ext/zstdruby/libzstd/compress/zstd_opt.c in zstd-ruby-1.5.5.1 vs ext/zstdruby/libzstd/compress/zstd_opt.c in zstd-ruby-1.5.6.0
- old
+ new
@@ -10,10 +10,13 @@
#include "zstd_compress_internal.h"
#include "hist.h"
#include "zstd_opt.h"
+#if !defined(ZSTD_EXCLUDE_BTLAZY2_BLOCK_COMPRESSOR) \
+ || !defined(ZSTD_EXCLUDE_BTOPT_BLOCK_COMPRESSOR) \
+ || !defined(ZSTD_EXCLUDE_BTULTRA_BLOCK_COMPRESSOR)
#define ZSTD_LITFREQ_ADD 2 /* scaling factor for litFreq, so that frequencies adapt faster to new stats */
#define ZSTD_MAX_PRICE (1<<30)
#define ZSTD_PREDEF_THRESHOLD 8 /* if srcSize < ZSTD_PREDEF_THRESHOLD, symbols' cost is assumed static, directly determined by pre-defined distributions */
@@ -262,10 +265,11 @@
* does not include price of literalLength symbol */
static U32 ZSTD_rawLiteralsCost(const BYTE* const literals, U32 const litLength,
const optState_t* const optPtr,
int optLevel)
{
+ DEBUGLOG(8, "ZSTD_rawLiteralsCost (%u literals)", litLength);
if (litLength == 0) return 0;
if (!ZSTD_compressedLiterals(optPtr))
return (litLength << 3) * BITCOST_MULTIPLIER; /* Uncompressed - 8 bytes per literal. */
@@ -400,13 +404,15 @@
}
/* Update hashTable3 up to ip (excluded)
Assumption : always within prefix (i.e. not within extDict) */
-static U32 ZSTD_insertAndFindFirstIndexHash3 (const ZSTD_matchState_t* ms,
- U32* nextToUpdate3,
- const BYTE* const ip)
+static
+ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
+U32 ZSTD_insertAndFindFirstIndexHash3 (const ZSTD_matchState_t* ms,
+ U32* nextToUpdate3,
+ const BYTE* const ip)
{
U32* const hashTable3 = ms->hashTable3;
U32 const hashLog3 = ms->hashLog3;
const BYTE* const base = ms->window.base;
U32 idx = *nextToUpdate3;
@@ -429,11 +435,13 @@
***************************************/
/** ZSTD_insertBt1() : add one or multiple positions to tree.
* @param ip assumed <= iend-8 .
* @param target The target of ZSTD_updateTree_internal() - we are filling to this position
* @return : nb of positions added */
-static U32 ZSTD_insertBt1(
+static
+ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
+U32 ZSTD_insertBt1(
const ZSTD_matchState_t* ms,
const BYTE* const ip, const BYTE* const iend,
U32 const target,
U32 const mls, const int extDict)
{
@@ -548,19 +556,20 @@
return MAX(positions, matchEndIdx - (curr + 8));
}
}
FORCE_INLINE_TEMPLATE
+ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
void ZSTD_updateTree_internal(
ZSTD_matchState_t* ms,
const BYTE* const ip, const BYTE* const iend,
const U32 mls, const ZSTD_dictMode_e dictMode)
{
const BYTE* const base = ms->window.base;
U32 const target = (U32)(ip - base);
U32 idx = ms->nextToUpdate;
- DEBUGLOG(6, "ZSTD_updateTree_internal, from %u to %u (dictMode:%u)",
+ DEBUGLOG(7, "ZSTD_updateTree_internal, from %u to %u (dictMode:%u)",
idx, target, dictMode);
while(idx < target) {
U32 const forward = ZSTD_insertBt1(ms, base+idx, iend, target, mls, dictMode == ZSTD_extDict);
assert(idx < (U32)(idx + forward));
@@ -573,11 +582,13 @@
void ZSTD_updateTree(ZSTD_matchState_t* ms, const BYTE* ip, const BYTE* iend) {
