2
|
1 |
/*
|
|
2 |
* Copyright 2000-2003 Sun Microsystems, Inc. All Rights Reserved.
|
|
3 |
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
|
|
4 |
*
|
|
5 |
* This code is free software; you can redistribute it and/or modify it
|
|
6 |
* under the terms of the GNU General Public License version 2 only, as
|
|
7 |
* published by the Free Software Foundation. Sun designates this
|
|
8 |
* particular file as subject to the "Classpath" exception as provided
|
|
9 |
* by Sun in the LICENSE file that accompanied this code.
|
|
10 |
*
|
|
11 |
* This code is distributed in the hope that it will be useful, but WITHOUT
|
|
12 |
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
|
13 |
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
|
14 |
* version 2 for more details (a copy is included in the LICENSE file that
|
|
15 |
* accompanied this code).
|
|
16 |
*
|
|
17 |
* You should have received a copy of the GNU General Public License version
|
|
18 |
* 2 along with this work; if not, write to the Free Software Foundation,
|
|
19 |
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
|
|
20 |
*
|
|
21 |
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
|
|
22 |
* CA 95054 USA or visit www.sun.com if you need additional information or
|
|
23 |
* have any questions.
|
|
24 |
*/
|
|
25 |
|
|
26 |
package javax.imageio.stream;
|
|
27 |
|
|
28 |
import java.util.ArrayList;
|
|
29 |
import java.io.InputStream;
|
|
30 |
import java.io.OutputStream;
|
|
31 |
import java.io.IOException;
|
|
32 |
|
|
33 |
/**
|
|
34 |
* Package-visible class consolidating common code for
|
|
35 |
* <code>MemoryCacheImageInputStream</code> and
|
|
36 |
* <code>MemoryCacheImageOutputStream</code>.
|
|
37 |
* This class keeps an <code>ArrayList</code> of 8K blocks,
|
|
38 |
* loaded sequentially. Blocks may only be disposed of
|
|
39 |
* from the index 0 forward. As blocks are freed, the
|
|
40 |
* corresponding entries in the array list are set to
|
|
41 |
* <code>null</code>, but no compacting is performed.
|
|
42 |
* This allows the index for each block to never change,
|
|
43 |
* and the length of the cache is always the same as the
|
|
44 |
* total amount of data ever cached. Cached data is
|
|
45 |
* therefore always contiguous from the point of last
|
|
46 |
* disposal to the current length.
|
|
47 |
*
|
|
48 |
* <p> The total number of blocks resident in the cache must not
|
|
49 |
* exceed <code>Integer.MAX_VALUE</code>. In practice, the limit of
|
|
50 |
* available memory will be exceeded long before this becomes an
|
|
51 |
* issue, since a full cache would contain 8192*2^31 = 16 terabytes of
|
|
52 |
* data.
|
|
53 |
*
|
|
54 |
* A <code>MemoryCache</code> may be reused after a call
|
|
55 |
* to <code>reset()</code>.
|
|
56 |
*/
|
|
57 |
class MemoryCache {
|
|
58 |
|
|
59 |
private static final int BUFFER_LENGTH = 8192;
|
|
60 |
|
|
61 |
private ArrayList cache = new ArrayList();
|
|
62 |
|
|
63 |
private long cacheStart = 0L;
|
|
64 |
|
|
65 |
/**
|
|
66 |
* The largest position ever written to the cache.
|
|
67 |
*/
|
|
68 |
private long length = 0L;
|
|
69 |
|
|
70 |
private byte[] getCacheBlock(long blockNum) throws IOException {
|
|
71 |
long blockOffset = blockNum - cacheStart;
|
|
72 |
if (blockOffset > Integer.MAX_VALUE) {
|
|
73 |
// This can only happen when the cache hits 16 terabytes of
|
|
74 |
// contiguous data...
|
|
75 |
throw new IOException("Cache addressing limit exceeded!");
|
|
76 |
}
|
|
77 |
return (byte[])cache.get((int)blockOffset);
|
|
78 |
}
|
|
79 |
|
|
80 |
/**
|
|
81 |
* Ensures that at least <code>pos</code> bytes are cached,
|
|
82 |
* or the end of the source is reached. The return value
|
|
83 |
* is equal to the smaller of <code>pos</code> and the
|
|
84 |
* length of the source.
