1 | /* |
2 | * Copyright (c) 2015-2016, Intel Corporation |
3 | * |
4 | * Redistribution and use in source and binary forms, with or without |
5 | * modification, are permitted provided that the following conditions are met: |
6 | * |
7 | * * Redistributions of source code must retain the above copyright notice, |
8 | * this list of conditions and the following disclaimer. |
9 | * * Redistributions in binary form must reproduce the above copyright |
10 | * notice, this list of conditions and the following disclaimer in the |
11 | * documentation and/or other materials provided with the distribution. |
12 | * * Neither the name of Intel Corporation nor the names of its contributors |
13 | * may be used to endorse or promote products derived from this software |
14 | * without specific prior written permission. |
15 | * |
16 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
17 | * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
18 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
19 | * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
20 | * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
21 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
22 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
23 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
24 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
25 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
26 | * POSSIBILITY OF SUCH DAMAGE. |
27 | */ |
28 | |
29 | /** \file |
30 | * \brief Bounded repeat compile-time code. |
31 | */ |
32 | #include "repeatcompile.h" |
33 | #include "util/bitutils.h" |
34 | #include "util/charreach.h" |
35 | #include "util/depth.h" |
36 | #include "util/dump_charclass.h" |
37 | #include "util/multibit_build.h" |
38 | #include "util/verify_types.h" |
39 | |
40 | #include <algorithm> |
41 | #include <cstring> // memset |
42 | #include <utility> |
43 | |
44 | using namespace std; |
45 | |
46 | namespace ue2 { |
47 | |
48 | /** \brief Calculate the number of slots required to store the given repeat in |
49 | * a RANGE model. */ |
50 | static |
51 | u32 numRangeSlots(u32 repeatMin, u32 repeatMax) { |
52 | assert(repeatMax > repeatMin); |
53 | |
54 | u32 d = repeatMax - repeatMin; |
55 | u32 slots = 2 * ((repeatMax / d) + 1); |
56 | return slots; |
57 | } |
58 | |
59 | static |
60 | u32 calcPackedBits(u64a val) { |
61 | assert(val); |
62 | if (val <= 1) { |
63 | return 1; |
64 | } |
65 | u32 bits = lg2_64(val - 1) + 1U; /* lg2 rounds down */ |
66 | DEBUG_PRINTF("packing %llu into %u bits\n" , val, bits); |
67 | return bits; |
68 | } |
69 | |
70 | /* returns the min number of bytes required to represent val options */ |
71 | u32 calcPackedBytes(u64a val) { |
72 | u32 rv = (calcPackedBits(val) + 7U) / 8U; |
73 | DEBUG_PRINTF("packing %llu into %u bytes\n" , val, rv); |
74 | return rv; |
75 | } |
76 | |
77 | static |
78 | u32 repeatRecurTable(struct RepeatStateInfo *info, const depth &repeatMax, |
79 | const u32 minPeriod) { |
80 | u32 repeatTmp = info->patchCount > 2 ? 64 : (u32)repeatMax; |
81 | u32 repeat_index = repeatTmp < minPeriod ? repeatTmp : minPeriod; |
82 | for (u32 i = 0; i <= repeat_index; i++) { |
83 | info->table.push_back(i + 1); |
84 | } |
85 | for (u32 i = minPeriod + 1; i <= repeatTmp; i++) { |
86 | info->table.push_back(info->table[i - 1] + info->table[i - minPeriod]); |
