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  }