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9e7f0924 MD |
1 | #ifndef _BABELTRACE_BITFIELD_H |
2 | #define _BABELTRACE_BITFIELD_H | |
3 | ||
4 | /* | |
fa81c5df | 5 | * Copyright 2010-2019 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
9e7f0924 MD |
6 | * |
7 | * Permission is hereby granted, free of charge, to any person obtaining a copy | |
8 | * of this software and associated documentation files (the "Software"), to deal | |
9 | * in the Software without restriction, including without limitation the rights | |
10 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
11 | * copies of the Software, and to permit persons to whom the Software is | |
12 | * furnished to do so, subject to the following conditions: | |
13 | * | |
14 | * The above copyright notice and this permission notice shall be included in | |
15 | * all copies or substantial portions of the Software. | |
d2428e87 MD |
16 | * |
17 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
18 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
19 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
20 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
21 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
22 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
23 | * SOFTWARE. | |
9e7f0924 MD |
24 | */ |
25 | ||
9f3fdbc6 MD |
26 | #include <stdint.h> /* C99 5.2.4.2 Numerical limits */ |
27 | #include <limits.h> /* C99 5.2.4.2 Numerical limits */ | |
3268eea0 | 28 | #include <stdbool.h> /* C99 7.16 bool type */ |
2ae57758 | 29 | #include <lttng/ust-endian.h> /* Non-standard BIG_ENDIAN, LITTLE_ENDIAN, BYTE_ORDER */ |
9e7f0924 | 30 | |
fa81c5df MD |
31 | /* |
32 | * This header strictly follows the C99 standard, except for use of the | |
33 | * compiler-specific __typeof__. | |
34 | */ | |
35 | ||
36 | /* | |
37 | * This bitfield header requires the compiler representation of signed | |
38 | * integers to be two's complement. | |
39 | */ | |
40 | #if (-1 != ~0) | |
41 | #error "bitfield.h requires the compiler representation of signed integers to be two's complement." | |
42 | #endif | |
9e7f0924 | 43 | |
17ce2a4a | 44 | #define _bt_is_signed_type(type) ((type) -1 < (type) 1) |
9e7f0924 | 45 | |
fa81c5df MD |
46 | /* |
47 | * Produce a build-time error if the condition `cond` is non-zero. | |
48 | * Evaluates as a size_t expression. | |
49 | */ | |
50 | #define _BT_BUILD_ASSERT(cond) \ | |
51 | sizeof(struct { int f:(2 * !!(cond) - 1); }) | |
52 | ||
53 | /* | |
54 | * Cast value `v` to an unsigned integer of the same size as `v`. | |
55 | */ | |
56 | #define _bt_cast_value_to_unsigned(v) \ | |
57 | (sizeof(v) == sizeof(uint8_t) ? (uint8_t) (v) : \ | |
58 | sizeof(v) == sizeof(uint16_t) ? (uint16_t) (v) : \ | |
59 | sizeof(v) == sizeof(uint32_t) ? (uint32_t) (v) : \ | |
60 | sizeof(v) == sizeof(uint64_t) ? (uint64_t) (v) : \ | |
61 | _BT_BUILD_ASSERT(sizeof(v) <= sizeof(uint64_t))) | |
62 | ||
63 | /* | |
