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1 | #ifndef _LTTNG_BITFIELD_H |
2 | #define _LTTNG_BITFIELD_H | |
3 | ||
4 | /* | |
5 | * BabelTrace | |
6 | * | |
7 | * Bitfields read/write functions. | |
8 | * | |
9 | * Copyright 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
10 | * | |
11 | * Permission is hereby granted, free of charge, to any person obtaining a copy | |
12 | * of this software and associated documentation files (the "Software"), to | |
13 | * deal in the Software without restriction, including without limitation the | |
14 | * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or | |
15 | * sell copies of the Software, and to permit persons to whom the Software is | |
16 | * furnished to do so, subject to the following conditions: | |
17 | * | |
18 | * The above copyright notice and this permission notice shall be included in | |
19 | * all copies or substantial portions of the Software. | |
20 | * | |
21 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
22 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
23 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
24 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
25 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING | |
26 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS | |
27 | * IN THE SOFTWARE. | |
28 | */ | |
29 | ||
30 | #include <assert.h> | |
31 | #include <stdint.h> /* C99 5.2.4.2 Numerical limits */ | |
32 | #include <limits.h> /* C99 5.2.4.2 Numerical limits */ | |
33 | ||
34 | #include <common/compat/endian.h> /* Non-standard BIG_ENDIAN, LITTLE_ENDIAN, BYTE_ORDER */ | |
35 | ||
36 | /* We can't shift a int from 32 bit, >> 32 and << 32 on int is undefined */ | |
37 | #define _piecewise_rshift(_v, _shift) \ | |
38 | ({ \ | |
39 | typeof(_v) ___v = (_v); \ | |
40 | typeof(_shift) ___shift = (_shift); \ | |
41 | unsigned long sb = (___shift) / (sizeof(___v) * CHAR_BIT - 1); \ | |
42 | unsigned long final = (___shift) % (sizeof(___v) * CHAR_BIT - 1); \ | |
43 | \ | |
44 | for (; sb; sb--) \ | |
45 | ___v >>= sizeof(___v) * CHAR_BIT - 1; \ | |
46 | ___v >>= final; \ | |
47 | }) | |
48 | ||
49 | #define _piecewise_lshift(_v, _shift) \ | |
50 | ({ \ | |
51 | typeof(_v) ___v = (_v); \ | |
52 | typeof(_shift) ___shift = (_shift); \ | |
53 | unsigned long sb = (___shift) / (sizeof(___v) * CHAR_BIT - 1); \ | |
54 | unsigned long final = (___shift) % (sizeof(___v) * CHAR_BIT - 1); \ | |
55 | \ | |
56 | for (; sb; sb--) \ | |
57 | ___v <<= sizeof(___v) * CHAR_BIT - 1; \ | |
58 | ___v <<= final; \ | |
59 | }) | |
60 | ||
61 | #define _is_signed_type(type) ((type) -1 < (type) 0) | |
62 | ||
63 | #define _unsigned_cast(type, v) \ | |
64 | ({ \ | |
65 | (sizeof(v) < sizeof(type)) ? \ | |
66 | ((type) (v)) & (~(~(type) 0 << (sizeof(v) * CHAR_BIT))) : \ | |
67 | (type) (v); \ | |
68 | }) | |
69 | ||
70 | /* | |
71 | * bitfield_write - write integer to a bitfield in native endianness | |
72 | * | |
73 | * Save integer to the bitfield, which starts at the "start" bit, has "len" | |
74 | * bits. | |
75 | * The inside of a bitfield is from high bits to low bits. | |
76 | * Uses native endianness. | |
