huf_compress.c File Reference

#include <string.h>
#include <stdio.h>
#include "compiler.h"
#include "bitstream.h"
#include "hist.h"
#include "fse.h"
#include "huf.h"
#include "error_private.h"

Include dependency graph for huf_compress.c:

Go to the source code of this file.

Classes
struct	HUF_CElt_s
struct	nodeElt_s
struct	rankPos
struct	HUF_buildCTable_wksp_tables
struct	HUF_compress_tables_t

Macros
#define	FSE_STATIC_LINKING_ONLY   /* FSE_optimalTableLog_internal */
#define	HUF_STATIC_LINKING_ONLY
#define	HUF_isError   ERR_isError
#define	HUF_STATIC_ASSERT(c)   DEBUG_STATIC_ASSERT(c) /* use only *after* variable declarations */
#define	MAX_FSE_TABLELOG_FOR_HUFF_HEADER   6
#define	RANK_POSITION_TABLE_SIZE   32
#define	STARTNODE   (HUF_SYMBOLVALUE_MAX+1)
#define	HUF_FLUSHBITS(s)   BIT_flushBits(s)
#define	HUF_FLUSHBITS_1(stream)    if (sizeof((stream)->bitContainer)*8 < HUF_TABLELOG_MAX*2+7) HUF_FLUSHBITS(stream)
#define	HUF_FLUSHBITS_2(stream)    if (sizeof((stream)->bitContainer)*8 < HUF_TABLELOG_MAX*4+7) HUF_FLUSHBITS(stream)

Typedefs
typedef struct nodeElt_s	nodeElt
typedef nodeElt	huffNodeTable[HUF_CTABLE_WORKSPACE_SIZE_U32]

Enumerations
enum	HUF_nbStreams_e { HUF_singleStream , HUF_fourStreams }

Functions
unsigned	HUF_optimalTableLog (unsigned maxTableLog, size_t srcSize, unsigned maxSymbolValue)
static size_t	HUF_compressWeights (void *dst, size_t dstSize, const void *weightTable, size_t wtSize)
size_t	HUF_writeCTable (void *dst, size_t maxDstSize, const HUF_CElt *CTable, unsigned maxSymbolValue, unsigned huffLog)
size_t	HUF_readCTable (HUF_CElt *CTable, unsigned *maxSymbolValuePtr, const void *src, size_t srcSize, unsigned *hasZeroWeights)
U32	HUF_getNbBits (const void *symbolTable, U32 symbolValue)
static U32	HUF_setMaxHeight (nodeElt *huffNode, U32 lastNonNull, U32 maxNbBits)
static void	HUF_sort (nodeElt *huffNode, const unsigned *count, U32 maxSymbolValue, rankPos *rankPosition)
size_t	HUF_buildCTable_wksp (HUF_CElt *tree, const unsigned *count, U32 maxSymbolValue, U32 maxNbBits, void *workSpace, size_t wkspSize)
size_t	HUF_buildCTable (HUF_CElt *tree, const unsigned *count, unsigned maxSymbolValue, unsigned maxNbBits)
size_t	HUF_estimateCompressedSize (const HUF_CElt *CTable, const unsigned *count, unsigned maxSymbolValue)
int	HUF_validateCTable (const HUF_CElt *CTable, const unsigned *count, unsigned maxSymbolValue)
size_t	HUF_compressBound (size_t size)
FORCE_INLINE_TEMPLATE void	HUF_encodeSymbol (BIT_CStream_t *bitCPtr, U32 symbol, const HUF_CElt *CTable)
FORCE_INLINE_TEMPLATE size_t	HUF_compress1X_usingCTable_internal_body (void *dst, size_t dstSize, const void *src, size_t srcSize, const HUF_CElt *CTable)
static size_t	HUF_compress1X_usingCTable_internal (void *dst, size_t dstSize, const void *src, size_t srcSize, const HUF_CElt *CTable, const int bmi2)
size_t	HUF_compress1X_usingCTable (void *dst, size_t dstSize, const void *src, size_t srcSize, const HUF_CElt *CTable)
static size_t	HUF_compress4X_usingCTable_internal (void *dst, size_t dstSize, const void *src, size_t srcSize, const HUF_CElt *CTable, int bmi2)
size_t	HUF_compress4X_usingCTable (void *dst, size_t dstSize, const void *src, size_t srcSize, const HUF_CElt *CTable)
static size_t	HUF_compressCTable_internal (BYTE *const ostart, BYTE *op, BYTE *const oend, const void *src, size_t srcSize, HUF_nbStreams_e nbStreams, const HUF_CElt *CTable, const int bmi2)
static size_t	HUF_compress_internal (void *dst, size_t dstSize, const void *src, size_t srcSize, unsigned maxSymbolValue, unsigned huffLog, HUF_nbStreams_e nbStreams, void *workSpace, size_t wkspSize, HUF_CElt *oldHufTable, HUF_repeat *repeat, int preferRepeat, const int bmi2)
size_t	HUF_compress1X_wksp (void *dst, size_t dstSize, const void *src, size_t srcSize, unsigned maxSymbolValue, unsigned huffLog, void *workSpace, size_t wkspSize)
size_t	HUF_compress1X_repeat (void *dst, size_t dstSize, const void *src, size_t srcSize, unsigned maxSymbolValue, unsigned huffLog, void *workSpace, size_t wkspSize, HUF_CElt *hufTable, HUF_repeat *repeat, int preferRepeat, int bmi2)
size_t	HUF_compress1X (void *dst, size_t dstSize, const void *src, size_t srcSize, unsigned maxSymbolValue, unsigned huffLog)
size_t	HUF_compress4X_wksp (void *dst, size_t dstSize, const void *src, size_t srcSize, unsigned maxSymbolValue, unsigned huffLog, void *workSpace, size_t wkspSize)
size_t	HUF_compress4X_repeat (void *dst, size_t dstSize, const void *src, size_t srcSize, unsigned maxSymbolValue, unsigned huffLog, void *workSpace, size_t wkspSize, HUF_CElt *hufTable, HUF_repeat *repeat, int preferRepeat, int bmi2)
size_t	HUF_compress2 (void *dst, size_t dstSize, const void *src, size_t srcSize, unsigned maxSymbolValue, unsigned huffLog)
size_t	HUF_compress (void *dst, size_t maxDstSize, const void *src, size_t srcSize)

Macro Definition Documentation

FSE_STATIC_LINKING_ONLY

#define FSE_STATIC_LINKING_ONLY   /* FSE_optimalTableLog_internal */

Definition at line 31 of file huf_compress.c.

