648db22b |
1 | /* |
2 | * Copyright (c) Meta Platforms, Inc. and affiliates. |
3 | * All rights reserved. |
4 | * |
5 | * This source code is licensed under both the BSD-style license (found in the |
6 | * LICENSE file in the root directory of this source tree) and the GPLv2 (found |
7 | * in the COPYING file in the root directory of this source tree). |
8 | */ |
9 | |
10 | #include <stdlib.h> /* malloc, free */ |
11 | #include <limits.h> /* UINT_MAX */ |
12 | #include <assert.h> |
13 | |
14 | #define XXH_STATIC_LINKING_ONLY |
15 | #include "xxhash.h" |
16 | |
17 | #define ZSTD_STATIC_LINKING_ONLY |
18 | #include "zstd.h" |
19 | #include "zstd_errors.h" |
20 | #include "mem.h" |
21 | |
22 | #include "zstd_seekable.h" |
23 | |
24 | #define CHECK_Z(f) { size_t const ret = (f); if (ret != 0) return ret; } |
25 | |
26 | #undef ERROR |
27 | #define ERROR(name) ((size_t)-ZSTD_error_##name) |
28 | |
29 | #undef MIN |
30 | #undef MAX |
31 | #define MIN(a, b) ((a) < (b) ? (a) : (b)) |
32 | #define MAX(a, b) ((a) > (b) ? (a) : (b)) |
33 | |
34 | typedef struct { |
35 | U32 cSize; |
36 | U32 dSize; |
37 | U32 checksum; |
38 | } framelogEntry_t; |
39 | |
40 | struct ZSTD_frameLog_s { |
41 | framelogEntry_t* entries; |
42 | U32 size; |
43 | U32 capacity; |
44 | |
45 | int checksumFlag; |
46 | |
47 | /* for use when streaming out the seek table */ |
48 | U32 seekTablePos; |
49 | U32 seekTableIndex; |
50 | } framelog_t; |
51 | |
52 | struct ZSTD_seekable_CStream_s { |
53 | ZSTD_CStream* cstream; |
54 | ZSTD_frameLog framelog; |
55 | |
56 | U32 frameCSize; |
57 | U32 frameDSize; |
58 | |
59 | XXH64_state_t xxhState; |
60 | |
61 | U32 maxFrameSize; |
62 | |
63 | int writingSeekTable; |
64 | }; |
65 | |
66 | static size_t ZSTD_seekable_frameLog_allocVec(ZSTD_frameLog* fl) |
67 | { |
68 | /* allocate some initial space */ |
69 | size_t const FRAMELOG_STARTING_CAPACITY = 16; |
70 | fl->entries = (framelogEntry_t*)malloc( |
71 | sizeof(framelogEntry_t) * FRAMELOG_STARTING_CAPACITY); |
72 | if (fl->entries == NULL) return ERROR(memory_allocation); |
73 | fl->capacity = (U32)FRAMELOG_STARTING_CAPACITY; |
74 | return 0; |
75 | } |
76 | |
77 | static size_t ZSTD_seekable_frameLog_freeVec(ZSTD_frameLog* fl) |
78 | { |
79 | if (fl != NULL) free(fl->entries); |
80 | return 0; |
81 | } |
82 | |
83 | ZSTD_frameLog* ZSTD_seekable_createFrameLog(int checksumFlag) |
84 | { |
85 | ZSTD_frameLog* const fl = (ZSTD_frameLog*)malloc(sizeof(ZSTD_frameLog)); |
86 | if (fl == NULL) return NULL; |
87 | |
88 | if (ZSTD_isError(ZSTD_seekable_frameLog_allocVec(fl))) { |
89 | free(fl); |
90 | return NULL; |
91 | } |
92 | |
93 | fl->checksumFlag = checksumFlag; |
94 | fl->seekTablePos = 0; |
95 | fl->seekTableIndex = 0; |
96 | fl->size = 0; |
97 | |
98 | return fl; |
99 | } |
100 | |
101 | size_t ZSTD_seekable_freeFrameLog(ZSTD_frameLog* fl) |
102 | { |
103 | ZSTD_seekable_frameLog_freeVec(fl); |
104 | free(fl); |
105 | return 0; |
106 | } |
107 | |
108 | ZSTD_seekable_CStream* ZSTD_seekable_createCStream(void) |