|
|
85 |
*/
|
|
86 |
public long loadFromStream(InputStream stream, long pos)
|
|
87 |
throws IOException {
|
|
88 |
// We've already got enough data cached
|
|
89 |
if (pos < length) {
|
|
90 |
return pos;
|
|
91 |
}
|
|
92 |
|
|
93 |
int offset = (int)(length % BUFFER_LENGTH);
|
|
94 |
byte [] buf = null;
|
|
95 |
|
|
96 |
long len = pos - length;
|
|
97 |
if (offset != 0) {
|
|
98 |
buf = getCacheBlock(length/BUFFER_LENGTH);
|
|
99 |
}
|
|
100 |
|
|
101 |
while (len > 0) {
|
|
102 |
if (buf == null) {
|
|
103 |
try {
|
|
104 |
buf = new byte[BUFFER_LENGTH];
|
|
105 |
} catch (OutOfMemoryError e) {
|
|
106 |
throw new IOException("No memory left for cache!");
|
|
107 |
}
|
|
108 |
offset = 0;
|
|
109 |
}
|
|
110 |
|
|
111 |
int left = BUFFER_LENGTH - offset;
|
|
112 |
int nbytes = (int)Math.min(len, (long)left);
|
|
113 |
nbytes = stream.read(buf, offset, nbytes);
|
|
114 |
if (nbytes == -1) {
|
|
115 |
return length; // EOF
|
|
116 |
}
|
|
117 |
|
|
118 |
if (offset == 0) {
|
|
119 |
cache.add(buf);
|
|
120 |
}
|
|
121 |
|
|
122 |
len -= nbytes;
|
|
123 |
length += nbytes;
|
|
124 |
offset += nbytes;
|
|
125 |
|
|
126 |
if (offset >= BUFFER_LENGTH) {
|
|
127 |
// we've filled the current buffer, so a new one will be
|
|
128 |
// allocated next time around (and offset will be reset to 0)
|
|
129 |
buf = null;
|
|
130 |
}
|
|
131 |
}
|
|
132 |
|
|
133 |
return pos;
|
|
134 |
}
|
|
135 |
|
|
136 |
/**
|
|
137 |
* Writes out a portion of the cache to an <code>OutputStream</code>.
|
|
138 |
* This method preserves no state about the output stream, and does
|
|
139 |
* not dispose of any blocks containing bytes written. To dispose
|
|
140 |
* blocks, use {@link #disposeBefore <code>disposeBefore()</code>}.
|
|
141 |
*
|
|
142 |
* @exception IndexOutOfBoundsException if any portion of
|
|
143 |
* the requested data is not in the cache (including if <code>pos</code>
|
|
144 |
* is in a block already disposed), or if either <code>pos</code> or
|
|
145 |
* <code>len</code> is < 0.
|
|
146 |
*/
|
|
147 |
public void writeToStream(OutputStream stream, long pos, long len)
|
|
148 |
throws IOException {
|
|
149 |
if (pos + len > length) {
|
|
150 |
throw new IndexOutOfBoundsException("Argument out of cache");
|
|
151 |
}
|
|
152 |
if ((pos < 0) || (len < 0)) {
|
|
153 |
throw new IndexOutOfBoundsException("Negative pos or len");
|
|
154 |
}
|
|
155 |
if (len == 0) {
|
|
156 |
return;
|
|
157 |
}
|
|
158 |
|
|
159 |
long bufIndex = pos/BUFFER_LENGTH;
|
|
160 |
if (bufIndex < cacheStart) {
|
|
161 |
throw new IndexOutOfBoundsException("pos already disposed");
|
|
162 |
}
|
|
163 |
int offset = (int)(pos % BUFFER_LENGTH);
|
|
164 |
|
|
165 |
byte[] buf = getCacheBlock(bufIndex++);
|
|
166 |
while (len > 0) {
|
|
167 |
if (buf == null) {
|
|
168 |
buf = getCacheBlock(bufIndex++);
|
|
169 |
offset = 0;
|
|
170 |
}
|
|
171 |
int nbytes = (int)Math.min(len, (long)(BUFFER_LENGTH - offset));
|
|
172 |
stream.write(buf, offset, nbytes);
|
|
173 |
buf = null;
|
|
174 |
len -= nbytes;
|
|
175 |
}
|
|
176 |
}
|
|
177 |
|
|
178 |
/**
|
|
179 |
* Ensure that there is space to write a byte at the given position.