HUF_FLUSHBITS

#define HUF_FLUSHBITS

(

s

)

BIT_flushBits(s)

Definition at line 449 of file huf_compress.c.

HUF_FLUSHBITS_1

#define HUF_FLUSHBITS_1

(

stream

)

if (sizeof((stream)->bitContainer)*8 < HUF_TABLELOG_MAX*2+7) HUF_FLUSHBITS(stream)

Definition at line 451 of file huf_compress.c.

HUF_FLUSHBITS_2

#define HUF_FLUSHBITS_2

(

stream

)

if (sizeof((stream)->bitContainer)*8 < HUF_TABLELOG_MAX*4+7) HUF_FLUSHBITS(stream)

Definition at line 454 of file huf_compress.c.

HUF_isError

#define HUF_isError   ERR_isError

Definition at line 41 of file huf_compress.c.

HUF_STATIC_ASSERT

#define HUF_STATIC_ASSERT

(

c

)

DEBUG_STATIC_ASSERT(c) /* use only *after* variable declarations */

Definition at line 42 of file huf_compress.c.

HUF_STATIC_LINKING_ONLY

#define HUF_STATIC_LINKING_ONLY

Definition at line 33 of file huf_compress.c.

MAX_FSE_TABLELOG_FOR_HUFF_HEADER

#define MAX_FSE_TABLELOG_FOR_HUFF_HEADER   6

Definition at line 62 of file huf_compress.c.

RANK_POSITION_TABLE_SIZE

#define RANK_POSITION_TABLE_SIZE   32

Definition at line 300 of file huf_compress.c.

STARTNODE

#define STARTNODE   (HUF_SYMBOLVALUE_MAX+1)

HUF_buildCTable_wksp() : Same as HUF_buildCTable(), but using externally allocated scratch buffer. workSpace must be aligned on 4-bytes boundaries, and be at least as large as sizeof(HUF_buildCTable_wksp_tables).

Definition at line 336 of file huf_compress.c.

Typedef Documentation

huffNodeTable

typedef nodeElt huffNodeTable[HUF_CTABLE_WORKSPACE_SIZE_U32]

Definition at line 298 of file huf_compress.c.

nodeElt

typedef struct nodeElt_s nodeElt

Enumeration Type Documentation

HUF_nbStreams_e

enum HUF_nbStreams_e

Enumerator
HUF_singleStream
HUF_fourStreams

Definition at line 610 of file huf_compress.c.

{ HUF_singleStream, HUF_fourStreams } HUF_nbStreams_e;

Function Documentation

HUF_buildCTable()

size_t HUF_buildCTable	(	HUF_CElt *	tree,
		const unsigned *	count,
		unsigned	maxSymbolValue,
		unsigned	maxNbBits
	)

HUF_buildCTable() :

Returns

: maxNbBits Note : count is used before tree is written, so they can safely overlap

Definition at line 416 of file huf_compress.c.

{
    HUF_buildCTable_wksp_tables workspace;
    return HUF_buildCTable_wksp(tree, count, maxSymbolValue, maxNbBits, &workspace, sizeof(workspace));
}

HUF_buildCTable_wksp()

size_t HUF_buildCTable_wksp	(	HUF_CElt *	tree,
		const unsigned *	count,
		U32	maxSymbolValue,
		U32	maxNbBits,
		void *	workSpace,
		size_t	wkspSize
	)

Definition at line 338 of file huf_compress.c.

{
    HUF_buildCTable_wksp_tables* const wksp_tables = (HUF_buildCTable_wksp_tables*)workSpace;
    nodeElt* const huffNode0 = wksp_tables->huffNodeTbl;
    nodeElt* const huffNode = huffNode0+1;
    int nonNullRank;
    int lowS, lowN;
    int nodeNb = STARTNODE;
    int n, nodeRoot;
 
    /* safety checks */
    if (((size_t)workSpace & 3) != 0) return ERROR(GENERIC);  /* must be aligned on 4-bytes boundaries */
    if (wkspSize < sizeof(HUF_buildCTable_wksp_tables))
      return ERROR(workSpace_tooSmall);
    if (maxNbBits == 0) maxNbBits = HUF_TABLELOG_DEFAULT;
    if (maxSymbolValue > HUF_SYMBOLVALUE_MAX)
      return ERROR(maxSymbolValue_tooLarge);
    memset(huffNode0, 0, sizeof(huffNodeTable));
 
    /* sort, decreasing order */
    HUF_sort(huffNode, count, maxSymbolValue, wksp_tables->rankPosition);
 
    /* init for parents */
    nonNullRank = (int)maxSymbolValue;
    while(huffNode[nonNullRank].count == 0) nonNullRank--;
    lowS = nonNullRank; nodeRoot = nodeNb + lowS - 1; lowN = nodeNb;
    huffNode[nodeNb].count = huffNode[lowS].count + huffNode[lowS-1].count;
    huffNode[lowS].parent = huffNode[lowS-1].parent = (U16)nodeNb;
    nodeNb++; lowS-=2;
    for (n=nodeNb; n<=nodeRoot; n++) huffNode[n].count = (U32)(1U<<30);
    huffNode0[0].count = (U32)(1U<<31);  /* fake entry, strong barrier */
 
