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refactored compression code

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This commit is contained in:
Yann Collet
2015-11-11 21:38:21 +01:00
parent 438abef903
commit 14983e7aed
3 changed files with 547 additions and 572 deletions
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lib/zstd_internal.h
+45 -208
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@@ -44,123 +44,58 @@ extern "C" {
#include "error.h"
/* **************************************
* Function body to include for inlining
****************************************/
static size_t ZSTD_read_ARCH(const void* p) { size_t r; memcpy(&r, p, sizeof(r)); return r; }
/* *************************************
* Common macros
***************************************/
#define MIN(a,b) ((a)<(b) ? (a) : (b))
static unsigned ZSTD_highbit(U32 val)
{
# if defined(_MSC_VER) /* Visual */
unsigned long r=0;
_BitScanReverse(&r, val);
return (unsigned)r;
# elif defined(__GNUC__) && (__GNUC__ >= 3) /* GCC Intrinsic */
return 31 - __builtin_clz(val);
# else /* Software version */
static const int DeBruijnClz[32] = { 0, 9, 1, 10, 13, 21, 2, 29, 11, 14, 16, 18, 22, 25, 3, 30, 8, 12, 20, 28, 15, 17, 24, 7, 19, 27, 23, 6, 26, 5, 4, 31 };
U32 v = val;
int r;
v |= v >> 1;
v |= v >> 2;
v |= v >> 4;
v |= v >> 8;
v |= v >> 16;
r = DeBruijnClz[(U32)(v * 0x07C4ACDDU) >> 27];
return r;
# endif
}
MEM_STATIC unsigned ZSTD_NbCommonBytes (register size_t val)
{
if (MEM_isLittleEndian())
{
if (MEM_64bits())
{
# if defined(_MSC_VER) && defined(_WIN64)
unsigned long r = 0;
_BitScanForward64( &r, (U64)val );
return (int)(r>>3);
# elif defined(__GNUC__) && (__GNUC__ >= 3)
return (__builtin_ctzll((U64)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 & -(long long)val) * 0x0218A392CDABBD3FULL)) >> 58];
# endif
}
else /* 32 bits */
{
# if defined(_MSC_VER)
unsigned long r=0;
_BitScanForward( &r, (U32)val );
return (int)(r>>3);
# elif defined(__GNUC__) && (__GNUC__ >= 3)
return (__builtin_ctz((U32)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];
# endif
}
}
else /* Big Endian CPU */
{
if (MEM_32bits())
{
# if defined(_MSC_VER) && defined(_WIN64)
unsigned long r = 0;
_BitScanReverse64( &r, val );
return (unsigned)(r>>3);
# elif defined(__GNUC__) && (__GNUC__ >= 3)
return (__builtin_clzll(val) >> 3);
# else
unsigned r;
const unsigned n32 = sizeof(size_t)*4; /* calculate this way due to compiler complaining in 32-bits mode */
if (!(val>>n32)) { r=4; } else { r=0; val>>=n32; }
if (!(val>>16)) { r+=2; val>>=8; } else { val>>=24; }
r += (!val);
return r;
# endif
}
else /* 32 bits */
{
# if defined(_MSC_VER)
unsigned long r = 0;
_BitScanReverse( &r, (unsigned long)val );
return (unsigned)(r>>3);
# elif defined(__GNUC__) && (__GNUC__ >= 3)
return (__builtin_clz((U32)val) >> 3);
# else
unsigned r;
if (!(val>>16)) { r=2; val>>=8; } else { r=0; val>>=24; }
r += (!val);
return r;
# endif
}
}
}
#define MAX(a,b) ((a)>(b) ? (a) : (b))
MEM_STATIC size_t ZSTD_count(const BYTE* pIn, const BYTE* pMatch, const BYTE* pInLimit)
{
const BYTE* const pStart = pIn;
/* *************************************
* Common constants
***************************************/
#define KB *(1 <<10)
#define MB *(1 <<20)
#define GB *(1U<<30)
while ((pIn<pInLimit-(sizeof(size_t)-1)))
{
size_t diff = ZSTD_read_ARCH(pMatch) ^ ZSTD_read_ARCH(pIn);
if (!diff) { pIn+=sizeof(size_t); pMatch+=sizeof(size_t); continue; }
pIn += ZSTD_NbCommonBytes(diff);
return (size_t)(pIn - pStart);
}
#define BLOCKSIZE (128 KB) /* define, for static allocation */
if (MEM_64bits()) if ((pIn<(pInLimit-3)) && (MEM_read32(pMatch) == MEM_read32(pIn))) { pIn+=4; pMatch+=4; }
if ((pIn<(pInLimit-1)) && (MEM_read16(pMatch) == MEM_read16(pIn))) { pIn+=2; pMatch+=2; }