64 | * Cast value `v` to an unsigned integer type of the size of type `type` | |
65 | * *without* sign-extension. | |
66 | * | |
67 | * The unsigned cast ensures that we're not shifting a negative value, | |
68 | * which is undefined in C. However, this limits the maximum type size | |
69 | * of `type` to 64-bit. Generate a compile-time error if the size of | |
70 | * `type` is larger than 64-bit. | |
71 | */ | |
72 | #define _bt_cast_value_to_unsigned_type(type, v) \ | |
73 | (sizeof(type) == sizeof(uint8_t) ? \ | |
74 | (uint8_t) _bt_cast_value_to_unsigned(v) : \ | |
75 | sizeof(type) == sizeof(uint16_t) ? \ | |
76 | (uint16_t) _bt_cast_value_to_unsigned(v) : \ | |
77 | sizeof(type) == sizeof(uint32_t) ? \ | |
78 | (uint32_t) _bt_cast_value_to_unsigned(v) : \ | |
79 | sizeof(type) == sizeof(uint64_t) ? \ | |
80 | (uint64_t) _bt_cast_value_to_unsigned(v) : \ | |
81 | _BT_BUILD_ASSERT(sizeof(v) <= sizeof(uint64_t))) | |
82 | ||
83 | /* | |
84 | * _bt_fill_mask evaluates to a "type" integer with all bits set. | |
85 | */ | |
86 | #define _bt_fill_mask(type) ((type) ~(type) 0) | |
87 | ||
88 | /* | |
89 | * Left shift a value `v` of `shift` bits. | |
90 | * | |
91 | * The type of `v` can be signed or unsigned integer. | |
92 | * The value of `shift` must be less than the size of `v` (in bits), | |
93 | * otherwise the behavior is undefined. | |
94 | * Evaluates to the result of the shift operation. | |
95 | * | |
96 | * According to the C99 standard, left shift of a left hand-side signed | |
97 | * type is undefined if it has a negative value or if the result cannot | |
98 | * be represented in the result type. This bitfield header discards the | |
99 | * bits that are left-shifted beyond the result type representation, | |
100 | * which is the behavior of an unsigned type left shift operation. | |
101 | * Therefore, always perform left shift on an unsigned type. | |
102 | * | |
103 | * This macro should not be used if `shift` can be greater or equal than | |
104 | * the bitwidth of `v`. See `_bt_safe_lshift`. | |
105 | */ | |
106 | #define _bt_lshift(v, shift) \ | |
107 | ((__typeof__(v)) (_bt_cast_value_to_unsigned(v) << (shift))) | |
108 | ||
109 | /* | |
110 | * Generate a mask of type `type` with the `length` least significant bits | |
111 | * cleared, and the most significant bits set. | |
112 | */ | |
113 | #define _bt_make_mask_complement(type, length) \ | |
114 | _bt_lshift(_bt_fill_mask(type), length) | |
115 | ||
116 | /* | |
117 | * Generate a mask of type `type` with the `length` least significant bits | |
118 | * set, and the most significant bits cleared. | |
119 | */ | |
120 | #define _bt_make_mask(type, length) \ | |
121 | ((type) ~_bt_make_mask_complement(type, length)) | |
122 | ||
123 | /* | |
124 | * Right shift a value `v` of `shift` bits. | |
125 | * | |
126 | * The type of `v` can be signed or unsigned integer. | |
127 | * The value of `shift` must be less than the size of `v` (in bits), | |