    /* create parents */
    while (nodeNb <= nodeRoot) {
        int const n1 = (huffNode[lowS].count < huffNode[lowN].count) ? lowS-- : lowN++;
        int const n2 = (huffNode[lowS].count < huffNode[lowN].count) ? lowS-- : lowN++;
        huffNode[nodeNb].count = huffNode[n1].count + huffNode[n2].count;
        huffNode[n1].parent = huffNode[n2].parent = (U16)nodeNb;
        nodeNb++;
    }
 
    /* distribute weights (unlimited tree height) */
    huffNode[nodeRoot].nbBits = 0;
    for (n=nodeRoot-1; n>=STARTNODE; n--)
        huffNode[n].nbBits = huffNode[ huffNode[n].parent ].nbBits + 1;
    for (n=0; n<=nonNullRank; n++)
        huffNode[n].nbBits = huffNode[ huffNode[n].parent ].nbBits + 1;
 
    /* enforce maxTableLog */
    maxNbBits = HUF_setMaxHeight(huffNode, (U32)nonNullRank, maxNbBits);
 
    /* fill result into tree (val, nbBits) */
    {   U16 nbPerRank[HUF_TABLELOG_MAX+1] = {0};
        U16 valPerRank[HUF_TABLELOG_MAX+1] = {0};
        int const alphabetSize = (int)(maxSymbolValue + 1);
        if (maxNbBits > HUF_TABLELOG_MAX) return ERROR(GENERIC);   /* check fit into table */
        for (n=0; n<=nonNullRank; n++)
            nbPerRank[huffNode[n].nbBits]++;
        /* determine stating value per rank */
        {   U16 min = 0;
            for (n=(int)maxNbBits; n>0; n--) {
                valPerRank[n] = min;      /* get starting value within each rank */
                min += nbPerRank[n];
                min >>= 1;
        }   }
        for (n=0; n<alphabetSize; n++)
            tree[huffNode[n].byte].nbBits = huffNode[n].nbBits;   /* push nbBits per symbol, symbol order */
        for (n=0; n<alphabetSize; n++)
            tree[n].val = valPerRank[tree[n].nbBits]++;   /* assign value within rank, symbol order */
    }
 
    return maxNbBits;
}

Referenced by HUF_buildCTable(), HUF_compress_internal(), and ZSTD_buildSuperBlockEntropy_literal().

HUF_compress()

size_t HUF_compress	(	void *	dst,
		size_t	dstCapacity,
		const void *	src,
		size_t	srcSize
	)

HUF_compress() : Compress content from buffer 'src', of size 'srcSize', into buffer 'dst'. 'dst' buffer must be already allocated. Compression runs faster if dstCapacity >= HUF_compressBound(srcSize). srcSize must be <= HUF_BLOCKSIZE_MAX == 128 KB.

Returns

: size of compressed data (<= dstCapacity). Special values : if return == 0, srcData is not compressible => Nothing is stored within dst !!! if HUF_isError(return), compression failed (more details using HUF_getErrorName())

Definition at line 795 of file huf_compress.c.

{
    return HUF_compress2(dst, maxDstSize, src, srcSize, 255, HUF_TABLELOG_DEFAULT);
}

HUF_compress1X()

size_t HUF_compress1X	(	void *	dst,
		size_t	dstSize,
		const void *	src,
		size_t	srcSize,
		unsigned	maxSymbolValue,
		unsigned	huffLog
	)

Definition at line 750 of file huf_compress.c.

{
    unsigned workSpace[HUF_WORKSPACE_SIZE_U32];
    return HUF_compress1X_wksp(dst, dstSize, src, srcSize, maxSymbolValue, huffLog, workSpace, sizeof(workSpace));
}

HUF_compress1X_repeat()

size_t HUF_compress1X_repeat	(	void *	dst,
		size_t	dstSize,
		const void *	src,
		size_t	srcSize,
		unsigned	maxSymbolValue,
		unsigned	huffLog,
		void *	workSpace,
		size_t	wkspSize,
		HUF_CElt *	hufTable,
		HUF_repeat *	repeat,
		int	preferRepeat,
		int	bmi2
	)

Definition at line 738 of file huf_compress.c.

{
    return HUF_compress_internal(dst, dstSize, src, srcSize,
                                 maxSymbolValue, huffLog, HUF_singleStream,
                                 workSpace, wkspSize, hufTable,
                                 repeat, preferRepeat, bmi2);
}

Referenced by ZSTD_compressLiterals().

HUF_compress1X_usingCTable()

size_t HUF_compress1X_usingCTable	(	void *	dst,
		size_t	dstSize,
		const void *	src,
		size_t	srcSize,
		const HUF_CElt *	CTable
	)

Definition at line 546 of file huf_compress.c.

{
    return HUF_compress1X_usingCTable_internal(dst, dstSize, src, srcSize, CTable, /* bmi2 */ 0);
}

Referenced by ZSTD_compressSubBlock_literal().

HUF_compress1X_usingCTable_internal()

static size_t HUF_compress1X_usingCTable_internal ( void *  dst, size_t  dstSize, const void *  src, size_t  srcSize, const HUF_CElt *  CTable, const int  bmi2  )

static

Definition at line 536 of file huf_compress.c.

{
    (void)bmi2;
    return HUF_compress1X_usingCTable_internal_body(dst, dstSize, src, srcSize, CTable);
}

Referenced by HUF_compress1X_usingCTable(), HUF_compress4X_usingCTable_internal(), and HUF_compressCTable_internal().

HUF_compress1X_usingCTable_internal_body()

FORCE_INLINE_TEMPLATE size_t HUF_compress1X_usingCTable_internal_body	(	void *	dst,
		size_t	dstSize,
		const void *	src,
		size_t	srcSize,
		const HUF_CElt *	CTable
	)

Definition at line 458 of file huf_compress.c.