if ((pIn<pInLimit) && (*pMatch == *pIn)) pIn++;
return (size_t)(pIn - pStart);
}
static const size_t ZSTD_blockHeaderSize = 3;
static const size_t ZSTD_frameHeaderSize = 4;
#define BIT7 128
#define BIT6 64
#define BIT5 32
#define BIT4 16
#define BIT1 2
#define BIT0 1
#define IS_RAW BIT0
#define IS_RLE BIT1
#define MINMATCH 4
#define REPCODE_STARTVALUE 4
#define MLbits 7
#define LLbits 6
#define Offbits 5
#define MaxML ((1<<MLbits) - 1)
#define MaxLL ((1<<LLbits) - 1)
#define MaxOff ((1<<Offbits)- 1)
#define MLFSELog 10
#define LLFSELog 10
#define OffFSELog 9
#define MaxSeq MAX(MaxLL, MaxML)
#define MIN_SEQUENCES_SIZE (2 /*seqNb*/ + 2 /*dumps*/ + 3 /*seqTables*/ + 1 /*bitStream*/)
#define MIN_CBLOCK_SIZE (3 /*litCSize*/ + MIN_SEQUENCES_SIZE)
typedef enum { bt_compressed, bt_raw, bt_rle, bt_end } blockType_t;
/* ******************************************
* Shared functions to include for inlining
********************************************/
static void ZSTD_copy8(void* dst, const void* src) { memcpy(dst, src, 8); }
#define COPY8(d,s) { ZSTD_copy8(d,s); d+=8; s+=8; }
@@ -177,104 +112,6 @@ static void ZSTD_wildcopy(void* dst, const void* src, size_t length)
}
typedef enum { bt_compressed, bt_raw, bt_rle, bt_end } blockType_t;
typedef struct
{
blockType_t blockType;
U32 origSize;
} blockProperties_t;
size_t ZSTD_noCompressBlock(void* op, size_t maxDstSize, const void* ip, size_t blockSize);
typedef struct {
void* buffer;
U32* offsetStart;
U32* offset;
BYTE* offCodeStart;
BYTE* offCode;
BYTE* litStart;
BYTE* lit;
BYTE* litLengthStart;
BYTE* litLength;
BYTE* matchLengthStart;
BYTE* matchLength;
BYTE* dumpsStart;
BYTE* dumps;
} seqStore_t;
void ZSTD_resetSeqStore(seqStore_t* ssPtr);
static const U32 g_searchStrength = 8;
#define REPCODE_STARTVALUE 4
#define MLbits 7
#define LLbits 6
#define Offbits 5
#define MaxML ((1<<MLbits) - 1)
#define MaxLL ((1<<LLbits) - 1)
#define MaxOff 31
#define MIN_SEQUENCES_SIZE (2 /*seqNb*/ + 2 /*dumps*/ + 3 /*seqTables*/ + 1 /*bitStream*/)
#define MIN_CBLOCK_SIZE (3 /*litCSize*/ + MIN_SEQUENCES_SIZE)
/** ZSTD_storeSeq
Store a sequence (literal length, literals, offset code and match length) into seqStore_t
@offsetCode : distance to match, or 0 == repCode
@matchCode : matchLength - MINMATCH
*/
MEM_STATIC void ZSTD_storeSeq(seqStore_t* seqStorePtr, size_t litLength, const BYTE* literals, size_t offsetCode, size_t matchCode)
{
#if 0
static const BYTE* g_start = NULL;
if (g_start==NULL) g_start = literals;
if (literals - g_start == 8695)
printf("pos %6u : %3u literals & match %3u bytes at distance %6u \n",
(U32)(literals - g_start), (U32)litLength, (U32)matchCode+4, (U32)offsetCode);
#endif
/* copy Literals */
ZSTD_wildcopy(seqStorePtr->lit, literals, litLength);
seqStorePtr->lit += litLength;
/* literal Length */
if (litLength >= MaxLL)
{
*(seqStorePtr->litLength++) = MaxLL;
if (litLength<255 + MaxLL)
*(seqStorePtr->dumps++) = (BYTE)(litLength - MaxLL);
else
{
*(seqStorePtr->dumps++) = 255;
MEM_writeLE32(seqStorePtr->dumps, (U32)litLength); seqStorePtr->dumps += 3;
}
}
else *(seqStorePtr->litLength++) = (BYTE)litLength;
/* match offset */
*(seqStorePtr->offset++) = (U32)offsetCode;
/* match Length */
if (matchCode >= MaxML)
{
*(seqStorePtr->matchLength++) = MaxML;
if (matchCode < 255+MaxML)
*(seqStorePtr->dumps++) = (BYTE)(matchCode - MaxML);
else
{
*(seqStorePtr->dumps++) = 255;
MEM_writeLE32(seqStorePtr->dumps, (U32)matchCode); seqStorePtr->dumps += 3;
}
}
else *(seqStorePtr->matchLength++) = (BYTE)matchCode;
}
/* prototype, body into zstd.c */
size_t ZSTD_compressSequences(BYTE* dst, size_t maxDstSize, const seqStore_t* seqStorePtr, size_t srcSize);
#if defined (__cplusplus)
}
#endif