128 | * otherwise the behavior is undefined. | |
129 | * Evaluates to the result of the shift operation. | |
130 | * | |
131 | * According to the C99 standard, right shift of a left hand-side signed | |
132 | * type which has a negative value is implementation defined. This | |
133 | * bitfield header relies on the right shift implementation carrying the | |
134 | * sign bit. If the compiler implementation has a different behavior, | |
135 | * emulate carrying the sign bit. | |
136 | * | |
137 | * This macro should not be used if `shift` can be greater or equal than | |
138 | * the bitwidth of `v`. See `_bt_safe_rshift`. | |
139 | */ | |
140 | #if ((-1 >> 1) == -1) | |
141 | #define _bt_rshift(v, shift) ((v) >> (shift)) | |
142 | #else | |
143 | #define _bt_rshift(v, shift) \ | |
144 | ((__typeof__(v)) ((_bt_cast_value_to_unsigned(v) >> (shift)) | \ | |
145 | ((v) < 0 ? _bt_make_mask_complement(__typeof__(v), \ | |
146 | sizeof(v) * CHAR_BIT - (shift)) : 0))) | |
147 | #endif | |
148 | ||
149 | /* | |
150 | * Right shift a signed or unsigned integer with `shift` value being an | |
151 | * arbitrary number of bits. `v` is modified by this macro. The shift | |
152 | * is transformed into a sequence of `_nr_partial_shifts` consecutive | |
153 | * shift operations, each of a number of bits smaller than the bitwidth | |
154 | * of `v`, ending with a shift of the number of left over bits. | |
155 | */ | |
156 | #define _bt_safe_rshift(v, shift) \ | |
157 | do { \ | |
158 | unsigned long _nr_partial_shifts = (shift) / (sizeof(v) * CHAR_BIT - 1); \ | |
159 | unsigned long _leftover_bits = (shift) % (sizeof(v) * CHAR_BIT - 1); \ | |
160 | \ | |
161 | for (; _nr_partial_shifts; _nr_partial_shifts--) \ | |
162 | (v) = _bt_rshift(v, sizeof(v) * CHAR_BIT - 1); \ | |
163 | (v) = _bt_rshift(v, _leftover_bits); \ | |
164 | } while (0) | |
165 | ||
166 | /* | |
167 | * Left shift a signed or unsigned integer with `shift` value being an | |
168 | * arbitrary number of bits. `v` is modified by this macro. The shift | |
169 | * is transformed into a sequence of `_nr_partial_shifts` consecutive | |
170 | * shift operations, each of a number of bits smaller than the bitwidth | |
171 | * of `v`, ending with a shift of the number of left over bits. | |
172 | */ | |
173 | #define _bt_safe_lshift(v, shift) \ | |
174 | do { \ | |
175 | unsigned long _nr_partial_shifts = (shift) / (sizeof(v) * CHAR_BIT - 1); \ | |
176 | unsigned long _leftover_bits = (shift) % (sizeof(v) * CHAR_BIT - 1); \ | |
177 | \ | |
178 | for (; _nr_partial_shifts; _nr_partial_shifts--) \ | |
179 | (v) = _bt_lshift(v, sizeof(v) * CHAR_BIT - 1); \ | |
180 | (v) = _bt_lshift(v, _leftover_bits); \ | |
181 | } while (0) | |
9e7f0924 MD |
182 | |
183 | /* | |
184 | * bt_bitfield_write - write integer to a bitfield in native endianness | |
185 | * | |
186 | * Save integer to the bitfield, which starts at the "start" bit, has "len" | |