|
|
180 |
*/
|
|
181 |
private void pad(long pos) throws IOException {
|
|
182 |
long currIndex = cacheStart + cache.size() - 1;
|
|
183 |
long lastIndex = pos/BUFFER_LENGTH;
|
|
184 |
long numNewBuffers = lastIndex - currIndex;
|
|
185 |
for (long i = 0; i < numNewBuffers; i++) {
|
|
186 |
try {
|
|
187 |
cache.add(new byte[BUFFER_LENGTH]);
|
|
188 |
} catch (OutOfMemoryError e) {
|
|
189 |
throw new IOException("No memory left for cache!");
|
|
190 |
}
|
|
191 |
}
|
|
192 |
}
|
|
193 |
|
|
194 |
/**
|
|
195 |
* Overwrites and/or appends the cache from a byte array.
|
|
196 |
* The length of the cache will be extended as needed to hold
|
|
197 |
* the incoming data.
|
|
198 |
*
|
|
199 |
* @param b an array of bytes containing data to be written.
|
|
200 |
* @param off the starting offset withing the data array.
|
|
201 |
* @param len the number of bytes to be written.
|
|
202 |
* @param pos the cache position at which to begin writing.
|
|
203 |
*
|
|
204 |
* @exception NullPointerException if <code>b</code> is <code>null</code>.
|
|
205 |
* @exception IndexOutOfBoundsException if <code>off</code>,
|
|
206 |
* <code>len</code>, or <code>pos</code> are negative,
|
|
207 |
* or if <code>off+len > b.length</code>.
|
|
208 |
*/
|
|
209 |
public void write(byte[] b, int off, int len, long pos)
|
|
210 |
throws IOException {
|
|
211 |
if (b == null) {
|
|
212 |
throw new NullPointerException("b == null!");
|
|
213 |
}
|
|
214 |
// Fix 4430357 - if off + len < 0, overflow occurred
|
|
215 |
if ((off < 0) || (len < 0) || (pos < 0) ||
|
|
216 |
(off + len > b.length) || (off + len < 0)) {
|
|
217 |
throw new IndexOutOfBoundsException();
|
|
218 |
}
|
|
219 |
|
|
220 |
// Ensure there is space for the incoming data
|
|
221 |
long lastPos = pos + len - 1;
|
|
222 |
if (lastPos >= length) {
|
|
223 |
pad(lastPos);
|
|
224 |
length = lastPos + 1;
|
|
225 |
}
|
|
226 |
|
|
227 |
// Copy the data into the cache, block by block
|
|
228 |
int offset = (int)(pos % BUFFER_LENGTH);
|
|
229 |
while (len > 0) {
|
|
230 |
byte[] buf = getCacheBlock(pos/BUFFER_LENGTH);
|
|
231 |
int nbytes = Math.min(len, BUFFER_LENGTH - offset);
|
|
232 |
System.arraycopy(b, off, buf, offset, nbytes);
|
|
233 |
|
|
234 |
pos += nbytes;
|
|
235 |
off += nbytes;
|
|
236 |
len -= nbytes;
|
|
237 |
offset = 0; // Always after the first time
|
|
238 |
}
|
|
239 |
}
|
|
240 |
|
|
241 |
/**
|
|
242 |
* Overwrites or appends a single byte to the cache.
|
|
243 |
* The length of the cache will be extended as needed to hold
|
|
244 |
* the incoming data.
|
|
245 |
*
|
|
246 |
* @param b an <code>int</code> whose 8 least significant bits
|
|
247 |
* will be written.
|
|
248 |
* @param pos the cache position at which to begin writing.
|
|
249 |
*
|
|
250 |
* @exception IndexOutOfBoundsException if <code>pos</code> is negative.
|
|
251 |
*/
|
|
252 |
public void write(int b, long pos) throws IOException {
|
|
253 |
if (pos < 0) {
|
|
254 |
throw new ArrayIndexOutOfBoundsException("pos < 0");
|
|
255 |
}
|
|
256 |
|
|
257 |
// Ensure there is space for the incoming data
|
|
258 |
if (pos >= length) {
|
|
259 |
pad(pos);
|
|
260 |
length = pos + 1;
|
|
261 |
}
|
|
262 |
|
|
263 |
// Insert the data.
|
|
264 |
byte[] buf = getCacheBlock(pos/BUFFER_LENGTH);
|
|
265 |
int offset = (int)(pos % BUFFER_LENGTH);
|
|
266 |
buf[offset] = (byte)b;
|
|
267 |
}
|
|
268 |
|
|
269 |
/**
|
|
270 |
* Returns the total length of data that has been cached,
|
|
271 |
* regardless of whether any early blocks have been disposed.