109 | { |
110 | ZSTD_seekable_CStream* const zcs = (ZSTD_seekable_CStream*)malloc(sizeof(ZSTD_seekable_CStream)); |
111 | if (zcs == NULL) return NULL; |
112 | |
113 | memset(zcs, 0, sizeof(*zcs)); |
114 | |
115 | zcs->cstream = ZSTD_createCStream(); |
116 | if (zcs->cstream == NULL) goto failed1; |
117 | |
118 | if (ZSTD_isError(ZSTD_seekable_frameLog_allocVec(&zcs->framelog))) goto failed2; |
119 | |
120 | return zcs; |
121 | |
122 | failed2: |
123 | ZSTD_freeCStream(zcs->cstream); |
124 | failed1: |
125 | free(zcs); |
126 | return NULL; |
127 | } |
128 | |
129 | size_t ZSTD_seekable_freeCStream(ZSTD_seekable_CStream* zcs) |
130 | { |
131 | if (zcs == NULL) return 0; /* support free on null */ |
132 | ZSTD_freeCStream(zcs->cstream); |
133 | ZSTD_seekable_frameLog_freeVec(&zcs->framelog); |
134 | free(zcs); |
135 | return 0; |
136 | } |
137 | |
138 | size_t ZSTD_seekable_initCStream(ZSTD_seekable_CStream* zcs, |
139 | int compressionLevel, |
140 | int checksumFlag, |
141 | unsigned maxFrameSize) |
142 | { |
143 | zcs->framelog.size = 0; |
144 | zcs->frameCSize = 0; |
145 | zcs->frameDSize = 0; |
146 | |
147 | /* make sure maxFrameSize has a reasonable value */ |
148 | if (maxFrameSize > ZSTD_SEEKABLE_MAX_FRAME_DECOMPRESSED_SIZE) { |
149 | return ERROR(frameParameter_unsupported); |
150 | } |
151 | |
152 | zcs->maxFrameSize = maxFrameSize ? |
153 | maxFrameSize : ZSTD_SEEKABLE_MAX_FRAME_DECOMPRESSED_SIZE; |
154 | |
155 | zcs->framelog.checksumFlag = checksumFlag; |
156 | if (zcs->framelog.checksumFlag) { |
157 | XXH64_reset(&zcs->xxhState, 0); |
158 | } |
159 | |
160 | zcs->framelog.seekTablePos = 0; |
161 | zcs->framelog.seekTableIndex = 0; |
162 | zcs->writingSeekTable = 0; |
163 | |
164 | return ZSTD_initCStream(zcs->cstream, compressionLevel); |
165 | } |
166 | |
167 | size_t ZSTD_seekable_logFrame(ZSTD_frameLog* fl, |
168 | unsigned compressedSize, |
169 | unsigned decompressedSize, |
170 | unsigned checksum) |
171 | { |
172 | if (fl->size == ZSTD_SEEKABLE_MAXFRAMES) |
173 | return ERROR(frameIndex_tooLarge); |
174 | |
175 | /* grow the buffer if required */ |
176 | if (fl->size == fl->capacity) { |
177 | /* exponential size increase for constant amortized runtime */ |
178 | size_t const newCapacity = fl->capacity * 2; |
179 | framelogEntry_t* const newEntries = (framelogEntry_t*)realloc(fl->entries, |
180 | sizeof(framelogEntry_t) * newCapacity); |
181 | |
182 | if (newEntries == NULL) return ERROR(memory_allocation); |
183 | |
184 | fl->entries = newEntries; |
185 | assert(newCapacity <= UINT_MAX); |
186 | fl->capacity = (U32)newCapacity; |
187 | } |
188 | |
189 | fl->entries[fl->size] = (framelogEntry_t){ |
190 | compressedSize, decompressedSize, checksum |
191 | }; |
192 | fl->size++; |
193 | |
194 | return 0; |
195 | } |
196 | |
197 | size_t ZSTD_seekable_endFrame(ZSTD_seekable_CStream* zcs, ZSTD_outBuffer* output) |
198 | { |
199 | size_t const prevOutPos = output->pos; |
200 | /* end the frame */ |
201 | size_t ret = ZSTD_endStream(zcs->cstream, output); |