187 | * bits. | |
188 | * The inside of a bitfield is from high bits to low bits. | |
189 | * Uses native endianness. | |
190 | * For unsigned "v", pad MSB with 0 if bitfield is larger than v. | |
191 | * For signed "v", sign-extend v if bitfield is larger than v. | |
192 | * | |
193 | * On little endian, bytes are placed from the less significant to the most | |
194 | * significant. Also, consecutive bitfields are placed from lower bits to higher | |
195 | * bits. | |
196 | * | |
197 | * On big endian, bytes are places from most significant to less significant. | |
198 | * Also, consecutive bitfields are placed from higher to lower bits. | |
199 | */ | |
200 | ||
2d6d0b43 | 201 | #define _bt_bitfield_write_le(ptr, type, start, length, v) \ |
9e7f0924 | 202 | do { \ |
2d6d0b43 MD |
203 | __typeof__(v) _v = (v); \ |
204 | type *_ptr = (void *) (ptr); \ | |
205 | unsigned long _start = (start), _length = (length); \ | |
206 | type _mask, _cmask; \ | |
207 | unsigned long _ts = sizeof(type) * CHAR_BIT; /* type size */ \ | |
208 | unsigned long _start_unit, _end_unit, _this_unit; \ | |
209 | unsigned long _end, _cshift; /* _cshift is "complement shift" */ \ | |
9e7f0924 | 210 | \ |
2d6d0b43 | 211 | if (!_length) \ |
9e7f0924 MD |
212 | break; \ |
213 | \ | |
2d6d0b43 MD |
214 | _end = _start + _length; \ |
215 | _start_unit = _start / _ts; \ | |
216 | _end_unit = (_end + (_ts - 1)) / _ts; \ | |
9e7f0924 MD |
217 | \ |
218 | /* Trim v high bits */ \ | |
2d6d0b43 MD |
219 | if (_length < sizeof(_v) * CHAR_BIT) \ |
220 | _v &= _bt_make_mask(__typeof__(_v), _length); \ | |
9e7f0924 MD |
221 | \ |
222 | /* We can now append v with a simple "or", shift it piece-wise */ \ | |
2d6d0b43 MD |
223 | _this_unit = _start_unit; \ |
224 | if (_start_unit == _end_unit - 1) { \ | |
225 | _mask = _bt_make_mask(type, _start % _ts); \ | |
226 | if (_end % _ts) \ | |
227 | _mask |= _bt_make_mask_complement(type, _end % _ts); \ | |
228 | _cmask = _bt_lshift((type) (_v), _start % _ts); \ | |
229 | _cmask &= ~_mask; \ | |
230 | _ptr[_this_unit] &= _mask; \ | |
231 | _ptr[_this_unit] |= _cmask; \ | |
9e7f0924 MD |
232 | break; \ |
233 | } \ | |
2d6d0b43 MD |
234 | if (_start % _ts) { \ |
235 | _cshift = _start % _ts; \ | |
236 | _mask = _bt_make_mask(type, _cshift); \ | |
237 | _cmask = _bt_lshift((type) (_v), _cshift); \ | |
238 | _cmask &= ~_mask; \ | |
239 | _ptr[_this_unit] &= _mask; \ | |
240 | _ptr[_this_unit] |= _cmask; \ | |
241 | _bt_safe_rshift(_v, _ts - _cshift); \ | |
242 | _start += _ts - _cshift; \ | |
243 | _this_unit++; \ | |
9e7f0924 | 244 | } \ |
2d6d0b43 MD |
245 | for (; _this_unit < _end_unit - 1; _this_unit++) { \ |
246 | _ptr[_this_unit] = (type) _v; \ | |
247 | _bt_safe_rshift(_v, _ts); \ | |
248 | _start += _ts; \ | |
9e7f0924 | 249 | } \ |
2d6d0b43 MD |
250 | if (_end % _ts) { \ |
251 | _mask = _bt_make_mask_complement(type, _end % _ts); \ | |
252 | _cmask = (type) _v; \ | |
253 | _cmask &= ~_mask; \ | |
