]> git.proxmox.com Git - mirror_edk2.git/blame - BaseTools/Source/C/BrotliCompress/enc/hash_longest_match_inc.h
BaseTools: Update Brotli Compress to the latest one 1.0.6
[mirror_edk2.git] / BaseTools / Source / C / BrotliCompress / enc / hash_longest_match_inc.h
CommitLineData
11b7501a
SB
1/* NOLINT(build/header_guard) */\r
2/* Copyright 2010 Google Inc. All Rights Reserved.\r
3\r
4 Distributed under MIT license.\r
5 See file LICENSE for detail or copy at https://opensource.org/licenses/MIT\r
6*/\r
7\r
dd4f667e 8/* template parameters: FN */\r
11b7501a
SB
9\r
10/* A (forgetful) hash table to the data seen by the compressor, to\r
11 help create backward references to previous data.\r
12\r
dd4f667e
LG
13 This is a hash map of fixed size (bucket_size_) to a ring buffer of\r
14 fixed size (block_size_). The ring buffer contains the last block_size_\r
11b7501a
SB
15 index positions of the given hash key in the compressed data. */\r
16\r
17#define HashLongestMatch HASHER()\r
18\r
11b7501a
SB
19static BROTLI_INLINE size_t FN(HashTypeLength)(void) { return 4; }\r
20static BROTLI_INLINE size_t FN(StoreLookahead)(void) { return 4; }\r
21\r
dd4f667e
LG
22/* HashBytes is the function that chooses the bucket to place the address in. */\r
23static uint32_t FN(HashBytes)(const uint8_t* data, const int shift) {\r
24 uint32_t h = BROTLI_UNALIGNED_LOAD32LE(data) * kHashMul32;\r
11b7501a
SB
25 /* The higher bits contain more mixture from the multiplication,\r
26 so we take our results from there. */\r
dd4f667e 27 return (uint32_t)(h >> shift);\r
11b7501a
SB
28}\r
29\r
30typedef struct HashLongestMatch {\r
dd4f667e
LG
31 /* Number of hash buckets. */\r
32 size_t bucket_size_;\r
33 /* Only block_size_ newest backward references are kept,\r
34 and the older are forgotten. */\r
35 size_t block_size_;\r
36 /* Left-shift for computing hash bucket index from hash value. */\r
37 int hash_shift_;\r
38 /* Mask for accessing entries in a block (in a ring-buffer manner). */\r
39 uint32_t block_mask_;\r
11b7501a 40\r
dd4f667e 41 /* --- Dynamic size members --- */\r
11b7501a 42\r
dd4f667e
LG
43 /* Number of entries in a particular bucket. */\r
44 /* uint16_t num[bucket_size]; */\r
11b7501a 45\r
dd4f667e
LG
46 /* Buckets containing block_size_ of backward references. */\r
47 /* uint32_t* buckets[bucket_size * block_size]; */\r
11b7501a
SB
48} HashLongestMatch;\r
49\r
dd4f667e
LG
50static BROTLI_INLINE HashLongestMatch* FN(Self)(HasherHandle handle) {\r
51 return (HashLongestMatch*)&(GetHasherCommon(handle)[1]);\r
11b7501a
SB
52}\r
53\r
dd4f667e
LG
54static BROTLI_INLINE uint16_t* FN(Num)(HashLongestMatch* self) {\r
55 return (uint16_t*)(&self[1]);\r
11b7501a
SB
56}\r
57\r
dd4f667e
LG
58static BROTLI_INLINE uint32_t* FN(Buckets)(HashLongestMatch* self) {\r
59 return (uint32_t*)(&FN(Num)(self)[self->bucket_size_]);\r
11b7501a
SB
60}\r
61\r
dd4f667e
LG
62static void FN(Initialize)(\r
63 HasherHandle handle, const BrotliEncoderParams* params) {\r
64 HasherCommon* common = GetHasherCommon(handle);\r
65 HashLongestMatch* self = FN(Self)(handle);\r
11b7501a 66 BROTLI_UNUSED(params);\r
dd4f667e
LG
67 self->hash_shift_ = 32 - common->params.bucket_bits;\r
68 self->bucket_size_ = (size_t)1 << common->params.bucket_bits;\r
69 self->block_size_ = (size_t)1 << common->params.block_bits;\r
70 self->block_mask_ = (uint32_t)(self->block_size_ - 1);\r
71}\r
72\r
73static void FN(Prepare)(HasherHandle handle, BROTLI_BOOL one_shot,\r
74 size_t input_size, const uint8_t* data) {\r
75 HashLongestMatch* self = FN(Self)(handle);\r
76 uint16_t* num = FN(Num)(self);\r
77 /* Partial preparation is 100 times slower (per socket). */\r
78 size_t partial_prepare_threshold = self->bucket_size_ >> 6;\r
79 if (one_shot && input_size <= partial_prepare_threshold) {\r
80 size_t i;\r
