contrib/lz4/lib/lz4opt.h in extlz4-0.2.4.3 vs contrib/lz4/lib/lz4opt.h in extlz4-0.2.5
- old
+ new
@@ -33,334 +33,324 @@
- LZ4 public forum : https://groups.google.com/forum/#!forum/lz4c
*/
#define LZ4_OPT_NUM (1<<12)
-
typedef struct {
- int off;
- int len;
-} LZ4HC_match_t;
-
-typedef struct {
int price;
int off;
int mlen;
int litlen;
} LZ4HC_optimal_t;
/* price in bytes */
-FORCE_INLINE size_t LZ4HC_literalsPrice(size_t litlen)
+LZ4_FORCE_INLINE int LZ4HC_literalsPrice(int const litlen)
{
- size_t price = litlen;
- if (litlen >= (size_t)RUN_MASK)
+ int price = litlen;
+ if (litlen >= (int)RUN_MASK)
price += 1 + (litlen-RUN_MASK)/255;
return price;
}
/* requires mlen >= MINMATCH */
-FORCE_INLINE size_t LZ4HC_sequencePrice(size_t litlen, size_t mlen)
+LZ4_FORCE_INLINE int LZ4HC_sequencePrice(int litlen, int mlen)
{
- size_t price = 2 + 1; /* 16-bit offset + token */
+ int price = 1 + 2 ; /* token + 16-bit offset */
price += LZ4HC_literalsPrice(litlen);
- if (mlen >= (size_t)(ML_MASK+MINMATCH))
- price+= 1 + (mlen-(ML_MASK+MINMATCH))/255;
+ if (mlen >= (int)(ML_MASK+MINMATCH))
+ price += 1 + (mlen-(ML_MASK+MINMATCH))/255;
return price;
}
/*-*************************************
-* Binary Tree search
+* Match finder
***************************************/
-FORCE_INLINE int LZ4HC_BinTree_InsertAndGetAllMatches (
- LZ4HC_CCtx_internal* ctx,
- const BYTE* const ip,
- const BYTE* const iHighLimit,
- size_t best_mlen,
- LZ4HC_match_t* matches,
- int* matchNum)
-{
- U16* const chainTable = ctx->chainTable;
- U32* const HashTable = ctx->hashTable;
- const BYTE* const base = ctx->base;
- const U32 dictLimit = ctx->dictLimit;
- const U32 current = (U32)(ip - base);
- const U32 lowLimit = (ctx->lowLimit + MAX_DISTANCE > current) ? ctx->lowLimit : current - (MAX_DISTANCE - 1);
- const BYTE* const dictBase = ctx->dictBase;
- const BYTE* match;
- int nbAttempts = ctx->searchNum;
- int mnum = 0;
- U16 *ptr0, *ptr1, delta0, delta1;
- U32 matchIndex;
- size_t matchLength = 0;
- U32* HashPos;
+typedef struct {
+ int off;
+ int len;
+} LZ4HC_match_t;
- if (ip + MINMATCH > iHighLimit) return 1;
-
- /* HC4 match finder */
- HashPos = &HashTable[LZ4HC_hashPtr(ip)];
- matchIndex = *HashPos;
- *HashPos = current;
-
- ptr0 = &DELTANEXTMAXD(current*2+1);
- ptr1 = &DELTANEXTMAXD(current*2);
- delta0 = delta1 = (U16)(current - matchIndex);
-
- while ((matchIndex < current) && (matchIndex>=lowLimit) && (nbAttempts)) {
- nbAttempts--;
- if (matchIndex >= dictLimit) {
- match = base + matchIndex;
- matchLength = LZ4_count(ip, match, iHighLimit);
- } else {
- const BYTE* vLimit = ip + (dictLimit - matchIndex);
- match = dictBase + matchIndex;
- if (vLimit > iHighLimit) vLimit = iHighLimit;
- matchLength = LZ4_count(ip, match, vLimit);
- if ((ip+matchLength == vLimit) && (vLimit < iHighLimit))
