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8e76f6ab | 1 | package be.nikiroo.utils.streams; |
33895a7b NR |
2 | |
3 | import java.io.IOException; | |
4 | import java.io.InputStream; | |
5 | import java.util.Arrays; | |
6 | ||
f8147a0e NR |
7 | import be.nikiroo.utils.StringUtils; |
8 | ||
33895a7b NR |
9 | /** |
10 | * A simple {@link InputStream} that is buffered with a bytes array. | |
11 | * <p> | |
12 | * It is mostly intended to be used as a base class to create new | |
13 | * {@link InputStream}s with special operation modes, and to give some default | |
14 | * methods. | |
15 | * | |
16 | * @author niki | |
17 | */ | |
18 | public class BufferedInputStream extends InputStream { | |
7194ac50 NR |
19 | /** |
20 | * The size of the internal buffer (can be different if you pass your own | |
21 | * buffer, of course). | |
22 | * <p> | |
23 | * A second buffer of twice the size can sometimes be created as needed for | |
24 | * the {@link BufferedInputStream#startsWith(byte[])} search operation. | |
25 | */ | |
26 | static private final int BUFFER_SIZE = 4096; | |
27 | ||
eeaa5ebc | 28 | /** The current position in the buffer. */ |
a26188d3 | 29 | protected int start; |
eeaa5ebc | 30 | /** The index of the last usable position of the buffer. */ |
a26188d3 | 31 | protected int stop; |
eeaa5ebc | 32 | /** The buffer itself. */ |
33895a7b | 33 | protected byte[] buffer; |
7194ac50 | 34 | /** An End-Of-File (or {@link InputStream}, here) marker. */ |
33895a7b NR |
35 | protected boolean eof; |
36 | ||
37 | private boolean closed; | |
38 | private InputStream in; | |
39 | private int openCounter; | |
40 | ||
41 | // special use, prefetched next buffer | |
42 | private byte[] buffer2; | |
43 | private int pos2; | |
44 | private int len2; | |
45 | private byte[] originalBuffer; | |
46 | ||
47 | private long bytesRead; | |
48 | ||
49 | /** | |
50 | * Create a new {@link BufferedInputStream} that wraps the given | |
51 | * {@link InputStream}. | |
52 | * | |
53 | * @param in | |
54 | * the {@link InputStream} to wrap | |
55 | */ | |
56 | public BufferedInputStream(InputStream in) { | |
57 | this.in = in; | |
58 | ||
7194ac50 | 59 | this.buffer = new byte[BUFFER_SIZE]; |
33895a7b | 60 | this.originalBuffer = this.buffer; |
a26188d3 NR |
61 | this.start = 0; |
62 | this.stop = 0; | |
33895a7b NR |
63 | } |
64 | ||
65 | /** | |
66 | * Create a new {@link BufferedInputStream} that wraps the given bytes array | |
67 | * as a data source. | |
68 | * | |
69 | * @param in | |
70 | * the array to wrap, cannot be NULL | |
71 | */ | |
72 | public BufferedInputStream(byte[] in) { | |
73 | this(in, 0, in.length); | |
74 | } | |
75 | ||
76 | /** | |
77 | * Create a new {@link BufferedInputStream} that wraps the given bytes array | |
78 | * as a data source. | |
79 | * | |
80 | * @param in | |
81 | * the array to wrap, cannot be NULL | |
82 | * @param offset | |
83 | * the offset to start the reading at | |
84 | * @param length | |
85 | * the number of bytes to take into account in the array, | |
86 | * starting from the offset | |
87 | * | |
88 | * @throws NullPointerException | |
89 | * if the array is NULL | |
90 | * @throws IndexOutOfBoundsException | |
91 | * if the offset and length do not correspond to the given array | |
92 | */ | |
93 | public BufferedInputStream(byte[] in, int offset, int length) { | |
94 | if (in == null) { | |
95 | throw new NullPointerException(); | |
96 | } else if (offset < 0 || length < 0 || length > in.length - offset) { | |
97 | throw new IndexOutOfBoundsException(); | |
98 | } | |
99 | ||
100 | this.in = null; | |
101 | ||
102 | this.buffer = in; | |
103 | this.originalBuffer = this.buffer; | |
a26188d3 NR |
104 | this.start = offset; |
