785 lines
33 KiB
C
785 lines
33 KiB
C
/*
|
|
* Copyright (c) 2016-present, Przemyslaw Skibinski, Yann Collet, Facebook, Inc.
|
|
* All rights reserved.
|
|
*
|
|
* This source code is licensed under both the BSD-style license (found in the
|
|
* LICENSE file in the root directory of this source tree) and the GPLv2 (found
|
|
* in the COPYING file in the root directory of this source tree).
|
|
* You may select, at your option, one of the above-listed licenses.
|
|
*/
|
|
|
|
#include "zstd_compress_internal.h"
|
|
#include "zstd_opt.h"
|
|
#include "zstd_lazy.h" /* ZSTD_updateTree, ZSTD_updateTree_extDict */
|
|
|
|
|
|
#define ZSTD_LITFREQ_ADD 2 /* scaling factor for litFreq, so that frequencies adapt faster to new stats. Also used for matchSum (?) */
|
|
#define ZSTD_FREQ_DIV 4 /* log factor when using previous stats to init next stats */
|
|
#define ZSTD_MAX_PRICE (1<<30)
|
|
|
|
|
|
/*-*************************************
|
|
* Price functions for optimal parser
|
|
***************************************/
|
|
static void ZSTD_setLog2Prices(optState_t* optPtr)
|
|
{
|
|
optPtr->log2litSum = ZSTD_highbit32(optPtr->litSum+1);
|
|
optPtr->log2litLengthSum = ZSTD_highbit32(optPtr->litLengthSum+1);
|
|
optPtr->log2matchLengthSum = ZSTD_highbit32(optPtr->matchLengthSum+1);
|
|
optPtr->log2offCodeSum = ZSTD_highbit32(optPtr->offCodeSum+1);
|
|
}
|
|
|
|
|
|
static void ZSTD_rescaleFreqs(optState_t* const optPtr,
|
|
const BYTE* const src, size_t const srcSize)
|
|
{
|
|
optPtr->staticPrices = 0;
|
|
|
|
if (optPtr->litLengthSum == 0) { /* first init */
|
|
unsigned u;
|
|
if (srcSize <= 1024) optPtr->staticPrices = 1;
|
|
|
|
assert(optPtr->litFreq!=NULL);
|
|
for (u=0; u<=MaxLit; u++)
|
|
optPtr->litFreq[u] = 0;
|
|
for (u=0; u<srcSize; u++)
|
|
optPtr->litFreq[src[u]]++;
|
|
optPtr->litSum = 0;
|
|
for (u=0; u<=MaxLit; u++) {
|
|
optPtr->litFreq[u] = 1 + (optPtr->litFreq[u] >> ZSTD_FREQ_DIV);
|
|
optPtr->litSum += optPtr->litFreq[u];
|
|
}
|
|
|
|
for (u=0; u<=MaxLL; u++)
|
|
optPtr->litLengthFreq[u] = 1;
|
|
optPtr->litLengthSum = MaxLL+1;
|
|
for (u=0; u<=MaxML; u++)
|
|
optPtr->matchLengthFreq[u] = 1;
|
|
optPtr->matchLengthSum = MaxML+1;
|
|
for (u=0; u<=MaxOff; u++)
|
|
optPtr->offCodeFreq[u] = 1;
|
|
optPtr->offCodeSum = (MaxOff+1);
|
|
|
|
} else {
|
|
unsigned u;
|
|
|
|
optPtr->litSum = 0;
|
|
for (u=0; u<=MaxLit; u++) {
|
|
optPtr->litFreq[u] = 1 + (optPtr->litFreq[u] >> (ZSTD_FREQ_DIV+1));
|
|
optPtr->litSum += optPtr->litFreq[u];
|
|
}
|
|
optPtr->litLengthSum = 0;
|
|
for (u=0; u<=MaxLL; u++) {
|
|
optPtr->litLengthFreq[u] = 1 + (optPtr->litLengthFreq[u]>>(ZSTD_FREQ_DIV+1));
|
|
optPtr->litLengthSum += optPtr->litLengthFreq[u];
|
|
}
|
|
optPtr->matchLengthSum = 0;
|
|
for (u=0; u<=MaxML; u++) {
|
|
optPtr->matchLengthFreq[u] = 1 + (optPtr->matchLengthFreq[u]>>ZSTD_FREQ_DIV);
|
|
optPtr->matchLengthSum += optPtr->matchLengthFreq[u];
|
|
}
|
|
optPtr->offCodeSum = 0;
|
|
for (u=0; u<=MaxOff; u++) {
|
|
optPtr->offCodeFreq[u] = 1 + (optPtr->offCodeFreq[u]>>ZSTD_FREQ_DIV);
|
|
optPtr->offCodeSum += optPtr->offCodeFreq[u];
|
|
}
|
|
}
|
|
|
|
ZSTD_setLog2Prices(optPtr);
|
|
}
|
|
|
|
|
|
/* ZSTD_rawLiteralsCost() :
|
|
* cost of literals (only) in given segment (which length can be null)
|
|
* does not include cost of literalLength symbol */
|
|
static U32 ZSTD_rawLiteralsCost(const BYTE* const literals, U32 const litLength,
|
|
const optState_t* const optPtr)
|
|
{
|
|
if (optPtr->staticPrices) return (litLength*6); /* 6 bit per literal - no statistic used */
|
|
if (litLength == 0) return 0;
|
|
|
|
/* literals */
|
|
{ U32 u;
|
|
U32 cost = litLength * optPtr->log2litSum;
|
|
for (u=0; u < litLength; u++)
