From ac3a8726644d4783eacf54212d23db01d1d30044 Mon Sep 17 00:00:00 2001 From: Peter Lieven Date: Mon, 27 Oct 2014 10:18:43 +0100 Subject: util: introduce MIN_NON_ZERO at least in block layer we have the case of limits being defined for a BlockDriverState. However, in this context often zero (0) has the special meanining of undefined which means no limit. If two of those limits are combined and the minimum is needed the minimum function should only return zero if both parameters are zero. Signed-off-by: Peter Lieven Reviewed-by: Max Reitz Signed-off-by: Stefan Hajnoczi --- include/qemu/osdep.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'include') diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h index 1565404f7e..c0324344d5 100644 --- a/include/qemu/osdep.h +++ b/include/qemu/osdep.h @@ -68,6 +68,12 @@ typedef signed int int_fast16_t; #define MAX(a, b) (((a) > (b)) ? (a) : (b)) #endif +/* Minimum function that returns zero only iff both values are zero. + * Intended for use with unsigned values only. */ +#ifndef MIN_NON_ZERO +#define MIN_NON_ZERO(a, b) (((a) != 0 && (a) < (b)) ? (a) : (b)) +#endif + #ifndef ROUND_UP #define ROUND_UP(n,d) (((n) + (d) - 1) & -(d)) #endif -- cgit v1.2.3