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1 | /* |
2 | * Copyright (c) Yann Collet, Facebook, Inc. | |
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 | * You may select, at your option, one of the above-listed licenses. | |
9 | */ | |
10 | ||
11 | #ifndef ZSTD_LDM_H | |
12 | #define ZSTD_LDM_H | |
13 | ||
14 | ||
15 | #include "zstd_compress_internal.h" /* ldmParams_t, U32 */ | |
16 | #include <linux/zstd.h> /* ZSTD_CCtx, size_t */ | |
17 | ||
18 | /*-************************************* | |
19 | * Long distance matching | |
20 | ***************************************/ | |
21 | ||
22 | #define ZSTD_LDM_DEFAULT_WINDOW_LOG ZSTD_WINDOWLOG_LIMIT_DEFAULT | |
23 | ||
24 | void ZSTD_ldm_fillHashTable( | |
25 | ldmState_t* state, const BYTE* ip, | |
26 | const BYTE* iend, ldmParams_t const* params); | |
27 | ||
28 | /* | |
29 | * ZSTD_ldm_generateSequences(): | |
30 | * | |
31 | * Generates the sequences using the long distance match finder. | |
32 | * Generates long range matching sequences in `sequences`, which parse a prefix | |
33 | * of the source. `sequences` must be large enough to store every sequence, | |
34 | * which can be checked with `ZSTD_ldm_getMaxNbSeq()`. | |
35 | * @returns 0 or an error code. | |
36 | * | |
37 | * NOTE: The user must have called ZSTD_window_update() for all of the input | |
38 | * they have, even if they pass it to ZSTD_ldm_generateSequences() in chunks. | |
39 | * NOTE: This function returns an error if it runs out of space to store | |
40 | * sequences. | |
41 | */ | |
42 | size_t ZSTD_ldm_generateSequences( | |
43 | ldmState_t* ldms, rawSeqStore_t* sequences, | |
44 | ldmParams_t const* params, void const* src, size_t srcSize); | |
45 | ||
46 | /* | |
47 | * ZSTD_ldm_blockCompress(): | |
48 | * | |
49 | * Compresses a block using the predefined sequences, along with a secondary | |
50 | * block compressor. The literals section of every sequence is passed to the | |
51 | * secondary block compressor, and those sequences are interspersed with the | |
52 | * predefined sequences. Returns the length of the last literals. | |
53 | * Updates `rawSeqStore.pos` to indicate how many sequences have been consumed. | |
54 | * `rawSeqStore.seq` may also be updated to split the last sequence between two | |
55 | * blocks. | |
56 | * @return The length of the last literals. | |
57 | * | |
58 | * NOTE: The source must be at most the maximum block size, but the predefined | |
59 | * sequences can be any size, and may be longer than the block. In the case that | |
60 | * they are longer than the block, the last sequences may need to be split into | |
61 | * two. We handle that case correctly, and update `rawSeqStore` appropriately. | |
62 | * NOTE: This function does not return any errors. | |
63 | */ | |
64 | size_t ZSTD_ldm_blockCompress(rawSeqStore_t* rawSeqStore, | |
65 | ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], | |
2aa14b1a | 66 | ZSTD_paramSwitch_e useRowMatchFinder, |
e0c1b49f NT |
67 | void const* src, size_t srcSize); |
68 | ||
69 | /* | |
70 | * ZSTD_ldm_skipSequences(): | |
71 | * | |
72 | * Skip past `srcSize` bytes worth of sequences in `rawSeqStore`. | |
73 | * Avoids emitting matches less than `minMatch` bytes. | |
74 | * Must be called for data that is not passed to ZSTD_ldm_blockCompress(). | |
75 | */ | |
76 | void ZSTD_ldm_skipSequences(rawSeqStore_t* rawSeqStore, size_t srcSize, | |
77 | U32 const minMatch); | |
78 | ||
79 | /* ZSTD_ldm_skipRawSeqStoreBytes(): | |
80 | * Moves forward in rawSeqStore by nbBytes, updating fields 'pos' and 'posInSequence'. | |
81 | * Not to be used in conjunction with ZSTD_ldm_skipSequences(). | |
82 | * Must be called for data with is not passed to ZSTD_ldm_blockCompress(). | |
83 | */ | |
84 | void ZSTD_ldm_skipRawSeqStoreBytes(rawSeqStore_t* rawSeqStore, size_t nbBytes); | |
85 | ||
86 | /* ZSTD_ldm_getTableSize() : | |
87 | * Estimate the space needed for long distance matching tables or 0 if LDM is | |
88 | * disabled. | |
89 | */ | |
90 | size_t ZSTD_ldm_getTableSize(ldmParams_t params); | |
91 | ||
92 | /* ZSTD_ldm_getSeqSpace() : | |
93 | * Return an upper bound on the number of sequences that can be produced by | |
94 | * the long distance matcher, or 0 if LDM is disabled. | |
95 | */ | |
96 | size_t ZSTD_ldm_getMaxNbSeq(ldmParams_t params, size_t maxChunkSize); | |
97 | ||
98 | /* ZSTD_ldm_adjustParameters() : | |
99 | * If the params->hashRateLog is not set, set it to its default value based on | |
100 | * windowLog and params->hashLog. | |
101 | * | |
102 | * Ensures that params->bucketSizeLog is <= params->hashLog (setting it to | |
103 | * params->hashLog if it is not). | |
104 | * | |
105 | * Ensures that the minMatchLength >= targetLength during optimal parsing. | |
106 | */ | |
107 | void ZSTD_ldm_adjustParameters(ldmParams_t* params, | |
108 | ZSTD_compressionParameters const* cParams); | |
109 | ||
110 | ||
111 | #endif /* ZSTD_FAST_H */ |