return (litLength*6) * BITCOST_MULTIPLIER; /* 6 bit per literal - no statistic used */
/* dynamic statistics */
- { U32 price = litLength * optPtr->litSumBasePrice;
- U32 u;
- for (u=0; u < litLength; u++)
- price -= WEIGHT(optPtr->litFreq[literals[u]], optLevel);
+ { U32 price, u;
+ for (u=0, price=0; u < litLength; u++) {
+ U32 const litWeight = WEIGHT(optPtr->litFreq[literals[u]], optLevel);
+ U32 litCost = optPtr->litSumBasePrice - litWeight;
+ //if (litCost < BITCOST_MULTIPLIER) litCost = BITCOST_MULTIPLIER; /* minimum 1 bit per symbol (huffman) */
+ price += litCost;
+ }
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,
- int optLevel)
-{
- return ZSTD_rawLiteralsCost(literals, litLength, optPtr, optLevel)
- + ZSTD_litLengthPrice(litLength, optPtr, optLevel);
-}
-
/* ZSTD_litLengthContribution() :
* @return ( cost(litlength) - cost(0) )
* this value can then be added to rawLiteralsCost()
return price;
}
+/* ZSTD_updateStats() :
+ * assumption : literals + litLengtn <= iend */
static void ZSTD_updateStats(optState_t* const optPtr,
U32 litLength, const BYTE* literals,
U32 offsetCode, U32 matchLength)
} }
/* save longer solution */
if (repLen > bestLength) {
- DEBUGLOG(8, "found rep-match %u of length %u",
- repCode - ll0, (U32)repLen);
+ DEBUGLOG(8, "found repCode %u (ll0:%u, offset:%u) of length %u",
+ repCode, ll0, repOffset, repLen);
bestLength = repLen;
matches[mnum].off = repCode - ll0;
matches[mnum].len = (U32)repLen;
}
if (matchLength > bestLength) {
- DEBUGLOG(8, "found match of length %u at distance %u",
- (U32)matchLength, current - matchIndex);
+ DEBUGLOG(8, "found match of length %u at distance %u (offCode=%u)",
+ (U32)matchLength, current - matchIndex, current - matchIndex + ZSTD_REP_MOVE);
assert(matchEndIdx > matchIndex);
if (matchLength > matchEndIdx - matchIndex)
matchEndIdx = matchIndex + (U32)matchLength;
}
-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,
- int optLevel)
-{
- 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, optLevel);
- 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,
- int optLevel)
-{
- return ZSTD_rawLiteralsCost_cached(cachedLitPrice, anchor, litlen, optStatePtr, optLevel)
- + ZSTD_litLengthPrice(litlen, optStatePtr, optLevel);
-}
-
-static int ZSTD_literalsContribution_cached(
- cachedLiteralPrice_t* const cachedLitPrice,
- const BYTE* const anchor, U32 const litlen,
- const optState_t* const optStatePtr,
- int optLevel)
+static U32 ZSTD_totalLen(ZSTD_optimal_t sol)
{
- int const contribution = ZSTD_rawLiteralsCost_cached(cachedLitPrice, anchor, litlen, optStatePtr, optLevel)
- + ZSTD_litLengthContribution(litlen, optStatePtr, optLevel);
- return contribution;
+ return sol.litlen + sol.mlen;
}
FORCE_INLINE_TEMPLATE size_t
ZSTD_optimal_t* const opt = optStatePtr->priceTable;
ZSTD_match_t* const matches = optStatePtr->matchTable;
- cachedLiteralPrice_t cachedLitPrice;
+ ZSTD_optimal_t lastSequence;
/* init */
DEBUGLOG(5, "ZSTD_compressBlock_opt_generic");
ms->nextToUpdate3 = ms->nextToUpdate;
ZSTD_rescaleFreqs(optStatePtr, (const BYTE*)src, srcSize, optLevel);
ip += (ip==prefixStart);
- 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);
/* initialize opt[0] */
{ U32 i ; for (i=0; i<ZSTD_REP_NUM; i++) opt[0].rep[i] = rep[i]; }
- opt[0].mlen = 1; /* means is_a_literal */
+ opt[0].mlen = 0; /* means is_a_literal */
opt[0].litlen = litlen;
+ opt[0].price = ZSTD_literalsContribution(anchor, litlen, optStatePtr, optLevel);
/* large match -> immediate encoding */
{ U32 const maxML = matches[nbMatches-1].len;
U32 const maxOffset = matches[nbMatches-1].off;
- DEBUGLOG(7, "found %u matches of maxLength=%u and maxOffset=%u at cPos=%u => start new serie",