81 for (i = 0; i < input_size; ++i) {\r
82 const uint32_t key = FN(HashBytes)(&data[i], self->hash_shift_);\r
83 num[key] = 0;\r
84 }\r
11b7501a 85 } else {\r
dd4f667e 86 memset(num, 0, self->bucket_size_ * sizeof(num[0]));\r
11b7501a
SB
87 }\r
88}\r
89\r
dd4f667e
LG
90static BROTLI_INLINE size_t FN(HashMemAllocInBytes)(\r
91 const BrotliEncoderParams* params, BROTLI_BOOL one_shot,\r
92 size_t input_size) {\r
93 size_t bucket_size = (size_t)1 << params->hasher.bucket_bits;\r
94 size_t block_size = (size_t)1 << params->hasher.block_bits;\r
95 BROTLI_UNUSED(one_shot);\r
96 BROTLI_UNUSED(input_size);\r
97 return sizeof(HashLongestMatch) + bucket_size * (2 + 4 * block_size);\r
98}\r
99\r
11b7501a
SB
100/* Look at 4 bytes at &data[ix & mask].\r
101 Compute a hash from these, and store the value of ix at that position. */\r
dd4f667e 102static BROTLI_INLINE void FN(Store)(HasherHandle handle, const uint8_t* data,\r
11b7501a 103 const size_t mask, const size_t ix) {\r
dd4f667e
LG
104 HashLongestMatch* self = FN(Self)(handle);\r
105 uint16_t* num = FN(Num)(self);\r
106 const uint32_t key = FN(HashBytes)(&data[ix & mask], self->hash_shift_);\r
107 const size_t minor_ix = num[key] & self->block_mask_;\r
108 const size_t offset =\r
109 minor_ix + (key << GetHasherCommon(handle)->params.block_bits);\r
110 FN(Buckets)(self)[offset] = (uint32_t)ix;\r
111 ++num[key];\r
11b7501a
SB
112}\r
113\r
dd4f667e
LG
114static BROTLI_INLINE void FN(StoreRange)(HasherHandle handle,\r
115 const uint8_t* data, const size_t mask, const size_t ix_start,\r
11b7501a
SB
116 const size_t ix_end) {\r
117 size_t i;\r
118 for (i = ix_start; i < ix_end; ++i) {\r
dd4f667e 119 FN(Store)(handle, data, mask, i);\r
11b7501a
SB
120 }\r
121}\r
122\r
dd4f667e 123static BROTLI_INLINE void FN(StitchToPreviousBlock)(HasherHandle handle,\r
11b7501a
SB
124 size_t num_bytes, size_t position, const uint8_t* ringbuffer,\r
125 size_t ringbuffer_mask) {\r
126 if (num_bytes >= FN(HashTypeLength)() - 1 && position >= 3) {\r
127 /* Prepare the hashes for three last bytes of the last write.\r
128 These could not be calculated before, since they require knowledge\r
129 of both the previous and the current block. */\r
dd4f667e
LG
130 FN(Store)(handle, ringbuffer, ringbuffer_mask, position - 3);\r
131 FN(Store)(handle, ringbuffer, ringbuffer_mask, position - 2);\r
132 FN(Store)(handle, ringbuffer, ringbuffer_mask, position - 1);\r
11b7501a
SB
133 }\r
134}\r
135\r
dd4f667e
LG
136static BROTLI_INLINE void FN(PrepareDistanceCache)(\r
137 HasherHandle handle, int* BROTLI_RESTRICT distance_cache) {\r
138 PrepareDistanceCache(distance_cache,\r
139 GetHasherCommon(handle)->params.num_last_distances_to_check);\r
140}\r
141\r
11b7501a
SB
142/* Find a longest backward match of &data[cur_ix] up to the length of\r
143 max_length and stores the position cur_ix in the hash table.\r
144\r
dd4f667e
LG
145 REQUIRES: FN(PrepareDistanceCache) must be invoked for current distance cache\r
146 values; if this method is invoked repeatedly with the same distance\r
147 cache values, it is enough to invoke FN(PrepareDistanceCache) once.\r
148\r
11b7501a
SB
149 Does not look for matches longer than max_length.\r
150 Does not look for matches further away than max_backward.\r
151 Writes the best match into |out|.\r
dd4f667e
LG
152 |out|->score is updated only if a better match is found. */\r
153static BROTLI_INLINE void FN(FindLongestMatch)(HasherHandle handle,\r
154 const BrotliEncoderDictionary* dictionary,\r
11b7501a
SB
155 const uint8_t* BROTLI_RESTRICT data, const size_t ring_buffer_mask,\r
156 const int* BROTLI_RESTRICT distance_cache, const size_t cur_ix,\r
dd4f667e
LG
157 const size_t max_length, const size_t max_backward, const size_t gap,\r
158 const size_t max_distance, HasherSearchResult* BROTLI_RESTRICT out) {\r
