1 ///////////////////////////////////////////////////////////////////////////////
3 /// \file lzma_encoder_presets.c
4 /// \brief Encoder presets
6 // Author: Lasse Collin
8 // This file has been put into the public domain.
9 // You can do whatever you want with this file.
11 ///////////////////////////////////////////////////////////////////////////////
16 extern LZMA_API(lzma_bool)
17 lzma_lzma_preset(lzma_options_lzma *options, uint32_t preset)
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;
23 if (level > 9 || (flags & ~supported_flags))
26 const uint32_t dict_shift = level <= 1 ? 16 : level + 17;
27 options->dict_size = UINT32_C(1) << dict_shift;
29 options->preset_dict = NULL;
30 options->preset_dict_size = 0;
32 options->lc = LZMA_LC_DEFAULT;
33 options->lp = LZMA_LP_DEFAULT;
34 options->pb = LZMA_PB_DEFAULT;
36 options->mode = level <= 2 ? LZMA_MODE_FAST : LZMA_MODE_NORMAL;
38 options->nice_len = level == 0 ? 8 : level <= 5 ? 32 : 64;
39 options->mf = level <= 1 ? LZMA_MF_HC3 : level <= 2 ? LZMA_MF_HC4
43 if (flags & LZMA_PRESET_EXTREME) {
44 options->lc = 4; // FIXME?
45 options->mode = LZMA_MODE_NORMAL;
46 options->mf = LZMA_MF_BT4;
47 options->nice_len = 273;