ZSTD_updateTree_internal(ms, ip, iend, ms->cParams.minMatch, ZSTD_noDict);
}
-FORCE_INLINE_TEMPLATE U32
+FORCE_INLINE_TEMPLATE
+ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
+U32
ZSTD_insertBtAndGetAllMatches (
ZSTD_match_t* matches, /* store result (found matches) in this table (presumed large enough) */
ZSTD_matchState_t* ms,
U32* nextToUpdate3,
const BYTE* const ip, const BYTE* const iLimit,
@@ -814,11 +825,13 @@
const BYTE*,
const U32 rep[ZSTD_REP_NUM],
U32 const ll0,
U32 const lengthToBeat);
-FORCE_INLINE_TEMPLATE U32 ZSTD_btGetAllMatches_internal(
+FORCE_INLINE_TEMPLATE
+ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
+U32 ZSTD_btGetAllMatches_internal(
ZSTD_match_t* matches,
ZSTD_matchState_t* ms,
U32* nextToUpdate3,
const BYTE* ip,
const BYTE* const iHighLimit,
@@ -1033,15 +1046,10 @@
/*-*******************************
* Optimal parser
*********************************/
-static U32 ZSTD_totalLen(ZSTD_optimal_t sol)
-{
- return sol.litlen + sol.mlen;
-}
-
#if 0 /* debug */
static void
listStats(const U32* table, int lastEltID)
{
@@ -1055,11 +1063,17 @@
RAWLOG(2, " \n");
}
#endif
-FORCE_INLINE_TEMPLATE size_t
+#define LIT_PRICE(_p) (int)ZSTD_rawLiteralsCost(_p, 1, optStatePtr, optLevel)
+#define LL_PRICE(_l) (int)ZSTD_litLengthPrice(_l, optStatePtr, optLevel)
+#define LL_INCPRICE(_l) (LL_PRICE(_l) - LL_PRICE(_l-1))
+
+FORCE_INLINE_TEMPLATE
+ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
+size_t
ZSTD_compressBlock_opt_generic(ZSTD_matchState_t* ms,
seqStore_t* seqStore,
U32 rep[ZSTD_REP_NUM],
const void* src, size_t srcSize,
const int optLevel,
@@ -1081,14 +1095,14 @@
U32 const minMatch = (cParams->minMatch == 3) ? 3 : 4;
U32 nextToUpdate3 = ms->nextToUpdate;
ZSTD_optimal_t* const opt = optStatePtr->priceTable;
ZSTD_match_t* const matches = optStatePtr->matchTable;
- ZSTD_optimal_t lastSequence;
+ ZSTD_optimal_t lastStretch;
ZSTD_optLdm_t optLdm;
- ZSTD_memset(&lastSequence, 0, sizeof(ZSTD_optimal_t));
+ ZSTD_memset(&lastStretch, 0, sizeof(ZSTD_optimal_t));
optLdm.seqStore = ms->ldmSeqStore ? *ms->ldmSeqStore : kNullRawSeqStore;
optLdm.endPosInBlock = optLdm.startPosInBlock = optLdm.offset = 0;
ZSTD_opt_getNextMatchAndUpdateSeqStore(&optLdm, (U32)(ip-istart), (U32)(iend-ip));
@@ -1106,125 +1120,160 @@
/* find first match */
{ U32 const litlen = (U32)(ip - anchor);
U32 const ll0 = !litlen;
U32 nbMatches = getAllMatches(matches, ms, &nextToUpdate3, ip, iend, rep, ll0, minMatch);
ZSTD_optLdm_processMatchCandidate(&optLdm, matches, &nbMatches,
- (U32)(ip-istart), (U32)(iend - ip));
- if (!nbMatches) { ip++; continue; }
+ (U32)(ip-istart), (U32)(iend-ip));
+ if (!nbMatches) {
+ DEBUGLOG(8, "no match found at cPos %u", (unsigned)(ip-istart));
+ ip++;
+ continue;
+ }
+ /* Match found: let's store this solution, and eventually find more candidates.
+ * During this forward pass, @opt is used to store stretches,
+ * defined as "a match followed by N literals".
+ * Note how this is different from a Sequence, which is "N literals followed by a match".