|
|
cost -= ZSTD_highbit32(optPtr->litFreq[literals[u]]+1);
|
|
return cost;
|
|
}
|
|
}
|
|
|
|
/* ZSTD_litLengthPrice() :
|
|
* cost of literalLength symbol */
|
|
static U32 ZSTD_litLengthPrice(U32 const litLength, const optState_t* const optPtr)
|
|
{
|
|
if (optPtr->staticPrices) return ZSTD_highbit32((U32)litLength+1);
|
|
|
|
/* literal Length */
|
|
{ U32 const llCode = ZSTD_LLcode(litLength);
|
|
U32 const price = LL_bits[llCode] + optPtr->log2litLengthSum - ZSTD_highbit32(optPtr->litLengthFreq[llCode]+1);
|
|
return price;
|
|
}
|
|
}
|
|
|
|
/* ZSTD_litLengthPrice() :
|
|
* cost of the literal part of a sequence,
|
|
* including literals themselves, and literalLength symbol */
|
|
static U32 ZSTD_fullLiteralsCost(const BYTE* const literals, U32 const litLength,
|
|
const optState_t* const optPtr)
|
|
{
|
|
return ZSTD_rawLiteralsCost(literals, litLength, optPtr)
|
|
+ ZSTD_litLengthPrice(litLength, optPtr);
|
|
}
|
|
|
|
/* ZSTD_litLengthContribution() :
|
|
* @return ( cost(litlength) - cost(0) )
|
|
* this value can then be added to rawLiteralsCost()
|
|
* to provide a cost which is directly comparable to a match ending at same position */
|
|
static int ZSTD_litLengthContribution(U32 const litLength, const optState_t* const optPtr)
|
|
{
|
|
if (optPtr->staticPrices) return ZSTD_highbit32(litLength+1);
|
|
|
|
/* literal Length */
|
|
{ U32 const llCode = ZSTD_LLcode(litLength);
|
|
int const contribution = LL_bits[llCode]
|
|
+ ZSTD_highbit32(optPtr->litLengthFreq[0]+1)
|
|
- ZSTD_highbit32(optPtr->litLengthFreq[llCode]+1);
|
|
#if 1
|
|
return contribution;
|
|
#else
|
|
return MAX(0, contribution); /* sometimes better, sometimes not ... */
|
|
#endif
|
|
}
|
|
}
|
|
|
|
/* ZSTD_literalsContribution() :
|
|
* creates a fake cost for the literals part of a sequence
|
|
* which can be compared to the ending cost of a match
|
|
* should a new match start at this position */
|
|
static int ZSTD_literalsContribution(const BYTE* const literals, U32 const litLength,
|
|
const optState_t* const optPtr)
|
|
{
|
|
int const contribution = ZSTD_rawLiteralsCost(literals, litLength, optPtr)
|
|
+ ZSTD_litLengthContribution(litLength, optPtr);
|
|
return contribution;
|
|
}
|
|
|
|
/* ZSTD_getMatchPrice() :
|
|
* Provides the cost of the match part (offset + matchLength) of a sequence
|
|
* Must be combined with ZSTD_fullLiteralsCost() to get the full cost of a sequence.
|
|
* optLevel: when <2, favors small offset for decompression speed (improved cache efficiency) */
|
|
FORCE_INLINE_TEMPLATE U32 ZSTD_getMatchPrice(
|
|
U32 const offset, U32 const matchLength,
|
|
const optState_t* const optPtr,
|
|
int const optLevel)
|
|
{
|
|
U32 price;
|
|
U32 const offCode = ZSTD_highbit32(offset+1);
|
|
U32 const mlBase = matchLength - MINMATCH;
|
|
assert(matchLength >= MINMATCH);
|
|
|
|
if (optPtr->staticPrices) /* fixed scheme, do not use statistics */
|
|
return ZSTD_highbit32((U32)mlBase+1) + 16 + offCode;
|
|
|
|
price = offCode + optPtr->log2offCodeSum - ZSTD_highbit32(optPtr->offCodeFreq[offCode]+1);
|
|
if ((optLevel<2) /*static*/ && offCode >= 20) price += (offCode-19)*2; /* handicap for long distance offsets, favor decompression speed */
|
|
|
|
/* match Length */
|
|
{ U32 const mlCode = ZSTD_MLcode(mlBase);
|
|
price += ML_bits[mlCode] + optPtr->log2matchLengthSum - ZSTD_highbit32(optPtr->matchLengthFreq[mlCode]+1);
|
|
}
|
|
|
|
DEBUGLOG(8, "ZSTD_getMatchPrice(ml:%u) = %u", matchLength, price);
|
|
return price;
|
|
}
|
|
|
|
static void ZSTD_updateStats(optState_t* const optPtr,
|
|
U32 litLength, const BYTE* literals,
|
|
U32 offsetCode, U32 matchLength)
|
|
{
|
|
/* literals */
|
|
{ U32 u;
|
|