159 HasherCommon* common = GetHasherCommon(handle);\r
160 HashLongestMatch* self = FN(Self)(handle);\r
161 uint16_t* num = FN(Num)(self);\r
162 uint32_t* buckets = FN(Buckets)(self);\r
11b7501a 163 const size_t cur_ix_masked = cur_ix & ring_buffer_mask;\r
11b7501a 164 /* Don't accept a short copy from far away. */\r
dd4f667e 165 score_t min_score = out->score;\r
11b7501a
SB
166 score_t best_score = out->score;\r
167 size_t best_len = out->len;\r
168 size_t i;\r
169 out->len = 0;\r
dd4f667e 170 out->len_code_delta = 0;\r
11b7501a 171 /* Try last distance first. */\r
dd4f667e
LG
172 for (i = 0; i < (size_t)common->params.num_last_distances_to_check; ++i) {\r
173 const size_t backward = (size_t)distance_cache[i];\r
11b7501a
SB
174 size_t prev_ix = (size_t)(cur_ix - backward);\r
175 if (prev_ix >= cur_ix) {\r
176 continue;\r
177 }\r
dd4f667e 178 if (BROTLI_PREDICT_FALSE(backward > max_backward)) {\r
11b7501a
SB
179 continue;\r
180 }\r
181 prev_ix &= ring_buffer_mask;\r
182\r
183 if (cur_ix_masked + best_len > ring_buffer_mask ||\r
184 prev_ix + best_len > ring_buffer_mask ||\r
185 data[cur_ix_masked + best_len] != data[prev_ix + best_len]) {\r
186 continue;\r
187 }\r
188 {\r
189 const size_t len = FindMatchLengthWithLimit(&data[prev_ix],\r
190 &data[cur_ix_masked],\r
191 max_length);\r
192 if (len >= 3 || (len == 2 && i < 2)) {\r
193 /* Comparing for >= 2 does not change the semantics, but just saves for\r
194 a few unnecessary binary logarithms in backward reference score,\r
195 since we are not interested in such short matches. */\r
dd4f667e 196 score_t score = BackwardReferenceScoreUsingLastDistance(len);\r
11b7501a 197 if (best_score < score) {\r
dd4f667e
LG
198 if (i != 0) score -= BackwardReferencePenaltyUsingLastDistance(i);\r
199 if (best_score < score) {\r
200 best_score = score;\r
201 best_len = len;\r
202 out->len = best_len;\r
203 out->distance = backward;\r
204 out->score = best_score;\r
205 }\r
11b7501a
SB
206 }\r
207 }\r
208 }\r
209 }\r
210 {\r
dd4f667e
LG
211 const uint32_t key =\r
212 FN(HashBytes)(&data[cur_ix_masked], self->hash_shift_);\r
213 uint32_t* BROTLI_RESTRICT bucket =\r
214 &buckets[key << common->params.block_bits];\r
11b7501a 215 const size_t down =\r
dd4f667e
LG
216 (num[key] > self->block_size_) ? (num[key] - self->block_size_) : 0u;\r
217 for (i = num[key]; i > down;) {\r
218 size_t prev_ix = bucket[--i & self->block_mask_];\r
11b7501a 219 const size_t backward = cur_ix - prev_ix;\r
dd4f667e 220 if (BROTLI_PREDICT_FALSE(backward > max_backward)) {\r
11b7501a
SB
221 break;\r
222 }\r
223 prev_ix &= ring_buffer_mask;\r
224 if (cur_ix_masked + best_len > ring_buffer_mask ||\r
225 prev_ix + best_len > ring_buffer_mask ||\r
226 data[cur_ix_masked + best_len] != data[prev_ix + best_len]) {\r
227 continue;\r
228 }\r
229 {\r
230 const size_t len = FindMatchLengthWithLimit(&data[prev_ix],\r
231 &data[cur_ix_masked],\r
232 max_length);\r
233 if (len >= 4) {\r
234 /* Comparing for >= 3 does not change the semantics, but just saves\r
235 for a few unnecessary binary logarithms in backward reference\r
236 score, since we are not interested in such short matches. */\r
237 score_t score = BackwardReferenceScore(len, backward);\r
238 if (best_score < score) {\r
239 best_score = score;\r
240 best_len = len;\r
241 out->len = best_len;\r
242 out->distance = backward;\r
243 out->score = best_score;\r
11b7501a
SB
244 }\r
245 }\r
246 }\r
247 }\r
dd4f667e
LG
248 bucket[num[key] & self->block_mask_] = (uint32_t)cur_ix;\r
249 ++num[key];\r
11b7501a 250 }\r
dd4f667e
LG
251 if (min_score == out->score) {\r
252 SearchInStaticDictionary(dictionary,\r
253 handle, &data[cur_ix_masked], max_length, max_backward + gap,\r
254 max_distance, out, BROTLI_FALSE);\r
11b7501a 255 }\r
11b7501a
SB
256}\r
257\r
11b7501a 258#undef HashLongestMatch\r