| /* |
| lz4opt.h - Optimal Mode of LZ4 |
| Copyright (C) 2015-2016, Przemyslaw Skibinski <inikep@gmail.com> |
| Note : this file is intended to be included within lz4hc.c |
| |
| BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php) |
| |
| Redistribution and use in source and binary forms, with or without |
| modification, are permitted provided that the following conditions are |
| met: |
| |
| * Redistributions of source code must retain the above copyright |
| notice, this list of conditions and the following disclaimer. |
| * Redistributions in binary form must reproduce the above |
| copyright notice, this list of conditions and the following disclaimer |
| in the documentation and/or other materials provided with the |
| distribution. |
| |
| THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| You can contact the author at : |
| - LZ4 source repository : https://github.com/lz4/lz4 |
| - LZ4 public forum : https://groups.google.com/forum/#!forum/lz4c |
| */ |
| |
| #define LZ4_LOG_PARSER(fmt, ...) //printf(fmt, __VA_ARGS__) |
| #define LZ4_LOG_PRICE(fmt, ...) //printf(fmt, __VA_ARGS__) |
| #define LZ4_LOG_ENCODE(fmt, ...) //printf(fmt, __VA_ARGS__) |
| |
| |
| #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 bits */ |
| FORCE_INLINE size_t LZ4HC_literalsPrice(size_t litlen) |
| { |
| size_t price = 8*litlen; |
| if (litlen >= (size_t)RUN_MASK) price+=8*(1+(litlen-RUN_MASK)/255); |
| return price; |
| } |
| |
| |
| /* requires mlen >= MINMATCH */ |
| FORCE_INLINE size_t LZ4HC_sequencePrice(size_t litlen, size_t mlen) |
| { |
| size_t price = 16 + 8; /* 16-bit offset + token */ |
| |
| price += LZ4HC_literalsPrice(litlen); |
| |
| mlen -= MINMATCH; |
| if (mlen >= (size_t)ML_MASK) price+=8*(1+(mlen-ML_MASK)/255); |
| |
| return price; |
| } |
| |
| |
| /*-************************************* |
| * Binary Tree search |
| ***************************************/ |
| 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; |
| |
| 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 (matchLength > best_mlen) { |
| best_mlen = matchLength; |
| if (matches) { |
| matches[mnum].off = (int)(ip - match); |
| 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 */ |
| |
| 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) |
| { |
| const BYTE* const base = ctx->base; |
| const U32 target = (U32)(ip - base); |
| U32 idx = ctx->nextToUpdateBT; |
| |
| while(idx < target) |
| idx += LZ4HC_BinTree_InsertAndGetAllMatches(ctx, base+idx, iHighLimit, 8, NULL, NULL); |
| } |
| |
| |
| /** 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->nextToUpdateBT) return 0; /* skipped area */ |
| if (fullUpdate) LZ4HC_updateBinTree(ctx, ip, iHighLimit); |
| best_mlen = LZ4HC_BinTree_InsertAndGetAllMatches(ctx, ip, iHighLimit, best_mlen, matches, &mnum); |
| ctx->nextToUpdateBT = (U32)(ip - ctx->base + best_mlen); |
| return mnum; |
| } |
| |
| |
| #define SET_PRICE(pos, mlen, offset, litlen, price) \ |
| { \ |
| while (last_pos < pos) { opt[last_pos+1].price = 1<<30; last_pos++; } \ |
| opt[pos].mlen = (int)mlen; \ |
| opt[pos].off = (int)offset; \ |
| opt[pos].litlen = (int)litlen; \ |
| opt[pos].price = (int)price; \ |
| LZ4_LOG_PARSER("%d: SET price[%d/%d]=%d litlen=%d len=%d off=%d\n", (int)(inr-source), pos, last_pos, opt[pos].price, opt[pos].litlen, opt[pos].mlen, opt[pos].off); \ |
| } |
| |
| |
| static int LZ4HC_compress_optimal ( |
| LZ4HC_CCtx_internal* ctx, |
| const char* const source, |
| char* dest, |
