lzma_encoder_presets.c File Reference

Encoder presets. More...

#include "common.h"

Go to the source code of this file.

Functions
	LZMA_API (lzma_bool)

Detailed Description

Encoder presets.

Note

xz needs this even when only decoding is enabled.

Definition in file lzma_encoder_presets.c.

Function Documentation

LZMA_API()

LZMA_API

(

lzma_bool

)

Definition at line 17 of file lzma_encoder_presets.c.

{
    const uint32_t level = preset & LZMA_PRESET_LEVEL_MASK;
    const uint32_t flags = preset & ~LZMA_PRESET_LEVEL_MASK;
    const uint32_t supported_flags = LZMA_PRESET_EXTREME;
 
    if (level > 9 || (flags & ~supported_flags))
        return true;
 
    options->preset_dict = NULL;
    options->preset_dict_size = 0;
 
    options->lc = LZMA_LC_DEFAULT;
    options->lp = LZMA_LP_DEFAULT;
    options->pb = LZMA_PB_DEFAULT;
 
    static const uint8_t dict_pow2[]
            = { 18, 20, 21, 22, 22, 23, 23, 24, 25, 26 };
    options->dict_size = UINT32_C(1) << dict_pow2[level];
 
    if (level <= 3) {
        options->mode = LZMA_MODE_FAST;
        options->mf = level == 0 ? LZMA_MF_HC3 : LZMA_MF_HC4;
        options->nice_len = level <= 1 ? 128 : 273;
        static const uint8_t depths[] = { 4, 8, 24, 48 };
        options->depth = depths[level];
    } else {
        options->mode = LZMA_MODE_NORMAL;
        options->mf = LZMA_MF_BT4;
        options->nice_len = level == 4 ? 16 : level == 5 ? 32 : 64;
        options->depth = 0;
    }
 
    if (flags & LZMA_PRESET_EXTREME) {
        options->mode = LZMA_MODE_NORMAL;
        options->mf = LZMA_MF_BT4;
        if (level == 3 || level == 5) {
            options->nice_len = 192;
            options->depth = 0;
        } else {
            options->nice_len = 273;
            options->depth = 512;
        }
    }
 
    return false;
}

References flags, level, LZMA_LC_DEFAULT, LZMA_LP_DEFAULT, LZMA_MF_BT4, LZMA_MF_HC3, LZMA_MF_HC4, LZMA_MODE_FAST, LZMA_MODE_NORMAL, LZMA_PB_DEFAULT, LZMA_PRESET_EXTREME, LZMA_PRESET_LEVEL_MASK, NULL, options, preset, and UINT32_C.