{
    const BYTE* ip = (const BYTE*) src;
    BYTE* const ostart = (BYTE*)dst;
    BYTE* const oend = ostart + dstSize;
    BYTE* op = ostart;
    size_t n;
    BIT_CStream_t bitC;
 
    /* init */
    if (dstSize < 8) return 0;   /* not enough space to compress */
    { size_t const initErr = BIT_initCStream(&bitC, op, (size_t)(oend-op));
      if (HUF_isError(initErr)) return 0; }
 
    n = srcSize & ~3;  /* join to mod 4 */
    switch (srcSize & 3)
    {
        case 3 : HUF_encodeSymbol(&bitC, ip[n+ 2], CTable);
                 HUF_FLUSHBITS_2(&bitC);
         /* fall-through */
        case 2 : HUF_encodeSymbol(&bitC, ip[n+ 1], CTable);
                 HUF_FLUSHBITS_1(&bitC);
         /* fall-through */
        case 1 : HUF_encodeSymbol(&bitC, ip[n+ 0], CTable);
                 HUF_FLUSHBITS(&bitC);
         /* fall-through */
        case 0 : /* fall-through */
        default: break;
    }
 
    for (; n>0; n-=4) {  /* note : n&3==0 at this stage */
        HUF_encodeSymbol(&bitC, ip[n- 1], CTable);
        HUF_FLUSHBITS_1(&bitC);
        HUF_encodeSymbol(&bitC, ip[n- 2], CTable);
        HUF_FLUSHBITS_2(&bitC);
        HUF_encodeSymbol(&bitC, ip[n- 3], CTable);
        HUF_FLUSHBITS_1(&bitC);
        HUF_encodeSymbol(&bitC, ip[n- 4], CTable);
        HUF_FLUSHBITS(&bitC);
    }
 
    return BIT_closeCStream(&bitC);
}

Referenced by HUF_compress1X_usingCTable_internal().

HUF_compress1X_wksp()

size_t HUF_compress1X_wksp	(	void *	dst,
		size_t	dstSize,
		const void *	src,
		size_t	srcSize,
		unsigned	maxSymbolValue,
		unsigned	huffLog,
		void *	workSpace,
		size_t	wkspSize
	)

Definition at line 727 of file huf_compress.c.

{
    return HUF_compress_internal(dst, dstSize, src, srcSize,
                                 maxSymbolValue, huffLog, HUF_singleStream,
                                 workSpace, wkspSize,
                                 NULL, NULL, 0, 0 /*bmi2*/);
}

Referenced by HUF_compress1X().

HUF_compress2()

size_t HUF_compress2	(	void *	dst,
		size_t	dstCapacity,
		const void *	src,
		size_t	srcSize,
		unsigned	maxSymbolValue,
		unsigned	tableLog
	)

HUF_compress2() : Same as HUF_compress(), but offers control over maxSymbolValue and tableLog. maxSymbolValue must be <= HUF_SYMBOLVALUE_MAX . tableLog must be <= HUF_TABLELOG_MAX .

Definition at line 787 of file huf_compress.c.

{
    unsigned workSpace[HUF_WORKSPACE_SIZE_U32];
    return HUF_compress4X_wksp(dst, dstSize, src, srcSize, maxSymbolValue, huffLog, workSpace, sizeof(workSpace));
}

Referenced by HUF_compress().

HUF_compress4X_repeat()

size_t HUF_compress4X_repeat	(	void *	dst,
		size_t	dstSize,
		const void *	src,
		size_t	srcSize,
		unsigned	maxSymbolValue,
		unsigned	huffLog,
		void *	workSpace,
		size_t	wkspSize,
		HUF_CElt *	hufTable,
		HUF_repeat *	repeat,
		int	preferRepeat,
		int	bmi2
	)

Definition at line 775 of file huf_compress.c.

{
    return HUF_compress_internal(dst, dstSize, src, srcSize,
                                 maxSymbolValue, huffLog, HUF_fourStreams,
                                 workSpace, wkspSize,
                                 hufTable, repeat, preferRepeat, bmi2);
}

Referenced by ZSTD_compressLiterals().

HUF_compress4X_usingCTable()

size_t HUF_compress4X_usingCTable	(	void *	dst,
		size_t	dstSize,
		const void *	src,
		size_t	srcSize,
		const HUF_CElt *	CTable
	)

Definition at line 605 of file huf_compress.c.

{
    return HUF_compress4X_usingCTable_internal(dst, dstSize, src, srcSize, CTable, /* bmi2 */ 0);
}

Referenced by ZSTD_compressSubBlock_literal().

HUF_compress4X_usingCTable_internal()

static size_t HUF_compress4X_usingCTable_internal ( void *  dst, size_t  dstSize, const void *  src, size_t  srcSize, const HUF_CElt *  CTable, int  bmi2  )

static

Definition at line 553 of file huf_compress.c.

{
    size_t const segmentSize = (srcSize+3)/4;   /* first 3 segments */
    const BYTE* ip = (const BYTE*) src;
    const BYTE* const iend = ip + srcSize;
    BYTE* const ostart = (BYTE*) dst;
    BYTE* const oend = ostart + dstSize;
    BYTE* op = ostart;
 
    if (dstSize < 6 + 1 + 1 + 1 + 8) return 0;   /* minimum space to compress successfully */
    if (srcSize < 12) return 0;   /* no saving possible : too small input */
    op += 6;   /* jumpTable */
 
    assert(op <= oend);
    {   CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, (size_t)(oend-op), ip, segmentSize, CTable, bmi2) );
        if (cSize==0) return 0;
        assert(cSize <= 65535);
        MEM_writeLE16(ostart, (U16)cSize);
        op += cSize;
    }
 