for (u=0; u < litLength; u++)
|
|
optPtr->litFreq[literals[u]] += ZSTD_LITFREQ_ADD;
|
|
optPtr->litSum += litLength*ZSTD_LITFREQ_ADD;
|
|
}
|
|
|
|
/* literal Length */
|
|
{ U32 const llCode = ZSTD_LLcode(litLength);
|
|
optPtr->litLengthFreq[llCode]++;
|
|
optPtr->litLengthSum++;
|
|
}
|
|
|
|
/* match offset code (0-2=>repCode; 3+=>offset+2) */
|
|
{ U32 const offCode = ZSTD_highbit32(offsetCode+1);
|
|
assert(offCode <= MaxOff);
|
|
optPtr->offCodeFreq[offCode]++;
|
|
optPtr->offCodeSum++;
|
|
}
|
|
|
|
/* match Length */
|
|
{ U32 const mlBase = matchLength - MINMATCH;
|
|
U32 const mlCode = ZSTD_MLcode(mlBase);
|
|
optPtr->matchLengthFreq[mlCode]++;
|
|
optPtr->matchLengthSum++;
|
|
}
|
|
}
|
|
|
|
|
|
/* ZSTD_readMINMATCH() :
|
|
* function safe only for comparisons
|
|
* assumption : memPtr must be at least 4 bytes before end of buffer */
|
|
MEM_STATIC U32 ZSTD_readMINMATCH(const void* memPtr, U32 length)
|
|
{
|
|
switch (length)
|
|
{
|
|
default :
|
|
case 4 : return MEM_read32(memPtr);
|
|
case 3 : if (MEM_isLittleEndian())
|
|
return MEM_read32(memPtr)<<8;
|
|
else
|
|
return MEM_read32(memPtr)>>8;
|
|
}
|
|
}
|
|
|
|
|
|
/* Update hashTable3 up to ip (excluded)
|
|
Assumption : always within prefix (i.e. not within extDict) */
|
|
static U32 ZSTD_insertAndFindFirstIndexHash3 (ZSTD_CCtx* const cctx, const BYTE* const ip)
|
|
{
|
|
U32* const hashTable3 = cctx->hashTable3;
|
|
U32 const hashLog3 = cctx->hashLog3;
|
|
const BYTE* const base = cctx->base;
|
|
U32 idx = cctx->nextToUpdate3;
|
|
U32 const target = cctx->nextToUpdate3 = (U32)(ip - base);
|
|
size_t const hash3 = ZSTD_hash3Ptr(ip, hashLog3);
|
|
|
|
while(idx < target) {
|
|
hashTable3[ZSTD_hash3Ptr(base+idx, hashLog3)] = idx;
|
|
idx++;
|
|
}
|
|
|
|
return hashTable3[hash3];
|
|
}
|
|
|
|
|
|
/*-*************************************
|
|
* Binary Tree search
|
|
***************************************/
|
|
FORCE_INLINE_TEMPLATE
|
|
U32 ZSTD_insertBtAndGetAllMatches (
|
|
ZSTD_CCtx* zc,
|
|
const BYTE* const ip, const BYTE* const iLimit, int const extDict,
|
|
U32 nbCompares, U32 const mls, U32 const sufficient_len,
|
|
U32 rep[ZSTD_REP_NUM], U32 const ll0,
|
|
ZSTD_match_t* matches, const U32 lengthToBeat)
|
|
{
|
|
const BYTE* const base = zc->base;
|
|
U32 const current = (U32)(ip-base);
|
|
U32 const hashLog = zc->appliedParams.cParams.hashLog;
|
|
U32 const minMatch = (mls==3) ? 3 : 4;
|
|
U32* const hashTable = zc->hashTable;
|
|
size_t const h = ZSTD_hashPtr(ip, hashLog, mls);
|
|
U32 matchIndex = hashTable[h];
|
|
U32* const bt = zc->chainTable;
|
|
U32 const btLog = zc->appliedParams.cParams.chainLog - 1;
|
|
U32 const btMask= (1U << btLog) - 1;
|
|
size_t commonLengthSmaller=0, commonLengthLarger=0;
|
|
const BYTE* const dictBase = zc->dictBase;
|
|
U32 const dictLimit = zc->dictLimit;
|
|
const BYTE* const dictEnd = dictBase + dictLimit;
|
|
const BYTE* const prefixStart = base + dictLimit;
|
|
U32 const btLow = btMask >= current ? 0 : current - btMask;
|
|
U32 const windowLow = zc->lowLimit;
|
|
U32* smallerPtr = bt + 2*(current&btMask);
|
|
U32* largerPtr = bt + 2*(current&btMask) + 1;
|
|
U32 matchEndIdx = current+8+1; /* farthest referenced position of any match => detects repetitive patterns */
|
|
U32 dummy32; /* to be nullified at the end */
|
|
U32 mnum = 0;
|
|
|
|
size_t bestLength = lengthToBeat-1;
|
|
DEBUGLOG(7, "ZSTD_insertBtAndGetAllMatches");
|
|
|
|
/* check repCode */
|
|
{ U32 const lastR = ZSTD_REP_NUM + ll0;
|
|
U32 repCode;
|
|
for (repCode = ll0; repCode < lastR; repCode++) {
|
|
U32 const repOffset = (repCode==ZSTD_REP_NUM) ? (rep[0] - 1) : rep[repCode];
|
|
U32 const repIndex = current - repOffset;
|
|
U32 repLen = 0;
|
|
