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Tweak the compression presets -0 .. -5. 

"Extreme" mode might need some further tweaking still.
Docs were not updated yet.
This commit is contained in:
Lasse Collin 2010-09-03 15:13:12 +03:00
parent 77fe5954cd
commit b4b1cbcb53
1 changed files with 19 additions and 10 deletions
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23
src/liblzma/lzma/lzma_encoder_presets.c
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@ -23,9 +23,6 @@ lzma_lzma_preset(lzma_options_lzma *options, uint32_t preset)
if (level > 9 || (flags & ~supported_flags))
return true;
const uint32_t dict_shift = level <= 1 ? 16 : level + 17;
options->dict_size = UINT32_C(1) << dict_shift;
options->preset_dict = NULL;
options->preset_dict_size = 0;
@ -33,20 +30,32 @@ lzma_lzma_preset(lzma_options_lzma *options, uint32_t preset)
options->lp = LZMA_LP_DEFAULT;
options->pb = LZMA_PB_DEFAULT;
options->mode = level <= 2 ? LZMA_MODE_FAST : LZMA_MODE_NORMAL;
options->dict_size = UINT32_C(1) << (uint8_t []){
18, 20, 21, 22, 22, 23, 23, 24, 25, 26 }[level];
options->nice_len = level == 0 ? 8 : level <= 5 ? 32 : 64;
options->mf = level <= 1 ? LZMA_MF_HC3 : level <= 2 ? LZMA_MF_HC4
: LZMA_MF_BT4;
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;
options->depth = (uint8_t []){ 4, 8, 24, 48 }[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->lc = 4; // FIXME?
options->mode = LZMA_MODE_NORMAL;
options->mf = LZMA_MF_BT4;
if (level == 3 || level == 5) {
options->nice_len = 192;
} else {
options->nice_len = 273;
options->depth = 512;
}
}
return false;
}