254 | _ptr[_this_unit] &= _mask; \ | |
255 | _ptr[_this_unit] |= _cmask; \ | |
9e7f0924 | 256 | } else \ |
2d6d0b43 | 257 | _ptr[_this_unit] = (type) _v; \ |
9e7f0924 MD |
258 | } while (0) |
259 | ||
2d6d0b43 | 260 | #define _bt_bitfield_write_be(ptr, type, start, length, v) \ |
9e7f0924 | 261 | do { \ |
2d6d0b43 MD |
262 | __typeof__(v) _v = (v); \ |
263 | type *_ptr = (void *) (ptr); \ | |
264 | unsigned long _start = (start), _length = (length); \ | |
265 | type _mask, _cmask; \ | |
266 | unsigned long _ts = sizeof(type) * CHAR_BIT; /* type size */ \ | |
267 | unsigned long _start_unit, _end_unit, _this_unit; \ | |
268 | unsigned long _end, _cshift; /* _cshift is "complement shift" */ \ | |
9e7f0924 | 269 | \ |
2d6d0b43 | 270 | if (!_length) \ |
9e7f0924 MD |
271 | break; \ |
272 | \ | |
2d6d0b43 MD |
273 | _end = _start + _length; \ |
274 | _start_unit = _start / _ts; \ | |
275 | _end_unit = (_end + (_ts - 1)) / _ts; \ | |
9e7f0924 MD |
276 | \ |
277 | /* Trim v high bits */ \ | |
2d6d0b43 MD |
278 | if (_length < sizeof(_v) * CHAR_BIT) \ |
279 | _v &= _bt_make_mask(__typeof__(_v), _length); \ | |
9e7f0924 MD |
280 | \ |
281 | /* We can now append v with a simple "or", shift it piece-wise */ \ | |
2d6d0b43 MD |
282 | _this_unit = _end_unit - 1; \ |
283 | if (_start_unit == _end_unit - 1) { \ | |
284 | _mask = _bt_make_mask(type, (_ts - (_end % _ts)) % _ts); \ | |
285 | if (_start % _ts) \ | |
286 | _mask |= _bt_make_mask_complement(type, _ts - (_start % _ts)); \ | |
287 | _cmask = _bt_lshift((type) (_v), (_ts - (_end % _ts)) % _ts); \ | |
288 | _cmask &= ~_mask; \ | |
289 | _ptr[_this_unit] &= _mask; \ | |
290 | _ptr[_this_unit] |= _cmask; \ | |
9e7f0924 MD |
291 | break; \ |
292 | } \ | |
2d6d0b43 MD |
293 | if (_end % _ts) { \ |
294 | _cshift = _end % _ts; \ | |
295 | _mask = _bt_make_mask(type, _ts - _cshift); \ | |
296 | _cmask = _bt_lshift((type) (_v), _ts - _cshift); \ | |
297 | _cmask &= ~_mask; \ | |
298 | _ptr[_this_unit] &= _mask; \ | |
299 | _ptr[_this_unit] |= _cmask; \ | |
300 | _bt_safe_rshift(_v, _cshift); \ | |
301 | _end -= _cshift; \ | |
302 | _this_unit--; \ | |
9e7f0924 | 303 | } \ |
2d6d0b43 MD |
304 | for (; (long) _this_unit >= (long) _start_unit + 1; _this_unit--) { \ |
305 | _ptr[_this_unit] = (type) _v; \ | |
306 | _bt_safe_rshift(_v, _ts); \ | |
307 | _end -= _ts; \ | |
9e7f0924 | 308 | } \ |
2d6d0b43 MD |
309 | if (_start % _ts) { \ |
310 | _mask = _bt_make_mask_complement(type, _ts - (_start % _ts)); \ | |
311 | _cmask = (type) _v; \ | |
312 | _cmask &= ~_mask; \ | |
313 | _ptr[_this_unit] &= _mask; \ | |
314 | _ptr[_this_unit] |= _cmask; \ | |
9e7f0924 | 315 | } else \ |
2d6d0b43 | 316 | _ptr[_this_unit] = (type) _v; \ |
9e7f0924 MD |
317 | } while (0) |
318 | ||
319 | /* | |
320 | * bt_bitfield_write - write integer to a bitfield in native endianness | |
321 | * bt_bitfield_write_le - write integer to a bitfield in little endian | |
