + + for (i = nelts; i-- > 1 ;) { + int j = random_upto(rs, i+1); + if (j != i) { + memcpy(tmp, carray + eltsize * i, eltsize); + memcpy(carray + eltsize * i, carray + eltsize * j, eltsize); + memcpy(carray + eltsize * j, tmp, eltsize); + } + } +} + /* vim: set shiftwidth=4 tabstop=8: */ diff --git a/puzzles.h b/puzzles.h index e05a3e4..1c3ae59 100644 --- a/puzzles.h +++ b/puzzles.h @@ -223,6 +223,9 @@ unsigned char *hex2bin(const char *in, int outlen); void game_mkhighlight(frontend *fe, float *ret, int background, int highlight, int lowlight); +/* Randomly shuffles an array of items. */ +void shuffle(void *array, int nelts, int eltsize, random_state *rs); + /* * version.c */