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zstd_opt: simplified ZSTD_getPrice() and ZSTD_updatePrice() interface

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ZSTD_getPrice() and ZSTD_updatePrice() accept normal matchlength as argument
instead of matchlength-MINMATCH,
which makes them easier / more logical to use and read.
Conversion is simply done internally.
This commit is contained in:
Yann Collet 2017-11-08 12:20:07 -08:00
parent bf730e2044
commit 5aa0352742
2 changed files with 26 additions and 25 deletions
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2
lib/compress/zstd_compress_internal.h
View File

@ -91,7 +91,7 @@ typedef struct {
U32 log2offCodeSum; /* pow2 to compare log2(offreq) to */
U32 factor; /* added to calculate ZSTD_getPrice() (but why?) */
/* end : updated by ZSTD_setLog2Prices */
U32 staticPrices; /* ? do not update statistics ? */
U32 staticPrices; /* prices follow a static cost structure, statistics are irrelevant */
U32 cachedPrice;
U32 cachedLitLength;
const BYTE* cachedLiterals;

49
lib/compress/zstd_opt.c
View File

@ -140,19 +140,19 @@ static U32 ZSTD_getLiteralPrice(optState_t* optPtr, U32 litLength, const BYTE* l
FORCE_INLINE_TEMPLATE U32 ZSTD_getPrice(optState_t* optPtr, U32 litLength, const BYTE* literals, U32 offset, U32 matchLength, const int ultra)
{
/* offset */
U32 price;
BYTE const offCode = (BYTE)ZSTD_highbit32(offset+1);
U32 const mlBase = matchLength - MINMATCH;
U32 price;
if (optPtr->staticPrices)
return ZSTD_getLiteralPrice(optPtr, litLength, literals) + ZSTD_highbit32((U32)matchLength+1) + 16 + offCode;
return ZSTD_getLiteralPrice(optPtr, litLength, literals) + ZSTD_highbit32((U32)mlBase+1) + 16 + offCode;
price = offCode + optPtr->log2offCodeSum - ZSTD_highbit32(optPtr->offCodeFreq[offCode]+1);
if (!ultra && offCode >= 20) price += (offCode-19)*2; /* handicap for long matches, to favor decompression speed */
/* match Length */
{ BYTE const ML_deltaCode = 36;
BYTE const mlCode = (matchLength>127) ? (BYTE)ZSTD_highbit32(matchLength) + ML_deltaCode : ML_Code[matchLength];
BYTE const mlCode = (mlBase>127) ? (BYTE)ZSTD_highbit32(mlBase) + ML_deltaCode : ML_Code[mlBase];
price += ML_bits[mlCode] + optPtr->log2matchLengthSum - ZSTD_highbit32(optPtr->matchLengthFreq[mlCode]+1);
}
@ -183,8 +183,9 @@ static void ZSTD_updatePrice(optState_t* optPtr, U32 litLength, const BYTE* lite
}
/* match Length */
{ const BYTE ML_deltaCode = 36;
const BYTE mlCode = (matchLength>127) ? (BYTE)ZSTD_highbit32(matchLength) + ML_deltaCode : ML_Code[matchLength];
{ U32 const mlBase = matchLength - MINMATCH;
const BYTE ML_deltaCode = 36;
const BYTE mlCode = (mlBase>127) ? (BYTE)ZSTD_highbit32(mlBase) + ML_deltaCode : ML_Code[mlBase];
optPtr->matchLengthFreq[mlCode]++;
optPtr->matchLengthSum++;
}
@ -465,7 +466,7 @@ size_t ZSTD_compressBlock_opt_generic(ZSTD_CCtx* ctx,
goto _storeSequence;
}
do {