322 | * bt_bitfield_write_be - write integer to a bitfield in big endian | |
323 | */ | |
324 | ||
9f3fdbc6 | 325 | #if (BYTE_ORDER == LITTLE_ENDIAN) |
9e7f0924 | 326 | |
2d6d0b43 MD |
327 | #define bt_bitfield_write(ptr, type, start, length, v) \ |
328 | _bt_bitfield_write_le(ptr, type, start, length, v) | |
9e7f0924 | 329 | |
2d6d0b43 MD |
330 | #define bt_bitfield_write_le(ptr, type, start, length, v) \ |
331 | _bt_bitfield_write_le(ptr, type, start, length, v) | |
fa81c5df | 332 | |
2d6d0b43 MD |
333 | #define bt_bitfield_write_be(ptr, type, start, length, v) \ |
334 | _bt_bitfield_write_be(ptr, unsigned char, start, length, v) | |
9e7f0924 | 335 | |
9f3fdbc6 | 336 | #elif (BYTE_ORDER == BIG_ENDIAN) |
9e7f0924 | 337 | |
2d6d0b43 MD |
338 | #define bt_bitfield_write(ptr, type, start, length, v) \ |
339 | _bt_bitfield_write_be(ptr, type, start, length, v) | |
9e7f0924 | 340 | |
2d6d0b43 MD |
341 | #define bt_bitfield_write_le(ptr, type, start, length, v) \ |
342 | _bt_bitfield_write_le(ptr, unsigned char, start, length, v) | |
fa81c5df | 343 | |
2d6d0b43 MD |
344 | #define bt_bitfield_write_be(ptr, type, start, length, v) \ |
345 | _bt_bitfield_write_be(ptr, type, start, length, v) | |
9e7f0924 MD |
346 | |
347 | #else /* (BYTE_ORDER == PDP_ENDIAN) */ | |
348 | ||
349 | #error "Byte order not supported" | |
350 | ||
351 | #endif | |
352 | ||
2d6d0b43 | 353 | #define _bt_bitfield_read_le(ptr, type, start, length, vptr) \ |
9e7f0924 | 354 | do { \ |
2d6d0b43 MD |
355 | __typeof__(*(vptr)) *_vptr = (vptr); \ |
356 | __typeof__(*_vptr) _v; \ | |
357 | type *_ptr = (void *) (ptr); \ | |
358 | unsigned long _start = (start), _length = (length); \ | |
359 | type _mask, _cmask; \ | |
360 | unsigned long _ts = sizeof(type) * CHAR_BIT; /* type size */ \ | |
361 | unsigned long _start_unit, _end_unit, _this_unit; \ | |
362 | unsigned long _end, _cshift; /* _cshift is "complement shift" */ \ | |
9e7f0924 | 363 | \ |
2d6d0b43 MD |
364 | if (!_length) { \ |
365 | *_vptr = 0; \ | |
9e7f0924 MD |
366 | break; \ |
367 | } \ | |
368 | \ | |
2d6d0b43 MD |
369 | _end = _start + _length; \ |
370 | _start_unit = _start / _ts; \ | |
371 | _end_unit = (_end + (_ts - 1)) / _ts; \ | |
9e7f0924 | 372 | \ |
2d6d0b43 | 373 | _this_unit = _end_unit - 1; \ |
17ce2a4a | 374 | if (_bt_is_signed_type(__typeof__(_v)) \ |
2d6d0b43 MD |
375 | && (_ptr[_this_unit] & _bt_lshift((type) 1, (_end % _ts ? _end % _ts : _ts) - 1))) \ |
376 | _v = ~(__typeof__(_v)) 0; \ | |
9e7f0924 | 377 | else \ |
2d6d0b43 MD |
378 | _v = 0; \ |
379 | if (_start_unit == _end_unit - 1) { \ | |
380 | _cmask = _ptr[_this_unit]; \ | |
381 | _cmask = _bt_rshift(_cmask, _start % _ts); \ | |
382 | if ((_end - _start) % _ts) { \ | |
383 | _mask = _bt_make_mask(type, _end - _start); \ | |
384 | _cmask &= _mask; \ | |
9e7f0924 | 385 | } \ |
2d6d0b43 MD |
386 | _bt_safe_lshift(_v, _end - _start); \ |
387 | _v |= _bt_cast_value_to_unsigned_type(__typeof__(_v), _cmask); \ | |