| int inputSize, |
| int maxOutputSize, |
| limitedOutput_directive limit, |
| const size_t sufficient_len, |
| const int fullUpdate |
| ) |
| { |
| LZ4HC_optimal_t opt[LZ4_OPT_NUM + 1]; |
| LZ4HC_match_t matches[LZ4_OPT_NUM + 1]; |
| const BYTE *inr; |
| size_t res, cur, cur2; |
| size_t i, llen, litlen, mlen, best_mlen, price, offset, best_off, match_num, last_pos; |
| |
| const BYTE* ip = (const BYTE*) source; |
| const BYTE* anchor = ip; |
| 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; |
| |
| /* init */ |
| ctx->end += inputSize; |
| ip++; |
| |
| /* Main Loop */ |
| while (ip < mflimit) { |
| memset(opt, 0, sizeof(LZ4HC_optimal_t)); |
| last_pos = 0; |
| llen = ip - anchor; |
| match_num = LZ4HC_BinTree_GetAllMatches(ctx, ip, matchlimit, MINMATCH-1, matches, fullUpdate); |
| if (!match_num) { ip++; continue; } |
| LZ4_LOG_PARSER("%d: match_num=%d last_pos=%d\n", (int)(ip-source), match_num, last_pos); |
| |
| if ((size_t)matches[match_num-1].len > sufficient_len) { |
| best_mlen = matches[match_num-1].len; |
| best_off = matches[match_num-1].off; |
| cur = 0; |
| last_pos = 1; |
| goto encode; |
| } |
| |
| /* set prices using matches at position = 0 */ |
| for (i = 0; i < match_num; i++) { |
| mlen = (i>0) ? (size_t)matches[i-1].len+1 : MINMATCH; |
| best_mlen = (matches[i].len < LZ4_OPT_NUM) ? matches[i].len : LZ4_OPT_NUM; |
| LZ4_LOG_PARSER("%d: start Found mlen=%d off=%d best_mlen=%d last_pos=%d\n", (int)(ip-source), matches[i].len, matches[i].off, best_mlen, last_pos); |
| while (mlen <= best_mlen) { |
| litlen = 0; |
| price = LZ4HC_sequencePrice(llen + litlen, mlen) - LZ4HC_literalsPrice(llen); |
| SET_PRICE(mlen, mlen, matches[i].off, litlen, price); |
| mlen++; |
| } |
| } |
| |
| if (last_pos < MINMATCH) { ip++; continue; } |
| |
| /* check further positions */ |
| opt[0].mlen = opt[1].mlen = 1; |
| for (cur = 1; cur <= last_pos; cur++) { |
| inr = ip + cur; |
| |
| if (opt[cur-1].mlen == 1) { |
| litlen = opt[cur-1].litlen + 1; |
| if (cur != litlen) { |
| price = opt[cur - litlen].price + LZ4HC_literalsPrice(litlen); |
| LZ4_LOG_PRICE("%d: TRY1 opt[%d].price=%d price=%d cur=%d litlen=%d\n", (int)(inr-source), cur - litlen, opt[cur - litlen].price, price, cur, litlen); |
| } else { |
| price = LZ4HC_literalsPrice(llen + litlen) - LZ4HC_literalsPrice(llen); |
| LZ4_LOG_PRICE("%d: TRY2 price=%d cur=%d litlen=%d llen=%d\n", (int)(inr-source), price, cur, litlen, llen); |
| } |
| } else { |
| litlen = 1; |
| price = opt[cur - 1].price + LZ4HC_literalsPrice(litlen); |
| LZ4_LOG_PRICE("%d: TRY3 price=%d cur=%d litlen=%d litonly=%d\n", (int)(inr-source), price, cur, litlen, LZ4HC_literalsPrice(litlen)); |
| } |
| |
| mlen = 1; |
| best_mlen = 0; |
| LZ4_LOG_PARSER("%d: TRY price=%d opt[%d].price=%d\n", (int)(inr-source), price, cur, opt[cur].price); |
| if (cur > last_pos || price < (size_t)opt[cur].price) |
| SET_PRICE(cur, mlen, best_mlen, litlen, price); |
| |
| if (cur == last_pos || inr >= mflimit) break; |
| LZ4_LOG_PARSER("%d: CURRENT price[%d/%d]=%d off=%d mlen=%d litlen=%d\n", (int)(inr-source), cur, last_pos, opt[cur].price, opt[cur].off, opt[cur].mlen, opt[cur].litlen); |
| |
| match_num = LZ4HC_BinTree_GetAllMatches(ctx, inr, matchlimit, MINMATCH-1, matches, fullUpdate); |
| LZ4_LOG_PARSER("%d: LZ4HC_BinTree_GetAllMatches match_num=%d\n", (int)(inr-source), match_num); |
| |
| if (match_num > 0 && (size_t)matches[match_num-1].len > sufficient_len) { |
| best_mlen = matches[match_num-1].len; |
