From 064af42167bf4fc9aaea2702d80ce08074b889c0 Mon Sep 17 00:00:00 2001 From: Ben Pfaff Date: Wed, 8 Jul 2009 13:19:16 -0700 Subject: Import from old repository commit 61ef2b42a9c4ba8e1600f15bb0236765edc2ad45. --- lib/sat-math.h | 46 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) create mode 100644 lib/sat-math.h (limited to 'lib/sat-math.h') diff --git a/lib/sat-math.h b/lib/sat-math.h new file mode 100644 index 00000000..84ff51ac --- /dev/null +++ b/lib/sat-math.h @@ -0,0 +1,46 @@ +/* + * Copyright (c) 2008 Nicira Networks. + * + * Permission to use, copy, modify, and/or distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +#ifndef SAT_MATH_H +#define SAT_MATH_H 1 + +#include +#include + +/* Saturating addition: overflow yields UINT_MAX. */ +static inline unsigned int +sat_add(unsigned int x, unsigned int y) +{ + return x + y >= x ? x + y : UINT_MAX; +} + +/* Saturating subtraction: underflow yields 0. */ +static inline unsigned int +sat_sub(unsigned int x, unsigned int y) +{ + return x >= y ? x - y : 0; +} + +/* Saturating multiplication: overflow yields UINT_MAX. */ +static inline unsigned int +sat_mul(unsigned int x, unsigned int y) +{ + return (!y ? 0 + : x <= UINT_MAX / y ? x * y + : UINT_MAX); +} + +#endif /* sat-math.h */ -- cgit v1.2.3