+ * Storing stretches allows us to store different match predecessors
+ * for each literal position part of a literals run. */
+
/* initialize opt[0] */
- { U32 i ; for (i=0; i<ZSTD_REP_NUM; i++) opt[0].rep[i] = rep[i]; }
- opt[0].mlen = 0; /* means is_a_literal */
+ opt[0].mlen = 0; /* there are only literals so far */
opt[0].litlen = litlen;
- /* We don't need to include the actual price of the literals because
- * it is static for the duration of the forward pass, and is included
- * in every price. We include the literal length to avoid negative
- * prices when we subtract the previous literal length.
+ /* No need to include the actual price of the literals before the first match
+ * because it is static for the duration of the forward pass, and is included
+ * in every subsequent price. But, we include the literal length because
+ * the cost variation of litlen depends on the value of litlen.
*/
- opt[0].price = (int)ZSTD_litLengthPrice(litlen, optStatePtr, optLevel);
+ opt[0].price = LL_PRICE(litlen);
+ ZSTD_STATIC_ASSERT(sizeof(opt[0].rep[0]) == sizeof(rep[0]));
+ ZSTD_memcpy(&opt[0].rep, rep, sizeof(opt[0].rep));
/* large match -> immediate encoding */
{ U32 const maxML = matches[nbMatches-1].len;
U32 const maxOffBase = matches[nbMatches-1].off;
DEBUGLOG(6, "found %u matches of maxLength=%u and maxOffBase=%u at cPos=%u => start new series",
nbMatches, maxML, maxOffBase, (U32)(ip-prefixStart));
if (maxML > sufficient_len) {
- lastSequence.litlen = litlen;
- lastSequence.mlen = maxML;
- lastSequence.off = maxOffBase;
- DEBUGLOG(6, "large match (%u>%u), immediate encoding",
+ lastStretch.litlen = 0;
+ lastStretch.mlen = maxML;
+ lastStretch.off = maxOffBase;
+ DEBUGLOG(6, "large match (%u>%u) => immediate encoding",
maxML, sufficient_len);
cur = 0;
- last_pos = ZSTD_totalLen(lastSequence);
+ last_pos = maxML;
goto _shortestPath;
} }
/* set prices for first matches starting position == 0 */
assert(opt[0].price >= 0);
- { U32 const literalsPrice = (U32)opt[0].price + ZSTD_litLengthPrice(0, optStatePtr, optLevel);
- U32 pos;
+ { U32 pos;
U32 matchNb;
for (pos = 1; pos < minMatch; pos++) {
- opt[pos].price = ZSTD_MAX_PRICE; /* mlen, litlen and price will be fixed during forward scanning */
+ opt[pos].price = ZSTD_MAX_PRICE;
+ opt[pos].mlen = 0;
+ opt[pos].litlen = litlen + pos;
}
for (matchNb = 0; matchNb < nbMatches; matchNb++) {
U32 const offBase = matches[matchNb].off;
U32 const end = matches[matchNb].len;
for ( ; pos <= end ; pos++ ) {
- U32 const matchPrice = ZSTD_getMatchPrice(offBase, pos, optStatePtr, optLevel);
- U32 const sequencePrice = literalsPrice + matchPrice;
+ int const matchPrice = (int)ZSTD_getMatchPrice(offBase, pos, optStatePtr, optLevel);
+ int const sequencePrice = opt[0].price + matchPrice;
DEBUGLOG(7, "rPos:%u => set initial price : %.2f",
- pos, ZSTD_fCost((int)sequencePrice));
+ pos, ZSTD_fCost(sequencePrice));
opt[pos].mlen = pos;
opt[pos].off = offBase;
- opt[pos].litlen = litlen;
- opt[pos].price = (int)sequencePrice;
- } }
+ opt[pos].litlen = 0; /* end of match */
+ opt[pos].price = sequencePrice + LL_PRICE(0);
+ }
+ }
last_pos = pos-1;
+ opt[pos].price = ZSTD_MAX_PRICE;
}
}
/* check further positions */
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)
+ 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 == 0) ? opt[cur-1].litlen + 1 : 1;
