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      1 /*
      2  * Copyright (C) 2007 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.dex.util;
     18 
     19 import java.io.File;
     20 import java.io.FileInputStream;
     21 import java.io.IOException;
     22 
     23 /**
     24  * File I/O utilities.
     25  */
     26 public final class FileUtils {
     27     private FileUtils() {
     28     }
     29 
     30     /**
     31      * Reads the named file, translating {@link IOException} to a
     32      * {@link RuntimeException} of some sort.
     33      *
     34      * @param fileName {@code non-null;} name of the file to read
     35      * @return {@code non-null;} contents of the file
     36      */
     37     public static byte[] readFile(String fileName) {
     38         File file = new File(fileName);
     39         return readFile(file);
     40     }
     41 
     42     /**
     43      * Reads the given file, translating {@link IOException} to a
     44      * {@link RuntimeException} of some sort.
     45      *
     46      * @param file {@code non-null;} the file to read
     47      * @return {@code non-null;} contents of the file
     48      */
     49     public static byte[] readFile(File file) {
     50         if (!file.exists()) {
     51             throw new RuntimeException(file + ": file not found");
     52         }
     53 
     54         if (!file.isFile()) {
     55             throw new RuntimeException(file + ": not a file");
     56         }
     57 
     58         if (!file.canRead()) {
     59             throw new RuntimeException(file + ": file not readable");
     60         }
     61 
     62         long longLength = file.length();
     63         int length = (int) longLength;
     64         if (length != longLength) {
     65             throw new RuntimeException(file + ": file too long");
     66         }
     67 
     68         byte[] result = new byte[length];
     69 
     70         try {
     71             FileInputStream in = new FileInputStream(file);
     72             int at = 0;
     73             while (length > 0) {
     74                 int amt = in.read(result, at, length);
     75                 if (amt == -1) {
     76                     throw new RuntimeException(file + ": unexpected EOF");
     77                 }
     78                 at += amt;
     79                 length -= amt;
     80             }
     81             in.close();
     82         } catch (IOException ex) {
     83             throw new RuntimeException(file + ": trouble reading", ex);
     84         }
     85 
     86         return result;
     87     }
     88 
     89     /**
     90      * Returns true if {@code fileName} names a .zip, .jar, or .apk.
     91      */
     92     public static boolean hasArchiveSuffix(String fileName) {
     93         return fileName.endsWith(".zip")
     94                 || fileName.endsWith(".jar")
     95                 || fileName.endsWith(".apk");
     96     }
     97 }
     98