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Merge pull request #1457 from facebook/btultra2.1 

btultra2 and very small input
dev
Yann Collet 2018-12-18 14:46:55 -08:00 committed by GitHub
parent 517d8c984c ef984e7307
commit 04baecaeed
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GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 73 additions and 27 deletions
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33
lib/common/debug.h
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@ -57,9 +57,9 @@ extern "C" {
#endif
/* static assert is triggered at compile time, leaving no runtime artefact,
* but can only work with compile-time constants.
* This variant can only be used inside a function. */
/* static assert is triggered at compile time, leaving no runtime artefact.
* static assert only works with compile-time constants.
* Also, this variant can only be used inside a function. */
#define DEBUG_STATIC_ASSERT(c) (void)sizeof(char[(c) ? 1 : -1])
@ -70,9 +70,19 @@ extern "C" {
# define DEBUGLEVEL 0
#endif
/* DEBUGFILE can be defined externally,
* typically through compiler command line.
* note : currently useless.
* Value must be stderr or stdout */
#ifndef DEBUGFILE
# define DEBUGFILE stderr
#endif
/* recommended values for DEBUGLEVEL :
* 0 : no debug, all run-time functions disabled
* 1 : no display, enables assert() only
* 0 : release mode, no debug, all run-time checks disabled
* 1 : enables assert() only, no display
* 2 : reserved, for currently active debug path
* 3 : events once per object lifetime (CCtx, CDict, etc.)
* 4 : events once per frame
@ -81,7 +91,7 @@ extern "C" {
* 7+: events at every position (*very* verbose)
*
* It's generally inconvenient to output traces > 5.
* In which case, it's possible to selectively enable higher verbosity levels
* In which case, it's possible to selectively trigger high verbosity levels
* by modifying g_debug_level.
*/
@ -95,11 +105,12 @@ extern "C" {
#if (DEBUGLEVEL>=2)
# include <stdio.h>
extern int g_debuglevel; /* here, this variable is only declared,
it actually lives in debug.c,
and is shared by the whole process.
It's typically used to enable very verbose levels
on selective conditions (such as position in src) */
extern int g_debuglevel; /* the variable is only declared,
it actually lives in debug.c,
and is shared by the whole process.
It's not thread-safe.
It's useful when enabling very verbose levels
on selective conditions (such as position in src) */
# define RAWLOG(l, ...) { \
if (l<=g_debuglevel) { \