388 | *_vptr = _v; \ | |
9e7f0924 MD |
389 | break; \ |
390 | } \ | |
2d6d0b43 MD |
391 | if (_end % _ts) { \ |
392 | _cshift = _end % _ts; \ | |
393 | _mask = _bt_make_mask(type, _cshift); \ | |
394 | _cmask = _ptr[_this_unit]; \ | |
395 | _cmask &= _mask; \ | |
396 | _bt_safe_lshift(_v, _cshift); \ | |
397 | _v |= _bt_cast_value_to_unsigned_type(__typeof__(_v), _cmask); \ | |
398 | _end -= _cshift; \ | |
399 | _this_unit--; \ | |
9e7f0924 | 400 | } \ |
2d6d0b43 MD |
401 | for (; (long) _this_unit >= (long) _start_unit + 1; _this_unit--) { \ |
402 | _bt_safe_lshift(_v, _ts); \ | |
403 | _v |= _bt_cast_value_to_unsigned_type(__typeof__(_v), _ptr[_this_unit]); \ | |
404 | _end -= _ts; \ | |
9e7f0924 | 405 | } \ |
2d6d0b43 MD |
406 | if (_start % _ts) { \ |
407 | _mask = _bt_make_mask(type, _ts - (_start % _ts)); \ | |
408 | _cmask = _ptr[_this_unit]; \ | |
409 | _cmask = _bt_rshift(_cmask, _start % _ts); \ | |
410 | _cmask &= _mask; \ | |
411 | _bt_safe_lshift(_v, _ts - (_start % _ts)); \ | |
412 | _v |= _bt_cast_value_to_unsigned_type(__typeof__(_v), _cmask); \ | |
9e7f0924 | 413 | } else { \ |
2d6d0b43 MD |
414 | _bt_safe_lshift(_v, _ts); \ |
415 | _v |= _bt_cast_value_to_unsigned_type(__typeof__(_v), _ptr[_this_unit]); \ | |
9e7f0924 | 416 | } \ |
2d6d0b43 | 417 | *_vptr = _v; \ |
9e7f0924 MD |
418 | } while (0) |
419 | ||
2d6d0b43 | 420 | #define _bt_bitfield_read_be(ptr, type, start, length, vptr) \ |
9e7f0924 | 421 | do { \ |
2d6d0b43 MD |
422 | __typeof__(*(vptr)) *_vptr = (vptr); \ |
423 | __typeof__(*_vptr) _v; \ | |
424 | type *_ptr = (void *) (ptr); \ | |
425 | unsigned long _start = (start), _length = (length); \ | |
426 | type _mask, _cmask; \ | |
427 | unsigned long _ts = sizeof(type) * CHAR_BIT; /* type size */ \ | |
428 | unsigned long _start_unit, _end_unit, _this_unit; \ | |
429 | unsigned long _end, _cshift; /* _cshift is "complement shift" */ \ | |
9e7f0924 | 430 | \ |
2d6d0b43 MD |
431 | if (!_length) { \ |
432 | *_vptr = 0; \ | |
9e7f0924 MD |
433 | break; \ |
434 | } \ | |
435 | \ | |
2d6d0b43 MD |
436 | _end = _start + _length; \ |
437 | _start_unit = _start / _ts; \ | |
438 | _end_unit = (_end + (_ts - 1)) / _ts; \ | |
9e7f0924 | 439 | \ |
2d6d0b43 | 440 | _this_unit = _start_unit; \ |
17ce2a4a | 441 | if (_bt_is_signed_type(__typeof__(_v)) \ |
2d6d0b43 MD |
442 | && (_ptr[_this_unit] & _bt_lshift((type) 1, _ts - (_start % _ts) - 1))) \ |
443 | _v = ~(__typeof__(_v)) 0; \ | |
9e7f0924 | 444 | else \ |
2d6d0b43 MD |
445 | _v = 0; \ |
446 | if (_start_unit == _end_unit - 1) { \ | |
447 | _cmask = _ptr[_this_unit]; \ | |
448 | _cmask = _bt_rshift(_cmask, (_ts - (_end % _ts)) % _ts); \ | |
449 | if ((_end - _start) % _ts) { \ | |
450 | _mask = _bt_make_mask(type, _end - _start); \ | |
451 | _cmask &= _mask; \ | |
9e7f0924 | 452 | } \ |
2d6d0b43 MD |
453 | _bt_safe_lshift(_v, _end - _start); \ |
454 | _v |= _bt_cast_value_to_unsigned_type(__typeof__(_v), _cmask); \ | |
455 | *_vptr = _v; \ | |
