1 /* 2 * Copyright (C) 2011 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 package com.android.internal.util; 18 19 import java.io.FileInputStream; 20 21 import android.os.StrictMode; 22 23 public class MemInfoReader { 24 byte[] mBuffer = new byte[1024]; 25 26 private long mTotalSize; 27 private long mFreeSize; 28 private long mCachedSize; 29 30 private boolean matchText(byte[] buffer, int index, String text) { 31 int N = text.length(); 32 if ((index+N) >= buffer.length) { 33 return false; 34 } 35 for (int i=0; i<N; i++) { 36 if (buffer[index+i] != text.charAt(i)) { 37 return false; 38 } 39 } 40 return true; 41 } 42 43 private long extractMemValue(byte[] buffer, int index) { 44 while (index < buffer.length && buffer[index] != '\n') { 45 if (buffer[index] >= '0' && buffer[index] <= '9') { 46 int start = index; 47 index++; 48 while (index < buffer.length && buffer[index] >= '0' 49 && buffer[index] <= '9') { 50 index++; 51 } 52 String str = new String(buffer, 0, start, index-start); 53 return ((long)Integer.parseInt(str)) * 1024; 54 } 55 index++; 56 } 57 return 0; 58 } 59 60 public void readMemInfo() { 61 // Permit disk reads here, as /proc/meminfo isn't really "on 62 // disk" and should be fast. TODO: make BlockGuard ignore 63 // /proc/ and /sys/ files perhaps? 64 StrictMode.ThreadPolicy savedPolicy = StrictMode.allowThreadDiskReads(); 65 try { 66 mTotalSize = 0; 67 mFreeSize = 0; 68 mCachedSize = 0; 69 FileInputStream is = new FileInputStream("/proc/meminfo"); 70 int len = is.read(mBuffer); 71 is.close(); 72 final int BUFLEN = mBuffer.length; 73 int count = 0; 74 for (int i=0; i<len && count < 3; i++) { 75 if (matchText(mBuffer, i, "MemTotal")) { 76 i += 8; 77 mTotalSize = extractMemValue(mBuffer, i); 78 count++; 79 } else if (matchText(mBuffer, i, "MemFree")) { 80 i += 7; 81 mFreeSize = extractMemValue(mBuffer, i); 82 count++; 83 } else if (matchText(mBuffer, i, "Cached")) { 84 i += 6; 85 mCachedSize = extractMemValue(mBuffer, i); 86 count++; 87 } 88 while (i < BUFLEN && mBuffer[i] != '\n') { 89 i++; 90 } 91 } 92 } catch (java.io.FileNotFoundException e) { 93 } catch (java.io.IOException e) { 94 } finally { 95 StrictMode.setThreadPolicy(savedPolicy); 96 } 97 } 98 99 public long getTotalSize() { 100 return mTotalSize; 101 } 102 103 public long getFreeSize() { 104 return mFreeSize; 105 } 106 107 public long getCachedSize() { 108 return mCachedSize; 109 } 110 } 111