77 | * For unsigned "v", pad MSB with 0 if bitfield is larger than v. | |
78 | * For signed "v", sign-extend v if bitfield is larger than v. | |
79 | * | |
80 | * On little endian, bytes are placed from the less significant to the most | |
81 | * significant. Also, consecutive bitfields are placed from lower bits to higher | |
82 | * bits. | |
83 | * | |
84 | * On big endian, bytes are places from most significant to less significant. | |
85 | * Also, consecutive bitfields are placed from higher to lower bits. | |
86 | */ | |
87 | ||
88 | #define _bitfield_write_le(_ptr, type, _start, _length, _v) \ | |
89 | do { \ | |
90 | typeof(_v) __v = (_v); \ | |
91 | type *__ptr = (void *) (_ptr); \ | |
92 | unsigned long __start = (_start), __length = (_length); \ | |
93 | type mask, cmask; \ | |
94 | unsigned long ts = sizeof(type) * CHAR_BIT; /* type size */ \ | |
95 | unsigned long start_unit, end_unit, this_unit; \ | |
96 | unsigned long end, cshift; /* cshift is "complement shift" */ \ | |
97 | \ | |
98 | if (!__length) \ | |
99 | break; \ | |
100 | \ | |
101 | end = __start + __length; \ | |
102 | start_unit = __start / ts; \ | |
103 | end_unit = (end + (ts - 1)) / ts; \ | |
104 | \ | |
105 | /* Trim v high bits */ \ | |
106 | if (__length < sizeof(__v) * CHAR_BIT) \ | |
107 | __v &= ~((~(typeof(__v)) 0) << __length); \ | |
108 | \ | |
109 | /* We can now append v with a simple "or", shift it piece-wise */ \ | |
110 | this_unit = start_unit; \ | |
111 | if (start_unit == end_unit - 1) { \ | |
112 | mask = ~((~(type) 0) << (__start % ts)); \ | |
113 | if (end % ts) \ | |
114 | mask |= (~(type) 0) << (end % ts); \ | |
115 | cmask = (type) __v << (__start % ts); \ | |
116 | cmask &= ~mask; \ | |
117 | __ptr[this_unit] &= mask; \ | |
118 | __ptr[this_unit] |= cmask; \ | |
119 | break; \ | |
120 | } \ | |
121 | if (__start % ts) { \ | |
122 | cshift = __start % ts; \ | |
123 | mask = ~((~(type) 0) << cshift); \ | |
124 | cmask = (type) __v << cshift; \ | |
125 | cmask &= ~mask; \ | |
126 | __ptr[this_unit] &= mask; \ | |
127 | __ptr[this_unit] |= cmask; \ | |
128 | __v = _piecewise_rshift(__v, ts - cshift); \ | |
129 | __start += ts - cshift; \ | |
130 | this_unit++; \ | |
131 | } \ | |
132 | for (; this_unit < end_unit - 1; this_unit++) { \ | |
133 | __ptr[this_unit] = (type) __v; \ | |
134 | __v = _piecewise_rshift(__v, ts); \ | |
135 | __start += ts; \ | |
136 | } \ | |
137 | if (end % ts) { \ | |
138 | mask = (~(type) 0) << (end % ts); \ | |
139 | cmask = (type) __v; \ | |
140 | cmask &= ~mask; \ | |
141 | __ptr[this_unit] &= mask; \ | |
142 | __ptr[this_unit] |= cmask; \ | |
143 | } else \ | |
144 | __ptr[this_unit] = (type) __v; \ | |
145 | } while (0) | |
146 | ||
147 | #define _bitfield_write_be(_ptr, type, _start, _length, _v) \ | |
148 | do { \ | |
149 | typeof(_v) __v = (_v); \ | |
150 | type *__ptr = (void *) (_ptr); \ | |
151 | unsigned long __start = (_start), __length = (_length); \ | |
152 | type mask, cmask; \ | |
153 | unsigned long ts = sizeof(type) * CHAR_BIT; /* type size */ \ | |
154 | unsigned long start_unit, end_unit, this_unit; \ | |
155 | unsigned long end, cshift; /* cshift is "complement shift" */ \ | |
156 | \ | |
157 | if (!__length) \ | |
