facebook
/
zstd
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

separate rawLiterals, fullLiterals and match costs 

removed one SET_PRICE() macro invocation
dev
Yann Collet 2017-11-28 12:14:46 -08:00
parent eee87cd6f2
commit 03f30d9dcb
1 changed files with 110 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

120
lib/compress/zstd_opt.c
View File

@ -96,6 +96,55 @@ static void ZSTD_rescaleFreqs(optState_t* optPtr, const BYTE* src, size_t srcSiz
}
static U32 ZSTD_rawLiteralsCost(const optState_t* const optPtr,
const BYTE* const literals, U32 const litLength)
{
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;
}
}
static U32 ZSTD_litLengthPrice(const optState_t* const optPtr, U32 const litLength)
{
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;
}
}
static U32 ZSTD_fullLiteralsCost(const optState_t* const optPtr,
const BYTE* const literals, U32 const litLength)
{
return ZSTD_rawLiteralsCost(optPtr, literals, litLength) + ZSTD_litLengthPrice(optPtr, litLength);
}
static U32 ZSTD_updateRawLiteralsCost(const optState_t* const optPtr,
U32 const previousCost,
const BYTE* const literals, U32 const litLength)
{
return previousCost + ZSTD_rawLiteralsCost(optPtr, literals, litLength);
}
static U32 ZSTD_newLiteralsCost(const optState_t* const optPtr,
U32 const previousCost, BYTE const newLiteral)
{
return previousCost
+ optPtr->log2litSum - ZSTD_highbit32(optPtr->litFreq[newLiteral]+1);
}
static U32 ZSTD_getLiteralPrice(optState_t* const optPtr,
U32 const litLength, const BYTE* const literals)
{
@ -139,10 +188,10 @@ static U32 ZSTD_getLiteralPrice(optState_t* const optPtr,
}
/* ZSTD_getPrice() :
/* ZSTD_getMatchPrice() :
* optLevel: when <2, favors small offset for decompression speed (improved cache efficiency) */
FORCE_INLINE_TEMPLATE U32 ZSTD_getPrice(optState_t* optPtr,
U32 const litLength, const BYTE* const literals, U32 const offset, U32 const matchLength,
FORCE_INLINE_TEMPLATE U32 ZSTD_getMatchPrice(optState_t* optPtr,
U32 const offset, U32 const matchLength,
int const optLevel)
{
U32 price;
@ -151,7 +200,7 @@ FORCE_INLINE_TEMPLATE U32 ZSTD_getPrice(optState_t* optPtr,
assert(matchLength >= MINMATCH);
if (optPtr->staticPrices) /* fixed scheme, do not use statistics */
return ZSTD_getLiteralPrice(optPtr, litLength, literals) + ZSTD_highbit32((U32)mlBase+1) + 16 + offCode;
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 */
@ -161,7 +210,18 @@ FORCE_INLINE_TEMPLATE U32 ZSTD_getPrice(optState_t* optPtr,
price += ML_bits[mlCode] + optPtr->log2matchLengthSum - ZSTD_highbit32(optPtr->matchLengthFreq[mlCode]+1);
}
price += ZSTD_getLiteralPrice(optPtr, litLength, literals) + optPtr->factor;
price += + optPtr->factor;
DEBUGLOG(8, "ZSTD_getMatchPrice(ml:%u) = %u", matchLength, price);
return price;
}
/* ZSTD_getPrice() :
* optLevel: when <2, favors small offset for decompression speed (improved cache efficiency) */
FORCE_INLINE_TEMPLATE U32 ZSTD_getPrice(optState_t* optPtr,
U32 const litLength, const BYTE* const literals, U32 const offset, U32 const matchLength,