- matchLength += LZ4_count(ip+matchLength, base+dictLimit, iHighLimit);
- if (matchIndex+matchLength >= dictLimit)
- match = base + matchIndex; /* to prepare for next usage of match[matchLength] */
- }
-
- if (matchLength > best_mlen) {
- best_mlen = matchLength;
- if (matches) {
- if (matchIndex >= dictLimit)
- matches[mnum].off = (int)(ip - match);
- else
- matches[mnum].off = (int)(ip - (base + matchIndex)); /* virtual matchpos */
- matches[mnum].len = (int)matchLength;
- mnum++;
- }
- if (best_mlen > LZ4_OPT_NUM) break;
- }
-
- if (ip+matchLength >= iHighLimit) /* equal : no way to know if inf or sup */
- break; /* drop , to guarantee consistency ; miss a bit of compression, but other solutions can corrupt the tree */
-
- DEBUGLOG(6, "ip :%016llX", (U64)ip);
- DEBUGLOG(6, "match:%016llX", (U64)match);
- if (*(ip+matchLength) < *(match+matchLength)) {
- *ptr0 = delta0;
- ptr0 = &DELTANEXTMAXD(matchIndex*2);
- if (*ptr0 == (U16)-1) break;
- delta0 = *ptr0;
- delta1 += delta0;
- matchIndex -= delta0;
- } else {
- *ptr1 = delta1;
- ptr1 = &DELTANEXTMAXD(matchIndex*2+1);
- if (*ptr1 == (U16)-1) break;
- delta1 = *ptr1;
- delta0 += delta1;
- matchIndex -= delta1;
- }
- }
-
- *ptr0 = (U16)-1;
- *ptr1 = (U16)-1;
- if (matchNum) *matchNum = mnum;
- /* if (best_mlen > 8) return best_mlen-8; */
- if (!matchNum) return 1;
- return 1;
-}
-
-
-FORCE_INLINE void LZ4HC_updateBinTree(LZ4HC_CCtx_internal* ctx, const BYTE* const ip, const BYTE* const iHighLimit)
+LZ4_FORCE_INLINE
+LZ4HC_match_t LZ4HC_FindLongerMatch(LZ4HC_CCtx_internal* const ctx,
+ const BYTE* ip, const BYTE* const iHighLimit,
+ int minLen, int nbSearches)
{
- const BYTE* const base = ctx->base;
- const U32 target = (U32)(ip - base);
- U32 idx = ctx->nextToUpdate;
- while(idx < target)
- idx += LZ4HC_BinTree_InsertAndGetAllMatches(ctx, base+idx, iHighLimit, 8, NULL, NULL);
+ LZ4HC_match_t match = { 0 , 0 };
+ const BYTE* matchPtr = NULL;
+ /* note : LZ4HC_InsertAndGetWiderMatch() is able to modify the starting position of a match (*startpos),
+ * but this won't be the case here, as we define iLowLimit==ip,
+ * so LZ4HC_InsertAndGetWiderMatch() won't be allowed to search past ip */
+ int const matchLength = LZ4HC_InsertAndGetWiderMatch(ctx,
+ ip, ip, iHighLimit, minLen, &matchPtr, &ip,
+ nbSearches, 1 /* patternAnalysis */);
+ if (matchLength <= minLen) return match;
+ match.len = matchLength;
+ match.off = (int)(ip-matchPtr);
+ return match;
}
-/** Tree updater, providing best match */
-FORCE_INLINE int LZ4HC_BinTree_GetAllMatches (
- LZ4HC_CCtx_internal* ctx,
- const BYTE* const ip, const BYTE* const iHighLimit,
- size_t best_mlen, LZ4HC_match_t* matches, const int fullUpdate)
-{
- int mnum = 0;
- if (ip < ctx->base + ctx->nextToUpdate) return 0; /* skipped area */
- if (fullUpdate) LZ4HC_updateBinTree(ctx, ip, iHighLimit);