158 | break; \ | |
159 | \ | |
160 | end = __start + __length; \ | |
161 | start_unit = __start / ts; \ | |
162 | end_unit = (end + (ts - 1)) / ts; \ | |
163 | \ | |
164 | /* Trim v high bits */ \ | |
165 | if (__length < sizeof(__v) * CHAR_BIT) \ | |
166 | __v &= ~((~(typeof(__v)) 0) << __length); \ | |
167 | \ | |
168 | /* We can now append v with a simple "or", shift it piece-wise */ \ | |
169 | this_unit = end_unit - 1; \ | |
170 | if (start_unit == end_unit - 1) { \ | |
171 | mask = ~((~(type) 0) << ((ts - (end % ts)) % ts)); \ | |
172 | if (__start % ts) \ | |
173 | mask |= (~((type) 0)) << (ts - (__start % ts)); \ | |
174 | cmask = (type) __v << ((ts - (end % ts)) % ts); \ | |
175 | cmask &= ~mask; \ | |
176 | __ptr[this_unit] &= mask; \ | |
177 | __ptr[this_unit] |= cmask; \ | |
178 | break; \ | |
179 | } \ | |
180 | if (end % ts) { \ | |
181 | cshift = end % ts; \ | |
182 | mask = ~((~(type) 0) << (ts - cshift)); \ | |
183 | cmask = (type) __v << (ts - cshift); \ | |
184 | cmask &= ~mask; \ | |
185 | __ptr[this_unit] &= mask; \ | |
186 | __ptr[this_unit] |= cmask; \ | |
187 | __v = _piecewise_rshift(__v, cshift); \ | |
188 | end -= cshift; \ | |
189 | this_unit--; \ | |
190 | } \ | |
191 | for (; (long) this_unit >= (long) start_unit + 1; this_unit--) { \ | |
192 | __ptr[this_unit] = (type) __v; \ | |
193 | __v = _piecewise_rshift(__v, ts); \ | |
194 | end -= ts; \ | |
195 | } \ | |
196 | if (__start % ts) { \ | |
197 | mask = (~(type) 0) << (ts - (__start % ts)); \ | |
198 | cmask = (type) __v; \ | |
199 | cmask &= ~mask; \ | |
200 | __ptr[this_unit] &= mask; \ | |
201 | __ptr[this_unit] |= cmask; \ | |
202 | } else \ | |
203 | __ptr[this_unit] = (type) __v; \ | |
204 | } while (0) | |
205 | ||
206 | /* | |
207 | * bitfield_write - write integer to a bitfield in native endianness | |
208 | * bitfield_write_le - write integer to a bitfield in little endian | |
209 | * bitfield_write_be - write integer to a bitfield in big endian | |
210 | */ | |
211 | ||
212 | #if (BYTE_ORDER == LITTLE_ENDIAN) | |
213 | ||
214 | #define bitfield_write(ptr, type, _start, _length, _v) \ | |
215 | _bitfield_write_le(ptr, type, _start, _length, _v) | |
216 | ||
217 | #define bitfield_write_le(ptr, type, _start, _length, _v) \ | |
218 | _bitfield_write_le(ptr, type, _start, _length, _v) | |
219 | ||
220 | #define bitfield_write_be(ptr, type, _start, _length, _v) \ | |
221 | _bitfield_write_be(ptr, unsigned char, _start, _length, _v) | |
222 | ||
223 | #elif (BYTE_ORDER == BIG_ENDIAN) | |
224 | ||
225 | #define bitfield_write(ptr, type, _start, _length, _v) \ | |
226 | _bitfield_write_be(ptr, type, _start, _length, _v) | |
227 | ||
228 | #define bitfield_write_le(ptr, type, _start, _length, _v) \ | |
229 | _bitfield_write_le(ptr, unsigned char, _start, _length, _v) | |
230 | ||
231 | #define bitfield_write_be(ptr, type, _start, _length, _v) \ | |
232 | _bitfield_write_be(ptr, type, _start, _length, _v) | |
233 | ||
234 | #else /* (BYTE_ORDER == PDP_ENDIAN) */ | |
235 | ||
236 | #error "Byte order not supported" | |
237 | ||
238 | #endif | |
239 | ||
240 | #define _bitfield_read_le(_ptr, type, _start, _length, _vptr) \ | |
