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486efb2e | 1 | /*******************************************************************************. |
733c614c | 2 | * Copyright (c) 2011, 2014 Ericsson, Ecole Polytechnique de Montreal and others |
486efb2e AM |
3 | * |
4 | * All rights reserved. This program and the accompanying materials are made | |
5 | * available under the terms of the Eclipse Public License v1.0 which | |
6 | * accompanies this distribution, and is available at | |
7 | * http://www.eclipse.org/legal/epl-v10.html | |
8 | * | |
2b50c5ac MK |
9 | * Contributors: |
10 | * Matthew Khouzam - Initial Design and implementation + overhaul | |
11 | * Francis Giraldeau - Initial API and implementation | |
12 | * Philippe Proulx - Some refinement and optimization | |
13 | * Etienne Bergeron <Etienne.Bergeron@gmail.com> - fix zero size read + cleanup | |
486efb2e AM |
14 | *******************************************************************************/ |
15 | ||
16 | package org.eclipse.linuxtools.ctf.core.event.io; | |
17 | ||
231c4e1f | 18 | import java.nio.BufferUnderflowException; |
486efb2e AM |
19 | import java.nio.ByteBuffer; |
20 | import java.nio.ByteOrder; | |
21 | ||
231c4e1f | 22 | import org.eclipse.jdt.annotation.NonNull; |
db8e8f7d AM |
23 | import org.eclipse.linuxtools.ctf.core.trace.CTFReaderException; |
24 | ||
486efb2e AM |
25 | /** |
26 | * <b><u>BitBuffer</u></b> | |
27 | * <p> | |
28 | * A bitwise buffer capable of accessing fields with bit offsets. | |
2b50c5ac | 29 | * |
486efb2e AM |
30 | * @since 2.0 |
31 | */ | |
0594c61c | 32 | public final class BitBuffer { |
486efb2e AM |
33 | |
34 | // ------------------------------------------------------------------------ | |
35 | // Constants | |
36 | // ------------------------------------------------------------------------ | |
37 | ||
38 | /* default bit width */ | |
39 | /** 8 bits to a char */ | |
40 | public static final int BIT_CHAR = 8; | |
41 | /** 16 bits to a short */ | |
42 | public static final int BIT_SHORT = 16; | |
43 | /** 32 bits to an int */ | |
44 | public static final int BIT_INT = 32; | |
45 | /** 32 bits to a float */ | |
46 | public static final int BIT_FLOAT = 32; | |
47 | /** 64 bits to a long */ | |
48 | public static final int BIT_LONG = 64; | |
49 | ||
50 | // ------------------------------------------------------------------------ | |
51 | // Attributes | |
52 | // ------------------------------------------------------------------------ | |
53 | ||
733c614c | 54 | private final ByteBuffer fBuffer; |
231c4e1f MK |
55 | |
56 | /** | |
57 | * Bit-buffer's position, maximum value = Integer.MAX_VALUE * 8 | |
58 | */ | |
4c67e724 MK |
59 | private long fPosition; |
60 | private ByteOrder fByteOrder; | |
486efb2e AM |
61 | |
62 | // ------------------------------------------------------------------------ | |
63 | // Constructors | |
64 | // ------------------------------------------------------------------------ | |
65 | /** | |
74e4b6b9 | 66 | * Default constructor, makes a big-endian buffer |
486efb2e AM |
67 | */ |
68 | public BitBuffer() { | |
69 | this(null, ByteOrder.BIG_ENDIAN); | |
70 | } | |
71 | ||
72 | /** | |
74e4b6b9 | 73 | * Constructor, makes a big-endian buffer |
486efb2e AM |
74 | * |
75 | * @param buf | |
76 | * the bytebuffer to read | |
77 | */ | |
