1 /////////////////////////////////////////////////////////////////////////////// 2 // 3 /// \file lzma_encoder_presets.c 4 /// \brief Encoder presets 5 /// \note xz needs this even when only decoding is enabled. 6 // 7 // Author: Lasse Collin 8 // 9 // This file has been put into the public domain. 10 // You can do whatever you want with this file. 11 // 12 /////////////////////////////////////////////////////////////////////////////// 13 14 #include "common.h" 15 16 17 extern LZMA_API(lzma_bool) 18 lzma_lzma_preset(lzma_options_lzma *options, uint32_t preset) 19 { 20 const uint32_t level = preset & LZMA_PRESET_LEVEL_MASK; 21 const uint32_t flags = preset & ~LZMA_PRESET_LEVEL_MASK; 22 const uint32_t supported_flags = LZMA_PRESET_EXTREME; 23 24 if (level > 9 || (flags & ~supported_flags)) 25 return true; 26 27 options->preset_dict = NULL; 28 options->preset_dict_size = 0; 29 30 options->lc = LZMA_LC_DEFAULT; 31 options->lp = LZMA_LP_DEFAULT; 32 options->pb = LZMA_PB_DEFAULT; 33 34 static const uint8_t dict_pow2[] 35 = { 18, 20, 21, 22, 22, 23, 23, 24, 25, 26 }; 36 options->dict_size = UINT32_C(1) << dict_pow2[level]; 37 38 if (level <= 3) { 39 options->mode = LZMA_MODE_FAST; 40 options->mf = level == 0 ? LZMA_MF_HC3 : LZMA_MF_HC4; 41 options->nice_len = level <= 1 ? 128 : 273; 42 static const uint8_t depths[] = { 4, 8, 24, 48 }; 43 options->depth = depths[level]; 44 } else { 45 options->mode = LZMA_MODE_NORMAL; 46 options->mf = LZMA_MF_BT4; 47 options->nice_len = level == 4 ? 16 : level == 5 ? 32 : 64; 48 options->depth = 0; 49 } 50 51 if (flags & LZMA_PRESET_EXTREME) { 52 options->mode = LZMA_MODE_NORMAL; 53 options->mf = LZMA_MF_BT4; 54 if (level == 3 || level == 5) { 55 options->nice_len = 192; 56 options->depth = 0; 57 } else { 58 options->nice_len = 273; 59 options->depth = 512; 60 } 61 } 62 63 return false; 64 } 65