U32 const repPrice = ZSTD_getPrice(optStatePtr, litlen, anchor, repCode - ll0, repLen - MINMATCH, ultra);
U32 const repPrice = ZSTD_getPrice(optStatePtr, litlen, anchor, repCode - ll0, repLen, ultra);
if (repLen > last_pos || repPrice < opt[repLen].price)
SET_PRICE(repLen, repLen, repCode, litlen, repPrice); /* note : macro modifies last_pos */
repLen--;
@ -492,7 +493,7 @@ size_t ZSTD_compressBlock_opt_generic(ZSTD_CCtx* ctx,
: matches[matchNb-1].len+1;
U32 const end = matches[matchNb].len;
while (pos <= end) {
U32 const matchPrice = ZSTD_getPrice(optStatePtr, litlen, anchor, matches[matchNb].off-1, pos - MINMATCH, ultra);
U32 const matchPrice = ZSTD_getPrice(optStatePtr, litlen, anchor, matches[matchNb].off-1, pos, ultra);
if (pos > last_pos || matchPrice < opt[pos].price)
SET_PRICE(pos, pos, matches[matchNb].off, litlen, matchPrice); /* note : macro modifies last_pos */
pos++;
@ -566,12 +567,12 @@ size_t ZSTD_compressBlock_opt_generic(ZSTD_CCtx* ctx,
if (opt[cur].mlen == 1) {
litlen = opt[cur].litlen;
if (cur > litlen) {
price = opt[cur - litlen].price + ZSTD_getPrice(optStatePtr, litlen, inr-litlen, best_off, mlen - MINMATCH, ultra);
price = opt[cur - litlen].price + ZSTD_getPrice(optStatePtr, litlen, inr-litlen, best_off, mlen, ultra);
} else
price = ZSTD_getPrice(optStatePtr, litlen, anchor, best_off, mlen - MINMATCH, ultra);
price = ZSTD_getPrice(optStatePtr, litlen, anchor, best_off, mlen, ultra);
} else {
litlen = 0;
price = opt[cur].price + ZSTD_getPrice(optStatePtr, 0, NULL, best_off, mlen - MINMATCH, ultra);
price = opt[cur].price + ZSTD_getPrice(optStatePtr, 0, NULL, best_off, mlen, ultra);
}
if (cur + mlen > last_pos || price <= opt[cur + mlen].price)
@ -598,12 +599,12 @@ size_t ZSTD_compressBlock_opt_generic(ZSTD_CCtx* ctx,
if (opt[cur].mlen == 1) {
litlen = opt[cur].litlen;
if (cur > litlen)
price = opt[cur - litlen].price + ZSTD_getPrice(optStatePtr, litlen, ip+cur-litlen, matches[u].off-1, mlen - MINMATCH, ultra);
price = opt[cur - litlen].price + ZSTD_getPrice(optStatePtr, litlen, ip+cur-litlen, matches[u].off-1, mlen, ultra);
else
price = ZSTD_getPrice(optStatePtr, litlen, anchor, matches[u].off-1, mlen - MINMATCH, ultra);
price = ZSTD_getPrice(optStatePtr, litlen, anchor, matches[u].off-1, mlen, ultra);
} else {
litlen = 0;
price = opt[cur].price + ZSTD_getPrice(optStatePtr, 0, NULL, matches[u].off-1, mlen - MINMATCH, ultra);
price = opt[cur].price + ZSTD_getPrice(optStatePtr, 0, NULL, matches[u].off-1, mlen, ultra);
}
if (cur + mlen > last_pos || (price < opt[cur + mlen].price))
@ -657,7 +658,7 @@ _storeSequence: /* cur, last_pos, best_mlen, best_off have to be set */
if (litLength==0) offset--;
}
ZSTD_updatePrice(optStatePtr, litLength, anchor, offset, mlen-MINMATCH);
ZSTD_updatePrice(optStatePtr, litLength, anchor, offset, mlen);
ZSTD_storeSeq(seqStorePtr, litLength, anchor, offset, mlen-MINMATCH);
anchor = ip = ip + mlen;
}