87 | if (info->table[i] < info->table[i - 1]) { |
88 | return i - 1; |
89 | } |
90 | } |
91 | return 0; |
92 | } |
93 | |
94 | static |
95 | u32 findOptimalPatchSize(struct RepeatStateInfo *info, const depth &repeatMax, |
96 | const u32 minPeriod, u32 rv) { |
97 | u32 cnt = 0; |
98 | u32 patch_bits = 0; |
99 | u32 total_size = 0; |
100 | u32 min = ~0U; |
101 | u32 patch_len = 0; |
102 | |
103 | if (!rv) { |
104 | rv = repeatMax; |
105 | } |
106 | |
107 | for (u32 i = minPeriod; i <= rv; i++) { |
108 | cnt = ((u32)repeatMax + (i - 1)) / i + 1; |
109 | |
110 | // no bit packing version |
111 | patch_bits = calcPackedBits(info->table[i]); |
112 | total_size = (patch_bits + 7U) / 8U * cnt; |
113 | |
114 | if (total_size < min) { |
115 | patch_len = i; |
116 | min = total_size; |
117 | info->patchCount = cnt; |
118 | } |
119 | } |
120 | return patch_len; |
121 | } |
122 | |
123 | RepeatStateInfo::RepeatStateInfo(enum RepeatType type, const depth &repeatMin, |
124 | const depth &repeatMax, u32 minPeriod) |
125 | : stateSize(0), packedCtrlSize(0), horizon(0), patchCount(0), |
126 | patchSize(0), encodingSize(0), patchesOffset(0) { |
127 | assert(repeatMin <= repeatMax); |
128 | assert(repeatMax.is_reachable()); |
129 | assert(minPeriod || type != REPEAT_SPARSE_OPTIMAL_P); |
130 | |
131 | switch (type) { |
132 | case REPEAT_FIRST: |
133 | assert(repeatMin.is_finite()); |
134 | stateSize = 0; // everything is in the control block. |
135 | horizon = repeatMin; |
136 | packedCtrlSize = calcPackedBytes(horizon + 1); |
137 | break; |
138 | case REPEAT_LAST: |
139 | assert(repeatMax.is_finite()); |
140 | stateSize = 0; // everything is in the control block. |
141 | horizon = repeatMax + 1; |
142 | packedCtrlSize = calcPackedBytes(horizon + 1); |
143 | break; |
144 | case REPEAT_RING: |
145 | assert(repeatMax.is_finite()); |
146 | stateSize = mmbit_size(repeatMax + 1); |
147 | horizon = repeatMax * 2 + 1; /* TODO: investigate tightening */ |
148 | // Packed offset member, plus two bytes for each ring index, reduced to |
149 | // one byte each if they'll fit in eight bits. |
150 | { |
151 | u32 offset_len = calcPackedBytes(horizon + 1); |
152 | u32 ring_indices_len = repeatMax < depth(254) ? 2 : 4; |
153 | packedCtrlSize = offset_len + ring_indices_len; |
154 | } |
155 | break; |
156 | case REPEAT_RANGE: |
157 | assert(repeatMax.is_finite()); |
158 | assert(repeatMin < repeatMax); |
159 | stateSize = numRangeSlots(repeatMin, repeatMax) * sizeof(u16); |
160 | horizon = repeatMax * 2 + 1; |
161 | // Packed offset member, plus one byte for the number of range |
162 | // elements. |
163 | packedCtrlSize = calcPackedBytes(horizon + 1) + 1; |
164 | break; |
165 | case REPEAT_BITMAP: |
166 | stateSize = 0; // everything is in the control block. |
167 | horizon = 0; // unused |
168 | packedCtrlSize = ROUNDUP_N(repeatMax + 1, 8) / 8; |
169 | break; |
170 | case REPEAT_SPARSE_OPTIMAL_P: |
171 | assert(minPeriod); |
172 | assert(repeatMax.is_finite()); |
173 | { |
174 | u32 rv = repeatRecurTable(this, repeatMax, minPeriod); |
175 | u32 repeatTmp = 0; |
176 | if ((u32)repeatMax < minPeriod) { |
177 | repeatTmp = repeatMax; |
178 | patchCount = 1; |
179 | } else { |
180 | // find optimal patch size |
181 | repeatTmp = |
182 | findOptimalPatchSize(this, repeatMax, minPeriod, rv); |
