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1 ///////////////////////////////////////////////////////////////////////////////
2 //
3 /// \file       lzma_encoder_presets.c
4 /// \brief      Encoder presets
5 /// \note       xz needs this even when only decoding is enabled.
6 //
7 //  Author:     Lasse Collin
8 //
9 //  This file has been put into the public domain.
10 //  You can do whatever you want with this file.
11 //
12 ///////////////////////////////////////////////////////////////////////////////
13
14 #include "common.h"
15
16
17 extern LZMA_API(lzma_bool)
18 lzma_lzma_preset(lzma_options_lzma *options, uint32_t preset)
19 {
20         const uint32_t level = preset & LZMA_PRESET_LEVEL_MASK;
21         const uint32_t flags = preset & ~LZMA_PRESET_LEVEL_MASK;
22         const uint32_t supported_flags = LZMA_PRESET_EXTREME;
23
24         if (level > 9 || (flags & ~supported_flags))
25                 return true;
26
27         options->preset_dict = NULL;
28         options->preset_dict_size = 0;
29
30         options->lc = LZMA_LC_DEFAULT;
31         options->lp = LZMA_LP_DEFAULT;
32         options->pb = LZMA_PB_DEFAULT;
33
34         static const uint8_t dict_pow2[]
35                         = { 18, 20, 21, 22, 22, 23, 23, 24, 25, 26 };
36         options->dict_size = UINT32_C(1) << dict_pow2[level];
37
38         if (level <= 3) {
39                 options->mode = LZMA_MODE_FAST;
40                 options->mf = level == 0 ? LZMA_MF_HC3 : LZMA_MF_HC4;
41                 options->nice_len = level <= 1 ? 128 : 273;
42                 static const uint8_t depths[] = { 4, 8, 24, 48 };
43                 options->depth = depths[level];
44         } else {
45                 options->mode = LZMA_MODE_NORMAL;
46                 options->mf = LZMA_MF_BT4;
47                 options->nice_len = level == 4 ? 16 : level == 5 ? 32 : 64;
48                 options->depth = 0;
49         }
50
51         if (flags & LZMA_PRESET_EXTREME) {
52                 options->mode = LZMA_MODE_NORMAL;
53                 options->mf = LZMA_MF_BT4;
54                 if (level == 3 || level == 5) {
55                         options->nice_len = 192;
56                         options->depth = 0;
57                 } else {
58                         options->nice_len = 273;
59                         options->depth = 512;
60                 }
61         }
62
63         return false;
64 }