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 16 extern LZMA_API(lzma_bool) 17 lzma_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 const uint32_t dict_shift = level <= 1 ? 16 : level + 17; 27 options->dict_size = UINT32_C(1) << dict_shift; 28 29 options->preset_dict = NULL; 30 options->preset_dict_size = 0; 31 32 options->lc = LZMA_LC_DEFAULT; 33 options->lp = LZMA_LP_DEFAULT; 34 options->pb = LZMA_PB_DEFAULT; 35 36 options->mode = level <= 2 ? LZMA_MODE_FAST : LZMA_MODE_NORMAL; 37 38 options->nice_len = level == 0 ? 8 : level <= 5 ? 32 : 64; 39 options->mf = level <= 1 ? LZMA_MF_HC3 : level <= 2 ? LZMA_MF_HC4 40 : LZMA_MF_BT4; 41 options->depth = 0; 42 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; 48 options->depth = 512; 49 } 50 51 return false; 52 } 53