202 | |
203 | zcs->frameCSize += (U32)(output->pos - prevOutPos); |
204 | |
205 | /* need to flush before doing the rest */ |
206 | if (ret) return ret; |
207 | |
208 | /* frame done */ |
209 | |
210 | /* store the frame data for later */ |
211 | ret = ZSTD_seekable_logFrame( |
212 | &zcs->framelog, zcs->frameCSize, zcs->frameDSize, |
213 | zcs->framelog.checksumFlag |
214 | ? XXH64_digest(&zcs->xxhState) & 0xFFFFFFFFU |
215 | : 0); |
216 | if (ret) return ret; |
217 | |
218 | /* reset for the next frame */ |
219 | zcs->frameCSize = 0; |
220 | zcs->frameDSize = 0; |
221 | |
222 | ZSTD_CCtx_reset(zcs->cstream, ZSTD_reset_session_only); |
223 | if (zcs->framelog.checksumFlag) XXH64_reset(&zcs->xxhState, 0); |
224 | |
225 | return 0; |
226 | } |
227 | |
228 | size_t ZSTD_seekable_compressStream(ZSTD_seekable_CStream* zcs, ZSTD_outBuffer* output, ZSTD_inBuffer* input) |
229 | { |
230 | const BYTE* const inBase = (const BYTE*) input->src + input->pos; |
231 | size_t inLen = input->size - input->pos; |
232 | |
233 | assert(zcs->maxFrameSize < INT_MAX); |
234 | ZSTD_CCtx_setParameter(zcs->cstream, ZSTD_c_srcSizeHint, (int)zcs->maxFrameSize); |
235 | inLen = MIN(inLen, (size_t)(zcs->maxFrameSize - zcs->frameDSize)); |
236 | |
237 | /* if we haven't finished flushing the last frame, don't start writing a new one */ |
238 | if (inLen > 0) { |
239 | ZSTD_inBuffer inTmp = { inBase, inLen, 0 }; |
240 | size_t const prevOutPos = output->pos; |
241 | |
242 | size_t const ret = ZSTD_compressStream(zcs->cstream, output, &inTmp); |
243 | |
244 | if (zcs->framelog.checksumFlag) { |
245 | XXH64_update(&zcs->xxhState, inBase, inTmp.pos); |
246 | } |
247 | |
248 | zcs->frameCSize += (U32)(output->pos - prevOutPos); |
249 | zcs->frameDSize += (U32)inTmp.pos; |
250 | |
251 | input->pos += inTmp.pos; |
252 | |
253 | if (ZSTD_isError(ret)) return ret; |
254 | } |
255 | |
256 | if (zcs->maxFrameSize == zcs->frameDSize) { |
257 | /* log the frame and start over */ |
258 | size_t const ret = ZSTD_seekable_endFrame(zcs, output); |
259 | if (ZSTD_isError(ret)) return ret; |
260 | |
261 | /* get the client ready for the next frame */ |
262 | return (size_t)zcs->maxFrameSize; |
263 | } |
264 | |
265 | return (size_t)(zcs->maxFrameSize - zcs->frameDSize); |
266 | } |
267 | |
268 | static inline size_t ZSTD_seekable_seekTableSize(const ZSTD_frameLog* fl) |
269 | { |
270 | size_t const sizePerFrame = 8 + (fl->checksumFlag?4:0); |
271 | size_t const seekTableLen = ZSTD_SKIPPABLEHEADERSIZE + |
272 | sizePerFrame * fl->size + |
273 | ZSTD_seekTableFooterSize; |
274 | |
275 | return seekTableLen; |
276 | } |
277 | |
278 | static inline size_t ZSTD_stwrite32(ZSTD_frameLog* fl, |
279 | ZSTD_outBuffer* output, U32 const value, |
280 | U32 const offset) |
281 | { |
282 | if (fl->seekTablePos < offset + 4) { |
283 | BYTE tmp[4]; /* so that we can work with buffers too small to write a whole word to */ |
284 | size_t const lenWrite = |
285 | MIN(output->size - output->pos, offset + 4 - fl->seekTablePos); |
