| /* |
| * Copyright (C) 2016 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. |
| */ |
| package android.car; |
| |
| import android.annotation.SystemApi; |
| |
| /** |
| * Collection of utilities for handling zones |
| * @hide |
| */ |
| @SystemApi |
| public final class VehicleZoneUtil { |
| |
| /** |
| * Change zone flag into index with available zones. |
| * For example with zoned of 0x80000001, 0x1 will be index 0 and 0x80000000 will be index 2. |
| * @param available zones, should not be zero |
| * @param zone flag for the zone to get index, should not be zero and should be one of the flags |
| * defined in zones. |
| * @return index of desired zone. |
| * @throws IllegalArgumentException if zones or zone is invalid. |
| */ |
| public static int zoneToIndex(int zones, int zone) throws IllegalArgumentException { |
| if ((zone == 0) || // check that zone is non-zero |
| ((zone & zones) != zone) || // check that zone is inside of zones |
| ((zone & (zone - 1)) != 0)) { // check that zone only has one bit set |
| throw new IllegalArgumentException("Invalid zones 0x" + Integer.toHexString(zones) + |
| " or zone 0x" + Integer.toHexString(zone)); |
| } |
| int index = -1; |
| while((zone & zones) != 0) { |
| index++; |
| zones &= zones - 1; |
| } |
| return index; |
| } |
| |
| /** |
| * Return number of zones (non-zero flag) from given zones. |
| */ |
| public static int getNumberOfZones(int zones) { |
| int numZones = 0; |
| while (zones != 0) { |
| zones &= zones - 1; |
| numZones++; |
| } |
| return numZones; |
| } |
| |
| /** |
| * Return bit flag of first zone. If zones is 0, it will just return 0. |
| * @param zones can be 0 if there is no zone |
| * @return |
| */ |
| public static int getFirstZone(int zones) { |
| if (zones == 0) { |
| return 0; |
| } |
| int xorFlag = zones & (zones - 1); |
| |
| return zones ^ xorFlag; |
| } |
| |
| /** |
| * Return bit flag of zone available after startingZone. For zones of 0x7 with startingZone of |
| * 0x2, it will return 0x4. If no zone exist after startingZone, it will return 0. |
| * @param zones |
| * @param startingZone A bit flag representing a zone. This does not necessarily be one of flags |
| * available in zones. |
| * @return |
| * @throws IllegalArgumentException If startingZone is invalid. |
| */ |
| public static int getNextZone(int zones, int startingZone) throws IllegalArgumentException { |
| if ((startingZone & (startingZone - 1)) != 0 || startingZone == 0) { |
| throw new IllegalArgumentException( |
| "Starting zone should represent only one bit flag: 0x" + |
| Integer.toHexString(startingZone)); |
| } |
| |
| // Create a mask that sets all bits above the current one |
| int mask = startingZone << 1; |
| mask -= 1; |
| mask = ~mask; |
| return getFirstZone(zones & mask); |
| } |
| |
| /** |
| * Return array of zone with each active zone in one index. This can be useful for iterating |
| * all available zones. |
| */ |
| public static int[] listAllZones(int zones) { |
| int numberOfZones = getNumberOfZones(zones); |
| int[] list = new int[numberOfZones]; |
| if (numberOfZones == 0) { |
| return list; |
| } |
| |
| int arrayIndex = 0; |
| while (zones != 0) { |
| int xorFlag = zones & (zones - 1); |
| int zone = zones ^ xorFlag; |
| list[arrayIndex++] = zone; |
| zones = xorFlag; |
| } |
| return list; |
| } |
| |
| private VehicleZoneUtil() {} |
| } |