lzma_encoder_presets.c revision 312518 
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
17extern LZMA_API(lzma_bool)
18lzma_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}
65