- best_mlen = LZ4HC_BinTree_InsertAndGetAllMatches(ctx, ip, iHighLimit, best_mlen, matches, &mnum);
- ctx->nextToUpdate = (U32)(ip - ctx->base + best_mlen);
- return mnum;
-}
-
-
-#define SET_PRICE(pos, ml, offset, ll, cost) \
-{ \
- while (last_pos < pos) { opt[last_pos+1].price = 1<<30; last_pos++; } \
- opt[pos].mlen = (int)ml; \
- opt[pos].off = (int)offset; \
- opt[pos].litlen = (int)ll; \
- opt[pos].price = (int)cost; \
-}
-
-
static int LZ4HC_compress_optimal (
LZ4HC_CCtx_internal* ctx,
const char* const source,
- char* dest,
- int inputSize,
- int maxOutputSize,
- limitedOutput_directive limit,
+ char* dst,
+ int* srcSizePtr,
+ int dstCapacity,
+ int const nbSearches,
size_t sufficient_len,
- const int fullUpdate
+ limitedOutput_directive limit,
+ int const fullUpdate
)
{
- LZ4HC_optimal_t opt[LZ4_OPT_NUM + 1]; /* this uses a bit too much stack memory to my taste ... */
- LZ4HC_match_t matches[LZ4_OPT_NUM + 1];
+#define TRAILING_LITERALS 3
+ LZ4HC_optimal_t opt[LZ4_OPT_NUM + TRAILING_LITERALS]; /* this uses a bit too much stack memory to my taste ... */
const BYTE* ip = (const BYTE*) source;
const BYTE* anchor = ip;
- const BYTE* const iend = ip + inputSize;
+ const BYTE* const iend = ip + *srcSizePtr;
const BYTE* const mflimit = iend - MFLIMIT;
- const BYTE* const matchlimit = (iend - LASTLITERALS);
- BYTE* op = (BYTE*) dest;
- BYTE* const oend = op + maxOutputSize;
+ const BYTE* const matchlimit = iend - LASTLITERALS;
+ BYTE* op = (BYTE*) dst;
+ BYTE* opSaved = (BYTE*) dst;
+ BYTE* oend = op + dstCapacity;
/* init */
DEBUGLOG(5, "LZ4HC_compress_optimal");
+ *srcSizePtr = 0;
+ if (limit == limitedDestSize) oend -= LASTLITERALS; /* Hack for support LZ4 format restriction */
if (sufficient_len >= LZ4_OPT_NUM) sufficient_len = LZ4_OPT_NUM-1;
- ctx->end += inputSize;
- ip++;
/* Main Loop */
+ assert(ip - anchor < LZ4_MAX_INPUT_SIZE);
while (ip < mflimit) {
- size_t const llen = ip - anchor;
- size_t last_pos = 0;
- size_t match_num, cur, best_mlen, best_off;
- memset(opt, 0, sizeof(LZ4HC_optimal_t)); /* memset only the first one */
+ int const llen = (int)(ip - anchor);
+ int best_mlen, best_off;
+ int cur, last_match_pos = 0;
- match_num = LZ4HC_BinTree_GetAllMatches(ctx, ip, matchlimit, MINMATCH-1, matches, fullUpdate);
- if (!match_num) { ip++; continue; }
+ LZ4HC_match_t const firstMatch = LZ4HC_FindLongerMatch(ctx, ip, matchlimit, MINMATCH-1, nbSearches);
+ if (firstMatch.len==0) { ip++; continue; }
- if ((size_t)matches[match_num-1].len > sufficient_len) {
+ if ((size_t)firstMatch.len > sufficient_len) {
/* good enough solution : immediate encoding */
- best_mlen = matches[match_num-1].len;
- best_off = matches[match_num-1].off;
- cur = 0;
- last_pos = 1;
- goto encode;
+ int const firstML = firstMatch.len;
+ const BYTE* const matchPos = ip - firstMatch.off;
+ opSaved = op;
