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author | yann.collet.73@gmail.com <yann.collet.73@gmail.com@650e7d94-2a16-8b24-b05c-7c0b3f6821cd> | 2013-01-08 07:23:07 (GMT) |
---|---|---|
committer | yann.collet.73@gmail.com <yann.collet.73@gmail.com@650e7d94-2a16-8b24-b05c-7c0b3f6821cd> | 2013-01-08 07:23:07 (GMT) |
commit | c1d7e4f67598d8a86ff5a912730f47f65c9cb8db (patch) | |
tree | ba4402868a41f85cc8e1d42a8d94b25a0f242518 /lz4hc.c | |
parent | 77417fc4c2d955bdf7ffd2b8d5a5f37157def5d5 (diff) | |
download | lz4-c1d7e4f67598d8a86ff5a912730f47f65c9cb8db.zip lz4-c1d7e4f67598d8a86ff5a912730f47f65c9cb8db.tar.gz lz4-c1d7e4f67598d8a86ff5a912730f47f65c9cb8db.tar.bz2 |
LZ4HC : compression speed improved under Visual
Bench mode : option to pause at the end
git-svn-id: https://lz4.googlecode.com/svn/trunk@88 650e7d94-2a16-8b24-b05c-7c0b3f6821cd
Diffstat (limited to 'lz4hc.c')
-rw-r--r-- | lz4hc.c | 753 |
1 files changed, 402 insertions, 351 deletions
@@ -83,8 +83,9 @@ #endif
#ifdef _MSC_VER
-#define inline __forceinline // Visual is not C99, but supports some kind of inline
-#include <intrin.h> // For Visual 2005
+# define inline __inline // Visual is not C99, but supports some kind of inline
+# define forceinline __forceinline
+# include <intrin.h> // For Visual 2005
# if LZ4_ARCH64 // 64-bit
# pragma intrinsic(_BitScanForward64) // For Visual 2005
# pragma intrinsic(_BitScanReverse64) // For Visual 2005
@@ -92,6 +93,12 @@ # pragma intrinsic(_BitScanForward) // For Visual 2005
# pragma intrinsic(_BitScanReverse) // For Visual 2005
# endif
+#else
+# ifdef __GNUC__
+# define forceinline inline __attribute__((always_inline))
+# else
+# define forceinline inline
+# endif
#endif
#ifdef _MSC_VER // Visual Studio
@@ -211,24 +218,23 @@ typedef struct _U64_S { U64 v; } U64_S; //************************************************************
typedef struct
{
- const BYTE* base;
- HTYPE hashTable[HASHTABLESIZE];
- U16 chainTable[MAXD];
- const BYTE* nextToUpdate;
+ const BYTE* base;
+ HTYPE hashTable[HASHTABLESIZE];
+ U16 chainTable[MAXD];
+ const BYTE* nextToUpdate;
} LZ4HC_Data_Structure;
//**************************************
// Macros
//**************************************
-#define LZ4_WILDCOPY(s,d,e) do { LZ4_COPYPACKET(s,d) } while (d<e);
-#define LZ4_BLINDCOPY(s,d,l) { BYTE* e=d+l; LZ4_WILDCOPY(s,d,e); d=e; }
-#define HASH_FUNCTION(i) (((i) * 2654435761U) >> ((MINMATCH*8)-HASH_LOG))
-#define HASH_VALUE(p) HASH_FUNCTION(A32(p))
-#define HASH_POINTER(p) (HashTable[HASH_VALUE(p)] + base)
-#define DELTANEXT(p) chainTable[(size_t)(p) & MAXD_MASK]
-#define GETNEXT(p) ((p) - (size_t)DELTANEXT(p))
-#define ADD_HASH(p) { size_t delta = (p) - HASH_POINTER(p); if (delta>MAX_DISTANCE) delta = MAX_DISTANCE; DELTANEXT(p) = (U16)delta; HashTable[HASH_VALUE(p)] = (p) - base; }
+#define LZ4_WILDCOPY(s,d,e) do { LZ4_COPYPACKET(s,d) } while (d<e);
+#define LZ4_BLINDCOPY(s,d,l) { BYTE* e=d+l; LZ4_WILDCOPY(s,d,e); d=e; }
+#define HASH_FUNCTION(i) (((i) * 2654435761U) >> ((MINMATCH*8)-HASH_LOG))
+#define HASH_VALUE(p) HASH_FUNCTION(A32(p))