78 | public BitBuffer(ByteBuffer buf) { | |
79 | this(buf, ByteOrder.BIG_ENDIAN); | |
80 | } | |
81 | ||
82 | /** | |
74e4b6b9 | 83 | * Constructor that is fully parameterizable |
486efb2e AM |
84 | * |
85 | * @param buf | |
86 | * the buffer to read | |
87 | * @param order | |
74e4b6b9 | 88 | * the byte order (big-endian, little-endian, network?) |
486efb2e AM |
89 | */ |
90 | public BitBuffer(ByteBuffer buf, ByteOrder order) { | |
733c614c | 91 | fBuffer = buf; |
486efb2e | 92 | setByteOrder(order); |
4c67e724 MK |
93 | resetPosition(); |
94 | } | |
95 | ||
96 | private void resetPosition() { | |
97 | fPosition = 0; | |
486efb2e AM |
98 | } |
99 | ||
100 | // ------------------------------------------------------------------------ | |
101 | // 'Get' operations on buffer | |
102 | // ------------------------------------------------------------------------ | |
103 | ||
104 | /** | |
105 | * Relative <i>get</i> method for reading 32-bit integer. | |
106 | * | |
107 | * Reads next four bytes from the current bit position according to current | |
108 | * byte order. | |
109 | * | |
2b50c5ac | 110 | * @return The int value (signed) read from the buffer |
db8e8f7d | 111 | * @throws CTFReaderException |
2b50c5ac MK |
112 | * An error occurred reading the long. This exception can be |
113 | * raised if the buffer tries to read out of bounds | |
486efb2e | 114 | */ |
db8e8f7d | 115 | public int getInt() throws CTFReaderException { |
0594c61c | 116 | return getInt(BIT_INT, true); |
486efb2e AM |
117 | } |
118 | ||
2b50c5ac MK |
119 | /** |
120 | * Relative <i>get</i> method for reading 64-bit integer. | |
121 | * | |
122 | * Reads next eight bytes from the current bit position according to current | |
123 | * byte order. | |
124 | * | |
125 | * @return The long value (signed) read from the buffer | |
126 | * @throws CTFReaderException | |
127 | * An error occurred reading the long. This exception can be | |
128 | * raised if the buffer tries to read out of bounds | |
c4767854 | 129 | * @since 3.0 |
2b50c5ac MK |
130 | */ |
131 | public long getLong() throws CTFReaderException { | |
132 | return get(BIT_LONG, true); | |
133 | } | |
134 | ||
135 | /** | |
136 | * Relative <i>get</i> method for reading long of <i>length</i> bits. | |
137 | * | |
138 | * Reads <i>length</i> bits starting at the current position. The result is | |
139 | * signed extended if <i>signed</i> is true. The current position is | |
140 | * increased of <i>length</i> bits. | |
141 | * | |
142 | * @param length | |
143 | * The length in bits of this integer | |
144 | * @param signed | |
145 | * The sign extended flag | |
146 | * @return The long value read from the buffer | |
147 | * @throws CTFReaderException | |
148 | * An error occurred reading the data. If more than 64 bits at a | |
149 | * time are read, or the buffer is read beyond its end, this | |
150 | * exception will be raised. | |
c4767854 | 151 | * @since 3.0 |
2b50c5ac MK |
152 | */ |
153 | public long get(int length, boolean signed) throws CTFReaderException { | |
154 | if (length > BIT_LONG) { | |
155 | throw new CTFReaderException("Cannot read a long longer than 64 bits. Rquested: " + length); //$NON-NLS-1$ | |
156 | } | |
157 | if (length > BIT_INT) { | |
158 | final int highShift = length - BIT_INT; | |
159 | long a = getInt(); | |
160 | long b = getInt(highShift, false); | |
