CpuMon.java :  » App » android-labs » com » google » android » netmeter » Android Open Source

/*
 * Copyright (C) 2008 Google Inc.
 *
 * 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.google.android.netmeter;

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.text.DecimalFormat;
import java.util.Vector;

import android.util.Log;
import android.widget.TextView;

public class CpuMon {
  final private String STAT_FILE = "/proc/stat";
  final private DecimalFormat mPercentFmt = new DecimalFormat("#0.0");
  
  private long mUser;
  private long mSystem;
  private long mTotal;
  
  private HistoryBuffer mHistory;
    
  private Vector<TextView> mDisplay;
  
  
  public CpuMon() {
    mHistory = new HistoryBuffer();
    readStats();
  }
  
  public HistoryBuffer getHistory() {
    return mHistory;
  }
  
  public void linkDisplay(Vector<TextView> display) {
    mDisplay = display;
    readStats();
  }
  
  public void unlinkDisplay() {
    mDisplay = null;
  }
  
  public boolean readStats() {
    FileReader fstream;
    try {
      fstream = new FileReader(STAT_FILE);
    } catch (FileNotFoundException e) {
      Log.e("MonNet", "Could not read " + STAT_FILE);
      return false;
    }
    BufferedReader in = new BufferedReader(fstream, 500);
    String line;
    try {
      while ((line = in.readLine()) != null) {
        if (line.startsWith("cpu")) {
          updateStats(line.trim().split("[ ]+"));
          return true;
        }
      }
    } catch (IOException e) {
      Log.e("MonNet", e.toString());
    }
    return false;
  }
  
  private void updateStats(String[] segs) {
    // user = user + nice
    long user = Long.parseLong(segs[1]) + Long.parseLong(segs[2]);
    // system = system + intr + soft_irq
    long system = Long.parseLong(segs[3]) + Long.parseLong(segs[6]) + Long.parseLong(segs[7]);
    // total = user + system + idle + io_wait
    long total = user + system + Long.parseLong(segs[4]) + Long.parseLong(segs[5]);
    
    if (mTotal != 0 || total >= mTotal) {
      long duser = user - mUser;
      long dsystem = system - mSystem;
      long dtotal = total - mTotal;
      if (mDisplay != null) {
        mDisplay.get(0).setText(mPercentFmt.format(
            (double)(duser+dsystem)*100.0/dtotal) + "% ("
        + mPercentFmt.format(
            (double)(duser)*100.0/dtotal) + "/"
        + mPercentFmt.format(
            (double)(dsystem)*100.0/dtotal) + ")");
      }
      mHistory.add((int)((duser + dsystem) * 100 / dtotal));
    } 
    mUser = user;
    mSystem = system;
    mTotal = total;
    
    
  }
}