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variable litblock header size

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This commit is contained in:
Yann Collet
2016-01-23 19:28:41 +01:00
parent dd283b1f4f
commit 59d1f79768
9 changed files with 339 additions and 158 deletions
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lib/zstd_compress.c
+175 -86
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@@ -40,7 +40,6 @@
# include <intrin.h> /* For Visual 2005 */
# pragma warning(disable : 4127) /* disable: C4127: conditional expression is constant */
#else
# define GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)
# ifdef __GNUC__
# define FORCE_INLINE static inline __attribute__((always_inline))
# else
@@ -64,10 +63,17 @@
/* *************************************
* Constants
***************************************/
ZSTDLIB_API unsigned ZSTD_maxCLevel(void) { return ZSTD_MAX_CLEVEL; }
static const U32 g_searchStrength = 8;
/* *************************************
* Helper functions
***************************************/
unsigned ZSTD_maxCLevel(void) { return ZSTD_MAX_CLEVEL; }
size_t ZSTD_compressBound(size_t srcSize) { return FSE_compressBound(srcSize) + 12; }
/* *************************************
* Sequence storage
***************************************/
@@ -116,7 +122,6 @@ struct ZSTD_CCtx_s
size_t hbSize;
char headerBuffer[ZSTD_frameHeaderSize_max];
seqStore_t seqStore; /* sequences storage ptrs */
U32* hashTable;
U32* contentTable;
@@ -236,11 +241,64 @@ static void ZSTD_reduceIndex (ZSTD_CCtx* zc,
/* *******************************************************
* Block entropic compression
*********************************************************/
size_t ZSTD_compressBound(size_t srcSize) /* maximum compressed size */
{
return FSE_compressBound(srcSize) + 12;
}
/* Block format description
Block = Literal Section - Sequences Section
Prerequisite : size of (compressed) block, maximum size of regenerated data
1) Literal Section
1.1) Header : 1-5 bytes
flags: 2 bits
00 compressed by Huff0
01 unused
10 is Raw (uncompressed)
11 is Rle
Note : using 01 => Huff0 with precomputed table ?
Note : delta map ? => compressed ?
1.1.1) Huff0-compressed literal block : 3-5 bytes
srcSize < 1 KB => 3 bytes (2-2-10-10)
srcSize < 17KB => 4 bytes (2-2-14-14)
else => 5 bytes (2-2-18-18)
big endian convention
1.1.2) Raw (uncompressed) literal block header : 1-3 bytes
size : 5 bits: (IS_RAW<<6) + (0<<4) + size
12 bits: (IS_RAW<<6) + (2<<4) + (size>>8)
size&255
20 bits: (IS_RAW<<6) + (3<<4) + (size>>16)
size>>8&255
size&255
1.1.3) Rle (repeated single byte) literal block header : 1-3 bytes
size : 5 bits: (IS_RLE<<6) + (0<<4) + size
12 bits: (IS_RLE<<6) + (2<<4) + (size>>8)
size&255
20 bits: (IS_RLE<<6) + (3<<4) + (size>>16)
size>>8&255
size&255
1.1.4) Unused
Use Huff0 w/ precalculated DTable ?
FSE ? => probably not, not efficient on literals
1.2) Literal block content
1.2.1) Huff0 block, using sizes from header
See Huff0 format
1.2.2) Raw content
1.2.3) single byte
1.2.4) _usingDTable variant ?