+ { U32 const litlen = opt[cur-1].litlen + 1;
int const price = opt[cur-1].price
- + (int)ZSTD_rawLiteralsCost(ip+cur-1, 1, optStatePtr, optLevel)
- + (int)ZSTD_litLengthPrice(litlen, optStatePtr, optLevel)
- - (int)ZSTD_litLengthPrice(litlen-1, optStatePtr, optLevel);
+ + LIT_PRICE(ip+cur-1)
+ + LL_INCPRICE(litlen);
assert(price < 1000000000); /* overflow check */
if (price <= opt[cur].price) {
+ ZSTD_optimal_t const prevMatch = opt[cur];
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] = opt[cur-1];
opt[cur].litlen = litlen;
opt[cur].price = price;
+ if ( (optLevel >= 1) /* additional check only for higher modes */
+ && (prevMatch.litlen == 0) /* replace a match */
+ && (LL_INCPRICE(1) < 0) /* ll1 is cheaper than ll0 */
+ && LIKELY(ip + cur < iend)
+ ) {
+ /* check next position, in case it would be cheaper */
+ int with1literal = prevMatch.price + LIT_PRICE(ip+cur) + LL_INCPRICE(1);
+ int withMoreLiterals = price + LIT_PRICE(ip+cur) + LL_INCPRICE(litlen+1);
+ DEBUGLOG(7, "then at next rPos %u : match+1lit %.2f vs %ulits %.2f",
+ cur+1, ZSTD_fCost(with1literal), litlen+1, ZSTD_fCost(withMoreLiterals));
+ if ( (with1literal < withMoreLiterals)
+ && (with1literal < opt[cur+1].price) ) {
+ /* update offset history - before it disappears */
+ U32 const prev = cur - prevMatch.mlen;
+ repcodes_t const newReps = ZSTD_newRep(opt[prev].rep, prevMatch.off, opt[prev].litlen==0);
+ assert(cur >= prevMatch.mlen);
+ DEBUGLOG(7, "==> match+1lit is cheaper (%.2f < %.2f) (hist:%u,%u,%u) !",
+ ZSTD_fCost(with1literal), ZSTD_fCost(withMoreLiterals),
+ newReps.rep[0], newReps.rep[1], newReps.rep[2] );
+ opt[cur+1] = prevMatch; /* mlen & offbase */
+ ZSTD_memcpy(opt[cur+1].rep, &newReps, sizeof(repcodes_t));
+ opt[cur+1].litlen = 1;
+ opt[cur+1].price = with1literal;
+ if (last_pos < cur+1) last_pos = cur+1;
+ }
+ }
} else {
- 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]);
+ DEBUGLOG(7, "cPos:%zi==rPos:%u : literal would cost more (%.2f>%.2f)",
+ inr-istart, cur, ZSTD_fCost(price), ZSTD_fCost(opt[cur].price));
}
}
- /* Set the repcodes of the current position. We must do it here
- * because we rely on the repcodes of the 2nd to last sequence being
- * correct to set the next chunks repcodes during the backward
- * traversal.
+ /* Offset history is not updated during match comparison.
+ * Do it here, now that the match is selected and confirmed.
*/
ZSTD_STATIC_ASSERT(sizeof(opt[cur].rep) == sizeof(repcodes_t));
assert(cur >= opt[cur].mlen);
- if (opt[cur].mlen != 0) {
+ if (opt[cur].litlen == 0) {
+ /* just finished a match => alter offset history */
U32 const prev = cur - opt[cur].mlen;
- repcodes_t const newReps = ZSTD_newRep(opt[prev].rep, opt[cur].off, opt[cur].litlen==0);
+ repcodes_t const newReps = ZSTD_newRep(opt[prev].rep, opt[cur].off, opt[prev].litlen==0);
ZSTD_memcpy(opt[cur].rep, &newReps, sizeof(repcodes_t));
- } else {
- ZSTD_memcpy(opt[cur].rep, opt[cur - 1].rep, sizeof(repcodes_t));
}
/* 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_test*/
&& (opt[cur+1].price <= opt[cur].price + (BITCOST_MULTIPLIER/2)) ) {
- DEBUGLOG(7, "move to next rPos:%u : price is <=", cur+1);
+ DEBUGLOG(7, "skip current position : next rPos(%u) price is cheaper", cur+1);
continue; /* skip unpromising positions; about ~+6% speed, -0.01 ratio */