+ if ( LZ4HC_encodeSequence(&ip, &op, &anchor, firstML, matchPos, limit, oend) ) /* updates ip, op and anchor */
+ goto _dest_overflow;
+ continue;
}
- /* set prices using matches at position = 0 */
- { size_t matchNb;
- for (matchNb = 0; matchNb < match_num; matchNb++) {
- size_t mlen = (matchNb>0) ? (size_t)matches[matchNb-1].len+1 : MINMATCH;
- best_mlen = matches[matchNb].len; /* necessarily < sufficient_len < LZ4_OPT_NUM */
- for ( ; mlen <= best_mlen ; mlen++) {
- size_t const cost = LZ4HC_sequencePrice(llen, mlen) - LZ4HC_literalsPrice(llen);
- SET_PRICE(mlen, mlen, matches[matchNb].off, 0, cost); /* updates last_pos and opt[pos] */
- } } }
+ /* set prices for first positions (literals) */
+ { int rPos;
+ for (rPos = 0 ; rPos < MINMATCH ; rPos++) {
+ int const cost = LZ4HC_literalsPrice(llen + rPos);
+ opt[rPos].mlen = 1;
+ opt[rPos].off = 0;
+ opt[rPos].litlen = llen + rPos;
+ opt[rPos].price = cost;
+ DEBUGLOG(7, "rPos:%3i => price:%3i (litlen=%i) -- initial setup",
+ rPos, cost, opt[rPos].litlen);
+ } }
+ /* set prices using initial match */
+ { int mlen = MINMATCH;
+ int const matchML = firstMatch.len; /* necessarily < sufficient_len < LZ4_OPT_NUM */
+ int const offset = firstMatch.off;
+ assert(matchML < LZ4_OPT_NUM);
+ for ( ; mlen <= matchML ; mlen++) {
+ int const cost = LZ4HC_sequencePrice(llen, mlen);
+ opt[mlen].mlen = mlen;
+ opt[mlen].off = offset;
+ opt[mlen].litlen = llen;
+ opt[mlen].price = cost;
+ DEBUGLOG(7, "rPos:%3i => price:%3i (matchlen=%i) -- initial setup",
+ mlen, cost, mlen);
+ } }
+ last_match_pos = firstMatch.len;
+ { int addLit;
+ for (addLit = 1; addLit <= TRAILING_LITERALS; addLit ++) {
+ opt[last_match_pos+addLit].mlen = 1; /* literal */
+ opt[last_match_pos+addLit].off = 0;
+ opt[last_match_pos+addLit].litlen = addLit;
+ opt[last_match_pos+addLit].price = opt[last_match_pos].price + LZ4HC_literalsPrice(addLit);
+ DEBUGLOG(7, "rPos:%3i => price:%3i (litlen=%i) -- initial setup",
+ last_match_pos+addLit, opt[last_match_pos+addLit].price, addLit);
+ } }
- if (last_pos < MINMATCH) { ip++; continue; } /* note : on clang at least, this test improves performance */
-
/* check further positions */
- opt[0].mlen = opt[1].mlen = 1;
- for (cur = 1; cur <= last_pos; cur++) {
+ for (cur = 1; cur < last_match_pos; cur++) {
const BYTE* const curPtr = ip + cur;
+ LZ4HC_match_t newMatch;
- /* establish baseline price if cur is literal */
- { size_t price, litlen;
- if (opt[cur-1].mlen == 1) {
- /* no match at previous position */
- litlen = opt[cur-1].litlen + 1;
- if (cur > litlen) {
- price = opt[cur - litlen].price + LZ4HC_literalsPrice(litlen);
- } else {
- price = LZ4HC_literalsPrice(llen + litlen) - LZ4HC_literalsPrice(llen);
- }
- } else {
- litlen = 1;
- price = opt[cur - 1].price + LZ4HC_literalsPrice(1);
- }
-
- if (price < (size_t)opt[cur].price)
- SET_PRICE(cur, 1 /*mlen*/, 0 /*off*/, litlen, price); /* note : increases last_pos */
