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/*
* Copyright 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef A_UTILS_H_
#define A_UTILS_H_
/* ============================ math templates ============================ */
/* T must be integer type, den must not be 0 */
template<class T>
inline static const T divRound(const T &nom, const T &den) {
if ((nom >= 0) ^ (den >= 0)) {
return (nom - den / 2) / den;
} else {
return (nom + den / 2) / den;
}
}
/* == ceil(nom / den). T must be integer type, den must not be 0 */
template<class T>
inline static const T divUp(const T &nom, const T &den) {
if (den < 0) {
return (nom < 0 ? nom + den + 1 : nom) / den;
} else {
return (nom < 0 ? nom : nom + den - 1) / den;
}
}
template<class T>
inline static T abs(const T &a) {
return a < 0 ? -a : a;
}
template<class T>
inline static const T &min(const T &a, const T &b) {
return a < b ? a : b;
}
template<class T>
inline static const T &max(const T &a, const T &b) {
return a > b ? a : b;
}
template<class T>
void ENSURE_UNSIGNED_TYPE() {
T TYPE_MUST_BE_UNSIGNED[(T)-1 < 0 ? -1 : 0] __unused;
}
// needle is in range [hayStart, hayStart + haySize)
template<class T, class U>
inline static bool isInRange(const T &hayStart, const U &haySize, const T &needle) {
ENSURE_UNSIGNED_TYPE<U>();
return (T)(hayStart + haySize) >= hayStart && needle >= hayStart && (U)(needle - hayStart) < haySize;
}
// [needleStart, needleStart + needleSize) is in range [hayStart, hayStart + haySize)
template<class T, class U>
inline static bool isInRange(
const T &hayStart, const U &haySize, const T &needleStart, const U &needleSize) {
ENSURE_UNSIGNED_TYPE<U>();
return isInRange(hayStart, haySize, needleStart)
&& (T)(needleStart + needleSize) >= needleStart
&& (U)(needleStart + needleSize - hayStart) <= haySize;
}
/* T must be integer type, period must be positive */
template<class T>
inline static T periodicError(const T &val, const T &period) {
T err = abs(val) % period;
return (err < (period / 2)) ? err : (period - err);
}
#endif // A_UTILS_H_
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