assert(current >= dictLimit);
|
|
if (repOffset-1 /* intentional overflow, discards 0 and -1 */ < current-dictLimit) { /* equivalent to `current > repIndex >= dictLimit` */
|
|
if (ZSTD_readMINMATCH(ip, minMatch) == ZSTD_readMINMATCH(ip - repOffset, minMatch)) {
|
|
repLen = (U32)ZSTD_count(ip+minMatch, ip+minMatch-repOffset, iLimit) + minMatch;
|
|
}
|
|
} else { /* repIndex < dictLimit || repIndex >= current */
|
|
const BYTE* const repMatch = dictBase + repIndex;
|
|
assert(current >= windowLow);
|
|
if ( extDict /* this case only valid in extDict mode */
|
|
&& ( ((repOffset-1) /*intentional overflow*/ < current - windowLow) /* equivalent to `current > repIndex >= windowLow` */
|
|
& (((U32)((dictLimit-1) - repIndex) >= 3) ) /* intentional overflow : do not test positions overlapping 2 memory segments */)
|
|
&& (ZSTD_readMINMATCH(ip, minMatch) == ZSTD_readMINMATCH(repMatch, minMatch)) ) {
|
|
repLen = (U32)ZSTD_count_2segments(ip+minMatch, repMatch+minMatch, iLimit, dictEnd, prefixStart) + minMatch;
|
|
} }
|
|
/* save longer solution */
|
|
if (repLen > bestLength) {
|
|
DEBUGLOG(8, "found rep-match %u of length %u",
|
|
repCode - ll0, (U32)repLen);
|
|
bestLength = repLen;
|
|
matches[mnum].off = repCode - ll0;
|
|
matches[mnum].len = (U32)repLen;
|
|
mnum++;
|
|
if ( (repLen > sufficient_len)
|
|
| (ip+repLen == iLimit) ) { /* best possible */
|
|
return mnum;
|
|
} } } }
|
|
|
|
/* HC3 match finder */
|
|
if ((mls == 3) /*static*/ && (bestLength < mls)) {
|
|
U32 const matchIndex3 = ZSTD_insertAndFindFirstIndexHash3 (zc, ip);
|
|
if ((matchIndex3 > windowLow)
|
|
& (current - matchIndex3 < (1<<18)) /*heuristic : longer distance likely too expensive*/ ) {
|
|
size_t mlen;
|
|
if ((!extDict) /*static*/ || (matchIndex3 >= dictLimit)) {
|
|
const BYTE* const match = base + matchIndex3;
|
|
mlen = ZSTD_count(ip, match, iLimit);
|
|
} else {
|
|
const BYTE* const match = dictBase + matchIndex3;
|
|
mlen = ZSTD_count_2segments(ip, match, iLimit, dictEnd, prefixStart);
|
|
}
|
|
|
|
/* save best solution */
|
|
if (mlen >= mls /* == 3 > bestLength */) {
|
|
DEBUGLOG(8, "found small match with hlog3, of length %u",
|
|
(U32)mlen);
|
|
bestLength = mlen;
|
|
assert(current > matchIndex3);
|
|
assert(mnum==0); /* no prior solution */
|
|
matches[0].off = (current - matchIndex3) + ZSTD_REP_MOVE;
|
|
matches[0].len = (U32)mlen;
|
|
mnum = 1;
|
|
if ( (mlen > sufficient_len) |
|
|
(ip+mlen == iLimit) ) { /* best possible length */
|
|
zc->nextToUpdate = current+1; /* skip insertion */
|
|
return 1;
|
|
} } } }
|
|
|
|
hashTable[h] = current; /* Update Hash Table */
|
|
|
|
while (nbCompares-- && (matchIndex > windowLow)) {
|
|
U32* const nextPtr = bt + 2*(matchIndex & btMask);
|
|
size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */
|
|
const BYTE* match;
|
|
assert(current > matchIndex);
|
|
|
|
if ((!extDict) || (matchIndex+matchLength >= dictLimit)) {
|
|
assert(matchIndex+matchLength >= dictLimit); /* ensure the condition is correct when !extDict */
|
|
match = base + matchIndex;
|
|
matchLength += ZSTD_count(ip+matchLength, match+matchLength, iLimit);
|
|
} else {
|
|
match = dictBase + matchIndex;
|
|
matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iLimit, dictEnd, prefixStart);
|
|
if (matchIndex+matchLength >= dictLimit)
|
|
match = base + matchIndex; /* prepare for match[matchLength] */
|
|
}
|
|
|
|
if (matchLength > bestLength) {
|
|
DEBUGLOG(8, "found match of length %u at distance %u",
|
|
(U32)matchLength, current - matchIndex);
|
|
assert(matchEndIdx > matchIndex);
|
|
if (matchLength > matchEndIdx - matchIndex)
|
|
matchEndIdx = matchIndex + (U32)matchLength;
|
|
bestLength = matchLength;
|
