001 /*
002 * Copyright 2010-2014 UnboundID Corp.
003 * All Rights Reserved.
004 */
005 /*
006 * Copyright (C) 2010-2014 UnboundID Corp.
007 *
008 * This program is free software; you can redistribute it and/or modify
009 * it under the terms of the GNU General Public License (GPLv2 only)
010 * or the terms of the GNU Lesser General Public License (LGPLv2.1 only)
011 * as published by the Free Software Foundation.
012 *
013 * This program is distributed in the hope that it will be useful,
014 * but WITHOUT ANY WARRANTY; without even the implied warranty of
015 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
016 * GNU General Public License for more details.
017 *
018 * You should have received a copy of the GNU General Public License
019 * along with this program; if not, see <http://www.gnu.org/licenses>.
020 */
021 package com.unboundid.util;
022
023
024
025 import java.io.IOException;
026 import java.io.OutputStream;
027 import java.io.Serializable;
028
029 import static com.unboundid.util.UtilityMessages.*;
030
031
032
033 /**
034 * This class provides an {@code OutputStream} implementation that writes data
035 * to a provided byte array. It is similar to the
036 * {@code java.io.ByteArrayOutputStream} class, except that it allows you to
037 * pass in the array that it uses, and the array will not grow over time.
038 */
039 @Mutable()
040 @ThreadSafety(level=ThreadSafetyLevel.NOT_THREADSAFE)
041 public final class FixedArrayOutputStream
042 extends OutputStream
043 implements Serializable
044 {
045 /**
046 * The serial version UID for this serializable class.
047 */
048 private static final long serialVersionUID = 4678108653480347534L;
049
050
051
052 // The byte array used by this class.
053 private final byte[] array;
054
055 // The initial position for this array.
056 private final int initialPosition;
057
058 // The maximum number of bytes that may be written.
059 private final int length;
060
061 // The maximum position at which data may be written.
062 private final int maxPosition;
063
064 // The current position at which data may be written.
065 private int pos;
066
067
068
069 /**
070 * Creates a new output stream that will write data to the provided array.
071 * It will use the entire array.
072 *
073 * @param array The array to which data will be written. It must not be
074 * {@code null}.
075 */
076 public FixedArrayOutputStream(final byte[] array)
077 {
078 this(array, 0, array.length);
079 }
080
081
082
083 /**
084 * Creates a new output stream that will write data to the provided array.
085 * It will use the specified portion of the array.
086 *
087 * @param array The array to which data will be written. It must not be
088 * {@code null}.
089 * @param pos The position at which to start writing data. It must be
090 * greater than or equal to zero and less than or equal to the
091 * length of the array.
092 * @param len The maximum number of bytes that may be written. It must
093 * be greater than or equal to zero and less than or equal to
094 * the difference between the length of the array and the
095 * provided {@code pos} value.
096 */
097 public FixedArrayOutputStream(final byte[] array, final int pos,
098 final int len)
099 {
100 this.array = array;
101 this.pos = pos;
102
103 initialPosition = pos;
104 maxPosition = pos + len;
105 length = len;
106
107 Validator.ensureTrue((pos >= 0),
108 "The position must be greater than or equal to zero.");
109 Validator.ensureTrue((len >= 0),
110 "The length must be greater than or equal to zero.");
111 Validator.ensureTrue((maxPosition <= array.length),
112 "The sum of pos and len must not exceed the array length.");
113 }
114
115
116
117 /**
118 * Retrieves the backing array used by this output stream.
119 *
120 * @return The backing array used by this output stream.
121 */
122 public byte[] getBackingArray()
123 {
124 return array;
125 }
126
127
128
129 /**
130 * Retrieves the initial position provided when this output stream was
131 * created.
132 *
133 * @return The initial position provided when this output stream was created.
134 */
135 public int getInitialPosition()
136 {
137 return initialPosition;
138 }
139
140
141
142 /**
143 * Retrieves the maximum number of bytes that may be written to this output
144 * stream.
145 *
146 * @return The maximum number of bytes that may be written to this output
147 * stream.
148 */
149 public int getLength()
150 {
151 return length;
152 }
153
154
155
156 /**
157 * Retrieves the number of bytes that have been written so far to this output
158 * stream.
159 *
160 * @return The number of bytes that have been written so far to this output
161 * stream.
162 */
163 public int getBytesWritten()
164 {
165 return (pos - initialPosition);
166 }
167
168
169
170 /**
171 * Closes this output stream. This has no effect.
172 */
173 @Override()
174 public void close()
175 {
176 // No implementation required.
177 }
178
179
180
181 /**
182 * Flushes this output stream. This has no effect.
183 */
184 @Override()
185 public void flush()
186 {
187 // No implementation required.
188 }
189
190
191
192 /**
193 * Writes the provided byte to this output stream.
194 *
195 * @param b The byte to be written.
196 *
197 * @throws IOException If an attempt was made to write beyond the end of the
198 * array.
199 */
200 @Override()
201 public void write(final int b)
202 throws IOException
203 {
204 if (pos >= maxPosition)
205 {
206 throw new IOException(ERR_FIXED_ARRAY_OS_WRITE_BEYOND_END.get());
207 }
208
209 array[pos++] = (byte) b;
210 }
211
212
213
214 /**
215 * Writes the contents of the provided array to this output stream.
216 *
217 * @param b The byte array containing the data to be written. It must not
218 * be {@code null}.
219 *
220 * @throws IOException If an attempt was made to write beyond the end of the
221 * array.
222 */
223 @Override()
224 public void write(final byte[] b)
225 throws IOException
226 {
227 write(b, 0, b.length);
228 }
229
230
231
232 /**
233 * Writes the contents of the provided array to this output stream.
234 *
235 * @param b The byte array containing the data to be written. It must not
236 * be {@code null}.
237 * @param off The offset within the provided array of the beginning of the
238 * data to be written. It must be greater than or equal to zero
239 * and less than or equal to the length of the provided array.
240 * @param len The number of bytes to be written. It must be greater than or
241 * equal to zero, and the sum of {@code off} and {@code len} must
242 * be less than the length of the provided array.
243 *
244 * @throws IOException If an attempt was made to write beyond the end of the
245 * array.
246 */
247 @Override()
248 public void write(final byte[] b, final int off, final int len)
249 throws IOException
250 {
251 Validator.ensureTrue((off >= 0),
252 "The provided offset must be greater than or equal to zero.");
253 Validator.ensureTrue((len >= 0),
254 "The provided length must be greater than or equal to zero.");
255 Validator.ensureTrue(((off + len) <= b.length),
256 "The sum of off and len must not exceed the array length.");
257
258 if ((pos + len) > maxPosition)
259 {
260 throw new IOException(ERR_FIXED_ARRAY_OS_WRITE_BEYOND_END.get());
261 }
262
263 System.arraycopy(b, off, array, pos, len);
264 pos += len;
265 }
266 }