From 782a4f3fece388a3b5e541f4b1b11f86f69d5921 Mon Sep 17 00:00:00 2001 From: Simon Tatham Date: Sun, 17 Jul 2005 12:12:16 +0000 Subject: [PATCH] Get rid of the malloc in shuffle(), by defining a subfunction memswap() which declares a fixed-size buffer on the stack and uses it multiple times if necessary. [originally from svn r6107] --- misc.c | 25 ++++++++++++++++++------- 1 file changed, 18 insertions(+), 7 deletions(-) diff --git a/misc.c b/misc.c index b832ee0..5ad4d0b 100644 --- a/misc.c +++ b/misc.c @@ -194,21 +194,32 @@ void game_mkhighlight(frontend *fe, float *ret, } } +void memswap(void *av, void *bv, int size) +{ + char tmpbuf[512]; + char *a = av, *b = bv; + + while (size > 0) { + int thislen = min(size, sizeof(tmpbuf)); + memcpy(tmpbuf, a, thislen); + memcpy(a, b, thislen); + memcpy(b, tmpbuf, thislen); + a += thislen; + b += thislen; + size -= thislen; + } +} + 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); - } + if (j != i) + memswap(carray + eltsize * i, carray + eltsize * j, eltsize); } - sfree(tmp); } void draw_rect_outline(frontend *fe, int x, int y, int w, int h, int colour) -- 2.30.2