|
|
272 |
* This value will only ever increase.
|
|
273 |
*/
|
|
274 |
public long getLength() {
|
|
275 |
return length;
|
|
276 |
}
|
|
277 |
|
|
278 |
/**
|
|
279 |
* Returns the single byte at the given position, as an
|
|
280 |
* <code>int</code>. Returns -1 if this position has
|
|
281 |
* not been cached or has been disposed.
|
|
282 |
*/
|
|
283 |
public int read(long pos) throws IOException {
|
|
284 |
if (pos >= length) {
|
|
285 |
return -1;
|
|
286 |
}
|
|
287 |
|
|
288 |
byte[] buf = getCacheBlock(pos/BUFFER_LENGTH);
|
|
289 |
if (buf == null) {
|
|
290 |
return -1;
|
|
291 |
}
|
|
292 |
|
|
293 |
return buf[(int)(pos % BUFFER_LENGTH)] & 0xff;
|
|
294 |
}
|
|
295 |
|
|
296 |
/**
|
|
297 |
* Copy <code>len</code> bytes from the cache, starting
|
|
298 |
* at cache position <code>pos</code>, into the array
|
|
299 |
* <code>b</code> at offset <code>off</code>.
|
|
300 |
*
|
|
301 |
* @exception NullPointerException if b is <code>null</code>
|
|
302 |
* @exception IndexOutOfBoundsException if <code>off</code>,
|
|
303 |
* <code>len</code> or <code>pos</code> are negative or if
|
|
304 |
* <code>off + len > b.length</code> or if any portion of the
|
|
305 |
* requested data is not in the cache (including if
|
|
306 |
* <code>pos</code> is in a block that has already been disposed).
|
|
307 |
*/
|
|
308 |
public void read(byte[] b, int off, int len, long pos)
|
|
309 |
throws IOException {
|
|
310 |
if (b == null) {
|
|
311 |
throw new NullPointerException("b == null!");
|
|
312 |
}
|
|
313 |
// Fix 4430357 - if off + len < 0, overflow occurred
|
|
314 |
if ((off < 0) || (len < 0) || (pos < 0) ||
|
|
315 |
(off + len > b.length) || (off + len < 0)) {
|
|
316 |
throw new IndexOutOfBoundsException();
|
|
317 |
}
|
|
318 |
if (pos + len > length) {
|
|
319 |
throw new IndexOutOfBoundsException();
|
|
320 |
}
|
|
321 |
|
|
322 |
long index = pos/BUFFER_LENGTH;
|
|
323 |
int offset = (int)pos % BUFFER_LENGTH;
|
|
324 |
while (len > 0) {
|
|
325 |
int nbytes = Math.min(len, BUFFER_LENGTH - offset);
|
|
326 |
byte[] buf = getCacheBlock(index++);
|
|
327 |
System.arraycopy(buf, offset, b, off, nbytes);
|
|
328 |
|
|
329 |
len -= nbytes;
|
|
330 |
off += nbytes;
|
|
331 |
offset = 0; // Always after the first time
|
|
332 |
}
|
|
333 |
}
|
|
334 |
|
|
335 |
/**
|
|
336 |
* Free the blocks up to the position <code>pos</code>.
|
|
337 |
* The byte at <code>pos</code> remains available.
|
|
338 |
*
|
|
339 |
* @exception IndexOutOfBoundsException if <code>pos</code>
|
|
340 |
* is in a block that has already been disposed.
|
|
341 |
*/
|
|
342 |
public void disposeBefore(long pos) {
|
|
343 |
long index = pos/BUFFER_LENGTH;
|
|
344 |
if (index < cacheStart) {
|
|
345 |
throw new IndexOutOfBoundsException("pos already disposed");
|
|
346 |
}
|
|
347 |
long numBlocks = Math.min(index - cacheStart, cache.size());
|
|
348 |
for (long i = 0; i < numBlocks; i++) {
|
|
349 |
cache.remove(0);
|
|
350 |
}
|
|
351 |
this.cacheStart = index;
|
|
352 |
}
|
|
353 |
|
|
354 |
/**
|
|
355 |
* Erase the entire cache contents and reset the length to 0.
|
|
356 |
* The cache object may subsequently be reused as though it had just
|
|
357 |
* been allocated.
|
|
358 |
*/
|
|
359 |
public void reset() {
|
|
360 |
cache.clear();
|
|
361 |
cacheStart = 0;
|
|
362 |
length = 0L;
|
|
363 |
}
|
|
364 |
}
|