161 | long retVal; | |
162 | /* Cast the signed-extended int into a unsigned int. */ | |
163 | a &= 0xFFFFFFFFL; | |
164 | b &= (1L << highShift) - 1L; | |
165 | ||
4c67e724 | 166 | retVal = (fByteOrder == ByteOrder.BIG_ENDIAN) ? ((a << highShift) | b) : ((b << BIT_INT) | a); |
2b50c5ac MK |
167 | /* sign extend */ |
168 | if (signed) { | |
169 | int signExtendBits = BIT_LONG - length; | |
170 | retVal = (retVal << signExtendBits) >> signExtendBits; | |
171 | } | |
172 | return retVal; | |
173 | } | |
174 | long retVal = getInt(length, signed); | |
175 | return (signed ? retVal : (retVal & 0xFFFFFFFFL)); | |
176 | } | |
177 | ||
231c4e1f MK |
178 | /** |
179 | * Relative bulk <i>get</i> method. | |
180 | * | |
181 | * <p> | |
182 | * This method transfers <strong>bytes</strong> from this buffer into the | |
183 | * given destination array. This method currently only supports reads | |
184 | * aligned to 8 bytes. It is up to the developer to shift the bits in | |
185 | * post-processing to do unaligned reads. | |
186 | * | |
187 | * @param dst | |
188 | * the bytes to write to | |
189 | * @throws BufferUnderflowException | |
190 | * - If there are fewer than length bytes remaining in this | |
191 | * buffer | |
192 | * @since 3.1 | |
193 | */ | |
194 | public void get(@NonNull byte[] dst) { | |
195 | fBuffer.position((int) (fPosition / 8)); | |
196 | fBuffer.get(dst); | |
197 | fPosition += dst.length * 8; | |
198 | } | |
199 | ||
486efb2e AM |
200 | /** |
201 | * Relative <i>get</i> method for reading integer of <i>length</i> bits. | |
202 | * | |
203 | * Reads <i>length</i> bits starting at the current position. The result is | |
204 | * signed extended if <i>signed</i> is true. The current position is | |
205 | * increased of <i>length</i> bits. | |
206 | * | |
207 | * @param length | |
208 | * The length in bits of this integer | |
209 | * @param signed | |
210 | * The sign extended flag | |
211 | * @return The int value read from the buffer | |
db8e8f7d AM |
212 | * @throws CTFReaderException |
213 | * An error occurred reading the data. When the buffer is read | |
214 | * beyond its end, this exception will be raised. | |
486efb2e | 215 | */ |
2b50c5ac | 216 | private int getInt(int length, boolean signed) throws CTFReaderException { |
74e4b6b9 EB |
217 | |
218 | /* Nothing to read. */ | |
486efb2e AM |
219 | if (length == 0) { |
220 | return 0; | |
221 | } | |
74e4b6b9 EB |
222 | |
223 | /* Validate that the buffer has enough bits. */ | |
224 | if (!canRead(length)) { | |
db8e8f7d AM |
225 | throw new CTFReaderException("Cannot read the integer, " + //$NON-NLS-1$ |
226 | "the buffer does not have enough remaining space. " + //$NON-NLS-1$ | |
227 | "Requested:" + length); //$NON-NLS-1$ | |
74e4b6b9 EB |
228 | } |
229 | ||
230 | /* Get the value from the byte buffer. */ | |
231 | int val = 0; | |
486efb2e AM |
232 | boolean gotIt = false; |
233 | ||
2b50c5ac MK |
234 | /* |
235 | * Try a fast read when the position is byte-aligned by using | |
236 | * java.nio.ByteBuffer's native methods | |
237 | */ | |
238 | /* | |
239 | * A faster alignment detection as the compiler cannot guaranty that pos | |
240 | * is always positive. | |
241 | */ | |
4c67e724 | 242 | if ((fPosition & (BitBuffer.BIT_CHAR - 1)) == 0) { |
486efb2e AM |
243 | switch (length) { |