}
assert(opt[cur].price >= 0);
- { U32 const ll0 = (opt[cur].mlen != 0);
- U32 const litlen = (opt[cur].mlen == 0) ? opt[cur].litlen : 0;
- U32 const previousPrice = (U32)opt[cur].price;
- U32 const basePrice = previousPrice + ZSTD_litLengthPrice(0, optStatePtr, optLevel);
+ { U32 const ll0 = (opt[cur].litlen == 0);
+ int const previousPrice = opt[cur].price;
+ int const basePrice = previousPrice + LL_PRICE(0);
U32 nbMatches = getAllMatches(matches, ms, &nextToUpdate3, inr, iend, opt[cur].rep, ll0, minMatch);
U32 matchNb;
ZSTD_optLdm_processMatchCandidate(&optLdm, matches, &nbMatches,
(U32)(inr-istart), (U32)(iend-inr));
@@ -1232,22 +1281,21 @@
if (!nbMatches) {
DEBUGLOG(7, "rPos:%u : no match found", cur);
continue;
}
- { U32 const maxML = matches[nbMatches-1].len;
- DEBUGLOG(7, "cPos:%zi==rPos:%u, found %u matches, of maxLength=%u",
- inr-istart, cur, nbMatches, maxML);
+ { U32 const longestML = matches[nbMatches-1].len;
+ DEBUGLOG(7, "cPos:%zi==rPos:%u, found %u matches, of longest ML=%u",
+ inr-istart, cur, nbMatches, longestML);
- if ( (maxML > sufficient_len)
- || (cur + maxML >= ZSTD_OPT_NUM) ) {
- 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 */
+ if ( (longestML > sufficient_len)
+ || (cur + longestML >= ZSTD_OPT_NUM)
+ || (ip + cur + longestML >= iend) ) {
+ lastStretch.mlen = longestML;
+ lastStretch.off = matches[nbMatches-1].off;
+ lastStretch.litlen = 0;
+ last_pos = cur + longestML;
goto _shortestPath;
} }
/* set prices using matches found at position == cur */
for (matchNb = 0; matchNb < nbMatches; matchNb++) {
@@ -1255,71 +1303,110 @@
U32 const lastML = matches[matchNb].len;
U32 const startML = (matchNb>0) ? matches[matchNb-1].len+1 : minMatch;
U32 mlen;
DEBUGLOG(7, "testing match %u => offBase=%4u, mlen=%2u, llen=%2u",
- matchNb, matches[matchNb].off, lastML, litlen);
+ matchNb, matches[matchNb].off, lastML, opt[cur].litlen);
for (mlen = lastML; mlen >= startML; mlen--) { /* scan downward */
U32 const pos = cur + mlen;
- int const price = (int)basePrice + (int)ZSTD_getMatchPrice(offset, mlen, optStatePtr, optLevel);
+ int const price = basePrice + (int)ZSTD_getMatchPrice(offset, mlen, optStatePtr, optLevel);
if ((pos > last_pos) || (price < 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 */
+ while (last_pos < pos) {
+ /* fill empty positions, for future comparisons */
+ last_pos++;
+ opt[last_pos].price = ZSTD_MAX_PRICE;
+ opt[last_pos].litlen = !0; /* just needs to be != 0, to mean "not an end of match" */
+ }
opt[pos].mlen = mlen;
opt[pos].off = offset;
- opt[pos].litlen = litlen;
+ opt[pos].litlen = 0;
opt[pos].price = price;
} 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 */
}
} } }
+ opt[last_pos+1].price = ZSTD_MAX_PRICE;
} /* for (cur = 1; cur <= last_pos; cur++) */
- 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*/
+ lastStretch = opt[last_pos];
+ assert(cur >= lastStretch.mlen);
+ cur = last_pos - lastStretch.mlen;
_shortestPath: /* cur, last_pos, best_mlen, best_off have to be set */
assert(opt[0].mlen == 0);
+ assert(last_pos >= lastStretch.mlen);
+ assert(cur == last_pos - lastStretch.mlen);
- /* Set the next chunk's repcodes based on the repcodes of the beginning
- * of the last match, and the last sequence. This avoids us having to
- * update them while traversing the sequences.
