AUtils.h revision 67a30ebfe785f7cd5ecfb0d2fb487e54536a3d48 
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
23template<class T>
24void ENSURE_UNSIGNED_TYPE() {
25    T TYPE_MUST_BE_UNSIGNED[(T)-1 < 0 ? -1 : 0];
26}
27
28// needle is in range [hayStart, hayStart + haySize)
29template<class T, class U>
30inline static bool isInRange(const T &hayStart, const U &haySize, const T &needle) {
31    ENSURE_UNSIGNED_TYPE<U>();
32    return (T)(hayStart + haySize) >= hayStart && needle >= hayStart && (U)(needle - hayStart) < haySize;
33}
34
35// [needleStart, needleStart + needleSize) is in range [hayStart, hayStart + haySize)
36template<class T, class U>
37inline static bool isInRange(
38        const T &hayStart, const U &haySize, const T &needleStart, const U &needleSize) {
39    ENSURE_UNSIGNED_TYPE<U>();
40    return isInRange(hayStart, haySize, needleStart)
41            && (T)(needleStart + needleSize) >= needleStart
42            && (U)(needleStart + needleSize - hayStart) <= haySize;
43}
44
45#endif  // A_UTILS_H_
46