+#define HASH_POINTER(p) (HashTable[HASH_VALUE(p)] + base)
+#define DELTANEXT(p) chainTable[(size_t)(p) & MAXD_MASK]
+#define GETNEXT(p) ((p) - (size_t)DELTANEXT(p))
//**************************************
@@ -246,11 +252,11 @@ inline static int LZ4_NbCommonBytes (register U64 val) #elif defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)
return (__builtin_clzll(val) >> 3);
#else
- int r;
- if (!(val>>32)) { r=4; } else { r=0; val>>=32; }
- if (!(val>>16)) { r+=2; val>>=8; } else { val>>=24; }
- r += (!val);
- return r;
+ int r;
+ if (!(val>>32)) { r=4; } else { r=0; val>>=32; }
+ if (!(val>>16)) { r+=2; val>>=8; } else { val>>=24; }
+ r += (!val);
+ return r;
#endif
#else
#if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)
@@ -260,8 +266,8 @@ inline static int LZ4_NbCommonBytes (register U64 val) #elif defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)
return (__builtin_ctzll(val) >> 3);
#else
- static const int DeBruijnBytePos[64] = { 0, 0, 0, 0, 0, 1, 1, 2, 0, 3, 1, 3, 1, 4, 2, 7, 0, 2, 3, 6, 1, 5, 3, 5, 1, 3, 4, 4, 2, 5, 6, 7, 7, 0, 1, 2, 3, 3, 4, 6, 2, 6, 5, 5, 3, 4, 5, 6, 7, 1, 2, 4, 6, 4, 4, 5, 7, 2, 6, 5, 7, 6, 7, 7 };
- return DeBruijnBytePos[((U64)((val & -val) * 0x0218A392CDABBD3F)) >> 58];
+ static const int DeBruijnBytePos[64] = { 0, 0, 0, 0, 0, 1, 1, 2, 0, 3, 1, 3, 1, 4, 2, 7, 0, 2, 3, 6, 1, 5, 3, 5, 1, 3, 4, 4, 2, 5, 6, 7, 7, 0, 1, 2, 3, 3, 4, 6, 2, 6, 5, 5, 3, 4, 5, 6, 7, 1, 2, 4, 6, 4, 4, 5, 7, 2, 6, 5, 7, 6, 7, 7 };
+ return DeBruijnBytePos[((U64)((val & -val) * 0x0218A392CDABBD3F)) >> 58];
#endif
#endif
}
@@ -272,27 +278,27 @@ inline static int LZ4_NbCommonBytes (register U32 val) {
#if defined(LZ4_BIG_ENDIAN)
#if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)
- unsigned long r = 0;
+ unsigned long r;
_BitScanReverse( &r, val );
return (int)(r>>3);
#elif defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)
return (__builtin_clz(val) >> 3);
#else
- int r;
- if (!(val>>16)) { r=2; val>>=8; } else { r=0; val>>=24; }
- r += (!val);
- return r;
+ int r;
+ if (!(val>>16)) { r=2; val>>=8; } else { r=0; val>>=24; }
+ r += (!val);
+ return r;
#endif
#else
#if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)
- unsigned long r = 0;
+ unsigned long r;
_BitScanForward( &r, val );
return (int)(r>>3);
#elif defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)
return (__builtin_ctz(val) >> 3);
#else
- static const int DeBruijnBytePos[32] = { 0, 0, 3, 0, 3, 1, 3, 0, 3, 2, 2, 1, 3, 2, 0, 1, 3, 3, 1, 2, 2, 2, 2, 0, 3, 1, 2, 0, 1, 0, 1, 1 };
- return DeBruijnBytePos[((U32)((val & -(S32)val) * 0x077CB531U)) >> 27];
+ static const int DeBruijnBytePos[32] = { 0, 0, 3, 0, 3, 1, 3, 0, 3, 2, 2, 1, 3, 2, 0, 1, 3, 3, 1, 2, 2, 2, 2, 0, 3, 1, 2, 0, 1, 0, 1, 1 };
+ return DeBruijnBytePos[((U32)((val & -(S32)val) * 0x077CB531U)) >> 27];
#endif
#endif
}
@@ -302,166 +308,211 @@ inline static int LZ4_NbCommonBytes (register U32 val) inline static int LZ4HC_Init (LZ4HC_Data_Structure* hc4, const BYTE* base)
{
- MEM_INIT((void*)hc4->hashTable, 0, sizeof(hc4->hashTable));