2) Sequences section
TO DO
*/
size_t ZSTD_noCompressBlock (void* dst, size_t maxDstSize, const void* src, size_t srcSize)
{
@@ -262,24 +320,60 @@ size_t ZSTD_noCompressBlock (void* dst, size_t maxDstSize, const void* src, size
static size_t ZSTD_noCompressLiterals (void* dst, size_t maxDstSize, const void* src, size_t srcSize)
{
BYTE* const ostart = (BYTE* const)dst;
const U32 flSize = 1 + (srcSize>31) + (srcSize>4095);
if (srcSize + 3 > maxDstSize) return ERROR(dstSize_tooSmall);
if (srcSize + flSize > maxDstSize) return ERROR(dstSize_tooSmall);
MEM_writeLE32(dst, ((U32)srcSize << 2) | IS_RAW);
memcpy(ostart + 3, src, srcSize);
return srcSize + 3;
switch(flSize)
{
case 1: /* 2 - 1 - 5 */
ostart[0] = (BYTE)((IS_RAW<<6) + (0<<5) + srcSize);
break;
case 2: /* 2 - 2 - 12 */
ostart[0] = (BYTE)((IS_RAW<<6) + (2<<4) + (srcSize >> 8));
ostart[1] = (BYTE)srcSize;
break;
default: /*note : should not be necessary : flSize is within {1,2,3} */
case 3: /* 2 - 2 - 20 */
ostart[0] = (BYTE)((IS_RAW<<6) + (3<<4) + (srcSize >> 16));
ostart[1] = (BYTE)(srcSize>>8);
ostart[2] = (BYTE)srcSize;
break;
}
memcpy(ostart + flSize, src, srcSize);
return srcSize + flSize;
}
static size_t ZSTD_compressRleLiteralsBlock (void* dst, size_t maxDstSize, const void* src, size_t srcSize)
{
BYTE* const ostart = (BYTE* const)dst;
U32 flSize = 1 + (srcSize>31) + (srcSize>4095);
(void)maxDstSize;
MEM_writeLE32(dst, ((U32)srcSize << 2) | IS_RLE); /* note : maxDstSize > litHeaderSize > 4 */
ostart[3] = *(const BYTE*)src;
return 4;
(void)maxDstSize; /* maxDstSize guaranteed to be >=4, hence large enough ? */
switch(flSize)
{
case 1: /* 2 - 1 - 5 */
ostart[0] = (BYTE)((IS_RLE<<6) + (0<<5) + srcSize);
break;
case 2: /* 2 - 2 - 12 */
ostart[0] = (BYTE)((IS_RLE<<6) + (2<<4) + (srcSize >> 8));
ostart[1] = (BYTE)srcSize;
break;
default: /*note : should not be necessary : flSize is necessary within {1,2,3} */
case 3: /* 2 - 2 - 20 */
ostart[0] = (BYTE)((IS_RLE<<6) + (3<<4) + (srcSize >> 16));
ostart[1] = (BYTE)(srcSize>>8);
ostart[2] = (BYTE)srcSize;
break;
}
ostart[flSize] = *(const BYTE*)src;
return flSize+1;
}
size_t ZSTD_minGain(size_t srcSize) { return (srcSize >> 6) + 1; }
static size_t ZSTD_compressLiterals (void* dst, size_t maxDstSize,
@@ -287,27 +381,41 @@ static size_t ZSTD_compressLiterals (void* dst, size_t maxDstSize,
{
const size_t minGain = ZSTD_minGain(srcSize);
BYTE* const ostart = (BYTE*)dst;
size_t hsize;
static const size_t litHeaderSize = 5;
size_t lhSize = 3 + (srcSize >= 1 KB) + (srcSize >= 16 KB);
size_t clitSize;
if (maxDstSize < litHeaderSize+1) return ERROR(dstSize_tooSmall); /* not enough space for compression */
if (maxDstSize < 4) return ERROR(dstSize_tooSmall); /* not enough space for compression */
hsize = HUF_compress(ostart+litHeaderSize, maxDstSize-litHeaderSize, src, srcSize);
clitSize = HUF_compress(ostart+lhSize, maxDstSize-lhSize, src, srcSize);
if ((hsize==0) || (hsize >= srcSize - minGain)) return ZSTD_noCompressLiterals(dst, maxDstSize, src, srcSize);
if (hsize==1) return ZSTD_compressRleLiteralsBlock(dst, maxDstSize, src, srcSize);