+ if (curPtr >= mflimit) break;
+ DEBUGLOG(7, "rPos:%u[%u] vs [%u]%u",
+ cur, opt[cur].price, opt[cur+1].price, cur+1);
+ if (fullUpdate) {
+ /* not useful to search here if next position has same (or lower) cost */
+ if ( (opt[cur+1].price <= opt[cur].price)
+ /* in some cases, next position has same cost, but cost rises sharply after, so a small match would still be beneficial */
+ && (opt[cur+MINMATCH].price < opt[cur].price + 3/*min seq price*/) )
+ continue;
+ } else {
+ /* not useful to search here if next position has same (or lower) cost */
+ if (opt[cur+1].price <= opt[cur].price) continue;
}
- if (cur == last_pos || curPtr >= mflimit) break;
+ DEBUGLOG(7, "search at rPos:%u", cur);
+ if (fullUpdate)
+ newMatch = LZ4HC_FindLongerMatch(ctx, curPtr, matchlimit, MINMATCH-1, nbSearches);
+ else
+ /* only test matches of minimum length; slightly faster, but misses a few bytes */
+ newMatch = LZ4HC_FindLongerMatch(ctx, curPtr, matchlimit, last_match_pos - cur, nbSearches);
+ if (!newMatch.len) continue;
- match_num = LZ4HC_BinTree_GetAllMatches(ctx, curPtr, matchlimit, MINMATCH-1, matches, fullUpdate);
- if ((match_num > 0) && (size_t)matches[match_num-1].len > sufficient_len) {
+ if ( ((size_t)newMatch.len > sufficient_len)
+ || (newMatch.len + cur >= LZ4_OPT_NUM) ) {
/* immediate encoding */
- best_mlen = matches[match_num-1].len;
- best_off = matches[match_num-1].off;
- last_pos = cur + 1;
+ best_mlen = newMatch.len;
+ best_off = newMatch.off;
+ last_match_pos = cur + 1;
goto encode;
}
- /* set prices using matches at position = cur */
- { size_t matchNb;
- for (matchNb = 0; matchNb < match_num; matchNb++) {
- size_t ml = (matchNb>0) ? (size_t)matches[matchNb-1].len+1 : MINMATCH;
- best_mlen = (cur + matches[matchNb].len < LZ4_OPT_NUM) ?
- (size_t)matches[matchNb].len : LZ4_OPT_NUM - cur;
+ /* before match : set price with literals at beginning */
+ { int const baseLitlen = opt[cur].litlen;
+ int litlen;
+ for (litlen = 1; litlen < MINMATCH; litlen++) {
+ int const price = opt[cur].price - LZ4HC_literalsPrice(baseLitlen) + LZ4HC_literalsPrice(baseLitlen+litlen);
+ int const pos = cur + litlen;
+ if (price < opt[pos].price) {
+ opt[pos].mlen = 1; /* literal */
+ opt[pos].off = 0;
+ opt[pos].litlen = baseLitlen+litlen;
+ opt[pos].price = price;
+ DEBUGLOG(7, "rPos:%3i => price:%3i (litlen=%i)",
+ pos, price, opt[pos].litlen);
+ } } }
- for ( ; ml <= best_mlen ; ml++) {
- size_t ll, price;
- if (opt[cur].mlen == 1) {
- ll = opt[cur].litlen;
- if (cur > ll)
- price = opt[cur - ll].price + LZ4HC_sequencePrice(ll, ml);
- else
- price = LZ4HC_sequencePrice(llen + ll, ml) - LZ4HC_literalsPrice(llen);
- } else {
- ll = 0;
- price = opt[cur].price + LZ4HC_sequencePrice(0, ml);
- }
+ /* set prices using match at position = cur */
+ { int const matchML = newMatch.len;
+ int ml = MINMATCH;