244 | case BitBuffer.BIT_CHAR: | |
245 | // Byte | |
4c67e724 | 246 | val = fBuffer.get((int) (fPosition / 8)); |
74e4b6b9 EB |
247 | if (!signed) { |
248 | val = val & 0xff; | |
486efb2e AM |
249 | } |
250 | gotIt = true; | |
251 | break; | |
252 | ||
253 | case BitBuffer.BIT_SHORT: | |
254 | // Word | |
4c67e724 | 255 | val = fBuffer.getShort((int) (fPosition / 8)); |
74e4b6b9 EB |
256 | if (!signed) { |
257 | val = val & 0xffff; | |
486efb2e AM |
258 | } |
259 | gotIt = true; | |
260 | break; | |
261 | ||
262 | case BitBuffer.BIT_INT: | |
263 | // Double word | |
4c67e724 | 264 | val = fBuffer.getInt((int) (fPosition / 8)); |
486efb2e AM |
265 | gotIt = true; |
266 | break; | |
267 | ||
268 | default: | |
269 | break; | |
270 | } | |
271 | } | |
74e4b6b9 EB |
272 | |
273 | /* When not byte-aligned, fall-back to a general decoder. */ | |
486efb2e AM |
274 | if (!gotIt) { |
275 | // Nothing read yet: use longer methods | |
4c67e724 MK |
276 | if (fByteOrder == ByteOrder.LITTLE_ENDIAN) { |
277 | val = getIntLE(fPosition, length, signed); | |
486efb2e | 278 | } else { |
4c67e724 | 279 | val = getIntBE(fPosition, length, signed); |
486efb2e AM |
280 | } |
281 | } | |
4c67e724 | 282 | fPosition += length; |
486efb2e AM |
283 | |
284 | return val; | |
285 | } | |
286 | ||
47ca6c05 | 287 | private int getIntBE(long index, int length, boolean signed) { |
c3ffbd61 MK |
288 | if ((length <= 0) || (length > BIT_INT)) { |
289 | throw new IllegalArgumentException("Length must be between 1-32 bits"); //$NON-NLS-1$ | |
290 | } | |
47ca6c05 SM |
291 | long end = index + length; |
292 | int startByte = (int) (index / BIT_CHAR); | |
293 | int endByte = (int) ((end + (BIT_CHAR - 1)) / BIT_CHAR); | |
486efb2e AM |
294 | int currByte, lshift, cshift, mask, cmask, cache; |
295 | int value = 0; | |
296 | ||
297 | currByte = startByte; | |
4c67e724 | 298 | cache = fBuffer.get(currByte) & 0xFF; |
486efb2e AM |
299 | boolean isNeg = (cache & (1 << (BIT_CHAR - (index % BIT_CHAR) - 1))) != 0; |
300 | if (signed && isNeg) { | |
301 | value = ~0; | |
302 | } | |
303 | if (startByte == (endByte - 1)) { | |
304 | cmask = cache >>> ((BIT_CHAR - (end % BIT_CHAR)) % BIT_CHAR); | |
305 | if (((length) % BIT_CHAR) > 0) { | |
306 | mask = ~((~0) << length); | |
307 | cmask &= mask; | |
308 | } | |
309 | value <<= length; | |
310 | value |= cmask; | |
311 | return value; | |
312 | } | |
47ca6c05 | 313 | cshift = (int) (index % BIT_CHAR); |
486efb2e AM |
314 | if (cshift > 0) { |
315 | mask = ~((~0) << (BIT_CHAR - cshift)); | |
316 | cmask = cache & mask; | |
317 | lshift = BIT_CHAR - cshift; | |
318 | value <<= lshift; | |
319 | value |= cmask; | |
486efb2e AM |
320 | currByte++; |
321 | } | |
322 | for (; currByte < (endByte - 1); currByte++) { | |
323 | value <<= BIT_CHAR; | |
4c67e724 | 324 | value |= fBuffer.get(currByte) & 0xFF; |
486efb2e | 325 | } |
47ca6c05 | 326 | lshift = (int) (end % BIT_CHAR); |
486efb2e AM |
327 | if (lshift > 0) { |
328 | mask = ~((~0) << lshift); | |
4c67e724 | 329 | cmask = fBuffer.get(currByte) & 0xFF; |
486efb2e AM |
330 | cmask >>>= BIT_CHAR - lshift; |
331 | cmask &= mask; | |
332 | value <<= lshift; | |
333 | value |= cmask; | |
334 | } else { | |
335 | value <<= BIT_CHAR; | |
4c67e724 | 336 | value |= fBuffer.get(currByte) & 0xFF; |
486efb2e AM |
337 | } |
338 | return value; | |
339 | } | |