- MEM_INIT(hc4->chainTable, 0xFF, sizeof(hc4->chainTable));
- hc4->nextToUpdate = base + LZ4_ARCH64;
- hc4->base = base;
- return 1;
+ MEM_INIT((void*)hc4->hashTable, 0, sizeof(hc4->hashTable));
+ MEM_INIT(hc4->chainTable, 0xFF, sizeof(hc4->chainTable));
+ hc4->nextToUpdate = base + LZ4_ARCH64;
+ hc4->base = base;
+ return 1;
}
inline static void* LZ4HC_Create (const BYTE* base)
{
- void* hc4 = ALLOCATOR(sizeof(LZ4HC_Data_Structure));
+ void* hc4 = ALLOCATOR(sizeof(LZ4HC_Data_Structure));
- LZ4HC_Init (hc4, base);
- return hc4;
+ LZ4HC_Init ((LZ4HC_Data_Structure*)hc4, base);
+ return hc4;
}
inline static int LZ4HC_Free (void** LZ4HC_Data)
{
- FREEMEM(*LZ4HC_Data);
- *LZ4HC_Data = NULL;
- return (1);
+ FREEMEM(*LZ4HC_Data);
+ *LZ4HC_Data = NULL;
+ return (1);
}
-inline static void LZ4HC_Insert (LZ4HC_Data_Structure* hc4, const BYTE* ip)
+// Update chains up to ip (excluded)
+forceinline static void LZ4HC_Insert (LZ4HC_Data_Structure* hc4, const BYTE* ip)
{
- U16* chainTable = hc4->chainTable;
- HTYPE* HashTable = hc4->hashTable;
- INITBASE(base,hc4->base);
-
- while(hc4->nextToUpdate < ip)
- {
- ADD_HASH(hc4->nextToUpdate);
- hc4->nextToUpdate++;
- }
+ U16* chainTable = hc4->chainTable;
+ HTYPE* HashTable = hc4->hashTable;
+ INITBASE(base,hc4->base);
+
+ while(hc4->nextToUpdate < ip)
+ {
+ const BYTE* p = hc4->nextToUpdate;
+ size_t delta = (p) - HASH_POINTER(p);
+ if (delta>MAX_DISTANCE) delta = MAX_DISTANCE;
+ DELTANEXT(p) = (U16)delta;
+ HashTable[HASH_VALUE(p)] = (p) - base;
+ hc4->nextToUpdate++;
+ }
}
-inline static int LZ4HC_InsertAndFindBestMatch (LZ4HC_Data_Structure* hc4, const BYTE* ip, const BYTE* const matchlimit, const BYTE** matchpos)
+forceinline static size_t LZ4HC_CommonLength (const BYTE* p1, const BYTE* p2, const BYTE* const matchlimit)
{
- U16* const chainTable = hc4->chainTable;
- HTYPE* const HashTable = hc4->hashTable;
- const BYTE* ref;
- INITBASE(base,hc4->base);
- int nbAttempts=MAX_NB_ATTEMPTS;
- int ml=0;
-
- // HC4 match finder
- LZ4HC_Insert(hc4, ip);
- ref = HASH_POINTER(ip);
- while ((ref >= (ip-MAX_DISTANCE)) && (nbAttempts))
- {
- nbAttempts--;
- if (*(ref+ml) == *(ip+ml))
- if (A32(ref) == A32(ip))
- {
- const BYTE* reft = ref+MINMATCH;
- const BYTE* ipt = ip+MINMATCH;
-
- while (ipt<matchlimit-(STEPSIZE-1))
- {
- UARCH diff = AARCH(reft) ^ AARCH(ipt);
- if (!diff) { ipt+=STEPSIZE; reft+=STEPSIZE; continue; }
- ipt += LZ4_NbCommonBytes(diff);
- goto _endCount;
- }
- if (LZ4_ARCH64) if ((ipt<(matchlimit-3)) && (A32(reft) == A32(ipt))) { ipt+=4; reft+=4; }
- if ((ipt<(matchlimit-1)) && (A16(reft) == A16(ipt))) { ipt+=2; reft+=2; }
- if ((ipt<matchlimit) && (*reft == *ipt)) ipt++;
-_endCount:
+ const BYTE* p1t = p1;
+
+ while (p1t<matchlimit-(STEPSIZE-1))
+ {
+ UARCH diff = AARCH(p2) ^ AARCH(p1t);
+ if (!diff) { p1t+=STEPSIZE; p2+=STEPSIZE; continue; }
+ p1t += LZ4_NbCommonBytes(diff);
+ return (p1t - p1);
+ }
+ if (LZ4_ARCH64) if ((p1t<(matchlimit-3)) && (A32(p2) == A32(p1t))) { p1t+=4; p2+=4; }
+ if ((p1t<(matchlimit-1)) && (A16(p2) == A16(p1t))) { p1t+=2; p2+=2; }
+ if ((p1t<matchlimit) && (*p2 == *p1t)) p1t++;
