ddidderr/zstd-rs
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

new initializer for ll price

Browse Source
This commit is contained in:
Yann Collet
2021-09-03 16:07:31 -07:00
parent f0fc8cb3e1
commit 27a8bbe265
3 changed files with 102 additions and 74 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lib/compress/zstd_opt.c
+34 -13
View File
@@ -24,11 +24,11 @@
* Price functions for optimal parser
***************************************/
#if 0 /* approximation at bit level */
#if 0 /* approximation at bit level (for tests) */
# define BITCOST_ACCURACY 0
# define BITCOST_MULTIPLIER (1 << BITCOST_ACCURACY)
# define WEIGHT(stat) ((void)opt, ZSTD_bitWeight(stat))
#elif 0 /* fractional bit accuracy */
# define WEIGHT(stat, opt) ((void)opt, ZSTD_bitWeight(stat))
#elif 0 /* fractional bit accuracy (for tests) */
# define BITCOST_ACCURACY 8
# define BITCOST_MULTIPLIER (1 << BITCOST_ACCURACY)
# define WEIGHT(stat,opt) ((void)opt, ZSTD_fracWeight(stat))
@@ -94,10 +94,21 @@ static U32 ZSTD_downscaleStat(unsigned* table, U32 lastEltIndex, int malus)
return sum;
}
static U32 sum_u32(const unsigned table[], size_t nbElts)
{
size_t n;
U32 total = 0;
for (n=0; n<nbElts; n++) {
total += table[n];
}
return total;
}
/* ZSTD_rescaleFreqs() :
* if first block (detected by optPtr->litLengthSum == 0) : init statistics
* take hints from dictionary if there is one
* or init from zero, using src for literals stats, or flat 1 for match symbols
* and init from zero if there is none,
* using src for literals stats, and baseline stats for sequence symbols
* otherwise downscale existing stats, to be used as seed for next block.
*/
static void
@@ -177,11 +188,16 @@ ZSTD_rescaleFreqs(optState_t* const optPtr,
optPtr->litSum = ZSTD_downscaleStat(optPtr->litFreq, MaxLit, 1);
}
{ unsigned ll;
for (ll=0; ll<=MaxLL; ll++)
optPtr->litLengthFreq[ll] = 1;
{ unsigned const baseLLfreqs[MaxLL+1] = {
4, 2, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1
};
memcpy(optPtr->litLengthFreq, baseLLfreqs, sizeof(baseLLfreqs)); optPtr->litLengthSum = sum_u32(baseLLfreqs, MaxLL+1);
//unsigned ll; for (ll=0; ll<=MaxLL; ll++) optPtr->litLengthFreq[ll] = 1; optPtr->litLengthSum = MaxLL+1;
}
optPtr->litLengthSum = MaxLL+1;
{ unsigned ml;
for (ml=0; ml<=MaxML; ml++)
@@ -189,11 +205,16 @@ ZSTD_rescaleFreqs(optState_t* const optPtr,
}
optPtr->matchLengthSum = MaxML+1;
{ unsigned of;
for (of=0; of<=MaxOff; of++)
optPtr->offCodeFreq[of] = 1;
{ unsigned const baseOFCfreqs[MaxOff+1] = {
8, 4, 3, 3, 3, 4, 4, 4,
4, 4, 3, 3, 3, 2, 2, 2,
1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1,
};
//memcpy(optPtr->offCodeFreq, baseOFCfreqs, sizeof(baseOFCfreqs)); optPtr->offCodeSum = sum_u32(baseOFCfreqs, MaxOff+1);
unsigned of; for (of=0; of<=MaxOff; of++) optPtr->offCodeFreq[of] = 1; optPtr->offCodeSum = MaxOff+1;
}
optPtr->offCodeSum = MaxOff+1;
}
@@ -901,11 +922,11 @@ static void ZSTD_optLdm_processMatchCandidate(ZSTD_optLdm_t* optLdm, ZSTD_match_
ZSTD_optLdm_maybeAddMatch(matches, nbMatches, optLdm, currPosInBlock);
}
/*-*******************************
* Optimal parser
*********************************/
static U32 ZSTD_totalLen(ZSTD_optimal_t sol)
{
return sol.litlen + sol.mlen;