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1 | /* |
2 | * Copyright (c) 2008 Nicira Networks. | |
3 | * | |
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4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
5 | * you may not use this file except in compliance with the License. | |
6 | * You may obtain a copy of the License at: | |
064af421 | 7 | * |
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8 | * http://www.apache.org/licenses/LICENSE-2.0 |
9 | * | |
10 | * Unless required by applicable law or agreed to in writing, software | |
11 | * distributed under the License is distributed on an "AS IS" BASIS, | |
12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
13 | * See the License for the specific language governing permissions and | |
14 | * limitations under the License. | |
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15 | */ |
16 | ||
17 | #ifndef SAT_MATH_H | |
18 | #define SAT_MATH_H 1 | |
19 | ||
20 | #include <assert.h> | |
21 | #include <limits.h> | |
22 | ||
23 | /* Saturating addition: overflow yields UINT_MAX. */ | |
24 | static inline unsigned int | |
25 | sat_add(unsigned int x, unsigned int y) | |
26 | { | |
27 | return x + y >= x ? x + y : UINT_MAX; | |
28 | } | |
29 | ||
30 | /* Saturating subtraction: underflow yields 0. */ | |
31 | static inline unsigned int | |
32 | sat_sub(unsigned int x, unsigned int y) | |
33 | { | |
34 | return x >= y ? x - y : 0; | |
35 | } | |
36 | ||
37 | /* Saturating multiplication: overflow yields UINT_MAX. */ | |
38 | static inline unsigned int | |
39 | sat_mul(unsigned int x, unsigned int y) | |
40 | { | |
41 | return (!y ? 0 | |
42 | : x <= UINT_MAX / y ? x * y | |
43 | : UINT_MAX); | |
44 | } | |
45 | ||
46 | #endif /* sat-math.h */ |