+ return (p1t - p1);
+}
- if (ipt-ip > ml) { ml = (int)(ipt-ip); *matchpos = ref; }
- }
- ref = GETNEXT(ref);
- }
- return ml;
+forceinline static int LZ4HC_InsertAndFindBestMatch (LZ4HC_Data_Structure* hc4, const BYTE* ip, const BYTE* const matchlimit, const BYTE** matchpos)
+{
+ U16* const chainTable = hc4->chainTable;
+ HTYPE* const HashTable = hc4->hashTable;
+ const BYTE* ref;
+ INITBASE(base,hc4->base);
+ int nbAttempts=MAX_NB_ATTEMPTS;
+ size_t ml=0;
+
+ // HC4 match finder
+ LZ4HC_Insert(hc4, ip);
+ ref = HASH_POINTER(ip);
+
+#if 1
+ if (ref >= ip-4) // potential repetition
+ {
+ if (A32(ref) == A32(ip)) // confirmed
+ {
+ const U16 delta = (U16)(ip-ref);
+ const BYTE* ptr = ip;
+ const BYTE* end;
+ ml = LZ4HC_CommonLength(ip+MINMATCH, ref+MINMATCH, matchlimit) + MINMATCH;
+ end = ip + ml - (MINMATCH-1);
+ while(ptr < end-delta)
+ {
+ DELTANEXT(ptr) = delta; // Pre-Load
+ ptr++;
+ }
+ do
+ {
+ DELTANEXT(ptr) = delta;
+ HashTable[HASH_VALUE(ptr)] = (ptr) - base; // Head of chain
+ ptr++;
+ } while(ptr < end);
+ hc4->nextToUpdate = end;
+ *matchpos = ref;
+ }
+ ref = GETNEXT(ref);
+ }
+#endif
+
+ while ((ref >= (ip-MAX_DISTANCE)) && (nbAttempts))
+ {
+ nbAttempts--;
+ if (*(ref+ml) == *(ip+ml))
+ if (A32(ref) == A32(ip))
+ {
+ size_t mlt = LZ4HC_CommonLength(ip+MINMATCH, ref+MINMATCH, matchlimit) + MINMATCH;
+ if (mlt > ml) { ml = mlt; *matchpos = ref; }
+ }
+ ref = GETNEXT(ref);
+ }
+
+ return (int)ml;
}
-inline static int LZ4HC_InsertAndGetWiderMatch (LZ4HC_Data_Structure* hc4, const BYTE* ip, const BYTE* startLimit, const BYTE* matchlimit, int longest, const BYTE** matchpos, const BYTE** startpos)
+forceinline static int LZ4HC_InsertAndGetWiderMatch (LZ4HC_Data_Structure* hc4, const BYTE* ip, const BYTE* startLimit, const BYTE* matchlimit, int longest, const BYTE** matchpos, const BYTE** startpos)
{
- U16* const chainTable = hc4->chainTable;
- HTYPE* const HashTable = hc4->hashTable;
- INITBASE(base,hc4->base);
- const BYTE* ref;
- int nbAttempts = MAX_NB_ATTEMPTS;
- int delta = (int)(ip-startLimit);
-
- // First Match
- LZ4HC_Insert(hc4, ip);
- ref = HASH_POINTER(ip);
-
- while ((ref >= ip-MAX_DISTANCE) && (ref >= hc4->base) && (nbAttempts))
- {
- nbAttempts--;
- if (*(startLimit + longest) == *(ref - delta + longest))
- if (A32(ref) == A32(ip))
- {
- const BYTE* reft = ref+MINMATCH;
- const BYTE* ipt = ip+MINMATCH;
- const BYTE* startt = ip;
-
- while (ipt<matchlimit-(STEPSIZE-1))
- {
- UARCH diff = AARCH(reft) ^ AARCH(ipt);
- if (!diff) { ipt+=STEPSIZE; reft+=STEPSIZE; continue; }
- ipt += LZ4_NbCommonBytes(diff);
- goto _endCount;
- }
- if (LZ4_ARCH64) if ((ipt<(matchlimit-3)) && (A32(reft) == A32(ipt))) { ipt+=4; reft+=4; }
- if ((ipt<(matchlimit-1)) && (A16(reft) == A16(ipt))) { ipt+=2; reft+=2; }
- if ((ipt<matchlimit) && (*reft == *ipt)) ipt++;
+ U16* const chainTable = hc4->chainTable;
+ HTYPE* const HashTable = hc4->hashTable;
+ INITBASE(base,hc4->base);
+ const BYTE* ref;
+ int nbAttempts = MAX_NB_ATTEMPTS;
+ int delta = (int)(ip-startLimit);
+
+ // First Match
+ LZ4HC_Insert(hc4, ip);
