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.gallery3d.exif; 18 19 import java.io.EOFException; 20 import java.io.FilterInputStream; 21 import java.io.IOException; 22 import java.io.InputStream; 23 import java.nio.ByteBuffer; 24 import java.nio.ByteOrder; 25 import java.nio.charset.Charset; 26 27 class CountedDataInputStream extends FilterInputStream { 28 29 private int mCount = 0; 30 31 // allocate a byte buffer for a long value; 32 private final byte mByteArray[] = new byte[8]; 33 private final ByteBuffer mByteBuffer = ByteBuffer.wrap(mByteArray); 34 CountedDataInputStream(InputStream in)35 protected CountedDataInputStream(InputStream in) { 36 super(in); 37 } 38 getReadByteCount()39 public int getReadByteCount() { 40 return mCount; 41 } 42 43 @Override read(byte[] b)44 public int read(byte[] b) throws IOException { 45 int r = in.read(b); 46 mCount += (r >= 0) ? r : 0; 47 return r; 48 } 49 50 @Override read(byte[] b, int off, int len)51 public int read(byte[] b, int off, int len) throws IOException { 52 int r = in.read(b, off, len); 53 mCount += (r >= 0) ? r : 0; 54 return r; 55 } 56 57 @Override read()58 public int read() throws IOException { 59 int r = in.read(); 60 mCount += (r >= 0) ? 1 : 0; 61 return r; 62 } 63 64 @Override skip(long length)65 public long skip(long length) throws IOException { 66 long skip = in.skip(length); 67 mCount += skip; 68 return skip; 69 } 70 skipOrThrow(long length)71 public void skipOrThrow(long length) throws IOException { 72 if (skip(length) != length) throw new EOFException(); 73 } 74 skipTo(long target)75 public void skipTo(long target) throws IOException { 76 long cur = mCount; 77 long diff = target - cur; 78 assert(diff >= 0); 79 skipOrThrow(diff); 80 } 81 readOrThrow(byte[] b, int off, int len)82 public void readOrThrow(byte[] b, int off, int len) throws IOException { 83 int r = read(b, off, len); 84 if (r != len) throw new EOFException(); 85 } 86 readOrThrow(byte[] b)87 public void readOrThrow(byte[] b) throws IOException { 88 readOrThrow(b, 0, b.length); 89 } 90 setByteOrder(ByteOrder order)91 public void setByteOrder(ByteOrder order) { 92 mByteBuffer.order(order); 93 } 94 getByteOrder()95 public ByteOrder getByteOrder() { 96 return mByteBuffer.order(); 97 } 98 readShort()99 public short readShort() throws IOException { 100 readOrThrow(mByteArray, 0 ,2); 101 mByteBuffer.rewind(); 102 return mByteBuffer.getShort(); 103 } 104 readUnsignedShort()105 public int readUnsignedShort() throws IOException { 106 return readShort() & 0xffff; 107 } 108 readInt()109 public int readInt() throws IOException { 110 readOrThrow(mByteArray, 0 , 4); 111 mByteBuffer.rewind(); 112 return mByteBuffer.getInt(); 113 } 114 readUnsignedInt()115 public long readUnsignedInt() throws IOException { 116 return readInt() & 0xffffffffL; 117 } 118 readLong()119 public long readLong() throws IOException { 120 readOrThrow(mByteArray, 0 , 8); 121 mByteBuffer.rewind(); 122 return mByteBuffer.getLong(); 123 } 124 readString(int n)125 public String readString(int n) throws IOException { 126 byte buf[] = new byte[n]; 127 readOrThrow(buf); 128 return new String(buf, "UTF8"); 129 } 130 readString(int n, Charset charset)131 public String readString(int n, Charset charset) throws IOException { 132 byte buf[] = new byte[n]; 133 readOrThrow(buf); 134 return new String(buf, charset); 135 } 136 }