if ((clitSize==0) || (clitSize >= srcSize - minGain)) return ZSTD_noCompressLiterals(dst, maxDstSize, src, srcSize);
if (clitSize==1) return ZSTD_compressRleLiteralsBlock(dst, maxDstSize, src, srcSize);
/* Build header */
switch(lhSize)
{
ostart[0] = (BYTE)(srcSize << 2); /* is a block, is compressed */
ostart[1] = (BYTE)(srcSize >> 6);
ostart[2] = (BYTE)(srcSize >>14);
ostart[2] += (BYTE)(hsize << 5);
ostart[3] = (BYTE)(hsize >> 3);
ostart[4] = (BYTE)(hsize >>11);
case 3: /* 2 - 2 - 10 - 10 */
ostart[0] = (BYTE) (srcSize>>6) + (0<< 4);
ostart[1] = (BYTE)((srcSize<<2) + (clitSize>>8));
ostart[2] = (BYTE)(clitSize);
break;
case 4: /* 2 - 2 - 14 - 14 */
ostart[0] = (BYTE)(srcSize>>10) + (2<<4);
ostart[1] = (BYTE)(srcSize>> 2);
ostart[2] = (BYTE)((srcSize<<6) + (clitSize>>8));
ostart[3] = (BYTE)(clitSize);
break;
default: /* should not be necessary, lhSize is {3,4,5} */
case 5: /* 2 - 2 - 18 - 18 */
ostart[0] = (BYTE)(srcSize>>14) + (3<<4);
ostart[1] = (BYTE)(srcSize>>6);
ostart[2] = (BYTE)((srcSize<<2) + (clitSize>>16));
ostart[3] = (BYTE)(clitSize>>8);
ostart[4] = (BYTE)(clitSize);
break;
}
return hsize+litHeaderSize;
return lhSize+clitSize;
}
@@ -754,8 +862,7 @@ static void ZSTD_fillHashTable (ZSTD_CCtx* zc, const void* end, const U32 mls)
FORCE_INLINE
size_t ZSTD_compressBlock_fast_generic(ZSTD_CCtx* zc,
void* dst, size_t maxDstSize,
void ZSTD_compressBlock_fast_generic(ZSTD_CCtx* zc,
const void* src, size_t srcSize,
const U32 mls)
{
@@ -848,38 +955,32 @@ size_t ZSTD_compressBlock_fast_generic(ZSTD_CCtx* zc,
memcpy(seqStorePtr->lit, anchor, lastLLSize);
seqStorePtr->lit += lastLLSize;
}
/* Finale compression stage */
return ZSTD_compressSequences(dst, maxDstSize,
seqStorePtr, srcSize);
}
size_t ZSTD_compressBlock_fast(ZSTD_CCtx* ctx,
void* dst, size_t maxDstSize,
const void* src, size_t srcSize)
void ZSTD_compressBlock_fast(ZSTD_CCtx* ctx,
const void* src, size_t srcSize)
{
const U32 mls = ctx->params.searchLength;
switch(mls)
{
default:
case 4 :
return ZSTD_compressBlock_fast_generic(ctx, dst, maxDstSize, src, srcSize, 4);
ZSTD_compressBlock_fast_generic(ctx, src, srcSize, 4); return;
case 5 :
return ZSTD_compressBlock_fast_generic(ctx, dst, maxDstSize, src, srcSize, 5);
ZSTD_compressBlock_fast_generic(ctx, src, srcSize, 5); return;
case 6 :
return ZSTD_compressBlock_fast_generic(ctx, dst, maxDstSize, src, srcSize, 6);
ZSTD_compressBlock_fast_generic(ctx, src, srcSize, 6); return;
case 7 :
return ZSTD_compressBlock_fast_generic(ctx, dst, maxDstSize, src, srcSize, 7);
ZSTD_compressBlock_fast_generic(ctx, src, srcSize, 7); return;
}
}
//FORCE_INLINE
size_t ZSTD_compressBlock_fast_extDict_generic(ZSTD_CCtx* ctx,
void* dst, size_t maxDstSize,
const void* src, size_t srcSize,
const U32 mls)
void ZSTD_compressBlock_fast_extDict_generic(ZSTD_CCtx* ctx,
const void* src, size_t srcSize,
const U32 mls)
{
U32* hashTable = ctx->hashTable;
const U32 hBits = ctx->params.hashLog;
@@ -989,15 +1090,10 @@ size_t ZSTD_compressBlock_fast_extDict_generic(ZSTD_CCtx* ctx,
memcpy(seqStorePtr->lit, anchor, lastLLSize);
seqStorePtr->lit += lastLLSize;
}
/* Finale compression stage */