340 | ||
47ca6c05 | 341 | private int getIntLE(long index, int length, boolean signed) { |
c3ffbd61 MK |
342 | if ((length <= 0) || (length > BIT_INT)) { |
343 | throw new IllegalArgumentException("Length must be between 1-32 bits"); //$NON-NLS-1$ | |
344 | } | |
47ca6c05 SM |
345 | long end = index + length; |
346 | int startByte = (int) (index / BIT_CHAR); | |
347 | int endByte = (int) ((end + (BIT_CHAR - 1)) / BIT_CHAR); | |
486efb2e AM |
348 | int currByte, lshift, cshift, mask, cmask, cache, mod; |
349 | int value = 0; | |
350 | ||
351 | currByte = endByte - 1; | |
4c67e724 | 352 | cache = fBuffer.get(currByte) & 0xFF; |
47ca6c05 | 353 | mod = (int) (end % BIT_CHAR); |
486efb2e AM |
354 | lshift = (mod > 0) ? mod : BIT_CHAR; |
355 | boolean isNeg = (cache & (1 << (lshift - 1))) != 0; | |
356 | if (signed && isNeg) { | |
357 | value = ~0; | |
358 | } | |
359 | if (startByte == (endByte - 1)) { | |
360 | cmask = cache >>> (index % BIT_CHAR); | |
361 | if (((length) % BIT_CHAR) > 0) { | |
362 | mask = ~((~0) << length); | |
363 | cmask &= mask; | |
364 | } | |
365 | value <<= length; | |
366 | value |= cmask; | |
367 | return value; | |
368 | } | |
47ca6c05 | 369 | cshift = (int) (end % BIT_CHAR); |
486efb2e AM |
370 | if (cshift > 0) { |
371 | mask = ~((~0) << cshift); | |
372 | cmask = cache & mask; | |
373 | value <<= cshift; | |
374 | value |= cmask; | |
486efb2e AM |
375 | currByte--; |
376 | } | |
377 | for (; currByte >= (startByte + 1); currByte--) { | |
378 | value <<= BIT_CHAR; | |
4c67e724 | 379 | value |= fBuffer.get(currByte) & 0xFF; |
486efb2e | 380 | } |
47ca6c05 | 381 | lshift = (int) (index % BIT_CHAR); |
486efb2e AM |
382 | if (lshift > 0) { |
383 | mask = ~((~0) << (BIT_CHAR - lshift)); | |
4c67e724 | 384 | cmask = fBuffer.get(currByte) & 0xFF; |
486efb2e AM |
385 | cmask >>>= lshift; |
386 | cmask &= mask; | |
387 | value <<= (BIT_CHAR - lshift); | |
388 | value |= cmask; | |
389 | } else { | |
390 | value <<= BIT_CHAR; | |
4c67e724 | 391 | value |= fBuffer.get(currByte) & 0xFF; |
486efb2e AM |
392 | } |
393 | return value; | |
394 | } | |
395 | ||
396 | // ------------------------------------------------------------------------ | |
397 | // 'Put' operations on buffer | |
398 | // ------------------------------------------------------------------------ | |
399 | ||
400 | /** | |
401 | * Relative <i>put</i> method to write signed 32-bit integer. | |
402 | * | |
403 | * Write four bytes starting from current bit position in the buffer | |
404 | * according to the current byte order. The current position is increased of | |
405 | * <i>length</i> bits. | |
406 | * | |
407 | * @param value | |
408 | * The int value to write | |
db8e8f7d AM |
409 | * @throws CTFReaderException |
410 | * An error occurred writing the data. If the buffer is written | |
411 | * beyond its end, this exception will be raised. | |
486efb2e | 412 | */ |
db8e8f7d | 413 | public void putInt(int value) throws CTFReaderException { |
486efb2e AM |
414 | putInt(BIT_INT, value); |
415 | } | |
416 | ||
417 | /** | |
418 | * Relative <i>put</i> method to write <i>length</i> bits integer. | |
419 | * | |
420 | * Writes <i>length</i> lower-order bits from the provided <i>value</i>, | |
421 | * starting from current bit position in the buffer. Sequential bytes are | |
