diff options
Diffstat (limited to 'lz4hc.c')
| -rw-r--r-- | lz4hc.c | 264 |
1 files changed, 29 insertions, 235 deletions
@@ -31,6 +31,10 @@ - LZ4 source repository : http://code.google.com/p/lz4/
*/
+/*
+Note : this source file requires "lz4hc_encoder.h"
+*/
+
//**************************************
// CPU Feature Detection
@@ -319,7 +323,7 @@ inline static int LZ4HC_Init (LZ4HC_Data_Structure* hc4, const BYTE* base) }
-inline static void* LZ4HC_Create (const BYTE* base)
+inline static void* LZ4HC_create (const BYTE* base)
{
void* hc4 = ALLOCATOR(sizeof(LZ4HC_Data_Structure));
@@ -328,7 +332,7 @@ inline static void* LZ4HC_Create (const BYTE* base) }
-inline static int LZ4HC_Free (void** LZ4HC_Data)
+inline static int LZ4HC_free (void** LZ4HC_Data)
{
FREEMEM(*LZ4HC_Data);
*LZ4HC_Data = NULL;
@@ -500,247 +504,37 @@ _endCount: }
-forceinline static int LZ4_encodeSequence(const BYTE** ip, BYTE** op, const BYTE** anchor, int matchLength, const BYTE* ref, BYTE* oend)
-{
- int length, len;
- BYTE* token;
-
- // Encode Literal length
- length = (int)(*ip - *anchor);
- token = (*op)++;
- if ((*op + length + (2 + 1 + LASTLITERALS) + (length>>8)) > oend) return 1; // Check output limit
- 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
- len = (int)(matchLength-MINMATCH);
- if (*op + (1 + LASTLITERALS) + (length>>8) > oend) return 1; // Check output limit
- if (len>=(int)ML_MASK) { *token+=ML_MASK; len-=ML_MASK; for(; len > 509 ; len-=510) { *(*op)++ = 255; *(*op)++ = 255; } if (len > 254) { len-=255; *(*op)++ = 255; } *(*op)++ = (BYTE)len; }
- else *token += (BYTE)len;
-
- // Prepare next loop
- *ip += matchLength;
- *anchor = *ip;
- return 0;
-}
-
-
-//****************************
-// Compression CODE
-//****************************
+//**************************************
+// Compression functions
+//**************************************
-int LZ4_compressHCCtx(LZ4HC_Data_Structure* ctx,
- const char* source,
+/*
+int LZ4_compressHC(
+ const char* source,
char* dest,
- int inputSize,
- int maxOutputSize)
-{
- 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;
-
- 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;
-
- 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
- {
- if (LZ4_encodeSequence(&ip, &op, &anchor, ml, ref, oend)) return 0;
- 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
- if (LZ4_encodeSequence(&ip, &op, &anchor, ml, ref, oend)) return 0;
- ip = start2;
- if (LZ4_encodeSequence(&ip, &op, &anchor, ml2, ref2, oend)) return 0;
- 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;
- }
- }
-
- if (LZ4_encodeSequence(&ip, &op, &anchor, ml, ref, oend)) return 0;
- 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);
- }
- }
- if (LZ4_encodeSequence(&ip, &op, &anchor, ml, ref, oend)) return 0;
-
- ip = start2;
- ref = ref2;
- ml = ml2;
-
- start2 = start3;
- ref2 = ref3;
- ml2 = ml3;
-
- goto _Search3;
-
- }
+ int inputSize)
- // Encode Last Literals
- {
- int lastRun = (int)(iend - anchor);
- if (((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;
- }
-
- // End
- return (int) (((char*)op)-dest);
-}
+Compress 'inputSize' bytes from 'source' into an output buffer 'dest'.
+Destination buffer must be already allocated, and sized at a minimum of LZ4_compressBound(inputSize).
+return : the number of bytes written in buffer 'dest'
+*/
+#define FUNCTION_NAME LZ4_compressHC
+#include "lz4hc_encoder.h"
-int LZ4_compressHC_limitedOutput(const char* source,
+/*
+int LZ4_compressHC_limitedOutput(
+ const char* source,
char* dest,
int inputSize,
int maxOutputSize)
-{
- void* ctx = LZ4HC_Create((const BYTE*)source);
- int result = LZ4_compressHCCtx(ctx, source, dest, inputSize, maxOutputSize);
- LZ4HC_Free (&ctx);
-
- return result;
-}
-
-int LZ4_compressHC(const char* source,
- char* dest,
- int inputSize)
-{
- return LZ4_compressHC_limitedOutput(source, dest, inputSize, LZ4_compressBound(inputSize)+1);
-}
+Compress 'inputSize' bytes from 'source' into an output buffer 'dest' of maximum size 'maxOutputSize'.
+If it cannot achieve it, compression will stop, and result of the function will be zero.
+return : the number of bytes written in buffer 'dest', or 0 if the compression fails
+*/
+#define FUNCTION_NAME LZ4_compressHC_limitedOutput
+#define LIMITED_OUTPUT
+#include "lz4hc_encoder.h"
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