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 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 options->dict_size = UINT32_C(1) << (uint8_t []){ 34 18, 20, 21, 22, 22, 23, 23, 24, 25, 26 }[level]; 35 36 if (level <= 3) { 37 options->mode = LZMA_MODE_FAST; 38 options->mf = level == 0 ? LZMA_MF_HC3 : LZMA_MF_HC4; 39 options->nice_len = level <= 1 ? 128 : 273; 40 options->depth = (uint8_t []){ 4, 8, 24, 48 }[level]; 41 } else { 42 options->mode = LZMA_MODE_NORMAL; 43 options->mf = LZMA_MF_BT4; 44 options->nice_len = level == 4 ? 16 : level == 5 ? 32 : 64; 45 options->depth = 0; 46 } 47 48 if (flags & LZMA_PRESET_EXTREME) { 49 options->mode = LZMA_MODE_NORMAL; 50 options->mf = LZMA_MF_BT4; 51 if (level == 3 || level == 5) { 52 options->nice_len = 192; 53 options->depth = 0; 54 } else { 55 options->nice_len = 273; 56 options->depth = 512; 57 } 58 } 59 60 return false; 61 } 62