183 | assert(patchCount < 65536); |
184 | } |
185 | DEBUG_PRINTF("repeat[%u %u], period=%u\n" , (u32)repeatMin, |
186 | (u32)repeatMax, minPeriod); |
187 | u64a maxVal = table[repeatTmp]; |
188 | encodingSize = calcPackedBytes(maxVal); |
189 | patchSize = repeatTmp; |
190 | assert(encodingSize <= 64); |
191 | |
192 | patchesOffset = mmbit_size(patchCount); |
193 | stateSize = patchesOffset + encodingSize * patchCount; |
194 | horizon = (repeatTmp * patchCount) * 2 + 1; |
195 | u32 ring_indices_len = patchCount < depth(254) ? 2 : 4; |
196 | packedCtrlSize = calcPackedBytes(horizon + 1) + ring_indices_len; |
197 | } |
198 | break; |
199 | case REPEAT_TRAILER: |
200 | assert(repeatMax.is_finite()); |
201 | assert(repeatMin <= depth(64)); |
202 | stateSize = 0; // everything is in the control block. |
203 | horizon = repeatMax + 1; |
204 | packedFieldSizes.resize(2); |
205 | packedFieldSizes[0] = calcPackedBits(horizon + 1); |
206 | packedFieldSizes[1] = repeatMin; |
207 | packedCtrlSize = (packedFieldSizes[0] + packedFieldSizes[1] + 7U) / 8U; |
208 | break; |
209 | case REPEAT_ALWAYS: |
210 | assert(repeatMin == 0ULL); |
211 | assert(repeatMax.is_infinite()); |
212 | stateSize = 0; // everything is in the control block. |
213 | horizon = 0; |
214 | packedCtrlSize = 0; |
215 | break; |
216 | } |
217 | DEBUG_PRINTF("stateSize=%u, packedCtrlSize=%u, horizon=%u\n" , stateSize, |
218 | packedCtrlSize, horizon); |
219 | |
220 | assert(packedCtrlSize <= sizeof(RepeatControl)); |
221 | } |
222 | |
223 | /** \brief Returns the packed control block size in bytes for a given bounded |
224 | * repeat. */ |
225 | static |
226 | u32 packedSize(enum RepeatType type, const depth &repeatMin, |
227 | const depth &repeatMax, u32 minPeriod) { |
228 | RepeatStateInfo rsi(type, repeatMin, repeatMax, minPeriod); |
229 | return rsi.packedCtrlSize; |
230 | } |
231 | |
232 | /** \brief Returns the stream state size in bytes for a given bounded |
233 | * repeat. */ |
234 | static |
235 | u32 streamStateSize(enum RepeatType type, const depth &repeatMin, |
236 | const depth &repeatMax, u32 minPeriod) { |
237 | RepeatStateInfo rsi(type, repeatMin, repeatMax, minPeriod); |
238 | return rsi.stateSize; |
239 | } |
240 | |
241 | enum RepeatType chooseRepeatType(const depth &repeatMin, const depth &repeatMax, |
242 | u32 minPeriod, bool is_reset, |
243 | bool has_external_guard) { |
244 | if (repeatMax.is_infinite()) { |
245 | if (has_external_guard && !repeatMin) { |
246 | return REPEAT_ALWAYS; |
247 | } else { |
248 | return REPEAT_FIRST; |
249 | } |
250 | } |
251 | |
252 | if (repeatMin == depth(0) || is_reset) { |
253 | return REPEAT_LAST; |
254 | } |
255 | |
256 | // Cases with max < 64 can be handled with either bitmap or trailer. We use |
257 | // whichever has smaller packed state. |
258 | |
259 | if (repeatMax < depth(64)) { |
260 | u32 bitmap_len = |
261 | packedSize(REPEAT_BITMAP, repeatMin, repeatMax, minPeriod); |
262 | u32 trailer_len = |
263 | packedSize(REPEAT_TRAILER, repeatMin, repeatMax, minPeriod); |
264 | return bitmap_len <= trailer_len ? REPEAT_BITMAP : REPEAT_TRAILER; |
265 | } |
266 | |
267 | if (repeatMin <= depth(64)) { |
268 | return REPEAT_TRAILER; |
269 | } |
270 | |
271 | u32 range_len = ~0U; |
272 | if (repeatMax > repeatMin && |
273 | numRangeSlots(repeatMin, repeatMax) <= REPEAT_RANGE_MAX_SLOTS) { |
