content: /*
   * Copyright (C) 2017 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 com.android.server.power.batterysaver;
  
  import android.util.ArrayMap;
  import android.util.Slog;
  
  import com.android.internal.annotations.GuardedBy;
  
  import java.util.Map;
  
  
  /**
   * Helper to parse a list of "core-number:frequency" pairs concatenated with / as a separator,
   * and convert them into a map of "filename -> value" that should be written to
   * /sys/.../scaling_max_freq.
   *
   * Example input: "0:1900800/4:2500000", which will be converted into:
   *   "/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq" "1900800"
   *   "/sys/devices/system/cpu/cpu4/cpufreq/scaling_max_freq" "2500000"
   *
   * Test:
   atest $ANDROID_BUILD_TOP/frameworks/base/services/tests/servicestests/src/com/android/server/power/batterysaver/CpuFrequenciesTest.java
   */
  public class CpuFrequencies {
      private static final String TAG = "CpuFrequencies";
  
      private final Object mLock = new Object();
  
      @GuardedBy("mLock")
      private final ArrayMap<Integer, Long> mCoreAndFrequencies = new ArrayMap<>();
  
      public CpuFrequencies() {
      }
  
      /**
       * Parse a string.
       */
      public CpuFrequencies parseString(String cpuNumberAndFrequencies) {
          synchronized (mLock) {
              mCoreAndFrequencies.clear();
              try {
                  for (String pair : cpuNumberAndFrequencies.split("/")) {
                      pair = pair.trim();
                      if (pair.length() == 0) {
                          continue;
                      }
                      final String[] coreAndFreq = pair.split(":", 2);
  
                      if (coreAndFreq.length != 2) {
                          throw new IllegalArgumentException("Wrong format");
                      }
                      final int core = Integer.parseInt(coreAndFreq[0]);
                      final long freq = Long.parseLong(coreAndFreq[1]);
  
                      mCoreAndFrequencies.put(core, freq);
                  }
              } catch (IllegalArgumentException e) {
                  Slog.wtf(TAG, "Invalid configuration: '" + cpuNumberAndFrequencies + "'");
              }
          }
          return this;
      }
  
      /**
       * Return a new map containing the filename-value pairs.
       */
      public ArrayMap<String, String> toSysFileMap() {
          final ArrayMap<String, String> map = new ArrayMap<>();
          addToSysFileMap(map);
          return map;
      }
  
      /**
       * Add the filename-value pairs to an existing map.
       */
      public void addToSysFileMap(Map<String, String> map) {
          synchronized (mLock) {
              final int size = mCoreAndFrequencies.size();
  
              for (int i = 0; i < size; i++) {
                  final int core = mCoreAndFrequencies.keyAt(i);
                  final long freq = mCoreAndFrequencies.valueAt(i);
  
                  final String file = "/sys/devices/system/cpu/cpu" + Integer.toString(core) +
                          "/cpufreq/scaling_max_freq";
  
                  map.put(file, Long.toString(freq));
              }
          }
      }
  }
  