int const optLevel)
{
U32 const price = ZSTD_getLiteralPrice(optPtr, litLength, literals) + ZSTD_getMatchPrice(optPtr, offset, matchLength, optLevel);
DEBUGLOG(8, "ZSTD_getPrice(ll:%u, ml:%u) = %u", litLength, matchLength, price);
return price;
}
@ -454,6 +514,39 @@ repcodes_t ZSTD_updateRep(U32 const rep[3], U32 const offset, U32 const ll0)
memcpy(opt[pos].rep, &rep_, sizeof(rep_)); \
}
typedef struct {
const BYTE* anchor;
U32 litlen;
U32 rawLitCost;
} cachedLiteralPrice_t;
static U32 ZSTD_updateCachedLPrice(const optState_t* const optStatePtr,
cachedLiteralPrice_t* const cachedLitPrice,
const BYTE* const anchor, U32 const litlen)
{
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(optStatePtr, startPosition, remainingLength);
cachedLitPrice->anchor = anchor;
cachedLitPrice->litlen = litlen;
cachedLitPrice->rawLitCost = rawLitCost;
return rawLitCost + ZSTD_litLengthPrice(optStatePtr, litlen);
}
}
FORCE_INLINE_TEMPLATE
size_t ZSTD_compressBlock_opt_generic(ZSTD_CCtx* ctx,
const void* src, size_t srcSize,
@ -476,6 +569,7 @@ size_t ZSTD_compressBlock_opt_generic(ZSTD_CCtx* ctx,
ZSTD_optimal_t* const opt = optStatePtr->priceTable;
ZSTD_match_t* const matches = optStatePtr->matchTable;
cachedLiteralPrice_t cachedLitPrice;
U32 rep[ZSTD_REP_NUM];
/* init */
@ -484,6 +578,7 @@ size_t ZSTD_compressBlock_opt_generic(ZSTD_CCtx* ctx,
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) {
@ -517,7 +612,8 @@ size_t ZSTD_compressBlock_opt_generic(ZSTD_CCtx* ctx,
} }
/* set prices for first matches starting position == 0 */
{ U32 pos;
{ U32 const literalsPrice = ZSTD_updateCachedLPrice(optStatePtr, &cachedLitPrice, anchor, litlen);
U32 pos;
U32 matchNb;
for (pos = 0; pos < minMatch; pos++) {
opt[pos].mlen = 1;
@ -528,7 +624,7 @@ size_t ZSTD_compressBlock_opt_generic(ZSTD_CCtx* ctx,
U32 const end = matches[matchNb].len;
repcodes_t const repHistory = ZSTD_updateRep(rep, offset, ll0);
for ( ; pos <= end ; pos++ ) {
U32 const matchPrice = ZSTD_getPrice(optStatePtr, litlen, anchor, offset, pos, optLevel);
U32 const matchPrice = literalsPrice + ZSTD_getMatchPrice(optStatePtr, offset, pos, optLevel);
DEBUGLOG(7, "rPos:%u => set initial price : %u",
pos, matchPrice);
opt[pos].mlen = pos;
@ -550,14 +646,18 @@ size_t ZSTD_compressBlock_opt_generic(ZSTD_CCtx* ctx,
{ U32 const litlen = (opt[cur-1].mlen == 1) ? opt[cur-1].litlen + 1 : 1;
U32 price;
if (cur > litlen) {
price = opt[cur - litlen].price + ZSTD_getLiteralPrice(optStatePtr, litlen, inr-litlen);
price = opt[cur - litlen].price + ZSTD_fullLiteralsCost(optStatePtr, inr-litlen, litlen);
} else {
price = ZSTD_getLiteralPrice(optStatePtr, litlen, anchor);
price = ZSTD_updateCachedLPrice(optStatePtr, &cachedLitPrice, anchor, litlen);
}
if (price <= opt[cur].price) {
DEBUGLOG(7, "rPos:%u : better price (%u<%u) using literal",
cur, price, opt[cur].price);
SET_PRICE(cur, 1/*mlen*/, 0/*offset*/, litlen, price, opt[cur-1].rep);
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 */