@ -748,7 +749,7 @@ size_t ZSTD_compressBlock_opt_extDict_generic(ZSTD_CCtx* ctx,
best_off = i - (ip==anchor);
litlen = opt[0].litlen;
do {
price = ZSTD_getPrice(optStatePtr, litlen, anchor, best_off, mlen - MINMATCH, ultra);
price = ZSTD_getPrice(optStatePtr, litlen, anchor, best_off, mlen, ultra);
if (mlen > last_pos || price < opt[mlen].price)
SET_PRICE(mlen, mlen, i, litlen, price); /* note : macro modifies last_pos */
mlen--;
@ -778,7 +779,7 @@ size_t ZSTD_compressBlock_opt_extDict_generic(ZSTD_CCtx* ctx,
best_mlen = matches[u].len;
litlen = opt[0].litlen;
while (mlen <= best_mlen) {
price = ZSTD_getPrice(optStatePtr, litlen, anchor, matches[u].off-1, mlen - MINMATCH, ultra);
price = ZSTD_getPrice(optStatePtr, litlen, anchor, matches[u].off-1, mlen, ultra);
if (mlen > last_pos || price < opt[mlen].price)
SET_PRICE(mlen, mlen, matches[u].off, litlen, price);
mlen++;
@ -849,12 +850,12 @@ size_t ZSTD_compressBlock_opt_extDict_generic(ZSTD_CCtx* ctx,
if (opt[cur].mlen == 1) {
litlen = opt[cur].litlen;
if (cur > litlen) {
price = opt[cur - litlen].price + ZSTD_getPrice(optStatePtr, litlen, inr-litlen, best_off, mlen - MINMATCH, ultra);
price = opt[cur - litlen].price + ZSTD_getPrice(optStatePtr, litlen, inr-litlen, best_off, mlen, ultra);
} else
price = ZSTD_getPrice(optStatePtr, litlen, anchor, best_off, mlen - MINMATCH, ultra);
price = ZSTD_getPrice(optStatePtr, litlen, anchor, best_off, mlen, ultra);
} else {
litlen = 0;
price = opt[cur].price + ZSTD_getPrice(optStatePtr, 0, NULL, best_off, mlen - MINMATCH, ultra);
price = opt[cur].price + ZSTD_getPrice(optStatePtr, 0, NULL, best_off, mlen, ultra);
}
if (cur + mlen > last_pos || price <= opt[cur + mlen].price)
@ -881,12 +882,12 @@ size_t ZSTD_compressBlock_opt_extDict_generic(ZSTD_CCtx* ctx,
if (opt[cur].mlen == 1) {
litlen = opt[cur].litlen;
if (cur > litlen)
price = opt[cur - litlen].price + ZSTD_getPrice(optStatePtr, litlen, ip+cur-litlen, matches[u].off-1, mlen - MINMATCH, ultra);
price = opt[cur - litlen].price + ZSTD_getPrice(optStatePtr, litlen, ip+cur-litlen, matches[u].off-1, mlen, ultra);
else
price = ZSTD_getPrice(optStatePtr, litlen, anchor, matches[u].off-1, mlen - MINMATCH, ultra);
price = ZSTD_getPrice(optStatePtr, litlen, anchor, matches[u].off-1, mlen, ultra);
} else {
litlen = 0;
price = opt[cur].price + ZSTD_getPrice(optStatePtr, 0, NULL, matches[u].off-1, mlen - MINMATCH, ultra);
price = opt[cur].price + ZSTD_getPrice(optStatePtr, 0, NULL, matches[u].off-1, mlen, ultra);
}
if (cur + mlen > last_pos || (price < opt[cur + mlen].price))
@ -941,7 +942,7 @@ _storeSequence: /* cur, last_pos, best_mlen, best_off have to be set */
if (litLength==0) offset--;
}
ZSTD_updatePrice(optStatePtr, litLength, anchor, offset, mlen-MINMATCH);
ZSTD_updatePrice(optStatePtr, litLength, anchor, offset, mlen);
ZSTD_storeSeq(seqStorePtr, litLength, anchor, offset, mlen-MINMATCH);
anchor = ip = ip + mlen;
} } /* for (cur=0; cur < last_pos; ) */