| best_off = matches[match_num-1].off; |
| last_pos = cur + 1; |
| goto encode; |
| } |
| |
| /* set prices using matches at position = cur */ |
| for (i = 0; i < match_num; i++) { |
| mlen = (i>0) ? (size_t)matches[i-1].len+1 : MINMATCH; |
| cur2 = cur; |
| best_mlen = (cur2 + matches[i].len < LZ4_OPT_NUM) ? (size_t)matches[i].len : LZ4_OPT_NUM - cur2; |
| LZ4_LOG_PARSER("%d: Found1 cur=%d cur2=%d mlen=%d off=%d best_mlen=%d last_pos=%d\n", (int)(inr-source), cur, cur2, matches[i].len, matches[i].off, best_mlen, last_pos); |
| |
| while (mlen <= best_mlen) { |
| if (opt[cur2].mlen == 1) { |
| litlen = opt[cur2].litlen; |
| |
| if (cur2 != litlen) |
| price = opt[cur2 - litlen].price + LZ4HC_sequencePrice(litlen, mlen); |
| else |
| price = LZ4HC_sequencePrice(llen + litlen, mlen) - LZ4HC_literalsPrice(llen); |
| } else { |
| litlen = 0; |
| price = opt[cur2].price + LZ4HC_sequencePrice(litlen, mlen); |
| } |
| |
| LZ4_LOG_PARSER("%d: Found2 mlen=%d best_mlen=%d off=%d price=%d litlen=%d price[%d]=%d\n", (int)(inr-source), mlen, best_mlen, matches[i].off, price, litlen, cur - litlen, opt[cur - litlen].price); |
| if (cur2 + mlen > last_pos || price < (size_t)opt[cur2 + mlen].price) { // || (((int)price == opt[cur2 + mlen].price) && (opt[cur2 + mlen-1].mlen == 1))) { |
| SET_PRICE(cur2 + mlen, mlen, matches[i].off, litlen, price); |
| } |
| mlen++; |
| } |
| } |
| } /* for (cur = 1; cur <= last_pos; cur++) */ |
| |
| best_mlen = opt[last_pos].mlen; |
| best_off = opt[last_pos].off; |
| cur = last_pos - best_mlen; |
| |
| encode: /* cur, last_pos, best_mlen, best_off have to be set */ |
| for (i = 1; i <= last_pos; i++) { |
| LZ4_LOG_PARSER("%d: price[%d/%d]=%d off=%d mlen=%d litlen=%d\n", (int)(ip-source+i), i, last_pos, opt[i].price, opt[i].off, opt[i].mlen, opt[i].litlen); |
| } |
| |
| LZ4_LOG_PARSER("%d: cur=%d/%d best_mlen=%d best_off=%d\n", (int)(ip-source+cur), cur, last_pos, best_mlen, best_off); |
| |
| opt[0].mlen = 1; |
| while (1) { |
| mlen = opt[cur].mlen; |
| offset = opt[cur].off; |
| opt[cur].mlen = (int)best_mlen; |
| opt[cur].off = (int)best_off; |
| best_mlen = mlen; |
| best_off = offset; |
| if (mlen > cur) break; |
| cur -= mlen; |
| } |
| |
| for (i = 0; i <= last_pos;) { |
| LZ4_LOG_PARSER("%d: price2[%d/%d]=%d off=%d mlen=%d litlen=%d\n", (int)(ip-source+i), i, last_pos, opt[i].price, opt[i].off, opt[i].mlen, opt[i].litlen); |
| i += opt[i].mlen; |
| } |
| |
| cur = 0; |
| while (cur < last_pos) { |
| LZ4_LOG_PARSER("%d: price3[%d/%d]=%d off=%d mlen=%d litlen=%d\n", (int)(ip-source+cur), cur, last_pos, opt[cur].price, opt[cur].off, opt[cur].mlen, opt[cur].litlen); |
| mlen = opt[cur].mlen; |
| if (mlen == 1) { ip++; cur++; continue; } |
| offset = opt[cur].off; |
| cur += mlen; |
| |
| LZ4_LOG_ENCODE("%d: ENCODE literals=%d off=%d mlen=%d ", (int)(ip-(const BYTE*)source), (int)(ip-anchor), (int)(offset), (int)mlen); |
| res = LZ4HC_encodeSequence(&ip, &op, &anchor, (int)mlen, ip - offset, limit, oend); |
| LZ4_LOG_ENCODE("out=%d\n", (int)((char*)op - dest)); |
| |
| if (res) return 0; |
| |
| LZ4_LOG_PARSER("%d: offset=%d\n", (int)(ip-source), offset); |
| } |
| } |
| |
| /* 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); |
| LZ4_LOG_ENCODE("%d: ENCODE_LAST literals=%d out=%d\n", (int)(ip-(const BYTE*)source), (int)(iend-anchor), (int)((char*)op-dest)); |
| memcpy(op, anchor, iend - anchor); |
| op += iend-anchor; |
| } |
| |
| /* End */ |
| return (int) ((char*)op-dest); |
| } |