+ ref = HASH_POINTER(ip);
+
+ while ((ref >= ip-MAX_DISTANCE) && (ref >= hc4->base) && (nbAttempts))
+ {
+ nbAttempts--;
+ if (*(startLimit + longest) == *(ref - delta + longest))
+ if (A32(ref) == A32(ip))
+ {
+#if 1
+ const BYTE* reft = ref+MINMATCH;
+ const BYTE* ipt = ip+MINMATCH;
+ const BYTE* startt = ip;
+
+ while (ipt<matchlimit-(STEPSIZE-1))
+ {
+ UARCH diff = AARCH(reft) ^ AARCH(ipt);
+ if (!diff) { ipt+=STEPSIZE; reft+=STEPSIZE; continue; }
+ ipt += LZ4_NbCommonBytes(diff);
+ goto _endCount;
+ }
+ if (LZ4_ARCH64) if ((ipt<(matchlimit-3)) && (A32(reft) == A32(ipt))) { ipt+=4; reft+=4; }
+ if ((ipt<(matchlimit-1)) && (A16(reft) == A16(ipt))) { ipt+=2; reft+=2; }
+ if ((ipt<matchlimit) && (*reft == *ipt)) ipt++;
_endCount:
+ reft = ref;
+#else
+ // Easier for code maintenance, but unfortunately slower too
+ const BYTE* startt = ip;
+ const BYTE* reft = ref;
+ const BYTE* ipt = ip + MINMATCH + LZ4HC_CommonLength(ip+MINMATCH, ref+MINMATCH, matchlimit);
+#endif
- reft = ref;
- while ((startt>startLimit) && (reft > hc4->base) && (startt[-1] == reft[-1])) {startt--; reft--;}
+ while ((startt>startLimit) && (reft > hc4->base) && (startt[-1] == reft[-1])) {startt--; reft--;}
- if ((ipt-startt) > longest)
- {
- longest = (int)(ipt-startt);
- *matchpos = reft;
- *startpos = startt;
- }
- }
- ref = GETNEXT(ref);
- }
+ if ((ipt-startt) > longest)
+ {
+ longest = (int)(ipt-startt);
+ *matchpos = reft;
+ *startpos = startt;
+ }
+ }
+ ref = GETNEXT(ref);
+ }
- return longest;
+ return longest;
}
-inline static int LZ4_encodeSequence(const BYTE** ip, BYTE** op, const BYTE** anchor, int ml, const BYTE* ref)
+forceinline static int LZ4_encodeSequence(const BYTE** ip, BYTE** op, const BYTE** anchor, int ml, const BYTE* ref)
{
- int length, len;
- BYTE* token;
+ int length, len;
+ BYTE* token;
- // Encode Literal length
- length = (int)(*ip - *anchor);
- token = (*op)++;
- 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 = (length<<ML_BITS);
+ // Encode Literal length
+ length = (int)(*ip - *anchor);
+ token = (*op)++;
+ 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 = (length<<ML_BITS);
- // Copy Literals
- LZ4_BLINDCOPY(*anchor, *op, length);
+ // Copy Literals
+ LZ4_BLINDCOPY(*anchor, *op, length);
- // Encode Offset
- LZ4_WRITE_LITTLEENDIAN_16(*op,(U16)(*ip-ref));
+ // Encode Offset
+ LZ4_WRITE_LITTLEENDIAN_16(*op,(U16)(*ip-ref));
- // Encode MatchLength
- len = (int)(ml-MINMATCH);
- 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 += len;
+ // Encode MatchLength
+ len = (int)(ml-MINMATCH);
+ 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 += len;
- // Prepare next loop
- *ip += ml;
- *anchor = *ip;
+ // Prepare next loop
+ *ip += ml;
+ *anchor = *ip;
- return 0;
+ return 0;
}
@@ -470,218 +521,218 @@ inline static int LZ4_encodeSequence(const BYTE** ip, BYTE** op, const BYTE** an //****************************
int LZ4_compressHCCtx(LZ4HC_Data_Structure* ctx,
- const char* source,
- char* dest,
- int isize)
+ const char* source,
+ char* dest,
+ int isize)
{
- const BYTE* ip = (const BYTE*) source;