105 | this.stop = length; | |
33895a7b NR |
106 | } |
107 | ||
108 | /** | |
109 | * Return this very same {@link BufferedInputStream}, but keep a counter of | |
110 | * how many streams were open this way. When calling | |
111 | * {@link BufferedInputStream#close()}, decrease this counter if it is not | |
112 | * already zero instead of actually closing the stream. | |
113 | * <p> | |
114 | * You are now responsible for it — you <b>must</b> close it. | |
115 | * <p> | |
116 | * This method allows you to use a wrapping stream around this one and still | |
117 | * close the wrapping stream. | |
118 | * | |
119 | * @return the same stream, but you are now responsible for closing it | |
120 | * | |
121 | * @throws IOException | |
122 | * in case of I/O error or if the stream is closed | |
123 | */ | |
124 | public synchronized InputStream open() throws IOException { | |
125 | checkClose(); | |
126 | openCounter++; | |
127 | return this; | |
128 | } | |
129 | ||
eeaa5ebc NR |
130 | /** |
131 | * Check if the current content (what will be read next) starts with the | |
132 | * given search term. | |
133 | * <p> | |
134 | * Note: the search term size <b>must</b> be smaller or equal the internal | |
135 | * buffer size. | |
136 | * | |
137 | * @param search | |
138 | * the term to search for | |
139 | * | |
140 | * @return TRUE if the content that will be read starts with it | |
141 | * | |
142 | * @throws IOException | |
143 | * in case of I/O error or if the size of the search term is | |
144 | * greater than the internal buffer | |
145 | */ | |
33895a7b | 146 | public boolean startsWiths(String search) throws IOException { |
f8147a0e | 147 | return startsWith(StringUtils.getBytes(search)); |
33895a7b NR |
148 | } |
149 | ||
eeaa5ebc NR |
150 | /** |
151 | * Check if the current content (what will be read next) starts with the | |
152 | * given search term. | |
153 | * <p> | |
154 | * Note: the search term size <b>must</b> be smaller or equal the internal | |
155 | * buffer size. | |
156 | * | |
157 | * @param search | |
158 | * the term to search for | |
159 | * | |
160 | * @return TRUE if the content that will be read starts with it | |
161 | * | |
162 | * @throws IOException | |
163 | * in case of I/O error or if the size of the search term is | |
164 | * greater than the internal buffer | |
165 | */ | |
33895a7b NR |
166 | public boolean startsWith(byte[] search) throws IOException { |
167 | if (search.length > originalBuffer.length) { | |
168 | throw new IOException( | |
169 | "This stream does not support searching for more than " | |
170 | + buffer.length + " bytes"); | |
171 | } | |
172 | ||
173 | checkClose(); | |
174 | ||
175 | if (available() < search.length) { | |
176 | preRead(); | |
177 | } | |
178 | ||
179 | if (available() >= search.length) { | |
180 | // Easy path | |
c8ce09c4 | 181 | return StreamUtils.startsWith(search, buffer, start, stop); |
33895a7b NR |
182 | } else if (!eof) { |
183 | // Harder path | |
184 | if (buffer2 == null && buffer.length == originalBuffer.length) { | |
185 | buffer2 = Arrays.copyOf(buffer, buffer.length * 2); | |
186 | ||
187 | pos2 = buffer.length; | |
028ff7c2 | 188 | len2 = read(in, buffer2, pos2, buffer.length); |
33895a7b NR |
189 | if (len2 > 0) { |
190 | bytesRead += len2; | |
191 | } | |
192 | ||
193 | // Note: here, len/len2 = INDEX of last good byte | |
194 | len2 += pos2; | |
195 | } | |
196 | ||
c8ce09c4 | 197 | return StreamUtils.startsWith(search, buffer2, pos2, len2); |
33895a7b NR |
198 | } |
199 | ||
200 | return false; | |
201 | } | |
202 | ||
203 | /** | |
204 | * The number of bytes read from the under-laying {@link InputStream}. | |
205 | * | |
206 | * @return the number of bytes | |
207 | */ | |