    ip += segmentSize;
    assert(op <= oend);
    {   CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, (size_t)(oend-op), ip, segmentSize, CTable, bmi2) );
        if (cSize==0) return 0;
        assert(cSize <= 65535);
        MEM_writeLE16(ostart+2, (U16)cSize);
        op += cSize;
    }
 
    ip += segmentSize;
    assert(op <= oend);
    {   CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, (size_t)(oend-op), ip, segmentSize, CTable, bmi2) );
        if (cSize==0) return 0;
        assert(cSize <= 65535);
        MEM_writeLE16(ostart+4, (U16)cSize);
        op += cSize;
    }
 
    ip += segmentSize;
    assert(op <= oend);
    assert(ip <= iend);
    {   CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, (size_t)(oend-op), ip, (size_t)(iend-ip), CTable, bmi2) );
        if (cSize==0) return 0;
        op += cSize;
    }
 
    return (size_t)(op-ostart);
}

Referenced by HUF_compress4X_usingCTable(), and HUF_compressCTable_internal().

HUF_compress4X_wksp()

size_t HUF_compress4X_wksp	(	void *	dst,
		size_t	dstSize,
		const void *	src,
		size_t	srcSize,
		unsigned	maxSymbolValue,
		unsigned	huffLog,
		void *	workSpace,
		size_t	wkspSize
	)

Definition at line 761 of file huf_compress.c.

{
    return HUF_compress_internal(dst, dstSize, src, srcSize,
                                 maxSymbolValue, huffLog, HUF_fourStreams,
                                 workSpace, wkspSize,
                                 NULL, NULL, 0, 0 /*bmi2*/);
}

Referenced by HUF_compress2().

HUF_compress_internal()

static size_t HUF_compress_internal ( void *  dst, size_t  dstSize, const void *  src, size_t  srcSize, unsigned  maxSymbolValue, unsigned  huffLog, HUF_nbStreams_e  nbStreams, void *  workSpace, size_t  wkspSize, HUF_CElt *  oldHufTable, HUF_repeat *  repeat, int  preferRepeat, const int  bmi2  )

static

Definition at line 638 of file huf_compress.c.

{
    HUF_compress_tables_t* const table = (HUF_compress_tables_t*)workSpace;
    BYTE* const ostart = (BYTE*)dst;
    BYTE* const oend = ostart + dstSize;
    BYTE* op = ostart;
 
    HUF_STATIC_ASSERT(sizeof(*table) <= HUF_WORKSPACE_SIZE);
 
    /* checks & inits */
    if (((size_t)workSpace & 3) != 0) return ERROR(GENERIC);  /* must be aligned on 4-bytes boundaries */
    if (wkspSize < HUF_WORKSPACE_SIZE) return ERROR(workSpace_tooSmall);
    if (!srcSize) return 0;  /* Uncompressed */
    if (!dstSize) return 0;  /* cannot fit anything within dst budget */
    if (srcSize > HUF_BLOCKSIZE_MAX) return ERROR(srcSize_wrong);   /* current block size limit */
    if (huffLog > HUF_TABLELOG_MAX) return ERROR(tableLog_tooLarge);
    if (maxSymbolValue > HUF_SYMBOLVALUE_MAX) return ERROR(maxSymbolValue_tooLarge);
    if (!maxSymbolValue) maxSymbolValue = HUF_SYMBOLVALUE_MAX;
    if (!huffLog) huffLog = HUF_TABLELOG_DEFAULT;
 
    /* Heuristic : If old table is valid, use it for small inputs */
    if (preferRepeat && repeat && *repeat == HUF_repeat_valid) {
        return HUF_compressCTable_internal(ostart, op, oend,
                                           src, srcSize,
                                           nbStreams, oldHufTable, bmi2);
    }
 
    /* Scan input and build symbol stats */
    {   CHECK_V_F(largest, HIST_count_wksp (table->count, &maxSymbolValue, (const BYTE*)src, srcSize, workSpace, wkspSize) );
        if (largest == srcSize) { *ostart = ((const BYTE*)src)[0]; return 1; }   /* single symbol, rle */
        if (largest <= (srcSize >> 7)+4) return 0;   /* heuristic : probably not compressible enough */
    }
 
    /* Check validity of previous table */
    if ( repeat
      && *repeat == HUF_repeat_check
      && !HUF_validateCTable(oldHufTable, table->count, maxSymbolValue)) {
        *repeat = HUF_repeat_none;
    }
    /* Heuristic : use existing table for small inputs */
    if (preferRepeat && repeat && *repeat != HUF_repeat_none) {
        return HUF_compressCTable_internal(ostart, op, oend,
                                           src, srcSize,
                                           nbStreams, oldHufTable, bmi2);
    }
 
    /* Build Huffman Tree */
    huffLog = HUF_optimalTableLog(huffLog, srcSize, maxSymbolValue);
    {   size_t const maxBits = HUF_buildCTable_wksp(table->CTable, table->count,
                                            maxSymbolValue, huffLog,
                                            &table->buildCTable_wksp, sizeof(table->buildCTable_wksp));
        CHECK_F(maxBits);
        huffLog = (U32)maxBits;
        /* Zero unused symbols in CTable, so we can check it for validity */
        memset(table->CTable + (maxSymbolValue + 1), 0,
               sizeof(table->CTable) - ((maxSymbolValue + 1) * sizeof(HUF_CElt)));
    }
 
    /* Write table description header */
    {   CHECK_V_F(hSize, HUF_writeCTable (op, dstSize, table->CTable, maxSymbolValue, huffLog) );
        /* Check if using previous huffman table is beneficial */
        if (repeat && *repeat != HUF_repeat_none) {
            size_t const oldSize = HUF_estimateCompressedSize(oldHufTable, table->count, maxSymbolValue);
            size_t const newSize = HUF_estimateCompressedSize(table->CTable, table->count, maxSymbolValue);
            if (oldSize <= hSize + newSize || hSize + 12 >= srcSize) {
                return HUF_compressCTable_internal(ostart, op, oend,
                                                   src, srcSize,
                                                   nbStreams, oldHufTable, bmi2);
        }   }
 
        /* Use the new huffman table */
        if (hSize + 12ul >= srcSize) { return 0; }
        op += hSize;
        if (repeat) { *repeat = HUF_repeat_none; }
        if (oldHufTable)
            memcpy(oldHufTable, table->CTable, sizeof(table->CTable));  /* Save new table */
    }
    return HUF_compressCTable_internal(ostart, op, oend,
                                       src, srcSize,
                                       nbStreams, table->CTable, bmi2);
}

Referenced by HUF_compress1X_repeat(), HUF_compress1X_wksp(), HUF_compress4X_repeat(), and HUF_compress4X_wksp().

