1 /*
2 * Copyright 2014 The Android Open Source Project
3 *
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
7 *
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.
15 */
16
17 #ifndef A_UTILS_H_
18
19 #define A_UTILS_H_
20
21 /* ============================ math templates ============================ */
22
23 /* T must be integer type, den must not be 0 */
24 template<class T>
divRound(const T & num,const T & den)25 inline static const T divRound(const T &num, const T &den) {
26 if ((num >= 0) ^ (den >= 0)) {
27 return (num - den / 2) / den;
28 } else {
29 return (num + den / 2) / den;
30 }
31 }
32
33 /* == ceil(num / den). T must be integer type, den must not be 0 */
34 template<class T>
divUp(const T & num,const T & den)35 inline static const T divUp(const T &num, const T &den) {
36 if (den < 0) {
37 return (num < 0 ? num + den + 1 : num) / den;
38 } else {
39 return (num < 0 ? num : num + den - 1) / den;
40 }
41 }
42
43 /* == ceil(num / den) * den. T must be integer type, alignment must be positive power of 2 */
44 template<class T, class U>
align(const T & num,const U & den)45 inline static const T align(const T &num, const U &den) {
46 return (num + (T)(den - 1)) & (T)~(den - 1);
47 }
48
49 template<class T>
abs(const T & a)50 inline static T abs(const T &a) {
51 return a < 0 ? -a : a;
52 }
53
54 template<class T>
min(const T & a,const T & b)55 inline static const T &min(const T &a, const T &b) {
56 return a < b ? a : b;
57 }
58
59 template<class T>
max(const T & a,const T & b)60 inline static const T &max(const T &a, const T &b) {
61 return a > b ? a : b;
62 }
63
64 template<class T>
ENSURE_UNSIGNED_TYPE()65 void ENSURE_UNSIGNED_TYPE() {
66 T TYPE_MUST_BE_UNSIGNED[(T)-1 < 0 ? -1 : 0] __unused;
67 }
68
69 // needle is in range [hayStart, hayStart + haySize)
70 template<class T, class U>
71 __attribute__((no_sanitize("integer")))
isInRange(const T & hayStart,const U & haySize,const T & needle)72 inline static bool isInRange(const T &hayStart, const U &haySize, const T &needle) {
73 ENSURE_UNSIGNED_TYPE<U>();
74 return (T)(hayStart + haySize) >= hayStart && needle >= hayStart && (U)(needle - hayStart) < haySize;
75 }
76
77 // [needleStart, needleStart + needleSize) is in range [hayStart, hayStart + haySize)
78 template<class T, class U>
79 __attribute__((no_sanitize("integer")))
isInRange(const T & hayStart,const U & haySize,const T & needleStart,const U & needleSize)80 inline static bool isInRange(
81 const T &hayStart, const U &haySize, const T &needleStart, const U &needleSize) {
82 ENSURE_UNSIGNED_TYPE<U>();
83 return isInRange(hayStart, haySize, needleStart)
84 && (T)(needleStart + needleSize) >= needleStart
85 && (U)(needleStart + needleSize - hayStart) <= haySize;
86 }
87
88 /* T must be integer type, period must be positive */
89 template<class T>
periodicError(const T & val,const T & period)90 inline static T periodicError(const T &val, const T &period) {
91 T err = abs(val) % period;
92 return (err < (period / 2)) ? err : (period - err);
93 }
94
95 #endif // A_UTILS_H_
96