diff options
Diffstat (limited to 'lib/lz4opt.h')
| -rw-r--r-- | lib/lz4opt.h | 58 |
1 files changed, 44 insertions, 14 deletions
diff --git a/lib/lz4opt.h b/lib/lz4opt.h index 1b215b4..ef7b725 100644 --- a/lib/lz4opt.h +++ b/lib/lz4opt.h @@ -195,12 +195,39 @@ LZ4_FORCE_INLINE int LZ4HC_BinTree_GetAllMatches ( } +LZ4_FORCE_INLINE +int LZ4HC_FindLongerMatch(LZ4HC_CCtx_internal* const ctx, /* Index table will be updated */ + const BYTE* const ip, const BYTE* const iHighLimit, + int longest, + const BYTE** matchpos, + const int maxNbAttempts) +{ + const BYTE* uselessPtr = ip; + return LZ4HC_InsertAndGetWiderMatch(ctx, ip, ip, iHighLimit, longest, matchpos, &uselessPtr, maxNbAttempts); +} + +LZ4_FORCE_INLINE int LZ4HC_HashChain_GetAllMatches ( + LZ4HC_CCtx_internal* ctx, + const BYTE* const ip, const BYTE* const iHighLimit, + size_t best_mlen, LZ4HC_match_t* matches, const int fullUpdate) +{ + const BYTE* matchPtr; + int matchLength = LZ4HC_FindLongerMatch(ctx, ip, iHighLimit, (int)best_mlen, &matchPtr, ctx->searchNum); + if (matchLength < MINMATCH) return 0; + assert(matches != NULL); + matches[0].len = matchLength; + matches[0].off = (int)(ip-matchPtr); + (void)fullUpdate; + return 1; +} + + static int LZ4HC_compress_optimal ( LZ4HC_CCtx_internal* ctx, const char* const source, - char* dest, + char* dst, int inputSize, - int maxOutputSize, + int dstCapacity, limitedOutput_directive limit, size_t sufficient_len, const int fullUpdate @@ -214,8 +241,8 @@ static int LZ4HC_compress_optimal ( const BYTE* const iend = ip + inputSize; const BYTE* const mflimit = iend - MFLIMIT; const BYTE* const matchlimit = (iend - LASTLITERALS); - BYTE* op = (BYTE*) dest; - BYTE* const oend = op + maxOutputSize; + BYTE* op = (BYTE*) dst; + BYTE* const oend = op + dstCapacity; /* init */ DEBUGLOG(5, "LZ4HC_compress_optimal"); @@ -230,7 +257,8 @@ static int LZ4HC_compress_optimal ( int best_mlen, best_off; int cur, last_match_pos = 0; - int const nb_matches_initial = LZ4HC_BinTree_GetAllMatches(ctx, ip, matchlimit, MINMATCH-1, matches, fullUpdate); + //int const nb_matches_initial = LZ4HC_BinTree_GetAllMatches(ctx, ip, matchlimit, MINMATCH-1, matches, fullUpdate); + int const nb_matches_initial = LZ4HC_HashChain_GetAllMatches(ctx, ip, matchlimit, MINMATCH-1, matches, fullUpdate); if (!nb_matches_initial) { ip++; continue; } if ((size_t)matches[nb_matches_initial-1].len > sufficient_len) { @@ -274,7 +302,9 @@ static int LZ4HC_compress_optimal ( const BYTE* const curPtr = ip + cur; int nb_matches; - /* establish baseline price if cur is literal */ + /* establish baseline price for cur as a literal. + * fixes unused positions (between 2 matches) + * and inefficient match stack */ { int price; int litlen; if (opt[cur-1].mlen == 1) { @@ -295,7 +325,8 @@ static int LZ4HC_compress_optimal ( if (cur == last_match_pos || curPtr >= mflimit) break; - nb_matches = LZ4HC_BinTree_GetAllMatches(ctx, curPtr, matchlimit, MINMATCH-1, matches, fullUpdate); + //nb_matches = LZ4HC_BinTree_GetAllMatches(ctx, curPtr, matchlimit, MINMATCH-1, matches, fullUpdate); + nb_matches = LZ4HC_HashChain_GetAllMatches(ctx, curPtr, matchlimit, MINMATCH-1, matches, fullUpdate); if ((nb_matches > 0) && (size_t)matches[nb_matches-1].len > sufficient_len) { /* immediate encoding */ best_mlen = matches[nb_matches-1].len; @@ -307,9 +338,9 @@ static int LZ4HC_compress_optimal ( /* set prices using matches at position = cur */ { int matchNb; for (matchNb = 0; matchNb < nb_matches; matchNb++) { - int ml = (matchNb>0) ? matches[matchNb-1].len+1 : MINMATCH; int const matchML = (cur + matches[matchNb].len < LZ4_OPT_NUM) ? matches[matchNb].len : (int)(LZ4_OPT_NUM - cur); + int ml = (matchNb>0) ? matches[matchNb-1].len+1 : MINMATCH; for ( ; ml <= matchML ; ml++) { int const pos = cur + ml; @@ -341,19 +372,18 @@ static int LZ4HC_compress_optimal ( 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 */ - opt[0].mlen = 1; { 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; + int const next_matchLength = opt[candidate_pos].mlen; /* can be 1, means literal */ int const next_offset = opt[candidate_pos].off; - assert(next_matchLength > 0); /* note : can be 1, means literal */ 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; } } @@ -362,7 +392,7 @@ encode: /* cur, last_match_pos, best_mlen, best_off must be set */ while (rPos < last_match_pos) { int const ml = opt[rPos].mlen; int const offset = opt[rPos].off; - if (ml == 1) { ip++; rPos++; continue; } /* literal */ + 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 <=65535)); @@ -374,7 +404,7 @@ encode: /* cur, last_match_pos, best_mlen, best_off must be set */ /* Encode Last Literals */ { int lastRun = (int)(iend - anchor); if ( (limit) - && (((char*)op - dest) + lastRun + 1 + ((lastRun+255-RUN_MASK)/255) > (U32)maxOutputSize)) + && (((char*)op - dst) + lastRun + 1 + ((lastRun+255-RUN_MASK)/255) > (U32)dstCapacity)) return 0; /* Check output limit */ if (lastRun >= (int)RUN_MASK) { *op++=(RUN_MASK<<ML_BITS); @@ -387,5 +417,5 @@ encode: /* cur, last_match_pos, best_mlen, best_off must be set */ } /* End */ - return (int) ((char*)op-dest); + return (int) ((char*)op-dst); } |