return 0;
}
-void* LZ4_createHC (char* inputBuffer)
+void* LZ4_createHC (const char* inputBuffer)
{
- LZ4_streamHC_t* hc4 = (LZ4_streamHC_t*)ALLOCATOR(1, sizeof(LZ4_streamHC_t));
+ LZ4_streamHC_t* hc4 = (LZ4_streamHC_t*)ALLOC(sizeof(LZ4_streamHC_t));
if (hc4 == NULL) return NULL; /* not enough memory */
LZ4HC_init (&hc4->internal_donotuse, (const BYTE*)inputBuffer);
- hc4->internal_donotuse.inputBuffer = (BYTE*)inputBuffer;
+ assert(sizeof(size_t) == sizeof(void*));
+ hc4->internal_donotuse.inputBuffer = (void*)(size_t)inputBuffer; /* ugly hack, circumvent -Wcast-qual */
return hc4;
}
{
LZ4HC_CCtx_internal* const hc4 = &((LZ4_streamHC_t*)LZ4HC_Data)->internal_donotuse;
int const dictSize = LZ4_saveDictHC((LZ4_streamHC_t*)LZ4HC_Data, (char*)(hc4->inputBuffer), 64 KB);
- return (char*)(hc4->inputBuffer + dictSize);
+ return (char*)(hc4->inputBuffer) + dictSize;
}
+
+
+ /* ================================================
+ * LZ4 Optimal parser (levels 10-12)
+ * ===============================================*/
+ typedef struct {
+ int price;
+ int off;
+ int mlen;
+ int litlen;
+ } LZ4HC_optimal_t;
+
+ /* price in bytes */
+ LZ4_FORCE_INLINE int LZ4HC_literalsPrice(int const litlen)
+ {
+ int price = litlen;
+ if (litlen >= (int)RUN_MASK)
+ price += 1 + (litlen-RUN_MASK)/255;
+ return price;
+ }
+
+
+ /* requires mlen >= MINMATCH */
+ LZ4_FORCE_INLINE int LZ4HC_sequencePrice(int litlen, int mlen)
+ {
+ int price = 1 + 2 ; /* token + 16-bit offset */
+
+ price += LZ4HC_literalsPrice(litlen);
+
+ if (mlen >= (int)(ML_MASK+MINMATCH))
+ price += 1 + (mlen-(ML_MASK+MINMATCH))/255;
+
+ return price;
+ }
+
+
+ typedef struct {
+ int off;
+ int len;
+ } LZ4HC_match_t;
+
+ LZ4_FORCE_INLINE LZ4HC_match_t
+ LZ4HC_FindLongerMatch(LZ4HC_CCtx_internal* const ctx,
+ const BYTE* ip, const BYTE* const iHighLimit,
+ int minLen, int nbSearches)
+ {
+ 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;
+ }
+
+
+ static int LZ4HC_compress_optimal (
+ LZ4HC_CCtx_internal* ctx,
+ const char* const source,
+ char* dst,
+ int* srcSizePtr,
+ int dstCapacity,
+ int const nbSearches,
+ size_t sufficient_len,
+ limitedOutput_directive limit,
+ int const fullUpdate
+ )
+ {
+ #define TRAILING_LITERALS 3
+ LZ4HC_optimal_t opt[LZ4_OPT_NUM + TRAILING_LITERALS]; /* ~64 KB, which is a bit large for stack... */
+
+ const BYTE* ip = (const BYTE*) source;
+ const BYTE* anchor = ip;
+ const BYTE* const iend = ip + *srcSizePtr;
+ const BYTE* const mflimit = iend - MFLIMIT;
+ 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;
+
+ /* Main Loop */
+ assert(ip - anchor < LZ4_MAX_INPUT_SIZE);
+ while (ip <= mflimit) {
+ int const llen = (int)(ip - anchor);
+ int best_mlen, best_off;
+ int cur, last_match_pos = 0;
+
+ LZ4HC_match_t const firstMatch = LZ4HC_FindLongerMatch(ctx, ip, matchlimit, MINMATCH-1, nbSearches);
+ if (firstMatch.len==0) { ip++; continue; }
+
+ if ((size_t)firstMatch.len > sufficient_len) {
+ /* good enough solution : immediate encoding */
+ 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 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);
+ } }
+
+ /* check further positions */
+ for (cur = 1; cur < last_match_pos; cur++) {
+ const BYTE* const curPtr = ip + cur;
+ LZ4HC_match_t newMatch;
+
+ 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;
+ }
+
+ 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;
+
+ if ( ((size_t)newMatch.len > sufficient_len)
+ || (newMatch.len + cur >= LZ4_OPT_NUM) ) {
+ /* immediate encoding */
+ best_mlen = newMatch.len;
+ best_off = newMatch.off;
+ last_match_pos = cur + 1;
+ goto encode;
+ }
+
+ /* 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);
+ } } }
+
+ /* set prices using match at position = cur */
+ { int const matchML = newMatch.len;
+ int ml = MINMATCH;
+
+ 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);
+ }
+
+ 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++) */
+
+ best_mlen = opt[last_match_pos].mlen;
+ best_off = opt[last_match_pos].off;
+ cur = last_match_pos - best_mlen;
+
+ 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 */
+ { 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 */
+ *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;
+ }
projects / platform / upstream / lz4.git / commitdiff