241 | do { \ | |
242 | typeof(*(_vptr)) *__vptr = (_vptr); \ | |
243 | typeof(*__vptr) __v; \ | |
244 | type *__ptr = (void *) (_ptr); \ | |
245 | unsigned long __start = (_start), __length = (_length); \ | |
246 | type mask, cmask; \ | |
247 | unsigned long ts = sizeof(type) * CHAR_BIT; /* type size */ \ | |
248 | unsigned long start_unit, end_unit, this_unit; \ | |
249 | unsigned long end, cshift; /* cshift is "complement shift" */ \ | |
250 | \ | |
251 | if (!__length) { \ | |
252 | *__vptr = 0; \ | |
253 | break; \ | |
254 | } \ | |
255 | \ | |
256 | end = __start + __length; \ | |
257 | start_unit = __start / ts; \ | |
258 | end_unit = (end + (ts - 1)) / ts; \ | |
259 | \ | |
260 | this_unit = end_unit - 1; \ | |
261 | if (_is_signed_type(typeof(__v)) \ | |
262 | && (__ptr[this_unit] & ((type) 1 << ((end % ts ? : ts) - 1)))) \ | |
263 | __v = ~(typeof(__v)) 0; \ | |
264 | else \ | |
265 | __v = 0; \ | |
266 | if (start_unit == end_unit - 1) { \ | |
267 | cmask = __ptr[this_unit]; \ | |
268 | cmask >>= (__start % ts); \ | |
269 | if ((end - __start) % ts) { \ | |
270 | mask = ~((~(type) 0) << (end - __start)); \ | |
271 | cmask &= mask; \ | |
272 | } \ | |
273 | __v = _piecewise_lshift(__v, end - __start); \ | |
274 | __v |= _unsigned_cast(typeof(__v), cmask); \ | |
275 | *__vptr = __v; \ | |
276 | break; \ | |
277 | } \ | |
278 | if (end % ts) { \ | |
279 | cshift = end % ts; \ | |
280 | mask = ~((~(type) 0) << cshift); \ | |
281 | cmask = __ptr[this_unit]; \ | |
282 | cmask &= mask; \ | |
283 | __v = _piecewise_lshift(__v, cshift); \ | |
284 | __v |= _unsigned_cast(typeof(__v), cmask); \ | |
285 | end -= cshift; \ | |
286 | this_unit--; \ | |
287 | } \ | |
288 | for (; (long) this_unit >= (long) start_unit + 1; this_unit--) { \ | |
289 | __v = _piecewise_lshift(__v, ts); \ | |
290 | __v |= _unsigned_cast(typeof(__v), __ptr[this_unit]);\ | |
291 | end -= ts; \ | |
292 | } \ | |
293 | if (__start % ts) { \ | |
294 | mask = ~((~(type) 0) << (ts - (__start % ts))); \ | |
295 | cmask = __ptr[this_unit]; \ | |
296 | cmask >>= (__start % ts); \ | |
297 | cmask &= mask; \ | |
298 | __v = _piecewise_lshift(__v, ts - (__start % ts)); \ | |
299 | __v |= _unsigned_cast(typeof(__v), cmask); \ | |
300 | } else { \ | |
301 | __v = _piecewise_lshift(__v, ts); \ | |
302 | __v |= _unsigned_cast(typeof(__v), __ptr[this_unit]);\ | |
303 | } \ | |
304 | *__vptr = __v; \ | |
305 | } while (0) | |
306 | ||
307 | #define _bitfield_read_be(_ptr, type, _start, _length, _vptr) \ | |
308 | do { \ | |
309 | typeof(*(_vptr)) *__vptr = (_vptr); \ | |
310 | typeof(*__vptr) __v; \ | |
311 | type *__ptr = (void *) (_ptr); \ | |
312 | unsigned long __start = (_start), __length = (_length); \ | |
313 | type mask, cmask; \ | |
314 | unsigned long ts = sizeof(type) * CHAR_BIT; /* type size */ \ | |
315 | unsigned long start_unit, end_unit, this_unit; \ | |
316 | unsigned long end, cshift; /* cshift is "complement shift" */ \ | |
317 | \ | |
318 | if (!__length) { \ | |
319 | *__vptr = 0; \ | |
320 | break; \ | |
321 | } \ | |
322 | \ | |
323 | end = __start + __length; \ | |
324 | start_unit = __start / ts; \ | |
325 | end_unit = (end + (ts - 1)) / ts; \ | |