208 | public long getBytesRead() { | |
209 | return bytesRead; | |
210 | } | |
211 | ||
212 | /** | |
213 | * Check if this stream is totally spent (no more data to read or to | |
214 | * process). | |
33895a7b NR |
215 | * |
216 | * @return TRUE if it is | |
028ff7c2 NR |
217 | * |
218 | * @throws IOException | |
219 | * in case of I/O error | |
33895a7b | 220 | */ |
028ff7c2 NR |
221 | public boolean eof() throws IOException { |
222 | if (closed) { | |
223 | return true; | |
224 | } | |
225 | ||
226 | preRead(); | |
227 | return !hasMoreData(); | |
33895a7b NR |
228 | } |
229 | ||
230 | @Override | |
231 | public int read() throws IOException { | |
232 | checkClose(); | |
233 | ||
234 | preRead(); | |
235 | if (eof) { | |
236 | return -1; | |
237 | } | |
238 | ||
a26188d3 | 239 | return buffer[start++]; |
33895a7b NR |
240 | } |
241 | ||
242 | @Override | |
243 | public int read(byte[] b) throws IOException { | |
244 | return read(b, 0, b.length); | |
245 | } | |
246 | ||
247 | @Override | |
248 | public int read(byte[] b, int boff, int blen) throws IOException { | |
249 | checkClose(); | |
250 | ||
251 | if (b == null) { | |
252 | throw new NullPointerException(); | |
253 | } else if (boff < 0 || blen < 0 || blen > b.length - boff) { | |
254 | throw new IndexOutOfBoundsException(); | |
255 | } else if (blen == 0) { | |
256 | return 0; | |
257 | } | |
258 | ||
259 | int done = 0; | |
260 | while (hasMoreData() && done < blen) { | |
261 | preRead(); | |
262 | if (hasMoreData()) { | |
f04d5e49 | 263 | int now = Math.min(blen - done, stop - start); |
33895a7b | 264 | if (now > 0) { |
a26188d3 NR |
265 | System.arraycopy(buffer, start, b, boff + done, now); |
266 | start += now; | |
33895a7b NR |
267 | done += now; |
268 | } | |
269 | } | |
270 | } | |
271 | ||
272 | return done > 0 ? done : -1; | |
273 | } | |
274 | ||
275 | @Override | |
276 | public long skip(long n) throws IOException { | |
277 | if (n <= 0) { | |
278 | return 0; | |
279 | } | |
280 | ||
281 | long skipped = 0; | |
282 | while (hasMoreData() && n > 0) { | |
283 | preRead(); | |
284 | ||
285 | long inBuffer = Math.min(n, available()); | |
a26188d3 | 286 | start += inBuffer; |
33895a7b NR |
287 | n -= inBuffer; |
288 | skipped += inBuffer; | |
289 | } | |
290 | ||
291 | return skipped; | |
292 | } | |
293 | ||
294 | @Override | |
295 | public int available() { | |
296 | if (closed) { | |
297 | return 0; | |
298 | } | |
299 | ||
a26188d3 | 300 | return Math.max(0, stop - start); |
33895a7b NR |
301 | } |
302 | ||
303 | /** | |
304 | * Closes this stream and releases any system resources associated with the | |
305 | * stream. | |
306 | * <p> | |
307 | * Including the under-laying {@link InputStream}. | |
308 | * <p> | |
309 | * <b>Note:</b> if you called the {@link BufferedInputStream#open()} method | |
310 | * prior to this one, it will just decrease the internal count of how many | |
311 | * open streams it held and do nothing else. The stream will actually be | |
312 | * closed when you have called {@link BufferedInputStream#close()} once more | |
313 | * than {@link BufferedInputStream#open()}. | |
314 | * | |
315 | * @exception IOException | |
316 | * in case of I/O error | |
317 | */ | |
318 | @Override | |
319 | public synchronized void close() throws IOException { | |
320 | close(true); | |
321 | } | |
322 | ||
323 | /** | |
324 | * Closes this stream and releases any system resources associated with the | |
325 | * stream. | |
326 | * <p> | |
327 | * Including the under-laying {@link InputStream} if | |
328 | * <tt>incudingSubStream</tt> is true. | |
329 | * <p> | |
330 | * You can call this method multiple times, it will not cause an | |
331 | * {@link IOException} for subsequent calls. | |
