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 */
24template<class T>
25inline static const T divRound(const T &nom, const T &den) {
26    if ((nom >= 0) ^ (den >= 0)) {
27        return (nom - den / 2) / den;
28    } else {
29        return (nom + den / 2) / den;
30    }
31}
32
33/* == ceil(nom / den). T must be integer type, den must not be 0 */
34template<class T>
35inline static const T divUp(const T &nom, const T &den) {
36    if (den < 0) {
37        return (nom < 0 ? nom + den + 1 : nom) / den;
38    } else {
39        return (nom < 0 ? nom : nom + den - 1) / den;
40    }
41}
42
43/* == ceil(nom / den) * den. T must be integer type, alignment must be positive power of 2 */
44template<class T, class U>
45inline static const T align(const T &nom, const U &den) {
46    return (nom + (T)(den - 1)) & (T)~(den - 1);
47}
48
49template<class T>
50inline static T abs(const T &a) {
51    return a < 0 ? -a : a;
52}
53
54template<class T>
55inline static const T &min(const T &a, const T &b) {
56    return a < b ? a : b;
57}
58
59template<class T>
60inline static const T &max(const T &a, const T &b) {
61    return a > b ? a : b;
62}
63
64template<class T>
65void 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)
70template<class T, class U>
71__attribute__((no_sanitize("integer")))
72inline 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)
78template<class T, class U>
79__attribute__((no_sanitize("integer")))
80inline 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 */
89template<class T>
90inline 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