422 | * written according to the current byte order. The sign bit is carried to | |
423 | * the MSB if signed is true. The sign bit is included in <i>length</i>. The | |
424 | * current position is increased of <i>length</i>. | |
425 | * | |
426 | * @param length | |
427 | * The number of bits to write | |
428 | * @param value | |
429 | * The value to write | |
db8e8f7d AM |
430 | * @throws CTFReaderException |
431 | * An error occurred writing the data. If the buffer is written | |
432 | * beyond its end, this exception will be raised. | |
486efb2e | 433 | */ |
db8e8f7d | 434 | public void putInt(int length, int value) throws CTFReaderException { |
4c67e724 | 435 | final long curPos = fPosition; |
486efb2e AM |
436 | |
437 | if (!canRead(length)) { | |
db8e8f7d AM |
438 | throw new CTFReaderException("Cannot write to bitbuffer, " //$NON-NLS-1$ |
439 | + "insufficient space. Requested: " + length); //$NON-NLS-1$ | |
486efb2e AM |
440 | } |
441 | if (length == 0) { | |
442 | return; | |
443 | } | |
4c67e724 | 444 | if (fByteOrder == ByteOrder.LITTLE_ENDIAN) { |
486efb2e AM |
445 | putIntLE(curPos, length, value); |
446 | } else { | |
447 | putIntBE(curPos, length, value); | |
448 | } | |
4c67e724 | 449 | fPosition += length; |
486efb2e AM |
450 | } |
451 | ||
47ca6c05 | 452 | private void putIntBE(long index, int length, int value) { |
c3ffbd61 MK |
453 | if ((length <= 0) || (length > BIT_INT)) { |
454 | throw new IllegalArgumentException("Length must be between 1-32 bits"); //$NON-NLS-1$ | |
455 | } | |
47ca6c05 SM |
456 | long end = index + length; |
457 | int startByte = (int) (index / BIT_CHAR); | |
458 | int endByte = (int) ((end + (BIT_CHAR - 1)) / BIT_CHAR); | |
486efb2e AM |
459 | int currByte, lshift, cshift, mask, cmask; |
460 | int correctedValue = value; | |
461 | ||
462 | /* | |
463 | * mask v high bits. Works for unsigned and two complement signed | |
464 | * numbers which value do not overflow on length bits. | |
465 | */ | |
466 | ||
467 | if (length < BIT_INT) { | |
468 | correctedValue &= ~(~0 << length); | |
469 | } | |
470 | ||
471 | /* sub byte */ | |
472 | if (startByte == (endByte - 1)) { | |
47ca6c05 | 473 | lshift = (int) ((BIT_CHAR - (end % BIT_CHAR)) % BIT_CHAR); |
486efb2e AM |
474 | mask = ~((~0) << lshift); |
475 | if ((index % BIT_CHAR) > 0) { | |
476 | mask |= (~(0)) << (BIT_CHAR - (index % BIT_CHAR)); | |
477 | } | |
478 | cmask = correctedValue << lshift; | |
479 | /* | |
74e4b6b9 EB |
480 | * low bits are cleared because of left-shift and high bits are |
481 | * already cleared | |
486efb2e AM |
482 | */ |
483 | cmask &= ~mask; | |
4c67e724 MK |
484 | int b = fBuffer.get(startByte) & 0xFF; |
485 | fBuffer.put(startByte, (byte) ((b & mask) | cmask)); | |
486efb2e AM |
486 | return; |
487 | } | |
488 | ||
489 | /* head byte contains MSB */ | |
490 | currByte = endByte - 1; | |
47ca6c05 | 491 | cshift = (int) (end % BIT_CHAR); |
486efb2e AM |
492 | if (cshift > 0) { |
493 | lshift = BIT_CHAR - cshift; | |
494 | mask = ~((~0) << lshift); | |
495 | cmask = correctedValue << lshift; | |
496 | cmask &= ~mask; | |
4c67e724 MK |
497 | int b = fBuffer.get(currByte) & 0xFF; |
498 | fBuffer.put(currByte, (byte) ((b & mask) | cmask)); | |
486efb2e | 499 | correctedValue >>>= cshift; |
486efb2e AM |
500 | currByte--; |
501 | } | |
502 | ||
503 | /* middle byte(s) */ | |
