zstd_lazy.c File Reference

#include "zstd_compress_internal.h"
#include "zstd_lazy.h"

Include dependency graph for zstd_lazy.c:

Go to the source code of this file.

Macros
#define	NEXT_IN_CHAIN(d, mask)   chainTable[(d) & (mask)]

Enumerations
enum	searchMethod_e { search_hashChain , search_binaryTree }

Functions
static void	ZSTD_updateDUBT (ZSTD_matchState_t *ms, const BYTE *ip, const BYTE *iend, U32 mls)
static void	ZSTD_insertDUBT1 (ZSTD_matchState_t *ms, U32 current, const BYTE *inputEnd, U32 nbCompares, U32 btLow, const ZSTD_dictMode_e dictMode)
static size_t	ZSTD_DUBT_findBetterDictMatch (ZSTD_matchState_t *ms, const BYTE *const ip, const BYTE *const iend, size_t *offsetPtr, size_t bestLength, U32 nbCompares, U32 const mls, const ZSTD_dictMode_e dictMode)
static size_t	ZSTD_DUBT_findBestMatch (ZSTD_matchState_t *ms, const BYTE *const ip, const BYTE *const iend, size_t *offsetPtr, U32 const mls, const ZSTD_dictMode_e dictMode)
FORCE_INLINE_TEMPLATE size_t	ZSTD_BtFindBestMatch (ZSTD_matchState_t *ms, const BYTE *const ip, const BYTE *const iLimit, size_t *offsetPtr, const U32 mls, const ZSTD_dictMode_e dictMode)
static size_t	ZSTD_BtFindBestMatch_selectMLS (ZSTD_matchState_t *ms, const BYTE *ip, const BYTE *const iLimit, size_t *offsetPtr)
static size_t	ZSTD_BtFindBestMatch_dictMatchState_selectMLS (ZSTD_matchState_t *ms, const BYTE *ip, const BYTE *const iLimit, size_t *offsetPtr)
static size_t	ZSTD_BtFindBestMatch_extDict_selectMLS (ZSTD_matchState_t *ms, const BYTE *ip, const BYTE *const iLimit, size_t *offsetPtr)
static U32	ZSTD_insertAndFindFirstIndex_internal (ZSTD_matchState_t *ms, const ZSTD_compressionParameters *const cParams, const BYTE *ip, U32 const mls)
U32	ZSTD_insertAndFindFirstIndex (ZSTD_matchState_t *ms, const BYTE *ip)
FORCE_INLINE_TEMPLATE size_t	ZSTD_HcFindBestMatch_generic (ZSTD_matchState_t *ms, const BYTE *const ip, const BYTE *const iLimit, size_t *offsetPtr, const U32 mls, const ZSTD_dictMode_e dictMode)
FORCE_INLINE_TEMPLATE size_t	ZSTD_HcFindBestMatch_selectMLS (ZSTD_matchState_t *ms, const BYTE *ip, const BYTE *const iLimit, size_t *offsetPtr)
static size_t	ZSTD_HcFindBestMatch_dictMatchState_selectMLS (ZSTD_matchState_t *ms, const BYTE *ip, const BYTE *const iLimit, size_t *offsetPtr)
FORCE_INLINE_TEMPLATE size_t	ZSTD_HcFindBestMatch_extDict_selectMLS (ZSTD_matchState_t *ms, const BYTE *ip, const BYTE *const iLimit, size_t *offsetPtr)
size_t	ZSTD_compressBlock_lazy_generic (ZSTD_matchState_t *ms, seqStore_t *seqStore, U32 rep[ZSTD_REP_NUM], const void *src, size_t srcSize, const searchMethod_e searchMethod, const U32 depth, ZSTD_dictMode_e const dictMode)
size_t	ZSTD_compressBlock_btlazy2 (ZSTD_matchState_t *ms, seqStore_t *seqStore, U32 rep[ZSTD_REP_NUM], void const *src, size_t srcSize)
size_t	ZSTD_compressBlock_lazy2 (ZSTD_matchState_t *ms, seqStore_t *seqStore, U32 rep[ZSTD_REP_NUM], void const *src, size_t srcSize)
size_t	ZSTD_compressBlock_lazy (ZSTD_matchState_t *ms, seqStore_t *seqStore, U32 rep[ZSTD_REP_NUM], void const *src, size_t srcSize)
size_t	ZSTD_compressBlock_greedy (ZSTD_matchState_t *ms, seqStore_t *seqStore, U32 rep[ZSTD_REP_NUM], void const *src, size_t srcSize)
size_t	ZSTD_compressBlock_btlazy2_dictMatchState (ZSTD_matchState_t *ms, seqStore_t *seqStore, U32 rep[ZSTD_REP_NUM], void const *src, size_t srcSize)
size_t	ZSTD_compressBlock_lazy2_dictMatchState (ZSTD_matchState_t *ms, seqStore_t *seqStore, U32 rep[ZSTD_REP_NUM], void const *src, size_t srcSize)
size_t	ZSTD_compressBlock_lazy_dictMatchState (ZSTD_matchState_t *ms, seqStore_t *seqStore, U32 rep[ZSTD_REP_NUM], void const *src, size_t srcSize)
size_t	ZSTD_compressBlock_greedy_dictMatchState (ZSTD_matchState_t *ms, seqStore_t *seqStore, U32 rep[ZSTD_REP_NUM], void const *src, size_t srcSize)
FORCE_INLINE_TEMPLATE size_t	ZSTD_compressBlock_lazy_extDict_generic (ZSTD_matchState_t *ms, seqStore_t *seqStore, U32 rep[ZSTD_REP_NUM], const void *src, size_t srcSize, const searchMethod_e searchMethod, const U32 depth)
size_t	ZSTD_compressBlock_greedy_extDict (ZSTD_matchState_t *ms, seqStore_t *seqStore, U32 rep[ZSTD_REP_NUM], void const *src, size_t srcSize)
size_t	ZSTD_compressBlock_lazy_extDict (ZSTD_matchState_t *ms, seqStore_t *seqStore, U32 rep[ZSTD_REP_NUM], void const *src, size_t srcSize)
size_t	ZSTD_compressBlock_lazy2_extDict (ZSTD_matchState_t *ms, seqStore_t *seqStore, U32 rep[ZSTD_REP_NUM], void const *src, size_t srcSize)
size_t	ZSTD_compressBlock_btlazy2_extDict (ZSTD_matchState_t *ms, seqStore_t *seqStore, U32 rep[ZSTD_REP_NUM], void const *src, size_t srcSize)