HUF_compressBound()

size_t HUF_compressBound

(

size_t

size

)

maximum compressed size (worst case)

Definition at line 441 of file huf_compress.c.

{ return HUF_COMPRESSBOUND(size); }

HUF_compressCTable_internal()

static size_t HUF_compressCTable_internal ( BYTE *const  ostart, BYTE *  op, BYTE *const  oend, const void *  src, size_t  srcSize, HUF_nbStreams_e  nbStreams, const HUF_CElt *  CTable, const int  bmi2  )

static

Definition at line 612 of file huf_compress.c.

{
    size_t const cSize = (nbStreams==HUF_singleStream) ?
                         HUF_compress1X_usingCTable_internal(op, (size_t)(oend - op), src, srcSize, CTable, bmi2) :
                         HUF_compress4X_usingCTable_internal(op, (size_t)(oend - op), src, srcSize, CTable, bmi2);
    if (HUF_isError(cSize)) { return cSize; }
    if (cSize==0) { return 0; }   /* uncompressible */
    op += cSize;
    /* check compressibility */
    assert(op >= ostart);
    if ((size_t)(op-ostart) >= srcSize-1) { return 0; }
    return (size_t)(op-ostart);
}

Referenced by HUF_compress_internal().

HUF_compressWeights()

static size_t HUF_compressWeights ( void *  dst, size_t  dstSize, const void *  weightTable, size_t  wtSize  )

static

Definition at line 63 of file huf_compress.c.

{
    BYTE* const ostart = (BYTE*) dst;
    BYTE* op = ostart;
    BYTE* const oend = ostart + dstSize;
 
    unsigned maxSymbolValue = HUF_TABLELOG_MAX;
    U32 tableLog = MAX_FSE_TABLELOG_FOR_HUFF_HEADER;
 
    FSE_CTable CTable[FSE_CTABLE_SIZE_U32(MAX_FSE_TABLELOG_FOR_HUFF_HEADER, HUF_TABLELOG_MAX)];
    BYTE scratchBuffer[1<<MAX_FSE_TABLELOG_FOR_HUFF_HEADER];
 
    unsigned count[HUF_TABLELOG_MAX+1];
    S16 norm[HUF_TABLELOG_MAX+1];
 
    /* init conditions */
    if (wtSize <= 1) return 0;  /* Not compressible */
 
    /* Scan input and build symbol stats */
    {   unsigned const maxCount = HIST_count_simple(count, &maxSymbolValue, weightTable, wtSize);   /* never fails */
        if (maxCount == wtSize) return 1;   /* only a single symbol in src : rle */
        if (maxCount == 1) return 0;        /* each symbol present maximum once => not compressible */
    }
 
    tableLog = FSE_optimalTableLog(tableLog, wtSize, maxSymbolValue);
    CHECK_F( FSE_normalizeCount(norm, tableLog, count, wtSize, maxSymbolValue) );
 
    /* Write table description header */
    {   CHECK_V_F(hSize, FSE_writeNCount(op, (size_t)(oend-op), norm, maxSymbolValue, tableLog) );
        op += hSize;
    }
 
    /* Compress */
    CHECK_F( FSE_buildCTable_wksp(CTable, norm, maxSymbolValue, tableLog, scratchBuffer, sizeof(scratchBuffer)) );
    {   CHECK_V_F(cSize, FSE_compress_usingCTable(op, (size_t)(oend - op), weightTable, wtSize, CTable) );
        if (cSize == 0) return 0;   /* not enough space for compressed data */
        op += cSize;
    }
 
    return (size_t)(op-ostart);
}

Referenced by HUF_writeCTable().

HUF_encodeSymbol()

FORCE_INLINE_TEMPLATE void HUF_encodeSymbol	(	BIT_CStream_t *	bitCPtr,
		U32	symbol,
		const HUF_CElt *	CTable
	)

Definition at line 444 of file huf_compress.c.

{
    BIT_addBitsFast(bitCPtr, CTable[symbol].val, CTable[symbol].nbBits);
}

Referenced by HUF_compress1X_usingCTable_internal_body().

HUF_estimateCompressedSize()

size_t HUF_estimateCompressedSize	(	const HUF_CElt *	CTable,
		const unsigned *	count,
		unsigned	maxSymbolValue
	)

Definition at line 422 of file huf_compress.c.

{
    size_t nbBits = 0;
    int s;
    for (s = 0; s <= (int)maxSymbolValue; ++s) {
        nbBits += CTable[s].nbBits * count[s];
    }
    return nbBits >> 3;
}

Referenced by HUF_compress_internal(), ZSTD_buildSuperBlockEntropy_literal(), and ZSTD_estimateSubBlockSize_literal().

HUF_getNbBits()

U32 HUF_getNbBits	(	const void *	symbolTable,
		U32	symbolValue
	)

Definition at line 200 of file huf_compress.c.

{
    const HUF_CElt* table = (const HUF_CElt*)symbolTable;
    assert(symbolValue <= HUF_SYMBOLVALUE_MAX);
    return table[symbolValue].nbBits;
}

Referenced by ZSTD_rescaleFreqs().

