lzma_encoder_presets.c revision 273498 
1///////////////////////////////////////////////////////////////////////////////
2//
3/// \file       lzma_encoder_presets.c
4/// \brief      Encoder presets
5//
6//  Author:     Lasse Collin
7//
8//  This file has been put into the public domain.
9//  You can do whatever you want with this file.
10//
11///////////////////////////////////////////////////////////////////////////////
12
13#include "common.h"
14
15
16extern LZMA_API(lzma_bool)
17lzma_lzma_preset(lzma_options_lzma *options, uint32_t preset)
18{
19	const uint32_t level = preset & LZMA_PRESET_LEVEL_MASK;
20	const uint32_t flags = preset & ~LZMA_PRESET_LEVEL_MASK;
21	const uint32_t supported_flags = LZMA_PRESET_EXTREME;
22
23	if (level > 9 || (flags & ~supported_flags))
24		return true;
25
26	options->preset_dict = NULL;
27	options->preset_dict_size = 0;
28
29	options->lc = LZMA_LC_DEFAULT;
30	options->lp = LZMA_LP_DEFAULT;
31	options->pb = LZMA_PB_DEFAULT;
32
33	static const uint8_t dict_pow2[]
34			= { 18, 20, 21, 22, 22, 23, 23, 24, 25, 26 };
35	options->dict_size = UINT32_C(1) << dict_pow2[level];
36
37	if (level <= 3) {
38		options->mode = LZMA_MODE_FAST;
39		options->mf = level == 0 ? LZMA_MF_HC3 : LZMA_MF_HC4;
40		options->nice_len = level <= 1 ? 128 : 273;
41		static const uint8_t depths[] = { 4, 8, 24, 48 };
42		options->depth = depths[level];
43	} else {
44		options->mode = LZMA_MODE_NORMAL;
45		options->mf = LZMA_MF_BT4;
46		options->nice_len = level == 4 ? 16 : level == 5 ? 32 : 64;
47		options->depth = 0;
48	}
49
50	if (flags & LZMA_PRESET_EXTREME) {
51		options->mode = LZMA_MODE_NORMAL;
52		options->mf = LZMA_MF_BT4;
53		if (level == 3 || level == 5) {
54			options->nice_len = 192;
55			options->depth = 0;
56		} else {
57			options->nice_len = 273;
58			options->depth = 512;
59		}
60	}
61
62	return false;
63}
64