274 | assert(numRangeSlots(repeatMin, repeatMax) < 256); // stored in u8 |
275 | range_len = |
276 | streamStateSize(REPEAT_RANGE, repeatMin, repeatMax, minPeriod); |
277 | } |
278 | |
279 | assert(repeatMax.is_finite()); |
280 | |
281 | u32 sparse_len = ~0U; |
282 | if (minPeriod > 6) { |
283 | sparse_len = |
284 | streamStateSize(REPEAT_SPARSE_OPTIMAL_P, repeatMin, repeatMax, minPeriod); |
285 | } |
286 | |
287 | if (range_len != ~0U || sparse_len != ~0U) { |
288 | return range_len < sparse_len ? REPEAT_RANGE : REPEAT_SPARSE_OPTIMAL_P; |
289 | } |
290 | |
291 | return REPEAT_RING; |
292 | } |
293 | |
294 | bool matches(vector<CharReach>::const_iterator a_it, |
295 | vector<CharReach>::const_iterator a_ite, |
296 | vector<CharReach>::const_iterator b_it, |
297 | UNUSED vector<CharReach>::const_iterator b_ite) { |
298 | for (; a_it != a_ite; ++a_it, ++b_it) { |
299 | assert(b_it != b_ite); |
300 | if ((*a_it & *b_it).none()) { |
301 | return false; |
302 | } |
303 | } |
304 | assert(b_it == b_ite); |
305 | return true; |
306 | } |
307 | |
308 | static |
309 | u32 minDistAfterA(const vector<CharReach> &a, const vector<CharReach> &b) { |
310 | /* we do not count the case where b can end at the same position as a */ |
311 | |
312 | for (u32 i = 1; i < b.size(); i++) { |
313 | u32 overlap_len = b.size() - i; |
314 | if (overlap_len <= a.size()) { |
315 | if (matches(a.end() - overlap_len, a.end(), |
316 | b.begin(), b.end() - i)) { |
317 | return i; |
318 | } |
319 | } else { |
320 | assert(overlap_len > a.size()); |
321 | if (matches(a.begin(), a.end(), |
322 | b.end() - i - a.size(), b.end() - i)) { |
323 | return i; |
324 | } |
325 | } |
326 | } |
327 | |
328 | return b.size(); |
329 | } |
330 | |
331 | vector<size_t> minResetDistToEnd(const vector<vector<CharReach>> &triggers, |
332 | const CharReach &cr) { |
333 | /* if a trigger does not reset the repeat, it gets a distance of trigger |
334 | length */ |
335 | vector<size_t> out; |
336 | for (const auto &trig : triggers) { |
337 | size_t size = trig.size(); |
338 | size_t i = 0; |
339 | for (; i < size; i++) { |
340 | if ((trig[size - i - 1] & cr).none()) { |
341 | break; |
342 | } |
343 | } |
344 | out.push_back(i); |
345 | } |
346 | |
347 | return out; |
348 | } |
349 | |
350 | #if defined(DEBUG) || defined(DUMP_SUPPORT) |
351 | |
352 | static UNUSED |
353 | string dumpTrigger(const vector<CharReach> &trigger) { |
354 | string s; |
355 | for (const auto &cr : trigger) { |
356 | s += describeClass(cr); |
357 | } |
358 | return s; |
359 | } |
360 | |
361 | #endif |
362 | |
363 | u32 minPeriod(const vector<vector<CharReach>> &triggers, const CharReach &cr, |
364 | bool *can_reset) { |
365 | assert(!triggers.empty()); |
366 | |
367 | u32 rv = ~0U; |
368 | *can_reset = true; |
369 | vector<size_t> min_reset_dist = minResetDistToEnd(triggers, cr); |
370 | |
371 | for (const auto &trigger : triggers) { |
372 | DEBUG_PRINTF("trigger: %s\n" , dumpTrigger(trigger).c_str()); |
373 | for (size_t j = 0; j < triggers.size(); j++) { |
374 | u32 min_ext = minDistAfterA(trigger, triggers[j]); |
375 | rv = min(rv, min_ext); |
376 | if (min_ext <= min_reset_dist[j]) { |
377 | *can_reset = false; |
378 | } |
379 | } |
380 | } |
381 | |
382 | DEBUG_PRINTF("min period %u\n" , rv); |
383 | return rv; |
384 | } |
385 | |
386 | } // namespace ue2 |
387 | |