326 | \ | |
327 | this_unit = start_unit; \ | |
328 | if (_is_signed_type(typeof(__v)) \ | |
329 | && (__ptr[this_unit] & ((type) 1 << (ts - (__start % ts) - 1)))) \ | |
330 | __v = ~(typeof(__v)) 0; \ | |
331 | else \ | |
332 | __v = 0; \ | |
333 | if (start_unit == end_unit - 1) { \ | |
334 | cmask = __ptr[this_unit]; \ | |
335 | cmask >>= (ts - (end % ts)) % ts; \ | |
336 | if ((end - __start) % ts) { \ | |
337 | mask = ~((~(type) 0) << (end - __start)); \ | |
338 | cmask &= mask; \ | |
339 | } \ | |
340 | __v = _piecewise_lshift(__v, end - __start); \ | |
341 | __v |= _unsigned_cast(typeof(__v), cmask); \ | |
342 | *__vptr = __v; \ | |
343 | break; \ | |
344 | } \ | |
345 | if (__start % ts) { \ | |
346 | cshift = __start % ts; \ | |
347 | mask = ~((~(type) 0) << (ts - cshift)); \ | |
348 | cmask = __ptr[this_unit]; \ | |
349 | cmask &= mask; \ | |
350 | __v = _piecewise_lshift(__v, ts - cshift); \ | |
351 | __v |= _unsigned_cast(typeof(__v), cmask); \ | |
352 | __start += ts - cshift; \ | |
353 | this_unit++; \ | |
354 | } \ | |
355 | for (; this_unit < end_unit - 1; this_unit++) { \ | |
356 | __v = _piecewise_lshift(__v, ts); \ | |
357 | __v |= _unsigned_cast(typeof(__v), __ptr[this_unit]);\ | |
358 | __start += ts; \ | |
359 | } \ | |
360 | if (end % ts) { \ | |
361 | mask = ~((~(type) 0) << (end % ts)); \ | |
362 | cmask = __ptr[this_unit]; \ | |
363 | cmask >>= ts - (end % ts); \ | |
364 | cmask &= mask; \ | |
365 | __v = _piecewise_lshift(__v, end % ts); \ | |
366 | __v |= _unsigned_cast(typeof(__v), cmask); \ | |
367 | } else { \ | |
368 | __v = _piecewise_lshift(__v, ts); \ | |
369 | __v |= _unsigned_cast(typeof(__v), __ptr[this_unit]);\ | |
370 | } \ | |
371 | *__vptr = __v; \ | |
372 | } while (0) | |
373 | ||
374 | /* | |
375 | * bitfield_read - read integer from a bitfield in native endianness | |
376 | * bitfield_read_le - read integer from a bitfield in little endian | |
377 | * bitfield_read_be - read integer from a bitfield in big endian | |
378 | */ | |
379 | ||
380 | #if (BYTE_ORDER == LITTLE_ENDIAN) | |
381 | ||
382 | #define bitfield_read(_ptr, type, _start, _length, _vptr) \ | |
383 | _bitfield_read_le(_ptr, type, _start, _length, _vptr) | |
384 | ||
385 | #define bitfield_read_le(_ptr, type, _start, _length, _vptr) \ | |
386 | _bitfield_read_le(_ptr, type, _start, _length, _vptr) | |
387 | ||
388 | #define bitfield_read_be(_ptr, type, _start, _length, _vptr) \ | |
389 | _bitfield_read_be(_ptr, unsigned char, _start, _length, _vptr) | |
390 | ||
391 | #elif (BYTE_ORDER == BIG_ENDIAN) | |
392 | ||
393 | #define bitfield_read(_ptr, type, _start, _length, _vptr) \ | |
394 | _bitfield_read_be(_ptr, type, _start, _length, _vptr) | |
395 | ||
396 | #define bitfield_read_le(_ptr, type, _start, _length, _vptr) \ | |
397 | _bitfield_read_le(_ptr, unsigned char, _start, _length, _vptr) | |
398 | ||
399 | #define bitfield_read_be(_ptr, type, _start, _length, _vptr) \ | |
400 | _bitfield_read_be(_ptr, type, _start, _length, _vptr) | |
401 | ||
402 | #else /* (BYTE_ORDER == PDP_ENDIAN) */ | |
403 | ||
404 | #error "Byte order not supported" | |
405 | ||
406 | #endif | |
407 | ||
408 | #endif /* _LTTNG_BITFIELD_H */ |