332 | * <p> | |
333 | * <b>Note:</b> if you called the {@link BufferedInputStream#open()} method | |
334 | * prior to this one, it will just decrease the internal count of how many | |
335 | * open streams it held and do nothing else. The stream will actually be | |
336 | * closed when you have called {@link BufferedInputStream#close()} once more | |
337 | * than {@link BufferedInputStream#open()}. | |
338 | * | |
eeaa5ebc NR |
339 | * @param includingSubStream |
340 | * also close the under-laying stream | |
341 | * | |
33895a7b NR |
342 | * @exception IOException |
343 | * in case of I/O error | |
344 | */ | |
345 | public synchronized void close(boolean includingSubStream) | |
346 | throws IOException { | |
347 | if (!closed) { | |
348 | if (openCounter > 0) { | |
349 | openCounter--; | |
350 | } else { | |
351 | closed = true; | |
352 | if (includingSubStream && in != null) { | |
353 | in.close(); | |
354 | } | |
355 | } | |
356 | } | |
357 | } | |
358 | ||
359 | /** | |
360 | * Check if we still have some data in the buffer and, if not, fetch some. | |
361 | * | |
362 | * @return TRUE if we fetched some data, FALSE if there are still some in | |
363 | * the buffer | |
364 | * | |
365 | * @throws IOException | |
366 | * in case of I/O error | |
367 | */ | |
368 | protected boolean preRead() throws IOException { | |
369 | boolean hasRead = false; | |
028ff7c2 | 370 | if (in != null && !eof && start >= stop) { |
a26188d3 | 371 | start = 0; |
33895a7b NR |
372 | if (buffer2 != null) { |
373 | buffer = buffer2; | |
a26188d3 NR |
374 | start = pos2; |
375 | stop = len2; | |
33895a7b NR |
376 | |
377 | buffer2 = null; | |
378 | pos2 = 0; | |
379 | len2 = 0; | |
380 | } else { | |
381 | buffer = originalBuffer; | |
382 | ||
028ff7c2 | 383 | stop = read(in, buffer, 0, buffer.length); |
a26188d3 NR |
384 | if (stop > 0) { |
385 | bytesRead += stop; | |
33895a7b NR |
386 | } |
387 | } | |
388 | ||
389 | hasRead = true; | |
390 | } | |
391 | ||
a26188d3 | 392 | if (start >= stop) { |
33895a7b NR |
393 | eof = true; |
394 | } | |
395 | ||
396 | return hasRead; | |
397 | } | |
398 | ||
399 | /** | |
400 | * Read the under-laying stream into the local buffer. | |
401 | * | |
402 | * @param in | |
403 | * the under-laying {@link InputStream} | |
404 | * @param buffer | |
405 | * the buffer we use in this {@link BufferedInputStream} | |
028ff7c2 NR |
406 | * @param off |
407 | * the offset | |
408 | * @param len | |
409 | * the length in bytes | |
33895a7b NR |
410 | * |
411 | * @return the number of bytes read | |
412 | * | |
413 | * @throws IOException | |
414 | * in case of I/O error | |
415 | */ | |
028ff7c2 NR |
416 | protected int read(InputStream in, byte[] buffer, int off, int len) |
417 | throws IOException { | |
418 | return in.read(buffer, off, len); | |
33895a7b NR |
419 | } |
420 | ||
421 | /** | |
028ff7c2 NR |
422 | * We have more data available in the buffer <b>or</b> we can, maybe, fetch |
423 | * more. | |
33895a7b NR |
424 | * |
425 | * @return TRUE if it is the case, FALSE if not | |
426 | */ | |
427 | protected boolean hasMoreData() { | |
028ff7c2 NR |
428 | if (closed) { |
429 | return false; | |
430 | } | |
431 | ||
432 | return (start < stop) || !eof; | |
33895a7b NR |
433 | } |
434 | ||
435 | /** | |
436 | * Check that the stream was not closed, and throw an {@link IOException} if | |
437 | * it was. | |
438 | * | |
439 | * @throws IOException | |
440 | * if it was closed | |
441 | */ | |
442 | protected void checkClose() throws IOException { | |
443 | if (closed) { | |
444 | throw new IOException( | |
eeaa5ebc | 445 | "This BufferedInputStream was closed, you cannot use it anymore."); |
33895a7b NR |
446 | } |
447 | } | |
33895a7b | 448 | } |