504 | for (; currByte >= (startByte + 1); currByte--) { | |
4c67e724 | 505 | fBuffer.put(currByte, (byte) correctedValue); |
486efb2e AM |
506 | correctedValue >>>= BIT_CHAR; |
507 | } | |
508 | /* end byte contains LSB */ | |
509 | if ((index % BIT_CHAR) > 0) { | |
510 | mask = (~0) << (BIT_CHAR - (index % BIT_CHAR)); | |
511 | cmask = correctedValue & ~mask; | |
4c67e724 MK |
512 | int b = fBuffer.get(currByte) & 0xFF; |
513 | fBuffer.put(currByte, (byte) ((b & mask) | cmask)); | |
486efb2e | 514 | } else { |
4c67e724 | 515 | fBuffer.put(currByte, (byte) correctedValue); |
486efb2e AM |
516 | } |
517 | } | |
518 | ||
47ca6c05 | 519 | private void putIntLE(long index, int length, int value) { |
c3ffbd61 MK |
520 | if ((length <= 0) || (length > BIT_INT)) { |
521 | throw new IllegalArgumentException("Length must be between 1-32 bits"); //$NON-NLS-1$ | |
522 | } | |
47ca6c05 SM |
523 | long end = index + length; |
524 | int startByte = (int) (index / BIT_CHAR); | |
525 | int endByte = (int) ((end + (BIT_CHAR - 1)) / BIT_CHAR); | |
486efb2e AM |
526 | int currByte, lshift, cshift, mask, cmask; |
527 | int correctedValue = value; | |
528 | ||
529 | /* | |
530 | * mask v high bits. Works for unsigned and two complement signed | |
531 | * numbers which value do not overflow on length bits. | |
532 | */ | |
533 | ||
534 | if (length < BIT_INT) { | |
535 | correctedValue &= ~(~0 << length); | |
536 | } | |
537 | ||
538 | /* sub byte */ | |
539 | if (startByte == (endByte - 1)) { | |
47ca6c05 | 540 | lshift = (int) (index % BIT_CHAR); |
486efb2e AM |
541 | mask = ~((~0) << lshift); |
542 | if ((end % BIT_CHAR) > 0) { | |
543 | mask |= (~(0)) << (end % BIT_CHAR); | |
544 | } | |
545 | cmask = correctedValue << lshift; | |
546 | /* | |
74e4b6b9 EB |
547 | * low bits are cleared because of left-shift and high bits are |
548 | * already cleared | |
486efb2e AM |
549 | */ |
550 | cmask &= ~mask; | |
4c67e724 MK |
551 | int b = fBuffer.get(startByte) & 0xFF; |
552 | fBuffer.put(startByte, (byte) ((b & mask) | cmask)); | |
486efb2e AM |
553 | return; |
554 | } | |
555 | ||
556 | /* head byte */ | |
557 | currByte = startByte; | |
47ca6c05 | 558 | cshift = (int) (index % BIT_CHAR); |
486efb2e AM |
559 | if (cshift > 0) { |
560 | mask = ~((~0) << cshift); | |
561 | cmask = correctedValue << cshift; | |
562 | cmask &= ~mask; | |
4c67e724 MK |
563 | int b = fBuffer.get(currByte) & 0xFF; |
564 | fBuffer.put(currByte, (byte) ((b & mask) | cmask)); | |
486efb2e | 565 | correctedValue >>>= BIT_CHAR - cshift; |
486efb2e AM |
566 | currByte++; |
567 | } | |
568 | ||
569 | /* middle byte(s) */ | |
570 | for (; currByte < (endByte - 1); currByte++) { | |
4c67e724 | 571 | fBuffer.put(currByte, (byte) correctedValue); |
486efb2e AM |
572 | correctedValue >>>= BIT_CHAR; |
573 | } | |
574 | /* end byte */ | |
575 | if ((end % BIT_CHAR) > 0) { | |
576 | mask = (~0) << (end % BIT_CHAR); | |
577 | cmask = correctedValue & ~mask; | |
4c67e724 MK |
578 | int b = fBuffer.get(currByte) & 0xFF; |
579 | fBuffer.put(currByte, (byte) ((b & mask) | cmask)); | |
486efb2e | 580 | } else { |
4c67e724 | 581 | fBuffer.put(currByte, (byte) correctedValue); |
486efb2e AM |
582 | } |
583 | } | |
584 | ||
585 | // ------------------------------------------------------------------------ | |
586 | // Buffer attributes handling | |