|
matches[mnum].off = (current - matchIndex) + ZSTD_REP_MOVE;
|
|
matches[mnum].len = (U32)matchLength;
|
|
mnum++;
|
|
if (matchLength > ZSTD_OPT_NUM) break;
|
|
if (ip+matchLength == iLimit) { /* equal : no way to know if inf or sup */
|
|
break; /* drop, to preserve bt consistency (miss a little bit of compression) */
|
|
}
|
|
}
|
|
|
|
if (match[matchLength] < ip[matchLength]) {
|
|
/* match smaller than current */
|
|
*smallerPtr = matchIndex; /* update smaller idx */
|
|
commonLengthSmaller = matchLength; /* all smaller will now have at least this guaranteed common length */
|
|
if (matchIndex <= btLow) { smallerPtr=&dummy32; break; } /* beyond tree size, stop the search */
|
|
smallerPtr = nextPtr+1; /* new candidate => larger than match, which was smaller than current */
|
|
matchIndex = nextPtr[1]; /* new matchIndex, larger than previous, closer to current */
|
|
} else {
|
|
*largerPtr = matchIndex;
|
|
commonLengthLarger = matchLength;
|
|
if (matchIndex <= btLow) { largerPtr=&dummy32; break; } /* beyond tree size, stop the search */
|
|
largerPtr = nextPtr;
|
|
matchIndex = nextPtr[0];
|
|
} }
|
|
|
|
*smallerPtr = *largerPtr = 0;
|
|
|
|
assert(matchEndIdx > current+8);
|
|
zc->nextToUpdate = matchEndIdx - 8; /* skip repetitive patterns */
|
|
return mnum;
|
|
}
|
|
|
|
|
|
FORCE_INLINE_TEMPLATE U32 ZSTD_BtGetAllMatches (
|
|
ZSTD_CCtx* zc, /* Index table will be updated */
|
|
const BYTE* ip, const BYTE* const iHighLimit, int const extDict,
|
|
U32 const maxNbAttempts, U32 const matchLengthSearch, U32 const sufficient_len,
|
|
U32 rep[ZSTD_REP_NUM], U32 const ll0,
|
|
ZSTD_match_t* matches, U32 const lengthToBeat)
|
|
{
|
|
DEBUGLOG(7, "ZSTD_BtGetAllMatches");
|
|
if (ip < zc->base + zc->nextToUpdate) return 0; /* skipped area */
|
|
if (extDict) ZSTD_updateTree_extDict(zc, ip, iHighLimit, maxNbAttempts, matchLengthSearch);
|
|
else ZSTD_updateTree(zc, ip, iHighLimit, maxNbAttempts, matchLengthSearch);
|
|
switch(matchLengthSearch)
|
|
{
|
|
case 3 : return ZSTD_insertBtAndGetAllMatches(zc, ip, iHighLimit, extDict, maxNbAttempts, 3, sufficient_len, rep, ll0, matches, lengthToBeat);
|
|
default :
|
|
case 4 : return ZSTD_insertBtAndGetAllMatches(zc, ip, iHighLimit, extDict, maxNbAttempts, 4, sufficient_len, rep, ll0, matches, lengthToBeat);
|
|
case 5 : return ZSTD_insertBtAndGetAllMatches(zc, ip, iHighLimit, extDict, maxNbAttempts, 5, sufficient_len, rep, ll0, matches, lengthToBeat);
|
|
case 7 :
|
|
case 6 : return ZSTD_insertBtAndGetAllMatches(zc, ip, iHighLimit, extDict, maxNbAttempts, 6, sufficient_len, rep, ll0, matches, lengthToBeat);
|
|
}
|
|
}
|
|
|
|
|
|
/*-*******************************
|
|
* Optimal parser
|
|
*********************************/
|
|
typedef struct repcodes_s {
|
|
U32 rep[3];
|
|
} repcodes_t;
|
|
|
|
repcodes_t ZSTD_updateRep(U32 const rep[3], U32 const offset, U32 const ll0)
|
|
{
|
|
repcodes_t newReps;
|
|
if (offset >= ZSTD_REP_NUM) { /* full offset */
|
|
newReps.rep[2] = rep[1];
|
|
newReps.rep[1] = rep[0];
|
|
newReps.rep[0] = offset - ZSTD_REP_MOVE;
|
|
} else { /* repcode */
|
|
U32 const repCode = offset + ll0;
|
|
if (repCode > 0) { /* note : if repCode==0, no change */
|
|
U32 const currentOffset = (repCode==ZSTD_REP_NUM) ? (rep[0] - 1) : rep[repCode];
|
|
newReps.rep[2] = (repCode >= 2) ? rep[1] : rep[2];
|
|
newReps.rep[1] = rep[0];
|
|
newReps.rep[0] = currentOffset;
|
|
} else { /* repCode == 0 */
|
|
memcpy(&newReps, rep, sizeof(newReps));
|
|
}
|
|
}
|
|
return newReps;
|
|
}
|
|
|
|
|
|
typedef struct {
|
|
const BYTE* anchor;
|
|
U32 litlen;
|
|
U32 rawLitCost;
|
|
} cachedLiteralPrice_t;
|
|
|
|
static U32 ZSTD_rawLiteralsCost_cached(
|
|