- if (cur + ml > last_pos || price < (size_t)opt[cur + ml].price) {
- SET_PRICE(cur + ml, ml, matches[matchNb].off, ll, price);
- } } } }
- } /* for (cur = 1; cur <= last_pos; cur++) */
+ assert(cur + newMatch.len < LZ4_OPT_NUM);
+ for ( ; ml <= matchML ; ml++) {
+ int const pos = cur + ml;
+ int const offset = newMatch.off;
+ int price;
+ int ll;
+ DEBUGLOG(7, "testing price rPos %i (last_match_pos=%i)",
+ pos, last_match_pos);
+ if (opt[cur].mlen == 1) {
+ ll = opt[cur].litlen;
+ price = ((cur > ll) ? opt[cur - ll].price : 0)
+ + LZ4HC_sequencePrice(ll, ml);
+ } else {
+ ll = 0;
+ price = opt[cur].price + LZ4HC_sequencePrice(0, ml);
+ }
- best_mlen = opt[last_pos].mlen;
- best_off = opt[last_pos].off;
- cur = last_pos - best_mlen;
+ if (pos > last_match_pos+TRAILING_LITERALS || price <= opt[pos].price) {
+ DEBUGLOG(7, "rPos:%3i => price:%3i (matchlen=%i)",
+ pos, price, ml);
+ assert(pos < LZ4_OPT_NUM);
+ if ( (ml == matchML) /* last pos of last match */
+ && (last_match_pos < pos) )
+ last_match_pos = pos;
+ opt[pos].mlen = ml;
+ opt[pos].off = offset;
+ opt[pos].litlen = ll;
+ opt[pos].price = price;
+ } } }
+ /* complete following positions with literals */
+ { int addLit;
+ for (addLit = 1; addLit <= TRAILING_LITERALS; addLit ++) {
+ opt[last_match_pos+addLit].mlen = 1; /* literal */
+ opt[last_match_pos+addLit].off = 0;
+ opt[last_match_pos+addLit].litlen = addLit;
+ opt[last_match_pos+addLit].price = opt[last_match_pos].price + LZ4HC_literalsPrice(addLit);
+ DEBUGLOG(7, "rPos:%3i => price:%3i (litlen=%i)", last_match_pos+addLit, opt[last_match_pos+addLit].price, addLit);
+ } }
+ } /* for (cur = 1; cur <= last_match_pos; cur++) */
-encode: /* cur, last_pos, best_mlen, best_off must be set */
- opt[0].mlen = 1;
- while (1) { /* from end to beginning */
- size_t const ml = opt[cur].mlen;
- int const offset = opt[cur].off;
- opt[cur].mlen = (int)best_mlen;
- opt[cur].off = (int)best_off;
- best_mlen = ml;
- best_off = offset;
- if (ml > cur) break; /* can this happen ? */
- cur -= ml;
- }
+ best_mlen = opt[last_match_pos].mlen;
+ best_off = opt[last_match_pos].off;
+ cur = last_match_pos - best_mlen;
- /* encode all recorded sequences */
- cur = 0;
- while (cur < last_pos) {
- int const ml = opt[cur].mlen;
- int const offset = opt[cur].off;
- if (ml == 1) { ip++; cur++; continue; }
- cur += ml;
- if ( LZ4HC_encodeSequence(&ip, &op, &anchor, ml, ip - offset, limit, oend) ) return 0;
- }
+encode: /* cur, last_match_pos, best_mlen, best_off must be set */
+ assert(cur < LZ4_OPT_NUM);
+ assert(last_match_pos >= 1); /* == 1 when only one candidate */
+ DEBUGLOG(6, "reverse traversal, looking for shortest path")
+ DEBUGLOG(6, "last_match_pos = %i", last_match_pos);
+ { int candidate_pos = cur;
+ int selected_matchLength = best_mlen;
+ int selected_offset = best_off;