- const BYTE* anchor = ip;
- const BYTE* const iend = ip + isize;
- const BYTE* const mflimit = iend - MFLIMIT;
- const BYTE* const matchlimit = (iend - LASTLITERALS);
-
- BYTE* op = (BYTE*) dest;
-
- 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;
+ const BYTE* ip = (const BYTE*) source;
+ const BYTE* anchor = ip;
+ const BYTE* const iend = ip + isize;
+ const BYTE* const mflimit = iend - MFLIMIT;
+ const BYTE* const matchlimit = (iend - LASTLITERALS);
+
+ BYTE* op = (BYTE*) dest;
+
+ 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
- {
- LZ4_encodeSequence(&ip, &op, &anchor, ml, ref);
- 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;
- }
+ 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
+ {
+ LZ4_encodeSequence(&ip, &op, &anchor, ml, ref);
+ 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)
- {
- if ((start2 - ip) < OPTIMAL_ML)
- {
- 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);
- }
- }
- // Now, encode 2 sequences
- LZ4_encodeSequence(&ip, &op, &anchor, ml, ref);
- ip = start2;
- LZ4_encodeSequence(&ip, &op, &anchor, ml2, ref2);
- 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;
- }
- }
-
- LZ4_encodeSequence(&ip, &op, &anchor, ml, ref);
- 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);
- }
- }
- LZ4_encodeSequence(&ip, &op, &anchor, ml, ref);
-
- ip = start2;
- ref = ref2;
- ml = ml2;
-
- start2 = start3;
- ref2 = ref3;
- ml2 = ml3;
-
- goto _Search3;
-
- }
-
- // Encode Last Literals
- {
- int lastRun = (int)(iend - anchor);
- 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++ = (lastRun<<ML_BITS);
- memcpy(op, anchor, iend - anchor);
- op += iend-anchor;
- }
-
- // End
- return (int) (((char*)op)-dest);
+ // 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)
+ {
+ if ((start2 - ip) < OPTIMAL_ML)
+ {
+ 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);
+ }
+ }
+ // Now, encode 2 sequences
+ LZ4_encodeSequence(&ip, &op, &anchor, ml, ref);
+ ip = start2;
+ LZ4_encodeSequence(&ip, &op, &anchor, ml2, ref2);
+ 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;
+ }
+ }
+
+ LZ4_encodeSequence(&ip, &op, &anchor, ml, ref);
+ 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);
+ }
+ }
+ LZ4_encodeSequence(&ip, &op, &anchor, ml, ref);
+
+ ip = start2;
+ ref = ref2;
+ ml = ml2;
+
+ start2 = start3;
+ ref2 = ref3;
+ ml2 = ml3;
+
+ goto _Search3;
+
+ }
+
+ // Encode Last Literals
+ {
+ int lastRun = (int)(iend - anchor);
+ 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++ = (lastRun<<ML_BITS);
+ memcpy(op, anchor, iend - anchor);
+ op += iend-anchor;
+ }
+
+ // End
+ return (int) (((char*)op)-dest);
}
int LZ4_compressHC(const char* source,
- char* dest,
- int isize)
+ char* dest,
+ int isize)
{
- void* ctx = LZ4HC_Create((const BYTE*)source);
- int result = LZ4_compressHCCtx(ctx, source, dest, isize);
- LZ4HC_Free (&ctx);
+ void* ctx = LZ4HC_Create((const BYTE*)source);
+ int result = LZ4_compressHCCtx(ctx, source, dest, isize);
+ LZ4HC_Free (&ctx);
- return result;
+ return result;
}
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