cachedLiteralPrice_t* const cachedLitPrice,
|
|
const BYTE* const anchor, U32 const litlen,
|
|
const optState_t* const optStatePtr)
|
|
{
|
|
U32 startCost;
|
|
U32 remainingLength;
|
|
const BYTE* startPosition;
|
|
|
|
if (anchor == cachedLitPrice->anchor) {
|
|
startCost = cachedLitPrice->rawLitCost;
|
|
startPosition = anchor + cachedLitPrice->litlen;
|
|
assert(litlen >= cachedLitPrice->litlen);
|
|
remainingLength = litlen - cachedLitPrice->litlen;
|
|
} else {
|
|
startCost = 0;
|
|
startPosition = anchor;
|
|
remainingLength = litlen;
|
|
}
|
|
|
|
{ U32 const rawLitCost = startCost + ZSTD_rawLiteralsCost(startPosition, remainingLength, optStatePtr);
|
|
cachedLitPrice->anchor = anchor;
|
|
cachedLitPrice->litlen = litlen;
|
|
cachedLitPrice->rawLitCost = rawLitCost;
|
|
return rawLitCost;
|
|
}
|
|
}
|
|
|
|
static U32 ZSTD_fullLiteralsCost_cached(
|
|
cachedLiteralPrice_t* const cachedLitPrice,
|
|
const BYTE* const anchor, U32 const litlen,
|
|
const optState_t* const optStatePtr)
|
|
{
|
|
return ZSTD_rawLiteralsCost_cached(cachedLitPrice, anchor, litlen, optStatePtr)
|
|
+ ZSTD_litLengthPrice(litlen, optStatePtr);
|
|
}
|
|
|
|
static int ZSTD_literalsContribution_cached(
|
|
cachedLiteralPrice_t* const cachedLitPrice,
|
|
const BYTE* const anchor, U32 const litlen,
|
|
const optState_t* const optStatePtr)
|
|
{
|
|
int const contribution = ZSTD_rawLiteralsCost_cached(cachedLitPrice, anchor, litlen, optStatePtr)
|
|
+ ZSTD_litLengthContribution(litlen, optStatePtr);
|
|
return contribution;
|
|
}
|
|
|
|
FORCE_INLINE_TEMPLATE
|
|
size_t ZSTD_compressBlock_opt_generic(ZSTD_CCtx* ctx,
|
|
const void* src, size_t srcSize,
|
|
const int optLevel, const int extDict)
|
|
{
|
|
seqStore_t* const seqStorePtr = &(ctx->seqStore);
|
|
optState_t* const optStatePtr = &(ctx->optState);
|
|
const BYTE* const istart = (const BYTE*)src;
|
|
const BYTE* ip = istart;
|
|
const BYTE* anchor = istart;
|
|
const BYTE* const iend = istart + srcSize;
|
|
const BYTE* const ilimit = iend - 8;
|
|
const BYTE* const base = ctx->base;
|
|
const BYTE* const prefixStart = base + ctx->dictLimit;
|
|
|
|
U32 const maxSearches = 1U << ctx->appliedParams.cParams.searchLog;
|
|
U32 const sufficient_len = MIN(ctx->appliedParams.cParams.targetLength, ZSTD_OPT_NUM -1);
|
|
U32 const mls = ctx->appliedParams.cParams.searchLength;
|
|
U32 const minMatch = (ctx->appliedParams.cParams.searchLength == 3) ? 3 : 4;
|
|
|
|
ZSTD_optimal_t* const opt = optStatePtr->priceTable;
|
|
ZSTD_match_t* const matches = optStatePtr->matchTable;
|
|
cachedLiteralPrice_t cachedLitPrice;
|
|
U32 rep[ZSTD_REP_NUM];
|
|
|
|
/* init */
|
|
DEBUGLOG(5, "ZSTD_compressBlock_opt_generic");
|
|
ctx->nextToUpdate3 = ctx->nextToUpdate;
|
|
ZSTD_rescaleFreqs(optStatePtr, (const BYTE*)src, srcSize);
|
|
ip += (ip==prefixStart);
|
|
{ int i; for (i=0; i<ZSTD_REP_NUM; i++) rep[i]=seqStorePtr->rep[i]; }
|
|
memset(&cachedLitPrice, 0, sizeof(cachedLitPrice));
|
|
|
|
/* Match Loop */
|
|
while (ip < ilimit) {
|
|
U32 cur, last_pos = 0;
|
|
U32 best_mlen, best_off;
|
|
|
|
/* find first match */
|
|
{ U32 const litlen = (U32)(ip - anchor);
|
|
U32 const ll0 = !litlen;
|
|
U32 const nbMatches = ZSTD_BtGetAllMatches(ctx, ip, iend, extDict, maxSearches, mls, sufficient_len, rep, ll0, matches, minMatch);
|
|
if (!nbMatches) { ip++; continue; }
|
|
|
|
/* initialize opt[0] */
|
|
{ U32 i ; for (i=0; i<ZSTD_REP_NUM; i++) opt[0].rep[i] = rep[i]; }
|
|
opt[0].mlen = 1;
|
|
opt[0].litlen = litlen;
|
|
|
|
/* large match -> immediate encoding */
|
|
{ U32 const maxML = matches[nbMatches-1].len;
|
|
DEBUGLOG(7, "found %u matches of maxLength=%u and offset=%u at cPos=%u => start new serie",
|
|