+ DEBUGLOG(6, "found %u matches of maxLength=%u and maxOffCode=%u at cPos=%u => start new serie",
nbMatches, maxML, maxOffset, (U32)(ip-prefixStart));
if (maxML > sufficient_len) {
- best_mlen = maxML;
- best_off = maxOffset;
- DEBUGLOG(7, "large match (%u>%u), immediate encoding",
- best_mlen, sufficient_len);
+ lastSequence.litlen = litlen;
+ lastSequence.mlen = maxML;
+ lastSequence.off = maxOffset;
+ DEBUGLOG(6, "large match (%u>%u), immediate encoding",
+ maxML, sufficient_len);
cur = 0;
- last_pos = 1;
+ last_pos = ZSTD_totalLen(lastSequence);
goto _shortestPath;
} }
/* set prices for first matches starting position == 0 */
- { U32 const literalsPrice = ZSTD_fullLiteralsCost_cached(&cachedLitPrice, anchor, litlen, optStatePtr, optLevel);
+ { U32 const literalsPrice = opt[0].price + ZSTD_litLengthPrice(0, optStatePtr, optLevel);
U32 pos;
U32 matchNb;
for (pos = 1; pos < minMatch; pos++) {
for (cur = 1; cur <= last_pos; cur++) {
const BYTE* const inr = ip + cur;
assert(cur < ZSTD_OPT_NUM);
+ DEBUGLOG(7, "cPos:%zi==rPos:%u", inr-istart, cur)
/* 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, optLevel);
- } else {
- price = ZSTD_literalsContribution_cached(&cachedLitPrice, anchor, litlen, optStatePtr, optLevel);
- }
+ { U32 const litlen = (opt[cur-1].mlen == 0) ? opt[cur-1].litlen + 1 : 1;
+ int const price = opt[cur-1].price
+ + ZSTD_rawLiteralsCost(ip+cur-1, 1, optStatePtr, optLevel)
+ + ZSTD_litLengthPrice(litlen, optStatePtr, optLevel)
+ - ZSTD_litLengthPrice(litlen-1, optStatePtr, optLevel);
assert(price < 1000000000); /* overflow check */
if (price <= opt[cur].price) {
- DEBUGLOG(7, "rPos:%u : better price (%.2f<=%.2f) using literal",
- cur, ZSTD_fCost(price), ZSTD_fCost(opt[cur].price));
- opt[cur].mlen = 1;
+ DEBUGLOG(7, "cPos:%zi==rPos:%u : better price (%.2f<=%.2f) using literal (ll==%u) (hist:%u,%u,%u)",
+ inr-istart, cur, ZSTD_fCost(price), ZSTD_fCost(opt[cur].price), litlen,
+ opt[cur-1].rep[0], opt[cur-1].rep[1], opt[cur-1].rep[2]);
+ opt[cur].mlen = 0;
opt[cur].off = 0;
opt[cur].litlen = litlen;
opt[cur].price = price;
memcpy(opt[cur].rep, opt[cur-1].rep, sizeof(opt[cur].rep));
} else {
- DEBUGLOG(7, "rPos:%u : literal would cost more (%.2f>%.2f)",
- cur, ZSTD_fCost(price), ZSTD_fCost(opt[cur].price));
+ DEBUGLOG(7, "cPos:%zi==rPos:%u : literal would cost more (%.2f>%.2f) (hist:%u,%u,%u)",
+ inr-istart, cur, ZSTD_fCost(price), ZSTD_fCost(opt[cur].price),
+ opt[cur].rep[0], opt[cur].rep[1], opt[cur].rep[2]);
}
}
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, optLevel);
+ { U32 const ll0 = (opt[cur].mlen != 0);
+ U32 const litlen = (opt[cur].mlen == 0) ? opt[cur].litlen : 0;
+ U32 const previousPrice = opt[cur].price;
+ U32 const basePrice = previousPrice + ZSTD_litLengthPrice(0, optStatePtr, optLevel);
U32 const nbMatches = ZSTD_BtGetAllMatches(ms, cParams, inr, iend, extDict, opt[cur].rep, ll0, matches, minMatch);
U32 matchNb;
if (!nbMatches) {
}
{ U32 const maxML = matches[nbMatches-1].len;
- DEBUGLOG(7, "rPos:%u, found %u matches, of maxLength=%u",
- cur, nbMatches, maxML);
+ DEBUGLOG(7, "cPos:%zi==rPos:%u, found %u matches, of maxLength=%u",
+ inr-istart, 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;
+ lastSequence.mlen = maxML;
+ lastSequence.off = matches[nbMatches-1].off;
+ lastSequence.litlen = litlen;
+ cur -= (opt[cur].mlen==0) ? opt[cur].litlen : 0; /* last sequence is actually only literals, fix cur to last match - note : may underflow, in which case, it's first sequence, and it's okay */
+ last_pos = cur + ZSTD_totalLen(lastSequence);
+ if (cur > ZSTD_OPT_NUM) cur = 0; /* underflow => first match */
goto _shortestPath;
} }
U32 const startML = (matchNb>0) ? matches[matchNb-1].len+1 : minMatch;