+ while (1) { /* from end to beginning */
+ int const next_matchLength = opt[candidate_pos].mlen; /* can be 1, means literal */
+ int const next_offset = opt[candidate_pos].off;
+ DEBUGLOG(6, "pos %i: sequence length %i", candidate_pos, selected_matchLength);
+ opt[candidate_pos].mlen = selected_matchLength;
+ opt[candidate_pos].off = selected_offset;
+ selected_matchLength = next_matchLength;
+ selected_offset = next_offset;
+ if (next_matchLength > candidate_pos) break; /* last match elected, first match to encode */
+ assert(next_matchLength > 0); /* can be 1, means literal */
+ candidate_pos -= next_matchLength;
+ } }
+
+ /* encode all recorded sequences in order */
+ { int rPos = 0; /* relative position (to ip) */
+ while (rPos < last_match_pos) {
+ int const ml = opt[rPos].mlen;
+ int const offset = opt[rPos].off;
+ if (ml == 1) { ip++; rPos++; continue; } /* literal; note: can end up with several literals, in which case, skip them */
+ rPos += ml;
+ assert(ml >= MINMATCH);
+ assert((offset >= 1) && (offset <= MAX_DISTANCE));
+ opSaved = op;
+ if ( LZ4HC_encodeSequence(&ip, &op, &anchor, ml, ip - offset, limit, oend) ) /* updates ip, op and anchor */
+ goto _dest_overflow;
+ } }
} /* while (ip < mflimit) */
+_last_literals:
/* Encode Last Literals */
- { int lastRun = (int)(iend - anchor);
- if ((limit) && (((char*)op - dest) + lastRun + 1 + ((lastRun+255-RUN_MASK)/255) > (U32)maxOutputSize)) return 0; /* Check output limit */
- if (lastRun>=(int)RUN_MASK) { *op++=(RUN_MASK<<ML_BITS); lastRun-=RUN_MASK; for(; lastRun > 254 ; lastRun-=255) *op++ = 255; *op++ = (BYTE) lastRun; }
- else *op++ = (BYTE)(lastRun<<ML_BITS);
- memcpy(op, anchor, iend - anchor);
- op += iend-anchor;
+ { size_t lastRunSize = (size_t)(iend - anchor); /* literals */
+ size_t litLength = (lastRunSize + 255 - RUN_MASK) / 255;
+ size_t const totalSize = 1 + litLength + lastRunSize;
+ if (limit == limitedDestSize) oend += LASTLITERALS; /* restore correct value */
+ if (limit && (op + totalSize > oend)) {
+ if (limit == limitedOutput) return 0; /* Check output limit */
+ /* adapt lastRunSize to fill 'dst' */
+ lastRunSize = (size_t)(oend - op) - 1;
+ litLength = (lastRunSize + 255 - RUN_MASK) / 255;
+ lastRunSize -= litLength;
+ }
+ ip = anchor + lastRunSize;
+
+ if (lastRunSize >= RUN_MASK) {
+ size_t accumulator = lastRunSize - RUN_MASK;
+ *op++ = (RUN_MASK << ML_BITS);
+ for(; accumulator >= 255 ; accumulator -= 255) *op++ = 255;
+ *op++ = (BYTE) accumulator;
+ } else {
+ *op++ = (BYTE)(lastRunSize << ML_BITS);
+ }
+ memcpy(op, anchor, lastRunSize);
+ op += lastRunSize;
}
/* End */
- return (int) ((char*)op-dest);
+ *srcSizePtr = (int) (((const char*)ip) - source);
+ return (int) ((char*)op-dst);
+
+_dest_overflow:
+ if (limit == limitedDestSize) {
+ op = opSaved; /* restore correct out pointer */
+ goto _last_literals;
+ }
+ return 0;
}