nbMatches, maxML, matches[nbMatches-1].off, (U32)(ip-prefixStart));
|
|
|
|
if (maxML > sufficient_len) {
|
|
best_mlen = maxML;
|
|
best_off = matches[nbMatches-1].off;
|
|
DEBUGLOG(7, "large match (%u>%u), immediate encoding",
|
|
best_mlen, sufficient_len);
|
|
cur = 0;
|
|
last_pos = 1;
|
|
goto _shortestPath;
|
|
} }
|
|
|
|
/* set prices for first matches starting position == 0 */
|
|
{ U32 const literalsPrice = ZSTD_fullLiteralsCost_cached(&cachedLitPrice, anchor, litlen, optStatePtr);
|
|
U32 pos;
|
|
U32 matchNb;
|
|
for (pos = 0; pos < minMatch; pos++) {
|
|
opt[pos].mlen = 1;
|
|
opt[pos].price = ZSTD_MAX_PRICE;
|
|
}
|
|
for (matchNb = 0; matchNb < nbMatches; matchNb++) {
|
|
U32 const offset = matches[matchNb].off;
|
|
U32 const end = matches[matchNb].len;
|
|
repcodes_t const repHistory = ZSTD_updateRep(rep, offset, ll0);
|
|
for ( ; pos <= end ; pos++ ) {
|
|
U32 const matchPrice = literalsPrice + ZSTD_getMatchPrice(offset, pos, optStatePtr, optLevel);
|
|
DEBUGLOG(7, "rPos:%u => set initial price : %u",
|
|
pos, matchPrice);
|
|
opt[pos].mlen = pos;
|
|
opt[pos].off = offset;
|
|
opt[pos].litlen = litlen;
|
|
opt[pos].price = matchPrice;
|
|
memcpy(opt[pos].rep, &repHistory, sizeof(repHistory));
|
|
} }
|
|
last_pos = pos-1;
|
|
}
|
|
}
|
|
|
|
/* check further positions */
|
|
for (cur = 1; cur <= last_pos; cur++) {
|
|
const BYTE* const inr = ip + cur;
|
|
assert(cur < ZSTD_OPT_NUM);
|
|
|
|
/* Fix current position with one literal if cheaper */
|
|
{ U32 const litlen = (opt[cur-1].mlen == 1) ? opt[cur-1].litlen + 1 : 1;
|
|
int price; /* note : contribution can be negative */
|
|
if (cur > litlen) {
|
|
price = opt[cur - litlen].price + ZSTD_literalsContribution(inr-litlen, litlen, optStatePtr);
|
|
} else {
|
|
price = ZSTD_literalsContribution_cached(&cachedLitPrice, anchor, litlen, optStatePtr);
|
|
}
|
|
assert(price < 1000000000); /* overflow check */
|
|
if (price <= opt[cur].price) {
|
|
DEBUGLOG(7, "rPos:%u : better price (%u<%u) using literal",
|
|
cur, price, opt[cur].price);
|
|
opt[cur].mlen = 1;
|
|
opt[cur].off = 0;
|
|
opt[cur].litlen = litlen;
|
|
opt[cur].price = price;
|
|
memcpy(opt[cur].rep, opt[cur-1].rep, sizeof(opt[cur].rep));
|
|
} }
|
|
|
|
/* last match must start at a minimum distance of 8 from oend */
|
|
if (inr > ilimit) continue;
|
|
|
|
if (cur == last_pos) break;
|
|
|
|
if ( (optLevel==0) /*static*/
|
|
&& (opt[cur+1].price <= opt[cur].price) )
|
|
continue; /* skip unpromising positions; about ~+6% speed, -0.01 ratio */
|
|
|
|
{ U32 const ll0 = (opt[cur].mlen != 1);
|
|
U32 const litlen = (opt[cur].mlen == 1) ? opt[cur].litlen : 0;
|
|
U32 const previousPrice = (cur > litlen) ? opt[cur-litlen].price : 0;
|
|
U32 const basePrice = previousPrice + ZSTD_fullLiteralsCost(inr-litlen, litlen, optStatePtr);
|
|
U32 const nbMatches = ZSTD_BtGetAllMatches(ctx, inr, iend, extDict, maxSearches, mls, sufficient_len, opt[cur].rep, ll0, matches, minMatch);
|
|
U32 matchNb;
|
|
if (!nbMatches) continue;
|
|
|
|
{ U32 const maxML = matches[nbMatches-1].len;
|
|
DEBUGLOG(7, "rPos:%u, found %u matches, of maxLength=%u",
|
|
cur, nbMatches, maxML);
|
|
|
|
if ( (maxML > sufficient_len)
|
|
| (cur + maxML >= ZSTD_OPT_NUM) ) {
|
|
best_mlen = maxML;
|
|
best_off = matches[nbMatches-1].off;
|
|
last_pos = cur + 1;
|
|
goto _shortestPath;
|
|
}
|
|
}
|
|
|
|
/* set prices using matches found at position == cur */
|
|
for (matchNb = 0; matchNb < nbMatches; matchNb++) {
|
|
U32 const offset = matches[matchNb].off;
|
|
repcodes_t const repHistory = ZSTD_updateRep(opt[cur].rep, offset, ll0);
|
|
U32 const lastML = matches[matchNb].len;
|
|
U32 const startML = (matchNb>0) ? matches[matchNb-1].len+1 : minMatch;
