1 /* 2 * Copyright (C) 2012 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.mail.photomanager; 18 19 import android.os.StrictMode; 20 21 import java.io.FileInputStream; 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 static 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 static 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' && buffer[index] <= '9') { 49 index++; 50 } 51 String str = new String(buffer, 0, start, index - start); 52 return ((long) Integer.parseInt(str)) * 1024; 53 } 54 index++; 55 } 56 return 0; 57 } 58 59 public void readMemInfo() { 60 // Permit disk reads here, as /proc/meminfo isn't really "on 61 // disk" and should be fast. TODO: make BlockGuard ignore 62 // /proc/ and /sys/ files perhaps? 63 StrictMode.ThreadPolicy savedPolicy = StrictMode.allowThreadDiskReads(); 64 try { 65 mTotalSize = 0; 66 mFreeSize = 0; 67 mCachedSize = 0; 68 FileInputStream is = new FileInputStream("/proc/meminfo"); 69 int len = is.read(mBuffer); 70 is.close(); 71 final int BUFLEN = mBuffer.length; 72 int count = 0; 73 for (int i = 0; i < len && count < 3; i++) { 74 if (matchText(mBuffer, i, "MemTotal")) { 75 i += 8; 76 mTotalSize = extractMemValue(mBuffer, i); 77 count++; 78 } else if (matchText(mBuffer, i, "MemFree")) { 79 i += 7; 80 mFreeSize = extractMemValue(mBuffer, i); 81 count++; 82 } else if (matchText(mBuffer, i, "Cached")) { 83 i += 6; 84 mCachedSize = extractMemValue(mBuffer, i); 85 count++; 86 } 87 while (i < BUFLEN && mBuffer[i] != '\n') { 88 i++; 89 } 90 } 91 } catch (java.io.FileNotFoundException e) { 92 } catch (java.io.IOException e) { 93 } finally { 94 StrictMode.setThreadPolicy(savedPolicy); 95 } 96 } 97 98 public long getTotalSize() { 99 return mTotalSize; 100 } 101 102 public long getFreeSize() { 103 return mFreeSize; 104 } 105 106 public long getCachedSize() { 107 return mCachedSize; 108 } 109 } 110
