| /* |
| LZ4 HC Encoder - Part of LZ4 HC algorithm |
| Copyright (C) 2011-2013, Yann Collet. |
| 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 homepage : http://fastcompression.blogspot.com/p/lz4.html |
| - LZ4 source repository : http://code.google.com/p/lz4/ |
| */ |
| |
| /* lz4hc_encoder.h must be included into lz4hc.c |
| The objective of this file is to create a single LZ4 compression function source |
| which will be instanciated multiple times with minor variations |
| depending on a set of #define. |
| */ |
| |
| //**************************** |
| // Check required defines |
| //**************************** |
| |
| #ifndef FUNCTION_NAME |
| # error "FUNTION_NAME is not defined" |
| #endif |
| |
| |
| //**************************** |
| // Local definitions |
| //**************************** |
| #define COMBINED_NAME_RAW(n1,n2) n1 ## n2 |
| #define COMBINED_NAME(n1,n2) COMBINED_NAME_RAW(n1,n2) |
| #define ENCODE_SEQUENCE_NAME COMBINED_NAME(FUNCTION_NAME,_encodeSequence) |
| #ifdef LIMITED_OUTPUT |
| # define ENCODE_SEQUENCE(i,o,a,m,r,d) if (ENCODE_SEQUENCE_NAME(i,o,a,m,r,d)) return 0; |
| #else |
| # define ENCODE_SEQUENCE(i,o,a,m,r,d) ENCODE_SEQUENCE_NAME(i,o,a,m,r) |
| #endif |
| |
| //**************************** |
| // Function code |
| //**************************** |
| |
| forceinline int ENCODE_SEQUENCE_NAME ( |
| const BYTE** ip, |
| BYTE** op, |
| const BYTE** anchor, |
| int matchLength, |
| const BYTE* ref |
| #ifdef LIMITED_OUTPUT |
| ,BYTE* oend |
| #endif |
| ) |
| { |
| int length, len; |
| BYTE* token; |
| |
| // Encode Literal length |
| length = (int)(*ip - *anchor); |
| token = (*op)++; |
| #ifdef LIMITED_OUTPUT |
| if ((*op + length + (2 + 1 + LASTLITERALS) + (length>>8)) > oend) return 1; // Check output limit |
| #endif |
| if (length>=(int)RUN_MASK) { *token=(RUN_MASK<<ML_BITS); len = length-RUN_MASK; for(; len > 254 ; len-=255) *(*op)++ = 255; *(*op)++ = (BYTE)len; } |
| else *token = (BYTE)(length<<ML_BITS); |
| |
| // Copy Literals |
| LZ4_BLINDCOPY(*anchor, *op, length); |
| |
| // Encode Offset |
| LZ4_WRITE_LITTLEENDIAN_16(*op,(U16)(*ip-ref)); |
| |
| // Encode MatchLength |
| length = (int)(matchLength-MINMATCH); |
| #ifdef LIMITED_OUTPUT |
| if (*op + (1 + LASTLITERALS) + (length>>8) > oend) return 1; // Check output limit |
| #endif |
| if (length>=(int)ML_MASK) { *token+=ML_MASK; length-=ML_MASK; for(; length > 509 ; length-=510) { *(*op)++ = 255; *(*op)++ = 255; } if (length > 254) { length-=255; *(*op)++ = 255; } *(*op)++ = (BYTE)length; } |
| else *token += (BYTE)(length); |
| |
| // Prepare next loop |
| *ip += matchLength; |
| *anchor = *ip; |
| |
| return 0; |
| } |
| |
| |
| int COMBINED_NAME(FUNCTION_NAME,_continue) ( |
| void* ctxvoid, |
| const char* source, |
| char* dest, |
| int inputSize |
| #ifdef LIMITED_OUTPUT |
| ,int maxOutputSize |
| #endif |
| ) |
| { |
| LZ4HC_Data_Structure* ctx = (LZ4HC_Data_Structure*) ctxvoid; |
| 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; |
| #ifdef LIMITED_OUTPUT |
| BYTE* const oend = op + maxOutputSize; |
| #endif |
| |
| int ml, ml2, ml3, ml0; |
| const BYTE* ref=NULL; |
| const BYTE* start2=NULL; |
| const BYTE* ref2=NULL; |
| const BYTE* start3=NULL; |
| const BYTE* ref3=NULL; |
| const BYTE* start0; |
| const BYTE* ref0; |
| |
| // Ensure blocks follow each other |
| if (ip != ctx->end) return 0; |
| ctx->end += inputSize; |
| |
| ip++; |
| |
| // Main Loop |
| while (ip < mflimit) |
| { |
| ml = LZ4HC_InsertAndFindBestMatch (ctx, ip, matchlimit, (&ref)); |
| if (!ml) { ip++; continue; } |
| |
| // saved, in case we would skip too much |
| start0 = ip; |
| ref0 = ref; |
| ml0 = ml; |
| |
| _Search2: |
| if (ip+ml < mflimit) |
| ml2 = LZ4HC_InsertAndGetWiderMatch(ctx, ip + ml - 2, ip + 1, matchlimit, ml, &ref2, &start2); |
| else ml2 = ml; |
| |
| if (ml2 == ml) // No better match |
| { |
| ENCODE_SEQUENCE(&ip, &op, &anchor, ml, ref, oend); |
| continue; |
| } |
| |
| if (start0 < ip) |
| { |