- */
- if (lastSequence.mlen != 0) {
- repcodes_t const reps = ZSTD_newRep(opt[cur].rep, lastSequence.off, lastSequence.litlen==0);
- ZSTD_memcpy(rep, &reps, sizeof(reps));
+ if (lastStretch.mlen==0) {
+ /* no solution : all matches have been converted into literals */
+ assert(lastStretch.litlen == (ip - anchor) + last_pos);
+ ip += last_pos;
+ continue;
+ }
+ assert(lastStretch.off > 0);
+
+ /* Update offset history */
+ if (lastStretch.litlen == 0) {
+ /* finishing on a match : update offset history */
+ repcodes_t const reps = ZSTD_newRep(opt[cur].rep, lastStretch.off, opt[cur].litlen==0);
+ ZSTD_memcpy(rep, &reps, sizeof(repcodes_t));
} else {
- ZSTD_memcpy(rep, opt[cur].rep, sizeof(repcodes_t));
+ ZSTD_memcpy(rep, lastStretch.rep, sizeof(repcodes_t));
+ assert(cur >= lastStretch.litlen);
+ cur -= lastStretch.litlen;
}
- { U32 const storeEnd = cur + 1;
+ /* Let's write the shortest path solution.
+ * It is stored in @opt in reverse order,
+ * starting from @storeEnd (==cur+2),
+ * effectively partially @opt overwriting.
+ * Content is changed too:
+ * - So far, @opt stored stretches, aka a match followed by literals
+ * - Now, it will store sequences, aka literals followed by a match
+ */
+ { U32 const storeEnd = cur + 2;
U32 storeStart = storeEnd;
- U32 seqPos = cur;
+ U32 stretchPos = cur;
DEBUGLOG(6, "start reverse traversal (last_pos:%u, cur:%u)",
last_pos, cur); (void)last_pos;
- 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]);
+ assert(storeEnd < ZSTD_OPT_SIZE);
+ DEBUGLOG(6, "last stretch copied into pos=%u (llen=%u,mlen=%u,ofc=%u)",
+ storeEnd, lastStretch.litlen, lastStretch.mlen, lastStretch.off);
+ if (lastStretch.litlen > 0) {
+ /* last "sequence" is unfinished: just a bunch of literals */
+ opt[storeEnd].litlen = lastStretch.litlen;
+ opt[storeEnd].mlen = 0;
+ storeStart = storeEnd-1;
+ opt[storeStart] = lastStretch;
+ } {
+ opt[storeEnd] = lastStretch; /* note: litlen will be fixed */
+ storeStart = storeEnd;
+ }
+ while (1) {
+ ZSTD_optimal_t nextStretch = opt[stretchPos];
+ opt[storeStart].litlen = nextStretch.litlen;
+ DEBUGLOG(6, "selected sequence (llen=%u,mlen=%u,ofc=%u)",
+ opt[storeStart].litlen, opt[storeStart].mlen, opt[storeStart].off);
+ if (nextStretch.mlen == 0) {
+ /* reaching beginning of segment */
+ break;
+ }
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;
+ opt[storeStart] = nextStretch; /* note: litlen will be fixed */
+ assert(nextStretch.litlen + nextStretch.mlen <= stretchPos);
+ stretchPos -= nextStretch.litlen + nextStretch.mlen;
}
/* save sequences */
- DEBUGLOG(6, "sending selected sequences into seqStore")
+ 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 offBase = opt[storePos].off;
@@ -1337,53 +1424,65 @@
ZSTD_updateStats(optStatePtr, llen, anchor, offBase, mlen);
ZSTD_storeSeq(seqStore, llen, anchor, iend, offBase, mlen);
anchor += advance;
ip = anchor;
} }
+ DEBUGLOG(7, "new offset history : %u, %u, %u", rep[0], rep[1], rep[2]);
+
+ /* update all costs */
ZSTD_setBasePrices(optStatePtr, optLevel);
}
} /* while (ip < ilimit) */
/* Return the last literals size */
return (size_t)(iend - anchor);
}
+#endif /* build exclusions */
+#ifndef ZSTD_EXCLUDE_BTOPT_BLOCK_COMPRESSOR
static size_t ZSTD_compressBlock_opt0(
ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
const void* src, size_t srcSize, const ZSTD_dictMode_e dictMode)
{
return ZSTD_compressBlock_opt_generic(ms, seqStore, rep, src, srcSize, 0 /* optLevel */, dictMode);