286 | MEM_writeLE32(tmp, value); |
287 | memcpy((BYTE*)output->dst + output->pos, |
288 | tmp + (fl->seekTablePos - offset), lenWrite); |
289 | output->pos += lenWrite; |
290 | fl->seekTablePos += (U32)lenWrite; |
291 | |
292 | if (lenWrite < 4) return ZSTD_seekable_seekTableSize(fl) - fl->seekTablePos; |
293 | } |
294 | return 0; |
295 | } |
296 | |
297 | size_t ZSTD_seekable_writeSeekTable(ZSTD_frameLog* fl, ZSTD_outBuffer* output) |
298 | { |
299 | /* seekTableIndex: the current index in the table and |
300 | * seekTableSize: the amount of the table written so far |
301 | * |
302 | * This function is written this way so that if it has to return early |
303 | * because of a small buffer, it can keep going where it left off. |
304 | */ |
305 | |
306 | size_t const sizePerFrame = 8 + (fl->checksumFlag?4:0); |
307 | size_t const seekTableLen = ZSTD_seekable_seekTableSize(fl); |
308 | |
309 | CHECK_Z(ZSTD_stwrite32(fl, output, ZSTD_MAGIC_SKIPPABLE_START | 0xE, 0)); |
310 | assert(seekTableLen <= (size_t)UINT_MAX); |
311 | CHECK_Z(ZSTD_stwrite32(fl, output, (U32)seekTableLen - ZSTD_SKIPPABLEHEADERSIZE, 4)); |
312 | |
313 | while (fl->seekTableIndex < fl->size) { |
314 | unsigned long long const start = ZSTD_SKIPPABLEHEADERSIZE + sizePerFrame * fl->seekTableIndex; |
315 | assert(start + 8 <= UINT_MAX); |
316 | CHECK_Z(ZSTD_stwrite32(fl, output, |
317 | fl->entries[fl->seekTableIndex].cSize, |
318 | (U32)start + 0)); |
319 | |
320 | CHECK_Z(ZSTD_stwrite32(fl, output, |
321 | fl->entries[fl->seekTableIndex].dSize, |
322 | (U32)start + 4)); |
323 | |
324 | if (fl->checksumFlag) { |
325 | CHECK_Z(ZSTD_stwrite32( |
326 | fl, output, fl->entries[fl->seekTableIndex].checksum, |
327 | (U32)start + 8)); |
328 | } |
329 | |
330 | fl->seekTableIndex++; |
331 | } |
332 | |
333 | assert(seekTableLen <= UINT_MAX); |
334 | CHECK_Z(ZSTD_stwrite32(fl, output, fl->size, |
335 | (U32)seekTableLen - ZSTD_seekTableFooterSize)); |
336 | |
337 | if (output->size - output->pos < 1) return seekTableLen - fl->seekTablePos; |
338 | if (fl->seekTablePos < seekTableLen - 4) { |
339 | BYTE const sfd = (BYTE)((fl->checksumFlag) << 7); |
340 | |
341 | ((BYTE*)output->dst)[output->pos] = sfd; |
342 | output->pos++; |
343 | fl->seekTablePos++; |
344 | } |
345 | |
346 | CHECK_Z(ZSTD_stwrite32(fl, output, ZSTD_SEEKABLE_MAGICNUMBER, |
347 | (U32)seekTableLen - 4)); |
348 | |
349 | if (fl->seekTablePos != seekTableLen) return ERROR(GENERIC); |
350 | return 0; |
351 | } |
352 | |
353 | size_t ZSTD_seekable_endStream(ZSTD_seekable_CStream* zcs, ZSTD_outBuffer* output) |
354 | { |
355 | if (!zcs->writingSeekTable) { |
356 | const size_t endFrame = ZSTD_seekable_endFrame(zcs, output); |
357 | if (ZSTD_isError(endFrame)) return endFrame; |
358 | /* return an accurate size hint */ |
359 | if (endFrame) return endFrame + ZSTD_seekable_seekTableSize(&zcs->framelog); |
360 | } |
361 | |
362 | zcs->writingSeekTable = 1; |
363 | |
364 | return ZSTD_seekable_writeSeekTable(&zcs->framelog, output); |
365 | } |