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