1 /* 2 * Copyright (C) 2011 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not 5 * use this file except in compliance with the License. You may obtain a copy of 6 * 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, WITHOUT 12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 13 * License for the specific language governing permissions and limitations under 14 * the License. 15 */ 16 17 package com.android.inputmethod.dictionarypack; 18 19 import java.io.File; 20 21 /** 22 * Immutable class to hold the address of an asset. 23 * As opposed to a normal file, an asset is usually represented as a contiguous byte array in 24 * the package file. Open it correctly thus requires the name of the package it is in, but 25 * also the offset in the file and the length of this data. This class encapsulates these three. 26 */ 27 final class AssetFileAddress { 28 public final String mFilename; 29 public final long mOffset; 30 public final long mLength; 31 32 public AssetFileAddress(final String filename, final long offset, final long length) { 33 mFilename = filename; 34 mOffset = offset; 35 mLength = length; 36 } 37 38 /** 39 * Makes an AssetFileAddress. This may return null. 40 * 41 * @param filename the filename. 42 * @return the address, or null if the file does not exist or the parameters are not valid. 43 */ 44 public static AssetFileAddress makeFromFileName(final String filename) { 45 if (null == filename) return null; 46 final File f = new File(filename); 47 if (!f.isFile()) return null; 48 return new AssetFileAddress(filename, 0l, f.length()); 49 } 50 51 /** 52 * Makes an AssetFileAddress. This may return null. 53 * 54 * @param filename the filename. 55 * @param offset the offset. 56 * @param length the length. 57 * @return the address, or null if the file does not exist or the parameters are not valid. 58 */ 59 public static AssetFileAddress makeFromFileNameAndOffset(final String filename, 60 final long offset, final long length) { 61 if (null == filename) return null; 62 final File f = new File(filename); 63 if (!f.isFile()) return null; 64 return new AssetFileAddress(filename, offset, length); 65 } 66 } 67
