1 /*
2  * Copyright 2020 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 android.media;
18 
19 import android.system.ErrnoException;
20 import android.system.Os;
21 import android.util.Log;
22 
23 import java.io.Closeable;
24 import java.io.FileDescriptor;
25 import java.io.IOException;
26 import java.io.InputStream;
27 import java.io.OutputStream;
28 
29 /**
30  * Package private utility class for ExifInterface.
31  */
32 class ExifInterfaceUtils {
33     private static final String TAG = "ExifInterface";
34 
35     /**
36      * Copies all of the bytes from {@code in} to {@code out}. Neither stream is closed.
37      * Returns the total number of bytes transferred.
38      */
copy(InputStream in, OutputStream out)39     public static int copy(InputStream in, OutputStream out) throws IOException {
40         int total = 0;
41         byte[] buffer = new byte[8192];
42         int c;
43         while ((c = in.read(buffer)) != -1) {
44             total += c;
45             out.write(buffer, 0, c);
46         }
47         return total;
48     }
49 
50     /**
51      * Copies the given number of the bytes from {@code in} to {@code out}. Neither stream is
52      * closed.
53      */
copy(InputStream in, OutputStream out, int numBytes)54     public static void copy(InputStream in, OutputStream out, int numBytes) throws IOException {
55         int remainder = numBytes;
56         byte[] buffer = new byte[8192];
57         while (remainder > 0) {
58             int bytesToRead = Math.min(remainder, 8192);
59             int bytesRead = in.read(buffer, 0, bytesToRead);
60             if (bytesRead != bytesToRead) {
61                 throw new IOException("Failed to copy the given amount of bytes from the input"
62                         + "stream to the output stream.");
63             }
64             remainder -= bytesRead;
65             out.write(buffer, 0, bytesRead);
66         }
67     }
68 
69     /**
70      * Convert given int[] to long[]. If long[] is given, just return it.
71      * Return null for other types of input.
72      */
convertToLongArray(Object inputObj)73     public static long[] convertToLongArray(Object inputObj) {
74         if (inputObj instanceof int[]) {
75             int[] input = (int[]) inputObj;
76             long[] result = new long[input.length];
77             for (int i = 0; i < input.length; i++) {
78                 result[i] = input[i];
79             }
80             return result;
81         } else if (inputObj instanceof long[]) {
82             return (long[]) inputObj;
83         }
84         return null;
85     }
86 
87     /**
88      * Convert given byte array to hex string.
89      */
byteArrayToHexString(byte[] bytes)90     public static String byteArrayToHexString(byte[] bytes) {
91         StringBuilder sb = new StringBuilder(bytes.length * 2);
92         for (int i = 0; i < bytes.length; i++) {
93             sb.append(String.format("%02x", bytes[i]));
94         }
95         return sb.toString();
96     }
97 
98     /**
99      * Checks if the start of the first byte array is equal to the second byte array.
100      */
startsWith(byte[] cur, byte[] val)101     public static boolean startsWith(byte[] cur, byte[] val) {
102         if (cur == null || val == null) return false;
103         if (cur.length < val.length) return false;
104         if (cur.length == 0 || val.length == 0) return false;
105         for (int i = 0; i < val.length; i++) {
106             if (cur[i] != val[i]) return false;
107         }
108         return true;
109     }
110 
111     /**
112      * Closes 'closeable', ignoring any checked exceptions. Does nothing if 'closeable' is null.
113      */
closeQuietly(Closeable closeable)114     public static void closeQuietly(Closeable closeable) {
115         if (closeable != null) {
116             try {
117                 closeable.close();
118             } catch (RuntimeException rethrown) {
119                 throw rethrown;
120             } catch (Exception ignored) {
121             }
122         }
123     }
124 
125     /**
126      * Closes a file descriptor that has been duplicated.
127      */
closeFileDescriptor(FileDescriptor fd)128     public static void closeFileDescriptor(FileDescriptor fd) {
129         try {
130             Os.close(fd);
131         } catch (ErrnoException ex) {
132             Log.e(TAG, "Error closing fd.", ex);
133         }
134     }
135 }
136