return ZSTD_compressSequences(dst, maxDstSize,
seqStorePtr, srcSize);
}
size_t ZSTD_compressBlock_fast_extDict(ZSTD_CCtx* ctx,
void* dst, size_t maxDstSize,
void ZSTD_compressBlock_fast_extDict(ZSTD_CCtx* ctx,
const void* src, size_t srcSize)
{
const U32 mls = ctx->params.searchLength;
@@ -1005,13 +1101,13 @@ size_t ZSTD_compressBlock_fast_extDict(ZSTD_CCtx* ctx,
{
default:
case 4 :
return ZSTD_compressBlock_fast_extDict_generic(ctx, dst, maxDstSize, src, srcSize, 4);
return ZSTD_compressBlock_fast_extDict_generic(ctx, src, srcSize, 4);
case 5 :
return ZSTD_compressBlock_fast_extDict_generic(ctx, dst, maxDstSize, src, srcSize, 5);
return ZSTD_compressBlock_fast_extDict_generic(ctx, src, srcSize, 5);
case 6 :
return ZSTD_compressBlock_fast_extDict_generic(ctx, dst, maxDstSize, src, srcSize, 6);
return ZSTD_compressBlock_fast_extDict_generic(ctx, src, srcSize, 6);
case 7 :
return ZSTD_compressBlock_fast_extDict_generic(ctx, dst, maxDstSize, src, srcSize, 7);
return ZSTD_compressBlock_fast_extDict_generic(ctx, src, srcSize, 7);
}
}
@@ -1415,8 +1511,8 @@ FORCE_INLINE size_t ZSTD_HcFindBestMatch_extDict_selectMLS (
* Common parser - lazy strategy
*********************************/
FORCE_INLINE
size_t ZSTD_compressBlock_lazy_generic(ZSTD_CCtx* ctx,
void* dst, size_t maxDstSize, const void* src, size_t srcSize,
void ZSTD_compressBlock_lazy_generic(ZSTD_CCtx* ctx,
const void* src, size_t srcSize,
const U32 searchMethod, const U32 depth)
{
seqStore_t* seqStorePtr = &(ctx->seqStore);
@@ -1559,36 +1655,32 @@ _storeSequence:
memcpy(seqStorePtr->lit, anchor, lastLLSize);
seqStorePtr->lit += lastLLSize;
}
/* Final compression stage */
return ZSTD_compressSequences(dst, maxDstSize,
seqStorePtr, srcSize);
}
size_t ZSTD_compressBlock_btlazy2(ZSTD_CCtx* ctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize)
static void ZSTD_compressBlock_btlazy2(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
{
return ZSTD_compressBlock_lazy_generic(ctx, dst, maxDstSize, src, srcSize, 1, 2);
return ZSTD_compressBlock_lazy_generic(ctx, src, srcSize, 1, 2);
}
size_t ZSTD_compressBlock_lazy2(ZSTD_CCtx* ctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize)
static void ZSTD_compressBlock_lazy2(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
{
return ZSTD_compressBlock_lazy_generic(ctx, dst, maxDstSize, src, srcSize, 0, 2);
return ZSTD_compressBlock_lazy_generic(ctx, src, srcSize, 0, 2);
}
size_t ZSTD_compressBlock_lazy(ZSTD_CCtx* ctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize)
static void ZSTD_compressBlock_lazy(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
{
return ZSTD_compressBlock_lazy_generic(ctx, dst, maxDstSize, src, srcSize, 0, 1);
return ZSTD_compressBlock_lazy_generic(ctx, src, srcSize, 0, 1);
}
size_t ZSTD_compressBlock_greedy(ZSTD_CCtx* ctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize)
static void ZSTD_compressBlock_greedy(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
{
return ZSTD_compressBlock_lazy_generic(ctx, dst, maxDstSize, src, srcSize, 0, 0);
return ZSTD_compressBlock_lazy_generic(ctx, src, srcSize, 0, 0);