| if (start2 < ip + ml0) // empirical |
| { |
| ip = start0; |
| ref = ref0; |
| ml = ml0; |
| } |
| } |
| |
| // Here, start0==ip |
| if ((start2 - ip) < 3) // First Match too small : removed |
| { |
| ml = ml2; |
| ip = start2; |
| ref =ref2; |
| goto _Search2; |
| } |
| |
| _Search3: |
| // Currently we have : |
| // ml2 > ml1, and |
| // ip1+3 <= ip2 (usually < ip1+ml1) |
| if ((start2 - ip) < OPTIMAL_ML) |
| { |
| int correction; |
| int new_ml = ml; |
| if (new_ml > OPTIMAL_ML) new_ml = OPTIMAL_ML; |
| if (ip+new_ml > start2 + ml2 - MINMATCH) new_ml = (int)(start2 - ip) + ml2 - MINMATCH; |
| correction = new_ml - (int)(start2 - ip); |
| if (correction > 0) |
| { |
| start2 += correction; |
| ref2 += correction; |
| ml2 -= correction; |
| } |
| } |
| // Now, we have start2 = ip+new_ml, with new_ml = min(ml, OPTIMAL_ML=18) |
| |
| if (start2 + ml2 < mflimit) |
| ml3 = LZ4HC_InsertAndGetWiderMatch(ctx, start2 + ml2 - 3, start2, matchlimit, ml2, &ref3, &start3); |
| else ml3 = ml2; |
| |
| if (ml3 == ml2) // No better match : 2 sequences to encode |
| { |
| // ip & ref are known; Now for ml |
| if (start2 < ip+ml) ml = (int)(start2 - ip); |
| // Now, encode 2 sequences |
| ENCODE_SEQUENCE(&ip, &op, &anchor, ml, ref, oend); |
| ip = start2; |
| ENCODE_SEQUENCE(&ip, &op, &anchor, ml2, ref2, oend); |
| continue; |
| } |
| |
| if (start3 < ip+ml+3) // Not enough space for match 2 : remove it |
| { |
| if (start3 >= (ip+ml)) // can write Seq1 immediately ==> Seq2 is removed, so Seq3 becomes Seq1 |
| { |
| if (start2 < ip+ml) |
| { |
| int correction = (int)(ip+ml - start2); |
| start2 += correction; |
| ref2 += correction; |
| ml2 -= correction; |
| if (ml2 < MINMATCH) |
| { |
| start2 = start3; |
| ref2 = ref3; |
| ml2 = ml3; |
| } |
| } |
| |
| ENCODE_SEQUENCE(&ip, &op, &anchor, ml, ref, oend); |
| ip = start3; |
| ref = ref3; |
| ml = ml3; |
| |
| start0 = start2; |
| ref0 = ref2; |
| ml0 = ml2; |
| goto _Search2; |
| } |
| |
| start2 = start3; |
| ref2 = ref3; |
| ml2 = ml3; |
| goto _Search3; |
| } |
| |
| // OK, now we have 3 ascending matches; let's write at least the first one |
| // ip & ref are known; Now for ml |
| if (start2 < ip+ml) |
| { |
| if ((start2 - ip) < (int)ML_MASK) |
| { |
| int correction; |
| if (ml > OPTIMAL_ML) ml = OPTIMAL_ML; |
| if (ip + ml > start2 + ml2 - MINMATCH) ml = (int)(start2 - ip) + ml2 - MINMATCH; |
| correction = ml - (int)(start2 - ip); |
| if (correction > 0) |
| { |
| start2 += correction; |
| ref2 += correction; |
| ml2 -= correction; |
| } |
| } |
| else |
| { |
| ml = (int)(start2 - ip); |
| } |
| } |
| ENCODE_SEQUENCE(&ip, &op, &anchor, ml, ref, oend); |
| |
| ip = start2; |
| ref = ref2; |
| ml = ml2; |
| |
| start2 = start3; |
| ref2 = ref3; |
| ml2 = ml3; |
| |
| goto _Search3; |
| |
| } |
| |
| // Encode Last Literals |
| { |
| int lastRun = (int)(iend - anchor); |
| #ifdef LIMITED_OUTPUT |
| if (((char*)op - dest) + lastRun + 1 + ((lastRun+255-RUN_MASK)/255) > (U32)maxOutputSize) return 0; // Check output limit |
| #endif |
| 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; |
| } |
| |
| // End |
| return (int) (((char*)op)-dest); |
| } |
| |
| |
| int FUNCTION_NAME (const char* source, |
| char* dest, |
| int inputSize |
| #ifdef LIMITED_OUTPUT |
| ,int maxOutputSize |
| #endif |
| ) |
| { |
| void* ctx = LZ4_createHC(source); |
| int result; |
| if (ctx==NULL) return 0; |
| #ifdef LIMITED_OUTPUT |
| result = COMBINED_NAME(FUNCTION_NAME,_continue) (ctx, source, dest, inputSize, maxOutputSize); |
| #else |
| result = COMBINED_NAME(FUNCTION_NAME,_continue) (ctx, source, dest, inputSize); |
| #endif |
| LZ4_freeHC(ctx); |
| |
| return result; |
| } |
| |
| |
| //**************************** |
| // Clean defines |
| //**************************** |
| |
| // Required defines |
| #undef FUNCTION_NAME |
| |
| // Locally Generated |
| #undef ENCODE_SEQUENCE |
| #undef ENCODE_SEQUENCE_NAME |
| |
| // Optional defines |
| #ifdef LIMITED_OUTPUT |
| #undef LIMITED_OUTPUT |
| #endif |
| |
| |