587 | // ------------------------------------------------------------------------ | |
588 | ||
589 | /** | |
590 | * Can this buffer be read for thus amount of bits? | |
591 | * | |
592 | * @param length | |
593 | * the length in bits to read | |
594 | * @return does the buffer have enough room to read the next "length" | |
595 | */ | |
596 | public boolean canRead(int length) { | |
4c67e724 | 597 | if (fBuffer == null) { |
486efb2e AM |
598 | return false; |
599 | } | |
600 | ||
4c67e724 | 601 | if ((fPosition + length) > (((long) fBuffer.capacity()) * BIT_CHAR)) { |
486efb2e AM |
602 | return false; |
603 | } | |
604 | return true; | |
605 | } | |
606 | ||
607 | /** | |
608 | * Sets the order of the buffer. | |
609 | * | |
610 | * @param order | |
611 | * The order of the buffer. | |
612 | */ | |
613 | public void setByteOrder(ByteOrder order) { | |
4c67e724 MK |
614 | fByteOrder = order; |
615 | if (fBuffer != null) { | |
616 | fBuffer.order(order); | |
486efb2e AM |
617 | } |
618 | } | |
619 | ||
620 | /** | |
621 | * Sets the order of the buffer. | |
622 | * | |
623 | * @return The order of the buffer. | |
624 | */ | |
625 | public ByteOrder getByteOrder() { | |
4c67e724 | 626 | return fByteOrder; |
486efb2e AM |
627 | } |
628 | ||
629 | /** | |
630 | * Sets the position in the buffer. | |
631 | * | |
632 | * @param newPosition | |
633 | * The new position of the buffer. | |
4c67e724 MK |
634 | * @throws CTFReaderException |
635 | * Thrown on out of bounds exceptions | |
c4767854 | 636 | * @since 3.0 |
486efb2e | 637 | */ |
4c67e724 MK |
638 | public void position(long newPosition) throws CTFReaderException { |
639 | ||
640 | if ((fBuffer != null) && (newPosition / 8) > fBuffer.capacity()) { | |
641 | throw new CTFReaderException("Out of bounds exception on a position move, attempting to access position: " + newPosition); //$NON-NLS-1$ | |
642 | } | |
643 | fPosition = newPosition; | |
486efb2e AM |
644 | } |
645 | ||
646 | /** | |
647 | * | |
648 | * Sets the position in the buffer. | |
649 | * | |
650 | * @return order The position of the buffer. | |
c4767854 | 651 | * @since 3.0 |
486efb2e | 652 | */ |
47ca6c05 | 653 | public long position() { |
4c67e724 | 654 | return fPosition; |
486efb2e AM |
655 | } |
656 | ||
657 | /** | |
658 | * Sets the byte buffer | |
659 | * | |
660 | * @param buf | |
661 | * the byte buffer | |
662 | */ | |
733c614c | 663 | @Deprecated |
486efb2e | 664 | public void setByteBuffer(ByteBuffer buf) { |
733c614c MK |
665 | /* |
666 | * to avoid "The method setByteBuffer(ByteBuffer) from the type | |
667 | * BitBuffer can be declared as static" | |
668 | */ | |
669 | long data = fPosition; | |
670 | fPosition = data; | |
671 | throw new UnsupportedOperationException("Bytebuffers are now final"); //$NON-NLS-1$ | |
672 | ||
486efb2e AM |
673 | } |
674 | ||
675 | /** | |
676 | * Gets the byte buffer | |
677 | * | |
678 | * @return The byte buffer | |
679 | */ | |
680 | public ByteBuffer getByteBuffer() { | |
4c67e724 | 681 | return fBuffer; |
486efb2e AM |
682 | } |
683 | ||
684 | /** | |
74e4b6b9 | 685 | * Resets the bitbuffer. |
486efb2e AM |
686 | */ |
687 | public void clear() { | |
4c67e724 MK |
688 | resetPosition(); |
689 | if (fBuffer == null) { | |
486efb2e AM |
690 | return; |
691 | } | |
4c67e724 | 692 | fBuffer.clear(); |
486efb2e AM |
693 | } |
694 | ||
695 | } |