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Commit | Line | Data |
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064af421 | 1 | /* |
74142432 | 2 | * Copyright (c) 2008, 2012, 2019 Nicira, Inc. |
064af421 | 3 | * |
a14bc59f BP |
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 | * |
a14bc59f BP |
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. | |
064af421 BP |
15 | */ |
16 | ||
17 | #ifndef SAT_MATH_H | |
18 | #define SAT_MATH_H 1 | |
19 | ||
064af421 | 20 | #include <limits.h> |
8c7be52d | 21 | #include "openvswitch/util.h" |
064af421 | 22 | |
74142432 BP |
23 | #ifndef __has_builtin |
24 | #define __has_builtin(x) 0 | |
25 | #endif | |
26 | ||
27 | /* Returns x + y, clamping out-of-range results into the range of the return | |
28 | * type. */ | |
064af421 BP |
29 | static inline unsigned int |
30 | sat_add(unsigned int x, unsigned int y) | |
31 | { | |
32 | return x + y >= x ? x + y : UINT_MAX; | |
33 | } | |
74142432 BP |
34 | static inline long long int |
35 | llsat_add__(long long int x, long long int y) | |
36 | { | |
37 | return (x >= 0 && y >= 0 && x > LLONG_MAX - y ? LLONG_MAX | |
38 | : x < 0 && y < 0 && x < LLONG_MIN - y ? LLONG_MIN | |
39 | : x + y); | |
40 | } | |
41 | static inline long long int | |
42 | llsat_add(long long int x, long long int y) | |
43 | { | |
0175bdd4 | 44 | #if (__GNUC__ >= 5 || __has_builtin(__builtin_saddll_overflow)) && !__CHECKER__ |
74142432 BP |
45 | long long int sum; |
46 | return (!__builtin_saddll_overflow(x, y, &sum) ? sum | |
47 | : x > 0 ? LLONG_MAX : LLONG_MIN); | |
48 | #else | |
49 | return llsat_add__(x, y); | |
50 | #endif | |
51 | } | |
064af421 | 52 | |
74142432 BP |
53 | /* Returns x - y, clamping out-of-range results into the range of the return |
54 | * type. */ | |
064af421 BP |
55 | static inline unsigned int |
56 | sat_sub(unsigned int x, unsigned int y) | |
57 | { | |
58 | return x >= y ? x - y : 0; | |
59 | } | |
74142432 BP |
60 | static inline long long int |
61 | llsat_sub__(long long int x, long long int y) | |
62 | { | |
63 | return (x >= 0 && y < 0 && x > LLONG_MAX + y ? LLONG_MAX | |
64 | : x < 0 && y >= 0 && x < LLONG_MIN + y ? LLONG_MIN | |
65 | : x - y); | |
66 | } | |
67 | static inline long long int | |
68 | llsat_sub(long long int x, long long int y) | |
69 | { | |
0175bdd4 | 70 | #if (__GNUC__ >= 5 || __has_builtin(__builtin_ssubll_overflow)) && !__CHECKER__ |
74142432 BP |
71 | long long int difference; |
72 | return (!__builtin_ssubll_overflow(x, y, &difference) ? difference | |
73 | : x >= 0 ? LLONG_MAX : LLONG_MIN); | |
74 | #else | |
75 | return llsat_sub__(x, y); | |
76 | #endif | |
77 | } | |
064af421 | 78 | |
74142432 BP |
79 | /* Returns x * y, clamping out-of-range results into the range of the return |
80 | * type. */ | |
064af421 BP |
81 | static inline unsigned int |
82 | sat_mul(unsigned int x, unsigned int y) | |
83 | { | |
8c7be52d | 84 | return OVS_SAT_MUL(x, y); |
064af421 | 85 | } |
74142432 BP |
86 | static inline long long int |
87 | llsat_mul__(long long int x, long long int y) | |
88 | { | |
89 | return ( x > 0 && y > 0 && x > LLONG_MAX / y ? LLONG_MAX | |
90 | : x < 0 && y > 0 && x < LLONG_MIN / y ? LLONG_MIN | |
91 | : x > 0 && y < 0 && y < LLONG_MIN / x ? LLONG_MIN | |
92 | /* Special case because -LLONG_MIN / -1 overflows: */ | |
93 | : x == LLONG_MIN && y == -1 ? LLONG_MAX | |
94 | : x < 0 && y < 0 && x < LLONG_MAX / y ? LLONG_MAX | |
95 | : x * y); | |
96 | } | |
97 | static inline long long int | |
98 | llsat_mul(long long int x, long long int y) | |
99 | { | |
0175bdd4 | 100 | #if (__GNUC__ >= 5 || __has_builtin(__builtin_smulll_overflow)) && !__CHECKER__ |
74142432 BP |
101 | long long int product; |
102 | return (!__builtin_smulll_overflow(x, y, &product) ? product | |
103 | : (x > 0) == (y > 0) ? LLONG_MAX : LLONG_MIN); | |
104 | #else | |
105 | return llsat_mul__(x, y); | |
106 | #endif | |
107 | } | |
064af421 BP |
108 | |
109 | #endif /* sat-math.h */ |