}
+#endif
+#ifndef ZSTD_EXCLUDE_BTULTRA_BLOCK_COMPRESSOR
static size_t ZSTD_compressBlock_opt2(
ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
const void* src, size_t srcSize, const ZSTD_dictMode_e dictMode)
{
return ZSTD_compressBlock_opt_generic(ms, seqStore, rep, src, srcSize, 2 /* optLevel */, dictMode);
}
+#endif
+#ifndef ZSTD_EXCLUDE_BTOPT_BLOCK_COMPRESSOR
size_t ZSTD_compressBlock_btopt(
ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
const void* src, size_t srcSize)
{
DEBUGLOG(5, "ZSTD_compressBlock_btopt");
return ZSTD_compressBlock_opt0(ms, seqStore, rep, src, srcSize, ZSTD_noDict);
}
+#endif
+#ifndef ZSTD_EXCLUDE_BTULTRA_BLOCK_COMPRESSOR
/* 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 cannot error out, its narrow contract 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
+ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
+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 */
ZSTD_memcpy(tmpRep, rep, sizeof(tmpRep));
DEBUGLOG(4, "ZSTD_initStats_ultra (srcSize=%zu)", srcSize);
@@ -1423,11 +1522,11 @@
* in order to seed next round's statistics with it.
* After 1st pass, function forgets history, and starts a new block.
* Consequently, this can only work if no data has been previously loaded in tables,
* aka, no dictionary, no prefix, no ldm preprocessing.
* The compression ratio gain is generally small (~0.5% on first block),
- ** the cost is 2x cpu time on first block. */
+ * the cost is 2x cpu time on first block. */
assert(srcSize <= ZSTD_BLOCKSIZE_MAX);
if ( (ms->opt.litLengthSum==0) /* first block */
&& (seqStore->sequences == seqStore->sequencesStart) /* no ldm */
&& (ms->window.dictLimit == ms->window.lowLimit) /* no dictionary */
&& (curr == ms->window.dictLimit) /* start of frame, nothing already loaded nor skipped */
@@ -1436,37 +1535,42 @@
ZSTD_initStats_ultra(ms, seqStore, rep, src, srcSize);
}
return ZSTD_compressBlock_opt2(ms, seqStore, rep, src, srcSize, ZSTD_noDict);
}
+#endif
+#ifndef ZSTD_EXCLUDE_BTOPT_BLOCK_COMPRESSOR
size_t ZSTD_compressBlock_btopt_dictMatchState(
ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
const void* src, size_t srcSize)
{
return ZSTD_compressBlock_opt0(ms, seqStore, rep, src, srcSize, ZSTD_dictMatchState);
}
-size_t ZSTD_compressBlock_btultra_dictMatchState(
+size_t ZSTD_compressBlock_btopt_extDict(
ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
const void* src, size_t srcSize)
{
- return ZSTD_compressBlock_opt2(ms, seqStore, rep, src, srcSize, ZSTD_dictMatchState);
+ return ZSTD_compressBlock_opt0(ms, seqStore, rep, src, srcSize, ZSTD_extDict);
}
+#endif
-size_t ZSTD_compressBlock_btopt_extDict(
+#ifndef ZSTD_EXCLUDE_BTULTRA_BLOCK_COMPRESSOR
+size_t ZSTD_compressBlock_btultra_dictMatchState(
ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
const void* src, size_t srcSize)
{
- return ZSTD_compressBlock_opt0(ms, seqStore, rep, src, srcSize, ZSTD_extDict);
+ return ZSTD_compressBlock_opt2(ms, seqStore, rep, src, srcSize, ZSTD_dictMatchState);
}
size_t ZSTD_compressBlock_btultra_extDict(
ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
const void* src, size_t srcSize)
{
return ZSTD_compressBlock_opt2(ms, seqStore, rep, src, srcSize, ZSTD_extDict);
}
+#endif
/* note : no btultra2 variant for extDict nor dictMatchState,
* because btultra2 is not meant to work with dictionaries
* and is only specific for the first block (no prefix) */