HUF_optimalTableLog()

unsigned HUF_optimalTableLog	(	unsigned	maxTableLog,
		size_t	srcSize,
		unsigned	maxSymbolValue
	)

Definition at line 48 of file huf_compress.c.

{
    return FSE_optimalTableLog_internal(maxTableLog, srcSize, maxSymbolValue, 1);
}

Referenced by HUF_compress_internal(), and ZSTD_buildSuperBlockEntropy_literal().

HUF_readCTable()

size_t HUF_readCTable	(	HUF_CElt *	CTable,
		unsigned *	maxSymbolValuePtr,
		const void *	src,
		size_t	srcSize,
		unsigned *	hasZeroWeights
	)

Definition at line 150 of file huf_compress.c.

{
    BYTE huffWeight[HUF_SYMBOLVALUE_MAX + 1];   /* init not required, even though some static analyzer may complain */
    U32 rankVal[HUF_TABLELOG_ABSOLUTEMAX + 1];   /* large enough for values from 0 to 16 */
    U32 tableLog = 0;
    U32 nbSymbols = 0;
 
    /* get symbol weights */
    CHECK_V_F(readSize, HUF_readStats(huffWeight, HUF_SYMBOLVALUE_MAX+1, rankVal, &nbSymbols, &tableLog, src, srcSize));
 
    /* check result */
    if (tableLog > HUF_TABLELOG_MAX) return ERROR(tableLog_tooLarge);
    if (nbSymbols > *maxSymbolValuePtr+1) return ERROR(maxSymbolValue_tooSmall);
 
    /* Prepare base value per rank */
    {   U32 n, nextRankStart = 0;
        for (n=1; n<=tableLog; n++) {
            U32 current = nextRankStart;
            nextRankStart += (rankVal[n] << (n-1));
            rankVal[n] = current;
    }   }
 
    /* fill nbBits */
    *hasZeroWeights = 0;
    {   U32 n; for (n=0; n<nbSymbols; n++) {
            const U32 w = huffWeight[n];
            *hasZeroWeights |= (w == 0);
            CTable[n].nbBits = (BYTE)(tableLog + 1 - w) & -(w != 0);
    }   }
 
    /* fill val */
    {   U16 nbPerRank[HUF_TABLELOG_MAX+2]  = {0};  /* support w=0=>n=tableLog+1 */
        U16 valPerRank[HUF_TABLELOG_MAX+2] = {0};
        { U32 n; for (n=0; n<nbSymbols; n++) nbPerRank[CTable[n].nbBits]++; }
        /* determine stating value per rank */
        valPerRank[tableLog+1] = 0;   /* for w==0 */
        {   U16 min = 0;
            U32 n; for (n=tableLog; n>0; n--) {  /* start at n=tablelog <-> w=1 */
                valPerRank[n] = min;     /* get starting value within each rank */
                min += nbPerRank[n];
                min >>= 1;
        }   }
        /* assign value within rank, symbol order */
        { U32 n; for (n=0; n<nbSymbols; n++) CTable[n].val = valPerRank[CTable[n].nbBits]++; }
    }
 
    *maxSymbolValuePtr = nbSymbols - 1;
    return readSize;
}

Referenced by ZSTD_loadCEntropy().

HUF_setMaxHeight()

static U32 HUF_setMaxHeight ( nodeElt *  huffNode, U32  lastNonNull, U32  maxNbBits  )

static

Definition at line 215 of file huf_compress.c.

{
    const U32 largestBits = huffNode[lastNonNull].nbBits;
    if (largestBits <= maxNbBits) return largestBits;   /* early exit : no elt > maxNbBits */
 
    /* there are several too large elements (at least >= 2) */
    {   int totalCost = 0;
        const U32 baseCost = 1 << (largestBits - maxNbBits);
        int n = (int)lastNonNull;
 
        while (huffNode[n].nbBits > maxNbBits) {
            totalCost += baseCost - (1 << (largestBits - huffNode[n].nbBits));
            huffNode[n].nbBits = (BYTE)maxNbBits;
            n --;
        }  /* n stops at huffNode[n].nbBits <= maxNbBits */
        while (huffNode[n].nbBits == maxNbBits) n--;   /* n end at index of smallest symbol using < maxNbBits */
 
        /* renorm totalCost */
        totalCost >>= (largestBits - maxNbBits);  /* note : totalCost is necessarily a multiple of baseCost */
 
        /* repay normalized cost */
        {   U32 const noSymbol = 0xF0F0F0F0;
            U32 rankLast[HUF_TABLELOG_MAX+2];
 
            /* Get pos of last (smallest) symbol per rank */
            memset(rankLast, 0xF0, sizeof(rankLast));
            {   U32 currentNbBits = maxNbBits;
                int pos;
                for (pos=n ; pos >= 0; pos--) {
                    if (huffNode[pos].nbBits >= currentNbBits) continue;
                    currentNbBits = huffNode[pos].nbBits;   /* < maxNbBits */
                    rankLast[maxNbBits-currentNbBits] = (U32)pos;
            }   }
 