U32 mlen;
- DEBUGLOG(7, "testing match %u => offCode=%u, mlen=%u, llen=%u",
+ DEBUGLOG(7, "testing match %u => offCode=%4u, mlen=%2u, llen=%2u",
matchNb, matches[matchNb].off, lastML, litlen);
for (mlen = lastML; mlen >= startML; mlen--) { /* scan downward */
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 (%.2f<%.2f)",
- pos, ZSTD_fCost(price), ZSTD_fCost(opt[pos].price));
+ DEBUGLOG(7, "rPos:%u (ml=%2u) => new better price (%.2f<%.2f)",
+ pos, mlen, ZSTD_fCost(price), ZSTD_fCost(opt[pos].price));
while (last_pos < pos) { opt[last_pos+1].price = ZSTD_MAX_PRICE; last_pos++; } /* fill empty positions */
opt[pos].mlen = mlen;
opt[pos].off = offset;
ZSTD_STATIC_ASSERT(sizeof(opt[pos].rep) == sizeof(repHistory));
memcpy(opt[pos].rep, &repHistory, sizeof(repHistory));
} else {
+ DEBUGLOG(7, "rPos:%u (ml=%2u) => new price is worse (%.2f>=%.2f)",
+ pos, mlen, ZSTD_fCost(price), ZSTD_fCost(opt[pos].price));
if (optLevel==0) break; /* early update abort; 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;
+ lastSequence = opt[last_pos];
+ cur = last_pos > ZSTD_totalLen(lastSequence) ? last_pos - ZSTD_totalLen(lastSequence) : 0; /* single sequence, and it starts before `ip` */
+ assert(cur < ZSTD_OPT_NUM); /* control overflow*/
_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];
+ assert(opt[0].mlen == 0);
+
+ { U32 const storeEnd = cur + 1;
+ U32 storeStart = storeEnd;
+ U32 seqPos = cur;
+
+ DEBUGLOG(6, "start reverse traversal (last_pos:%u, cur:%u)",
+ last_pos, cur);
+ assert(storeEnd < ZSTD_OPT_NUM);
+ DEBUGLOG(6, "last sequence copied into pos=%u (llen=%u,mlen=%u,ofc=%u)",
+ storeEnd, lastSequence.litlen, lastSequence.mlen, lastSequence.off);
+ opt[storeEnd] = lastSequence;
+ while (seqPos > 0) {
+ U32 const backDist = ZSTD_totalLen(opt[seqPos]);
+ storeStart--;
+ DEBUGLOG(6, "sequence from rPos=%u copied into pos=%u (llen=%u,mlen=%u,ofc=%u)",
+ seqPos, storeStart, opt[seqPos].litlen, opt[seqPos].mlen, opt[seqPos].off);
+ opt[storeStart] = opt[seqPos];
+ seqPos = (seqPos > backDist) ? seqPos - backDist : 0;
+ }
+
+ /* save sequences */
+ DEBUGLOG(6, "sending selected sequences into seqStore")
+ { U32 storePos;
+ for (storePos=storeStart; storePos <= storeEnd; storePos++) {
+ U32 const llen = opt[storePos].litlen;
+ U32 const mlen = opt[storePos].mlen;
+ U32 const offCode = opt[storePos].off;
+ U32 const advance = llen + mlen;
+ DEBUGLOG(6, "considering seq starting at %zi, llen=%u, mlen=%u",
+ anchor - istart, llen, mlen);
+
+ if (mlen==0) { /* only literals => must be last "sequence", actually starting a new stream of sequences */
+ assert(storePos == storeEnd); /* must be last sequence */
+ ip = anchor + llen; /* last "sequence" is a bunch of literals => don't progress anchor */
+ continue; /* will finish */
+ }
+
+ /* repcodes update : like ZSTD_updateRep(), but update in place */
+ if (offCode >= ZSTD_REP_NUM) { /* full offset */
+ rep[2] = rep[1];
rep[1] = rep[0];
- rep[0] = currentOffset;
- } }
+ rep[0] = offCode - ZSTD_REP_MOVE;
+ } else { /* repcode */
+ U32 const repCode = offCode + (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;
+ } }
+
+ assert(anchor + llen <= iend);
+ ZSTD_updateStats(optStatePtr, llen, anchor, offCode, mlen);
+ ZSTD_storeSeq(seqStore, llen, anchor, offCode, mlen-MINMATCH);
+ anchor += advance;
+ ip = anchor;
+ } }
+ ZSTD_setBasePrices(optStatePtr, optLevel);
+ }
- ZSTD_updateStats(optStatePtr, llen, anchor, offset, mlen);
- ZSTD_storeSeq(seqStore, llen, anchor, offset, mlen-MINMATCH);
- anchor = ip;
- } }
- ZSTD_setBasePrices(optStatePtr, optLevel);
} /* while (ip < ilimit) */
/* Return the last literals size */
projects / thirdparty / zstd.git / commitdiff