Macro Definition Documentation

NEXT_IN_CHAIN

#define NEXT_IN_CHAIN	(		d,
			mask
	)		chainTable[(d) & (mask)]

Definition at line 445 of file zstd_lazy.c.

Enumeration Type Documentation

searchMethod_e

enum searchMethod_e

Enumerator
search_hashChain
search_binaryTree

Definition at line 622 of file zstd_lazy.c.

{ search_hashChain, search_binaryTree } searchMethod_e;

Function Documentation

ZSTD_BtFindBestMatch()

FORCE_INLINE_TEMPLATE size_t ZSTD_BtFindBestMatch	(	ZSTD_matchState_t *	ms,
		const BYTE *const	ip,
		const BYTE *const	iLimit,
		size_t *	offsetPtr,
		const U32	mls,
		const ZSTD_dictMode_e	dictMode
	)

ZSTD_BtFindBestMatch() : Tree updater, providing best match

Definition at line 380 of file zstd_lazy.c.

{
    DEBUGLOG(7, "ZSTD_BtFindBestMatch");
    if (ip < ms->window.base + ms->nextToUpdate) return 0;   /* skipped area */
    ZSTD_updateDUBT(ms, ip, iLimit, mls);
    return ZSTD_DUBT_findBestMatch(ms, ip, iLimit, offsetPtr, mls, dictMode);
}

Referenced by ZSTD_BtFindBestMatch_dictMatchState_selectMLS(), ZSTD_BtFindBestMatch_extDict_selectMLS(), and ZSTD_BtFindBestMatch_selectMLS().

ZSTD_BtFindBestMatch_dictMatchState_selectMLS()

static size_t ZSTD_BtFindBestMatch_dictMatchState_selectMLS ( ZSTD_matchState_t *  ms, const BYTE *  ip, const BYTE *const  iLimit, size_t *  offsetPtr  )

static

Definition at line 409 of file zstd_lazy.c.