67
lib/compress/zstd_opt.c
View File

@ -17,6 +17,8 @@
#define ZSTD_FREQ_DIV 4 /* log factor when using previous stats to init next stats */
#define ZSTD_MAX_PRICE (1<<30)
#define ZSTD_PREDEF_THRESHOLD 1024 /* if srcSize < ZSTD_PREDEF_THRESHOLD, symbols' cost is assumed static, directly determined by pre-defined distributions */
/*-*************************************
* Price functions for optimal parser
@ -67,25 +69,36 @@ static void ZSTD_setBasePrices(optState_t* optPtr, int optLevel)
}
/* ZSTD_downscaleStat() :
* reduce all elements in table by a factor 2^(ZSTD_FREQ_DIV+malus)
* return the resulting sum of elements */
static U32 ZSTD_downscaleStat(U32* table, U32 lastEltIndex, int malus)
{
U32 s, sum=0;
DEBUGLOG(5, "ZSTD_downscaleStat (nbElts=%u)", lastEltIndex+1);
assert(ZSTD_FREQ_DIV+malus > 0 && ZSTD_FREQ_DIV+malus < 31);
for (s=0; s<=lastEltIndex; s++) {
for (s=0; s<lastEltIndex+1; s++) {
table[s] = 1 + (table[s] >> (ZSTD_FREQ_DIV+malus));
sum += table[s];
}
return sum;
}
static void ZSTD_rescaleFreqs(optState_t* const optPtr,
const BYTE* const src, size_t const srcSize,
int optLevel)
/* 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
* otherwise downscale existing stats, to be used as seed for next block.
*/
static void
ZSTD_rescaleFreqs(optState_t* const optPtr,
const BYTE* const src, size_t const srcSize,
int optLevel)
{
optPtr->priceType = zop_dynamic;
if (optPtr->litLengthSum == 0) { /* first block : init */
if (srcSize <= 1024) /* heuristic */
if (srcSize <= ZSTD_PREDEF_THRESHOLD) /* heuristic */
optPtr->priceType = zop_predef;
assert(optPtr->symbolCosts != NULL);
@ -778,6 +791,23 @@ static U32 ZSTD_totalLen(ZSTD_optimal_t sol)
return sol.litlen + sol.mlen;
}
#if 0 /* debug */
static void
listStats(const U32* table, int lastEltID)
{
int const nbElts = lastEltID + 1;
int enb;
for (enb=0; enb < nbElts; enb++) {
(void)table;
//RAWLOG(2, "%3i:%3i, ", enb, table[enb]);
RAWLOG(2, "%4i,", table[enb]);
}
RAWLOG(2, " \n");
}
#endif
FORCE_INLINE_TEMPLATE size_t
ZSTD_compressBlock_opt_generic(ZSTD_matchState_t* ms,
seqStore_t* seqStore,
@ -1054,8 +1084,8 @@ size_t ZSTD_compressBlock_btopt(
static U32 ZSTD_upscaleStat(U32* table, U32 lastEltIndex, int bonus)
{
U32 s, sum=0;
assert(ZSTD_FREQ_DIV+bonus > 0);
for (s=0; s<=lastEltIndex; s++) {
assert(ZSTD_FREQ_DIV+bonus >= 0);
for (s=0; s<lastEltIndex+1; s++) {
table[s] <<= ZSTD_FREQ_DIV+bonus;
table[s]--;
sum += table[s];
@ -1067,28 +1097,32 @@ static U32 ZSTD_upscaleStat(U32* table, U32 lastEltIndex, int bonus)
MEM_STATIC void ZSTD_upscaleStats(optState_t* optPtr)
{
optPtr->litSum = ZSTD_upscaleStat(optPtr->litFreq, MaxLit, 0);
optPtr->litLengthSum = ZSTD_upscaleStat(optPtr->litLengthFreq, MaxLL, 1);
optPtr->matchLengthSum = ZSTD_upscaleStat(optPtr->matchLengthFreq, MaxML, 1);
optPtr->offCodeSum = ZSTD_upscaleStat(optPtr->offCodeFreq, MaxOff, 1);
optPtr->litLengthSum = ZSTD_upscaleStat(optPtr->litLengthFreq, MaxLL, 0);
optPtr->matchLengthSum = ZSTD_upscaleStat(optPtr->matchLengthFreq, MaxML, 0);
optPtr->offCodeSum = ZSTD_upscaleStat(optPtr->offCodeFreq, MaxOff, 0);
}
/* ZSTD_initStats_ultra():
* make a first compression pass, just to seed stats with more accurate starting values.
* only works on first block, with no dictionary and no ldm.
* this function must not fail, hence its usage conditions must be respected.
* this function cannot error, hence its constract must be respected.
*/
static void ZSTD_initStats_ultra(
ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
const void* src, size_t srcSize)
static void
ZSTD_initStats_ultra(ZSTD_matchState_t* ms,
seqStore_t* seqStore,
U32 rep[ZSTD_REP_NUM],
const void* src, size_t srcSize)
{
U32 tmpRep[ZSTD_REP_NUM]; /* updated rep codes will sink here */
memcpy(tmpRep, rep, sizeof(tmpRep));
DEBUGLOG(5, "ZSTD_initStats_ultra (srcSize=%zu)", srcSize);
DEBUGLOG(5, "repCodes: %u, %u, %u", tmpRep[0], tmpRep[1], tmpRep[2]);
assert(ms->opt.litLengthSum == 0); /* first block */
assert(seqStore->sequences == seqStore->sequencesStart); /* no ldm */
assert(ms->window.dictLimit == ms->window.lowLimit); /* no dictionary */
assert(ms->window.dictLimit - ms->nextToUpdate <= 1); /* no prefix (note: intentional overflow, defined as 2-complement) */
memcpy(tmpRep, rep, sizeof(tmpRep));
ZSTD_compressBlock_opt_generic(ms, seqStore, tmpRep, src, srcSize, 2 /*optLevel*/, ZSTD_noDict); /* generate stats into ms->opt*/
/* invalidate first scan from history */
@ -1117,7 +1151,7 @@ size_t ZSTD_compressBlock_btultra2(
{
DEBUGLOG(5, "ZSTD_compressBlock_btultra2 (srcSize=%zu)", srcSize);
/* 2-pass strategy
/* 2-pass strategy:
* this strategy makes a first pass over first block to collect statistics
* and seed next round's statistics with it.
* After 1st pass, function forgets everything, and starts a new block.
@ -1130,6 +1164,7 @@ size_t ZSTD_compressBlock_btultra2(
&& (seqStore->sequences == seqStore->sequencesStart) /* no ldm */
&& (ms->window.dictLimit == ms->window.lowLimit) /* no dictionary */
&& (ms->window.dictLimit - ms->nextToUpdate <= 1) /* no prefix (note: intentional overflow, defined as 2-complement) */
&& (srcSize > ZSTD_PREDEF_THRESHOLD)
) {
ZSTD_initStats_ultra(ms, seqStore, rep, src, srcSize);
}