9e7f0924 MD |
456 | break; \ |
457 | } \ | |
2d6d0b43 MD |
458 | if (_start % _ts) { \ |
459 | _cshift = _start % _ts; \ | |
460 | _mask = _bt_make_mask(type, _ts - _cshift); \ | |
461 | _cmask = _ptr[_this_unit]; \ | |
462 | _cmask &= _mask; \ | |
463 | _bt_safe_lshift(_v, _ts - _cshift); \ | |
464 | _v |= _bt_cast_value_to_unsigned_type(__typeof__(_v), _cmask); \ | |
465 | _start += _ts - _cshift; \ | |
466 | _this_unit++; \ | |
9e7f0924 | 467 | } \ |
2d6d0b43 MD |
468 | for (; _this_unit < _end_unit - 1; _this_unit++) { \ |
469 | _bt_safe_lshift(_v, _ts); \ | |
470 | _v |= _bt_cast_value_to_unsigned_type(__typeof__(_v), _ptr[_this_unit]); \ | |
471 | _start += _ts; \ | |
9e7f0924 | 472 | } \ |
2d6d0b43 MD |
473 | if (_end % _ts) { \ |
474 | _mask = _bt_make_mask(type, _end % _ts); \ | |
475 | _cmask = _ptr[_this_unit]; \ | |
476 | _cmask = _bt_rshift(_cmask, _ts - (_end % _ts)); \ | |
477 | _cmask &= _mask; \ | |
478 | _bt_safe_lshift(_v, _end % _ts); \ | |
479 | _v |= _bt_cast_value_to_unsigned_type(__typeof__(_v), _cmask); \ | |
9e7f0924 | 480 | } else { \ |
2d6d0b43 MD |
481 | _bt_safe_lshift(_v, _ts); \ |
482 | _v |= _bt_cast_value_to_unsigned_type(__typeof__(_v), _ptr[_this_unit]); \ | |
9e7f0924 | 483 | } \ |
2d6d0b43 | 484 | *_vptr = _v; \ |
9e7f0924 MD |
485 | } while (0) |
486 | ||
487 | /* | |
488 | * bt_bitfield_read - read integer from a bitfield in native endianness | |
489 | * bt_bitfield_read_le - read integer from a bitfield in little endian | |
490 | * bt_bitfield_read_be - read integer from a bitfield in big endian | |
491 | */ | |
492 | ||
9f3fdbc6 | 493 | #if (BYTE_ORDER == LITTLE_ENDIAN) |
9e7f0924 | 494 | |
2d6d0b43 MD |
495 | #define bt_bitfield_read(ptr, type, start, length, vptr) \ |
496 | _bt_bitfield_read_le(ptr, type, start, length, vptr) | |
9e7f0924 | 497 | |
2d6d0b43 MD |
498 | #define bt_bitfield_read_le(ptr, type, start, length, vptr) \ |
499 | _bt_bitfield_read_le(ptr, type, start, length, vptr) | |
fa81c5df | 500 | |
2d6d0b43 MD |
501 | #define bt_bitfield_read_be(ptr, type, start, length, vptr) \ |
502 | _bt_bitfield_read_be(ptr, unsigned char, start, length, vptr) | |
9e7f0924 | 503 | |
9f3fdbc6 | 504 | #elif (BYTE_ORDER == BIG_ENDIAN) |
9e7f0924 | 505 | |
2d6d0b43 MD |
506 | #define bt_bitfield_read(ptr, type, start, length, vptr) \ |
507 | _bt_bitfield_read_be(ptr, type, start, length, vptr) | |
9e7f0924 | 508 | |
2d6d0b43 MD |
509 | #define bt_bitfield_read_le(ptr, type, start, length, vptr) \ |
510 | _bt_bitfield_read_le(ptr, unsigned char, start, length, vptr) | |
fa81c5df | 511 | |
2d6d0b43 MD |
512 | #define bt_bitfield_read_be(ptr, type, start, length, vptr) \ |
513 | _bt_bitfield_read_be(ptr, type, start, length, vptr) | |
9e7f0924 | 514 | |
9f3fdbc6 | 515 | #else /* (BYTE_ORDER == PDP_ENDIAN) */ |
9e7f0924 MD |
516 | |
517 | #error "Byte order not supported" | |
518 | ||
519 | #endif | |
520 | ||
521 | #endif /* _BABELTRACE_BITFIELD_H */ |