|
|
U32 mlen;
|
|
|
|
DEBUGLOG(7, "testing match %u => offCode=%u, mlen=%u, llen=%u",
|
|
matchNb, matches[matchNb].off, lastML, litlen);
|
|
|
|
for (mlen = lastML; mlen >= startML; mlen--) {
|
|
U32 const pos = cur + mlen;
|
|
int const price = basePrice + ZSTD_getMatchPrice(offset, mlen, optStatePtr, optLevel);
|
|
|
|
if ((pos > last_pos) || (price < opt[pos].price)) {
|
|
DEBUGLOG(7, "rPos:%u => new better price (%u<%u)",
|
|
pos, price, opt[pos].price);
|
|
while (last_pos < pos) { opt[last_pos+1].price = ZSTD_MAX_PRICE; last_pos++; }
|
|
opt[pos].mlen = mlen;
|
|
opt[pos].off = offset;
|
|
opt[pos].litlen = litlen;
|
|
opt[pos].price = price;
|
|
memcpy(opt[pos].rep, &repHistory, sizeof(repHistory));
|
|
} else {
|
|
if (optLevel==0) break; /* gets ~+10% speed for about -0.01 ratio loss */
|
|
}
|
|
} } }
|
|
} /* for (cur = 1; cur <= last_pos; cur++) */
|
|
|
|
best_mlen = opt[last_pos].mlen;
|
|
best_off = opt[last_pos].off;
|
|
cur = last_pos - best_mlen;
|
|
|
|
_shortestPath: /* cur, last_pos, best_mlen, best_off have to be set */
|
|
assert(opt[0].mlen == 1);
|
|
|
|
/* reverse traversal */
|
|
DEBUGLOG(7, "start reverse traversal (last_pos:%u, cur:%u)",
|
|
last_pos, cur);
|
|
{ U32 selectedMatchLength = best_mlen;
|
|
U32 selectedOffset = best_off;
|
|
U32 pos = cur;
|
|
while (1) {
|
|
U32 const mlen = opt[pos].mlen;
|
|
U32 const off = opt[pos].off;
|
|
opt[pos].mlen = selectedMatchLength;
|
|
opt[pos].off = selectedOffset;
|
|
selectedMatchLength = mlen;
|
|
selectedOffset = off;
|
|
if (mlen > pos) break;
|
|
pos -= mlen;
|
|
} }
|
|
|
|
/* save sequences */
|
|
{ U32 pos;
|
|
for (pos=0; pos < last_pos; ) {
|
|
U32 const llen = (U32)(ip - anchor);
|
|
U32 const mlen = opt[pos].mlen;
|
|
U32 const offset = opt[pos].off;
|
|
if (mlen == 1) { ip++; pos++; continue; } /* literal position => move on */
|
|
pos += mlen; ip += mlen;
|
|
|
|
/* repcodes update : like ZSTD_updateRep(), but update in place */
|
|
if (offset >= ZSTD_REP_NUM) { /* full offset */
|
|
rep[2] = rep[1];
|
|
rep[1] = rep[0];
|
|
rep[0] = offset - ZSTD_REP_MOVE;
|
|
} else { /* repcode */
|
|
U32 const repCode = offset + (llen==0);
|
|
if (repCode) { /* note : if repCode==0, no change */
|
|
U32 const currentOffset = (repCode==ZSTD_REP_NUM) ? (rep[0] - 1) : rep[repCode];
|
|
if (repCode >= 2) rep[2] = rep[1];
|
|
rep[1] = rep[0];
|
|
rep[0] = currentOffset;
|
|
}
|
|
}
|
|
|
|
ZSTD_updateStats(optStatePtr, llen, anchor, offset, mlen);
|
|
ZSTD_storeSeq(seqStorePtr, llen, anchor, offset, mlen-MINMATCH);
|
|
anchor = ip;
|
|
} }
|
|
ZSTD_setLog2Prices(optStatePtr);
|
|
} /* while (ip < ilimit) */
|
|
|
|
/* Save reps for next block */
|
|
{ int i; for (i=0; i<ZSTD_REP_NUM; i++) seqStorePtr->repToConfirm[i] = rep[i]; }
|
|
|
|
/* Return the last literals size */
|
|
return iend - anchor;
|
|
}
|
|
|
|
|
|
size_t ZSTD_compressBlock_btopt(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
|
|
{
|
|
DEBUGLOG(5, "ZSTD_compressBlock_btopt");
|
|
return ZSTD_compressBlock_opt_generic(ctx, src, srcSize, 0 /*optLevel*/, 0 /*extDict*/);
|
|
}
|
|
|
|
size_t ZSTD_compressBlock_btultra(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
|
|
{
|
|
return ZSTD_compressBlock_opt_generic(ctx, src, srcSize, 2 /*optLevel*/, 0 /*extDict*/);
|
|
}
|
|
|
|
size_t ZSTD_compressBlock_btopt_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
|
|
{
|
|
return ZSTD_compressBlock_opt_generic(ctx, src, srcSize, 0 /*optLevel*/, 1 /*extDict*/);
|
|
}
|
|
|
|
size_t ZSTD_compressBlock_btultra_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
|
|
{
|
|
return ZSTD_compressBlock_opt_generic(ctx, src, srcSize, 2 /*optLevel*/, 1 /*extDict*/);
|
|
}
|