}
FORCE_INLINE
size_t ZSTD_compressBlock_lazy_extDict_generic(ZSTD_CCtx* ctx,
void* dst, size_t maxDstSize, const void* src, size_t srcSize,
void ZSTD_compressBlock_lazy_extDict_generic(ZSTD_CCtx* ctx,
const void* src, size_t srcSize,
const U32 searchMethod, const U32 depth)
{
seqStore_t* seqStorePtr = &(ctx->seqStore);
@@ -1778,36 +1870,32 @@ _storeSequence:
memcpy(seqStorePtr->lit, anchor, lastLLSize);
seqStorePtr->lit += lastLLSize;
}
/* Final compression stage */
return ZSTD_compressSequences(dst, maxDstSize,
seqStorePtr, srcSize);
}
size_t ZSTD_compressBlock_greedy_extDict(ZSTD_CCtx* ctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize)
void ZSTD_compressBlock_greedy_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
{
return ZSTD_compressBlock_lazy_extDict_generic(ctx, dst, maxDstSize, src, srcSize, 0, 0);
return ZSTD_compressBlock_lazy_extDict_generic(ctx, src, srcSize, 0, 0);
}
size_t ZSTD_compressBlock_lazy_extDict(ZSTD_CCtx* ctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize)
static void ZSTD_compressBlock_lazy_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
{
return ZSTD_compressBlock_lazy_extDict_generic(ctx, dst, maxDstSize, src, srcSize, 0, 1);
return ZSTD_compressBlock_lazy_extDict_generic(ctx, src, srcSize, 0, 1);
}
size_t ZSTD_compressBlock_lazy2_extDict(ZSTD_CCtx* ctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize)
static void ZSTD_compressBlock_lazy2_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
{
return ZSTD_compressBlock_lazy_extDict_generic(ctx, dst, maxDstSize, src, srcSize, 0, 2);
return ZSTD_compressBlock_lazy_extDict_generic(ctx, src, srcSize, 0, 2);
}
static size_t ZSTD_compressBlock_btlazy2_extDict(ZSTD_CCtx* ctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize)
static void ZSTD_compressBlock_btlazy2_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
{
return ZSTD_compressBlock_lazy_extDict_generic(ctx, dst, maxDstSize, src, srcSize, 1, 2);
return ZSTD_compressBlock_lazy_extDict_generic(ctx, src, srcSize, 1, 2);
}
typedef size_t (*ZSTD_blockCompressor) (ZSTD_CCtx* ctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize);
typedef void (*ZSTD_blockCompressor) (ZSTD_CCtx* ctx, const void* src, size_t srcSize);
static ZSTD_blockCompressor ZSTD_selectBlockCompressor(ZSTD_strategy strat, int extDict)
ZSTD_blockCompressor ZSTD_selectBlockCompressor(ZSTD_strategy strat, int extDict)
{
static const ZSTD_blockCompressor blockCompressor[2][5] = {
{ ZSTD_compressBlock_fast, ZSTD_compressBlock_greedy, ZSTD_compressBlock_lazy,ZSTD_compressBlock_lazy2, ZSTD_compressBlock_btlazy2 },
@@ -1822,7 +1910,8 @@ static size_t ZSTD_compressBlock_internal(ZSTD_CCtx* zc, void* dst, size_t maxDs
{
ZSTD_blockCompressor blockCompressor = ZSTD_selectBlockCompressor(zc->params.strategy, zc->lowLimit < zc->dictLimit);
if (srcSize < MIN_CBLOCK_SIZE+3) return 0; /* don't even attempt compression below a certain srcSize */
return blockCompressor(zc, dst, maxDstSize, src, srcSize);
blockCompressor(zc, src, srcSize);
return ZSTD_compressSequences(dst, maxDstSize, &(zc->seqStore), srcSize);
}