            while (totalCost > 0) {
                U32 nBitsToDecrease = BIT_highbit32((U32)totalCost) + 1;
                for ( ; nBitsToDecrease > 1; nBitsToDecrease--) {
                    U32 const highPos = rankLast[nBitsToDecrease];
                    U32 const lowPos = rankLast[nBitsToDecrease-1];
                    if (highPos == noSymbol) continue;
                    if (lowPos == noSymbol) break;
                    {   U32 const highTotal = huffNode[highPos].count;
                        U32 const lowTotal = 2 * huffNode[lowPos].count;
                        if (highTotal <= lowTotal) break;
                }   }
                /* only triggered when no more rank 1 symbol left => find closest one (note : there is necessarily at least one !) */
                /* HUF_MAX_TABLELOG test just to please gcc 5+; but it should not be necessary */
                while ((nBitsToDecrease<=HUF_TABLELOG_MAX) && (rankLast[nBitsToDecrease] == noSymbol))
                    nBitsToDecrease ++;
                totalCost -= 1 << (nBitsToDecrease-1);
                if (rankLast[nBitsToDecrease-1] == noSymbol)
                    rankLast[nBitsToDecrease-1] = rankLast[nBitsToDecrease];   /* this rank is no longer empty */
                huffNode[rankLast[nBitsToDecrease]].nbBits ++;
                if (rankLast[nBitsToDecrease] == 0)    /* special case, reached largest symbol */
                    rankLast[nBitsToDecrease] = noSymbol;
                else {
                    rankLast[nBitsToDecrease]--;
                    if (huffNode[rankLast[nBitsToDecrease]].nbBits != maxNbBits-nBitsToDecrease)
                        rankLast[nBitsToDecrease] = noSymbol;   /* this rank is now empty */
            }   }   /* while (totalCost > 0) */
 
            while (totalCost < 0) {  /* Sometimes, cost correction overshoot */
                if (rankLast[1] == noSymbol) {  /* special case : no rank 1 symbol (using maxNbBits-1); let's create one from largest rank 0 (using maxNbBits) */
                    while (huffNode[n].nbBits == maxNbBits) n--;
                    huffNode[n+1].nbBits--;
                    assert(n >= 0);
                    rankLast[1] = (U32)(n+1);
                    totalCost++;
                    continue;
                }
                huffNode[ rankLast[1] + 1 ].nbBits--;
                rankLast[1]++;
                totalCost ++;
    }   }   }   /* there are several too large elements (at least >= 2) */
 
    return maxNbBits;
}

Referenced by HUF_buildCTable_wksp().

HUF_sort()

static void HUF_sort ( nodeElt *  huffNode, const unsigned *  count, U32  maxSymbolValue, rankPos *  rankPosition  )

static

Definition at line 307 of file huf_compress.c.

{
    U32 n;
 
    memset(rankPosition, 0, sizeof(*rankPosition) * RANK_POSITION_TABLE_SIZE);
    for (n=0; n<=maxSymbolValue; n++) {
        U32 r = BIT_highbit32(count[n] + 1);
        rankPosition[r].base ++;
    }
    for (n=30; n>0; n--) rankPosition[n-1].base += rankPosition[n].base;
    for (n=0; n<32; n++) rankPosition[n].current = rankPosition[n].base;
    for (n=0; n<=maxSymbolValue; n++) {
        U32 const c = count[n];
        U32 const r = BIT_highbit32(c+1) + 1;
        U32 pos = rankPosition[r].current++;
        while ((pos > rankPosition[r].base) && (c > huffNode[pos-1].count)) {
            huffNode[pos] = huffNode[pos-1];
            pos--;
        }
        huffNode[pos].count = c;
        huffNode[pos].byte  = (BYTE)n;
    }
}

Referenced by HUF_buildCTable_wksp().

HUF_validateCTable()

int HUF_validateCTable	(	const HUF_CElt *	CTable,
		const unsigned *	count,
		unsigned	maxSymbolValue
	)

Definition at line 432 of file huf_compress.c.

                                                                                               {
  int bad = 0;
  int s;
  for (s = 0; s <= (int)maxSymbolValue; ++s) {
    bad |= (count[s] != 0) & (CTable[s].nbBits == 0);
  }
  return !bad;
}

Referenced by HUF_compress_internal(), and ZSTD_buildSuperBlockEntropy_literal().

HUF_writeCTable()

size_t HUF_writeCTable	(	void *	dst,
		size_t	maxDstSize,
		const HUF_CElt *	CTable,
		unsigned	maxSymbolValue,
		unsigned	huffLog
	)

HUF_writeCTable() : CTable : Huffman tree to save, using huf representation.

Returns

: size of saved CTable

Definition at line 114 of file huf_compress.c.

{
    BYTE bitsToWeight[HUF_TABLELOG_MAX + 1];   /* precomputed conversion table */
    BYTE huffWeight[HUF_SYMBOLVALUE_MAX];
    BYTE* op = (BYTE*)dst;
    U32 n;
 
     /* check conditions */
    if (maxSymbolValue > HUF_SYMBOLVALUE_MAX) return ERROR(maxSymbolValue_tooLarge);
 
    /* convert to weight */
    bitsToWeight[0] = 0;
    for (n=1; n<huffLog+1; n++)
        bitsToWeight[n] = (BYTE)(huffLog + 1 - n);
    for (n=0; n<maxSymbolValue; n++)
        huffWeight[n] = bitsToWeight[CTable[n].nbBits];
 
    /* attempt weights compression by FSE */
    {   CHECK_V_F(hSize, HUF_compressWeights(op+1, maxDstSize-1, huffWeight, maxSymbolValue) );
        if ((hSize>1) & (hSize < maxSymbolValue/2)) {   /* FSE compressed */
            op[0] = (BYTE)hSize;
            return hSize+1;
    }   }
 
    /* write raw values as 4-bits (max : 15) */
    if (maxSymbolValue > (256-128)) return ERROR(GENERIC);   /* should not happen : likely means source cannot be compressed */
    if (((maxSymbolValue+1)/2) + 1 > maxDstSize) return ERROR(dstSize_tooSmall);   /* not enough space within dst buffer */
    op[0] = (BYTE)(128 /*special case*/ + (maxSymbolValue-1));
    huffWeight[maxSymbolValue] = 0;   /* to be sure it doesn't cause msan issue in final combination */
    for (n=0; n<maxSymbolValue; n+=2)
        op[(n/2)+1] = (BYTE)((huffWeight[n] << 4) + huffWeight[n+1]);
    return ((maxSymbolValue+1)/2) + 1;
}

Referenced by HUF_compress_internal(), and ZSTD_buildSuperBlockEntropy_literal().