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 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