{
    switch(ms->cParams.minMatch)
    {
    default : /* includes case 3 */
    case 4 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 4, ZSTD_dictMatchState);
    case 5 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 5, ZSTD_dictMatchState);
    case 7 :
    case 6 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 6, ZSTD_dictMatchState);
    }
}

Referenced by ZSTD_compressBlock_lazy_generic().

ZSTD_BtFindBestMatch_extDict_selectMLS()

static size_t ZSTD_BtFindBestMatch_extDict_selectMLS ( ZSTD_matchState_t *  ms, const BYTE *  ip, const BYTE *const  iLimit, size_t *  offsetPtr  )

static

Definition at line 425 of file zstd_lazy.c.

{
    switch(ms->cParams.minMatch)
    {
    default : /* includes case 3 */
    case 4 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 4, ZSTD_extDict);
    case 5 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 5, ZSTD_extDict);
    case 7 :
    case 6 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 6, ZSTD_extDict);
    }
}

Referenced by ZSTD_compressBlock_lazy_extDict_generic().

ZSTD_BtFindBestMatch_selectMLS()

static size_t ZSTD_BtFindBestMatch_selectMLS ( ZSTD_matchState_t *  ms, const BYTE *  ip, const BYTE *const  iLimit, size_t *  offsetPtr  )

static

Definition at line 394 of file zstd_lazy.c.

{
    switch(ms->cParams.minMatch)
    {
    default : /* includes case 3 */
    case 4 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 4, ZSTD_noDict);
    case 5 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 5, ZSTD_noDict);
    case 7 :
    case 6 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 6, ZSTD_noDict);
    }
}

Referenced by ZSTD_compressBlock_lazy_generic().

ZSTD_compressBlock_btlazy2()

size_t ZSTD_compressBlock_btlazy2	(	ZSTD_matchState_t *	ms,
		seqStore_t *	seqStore,
		U32	rep[ZSTD_REP_NUM],
		void const *	src,
		size_t	srcSize
	)

used in ZSTD_reduceIndex(). preemptively increase value of ZSTD_DUBT_UNSORTED_MARK

Definition at line 871 of file zstd_lazy.c.

{
    return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_binaryTree, 2, ZSTD_noDict);
}

Referenced by ZSTD_selectBlockCompressor().

ZSTD_compressBlock_btlazy2_dictMatchState()

size_t ZSTD_compressBlock_btlazy2_dictMatchState	(	ZSTD_matchState_t *	ms,
		seqStore_t *	seqStore,
		U32	rep[ZSTD_REP_NUM],
		void const *	src,
		size_t	srcSize
	)

Definition at line 899 of file zstd_lazy.c.

{
    return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_binaryTree, 2, ZSTD_dictMatchState);
}

Referenced by ZSTD_selectBlockCompressor().

ZSTD_compressBlock_btlazy2_extDict()

size_t ZSTD_compressBlock_btlazy2_extDict	(	ZSTD_matchState_t *	ms,
		seqStore_t *	seqStore,
		U32	rep[ZSTD_REP_NUM],
		void const *	src,
		size_t	srcSize
	)

Definition at line 1132 of file zstd_lazy.c.

{
    return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, search_binaryTree, 2);
}

Referenced by ZSTD_selectBlockCompressor().

ZSTD_compressBlock_greedy()

size_t ZSTD_compressBlock_greedy	(	ZSTD_matchState_t *	ms,
		seqStore_t *	seqStore,
		U32	rep[ZSTD_REP_NUM],
		void const *	src,
		size_t	srcSize
	)

Definition at line 892 of file zstd_lazy.c.

{
    return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 0, ZSTD_noDict);
}

Referenced by ZSTD_selectBlockCompressor().

ZSTD_compressBlock_greedy_dictMatchState()

size_t ZSTD_compressBlock_greedy_dictMatchState	(	ZSTD_matchState_t *	ms,
		seqStore_t *	seqStore,
		U32	rep[ZSTD_REP_NUM],
		void const *	src,
		size_t	srcSize
	)

Definition at line 920 of file zstd_lazy.c.

{
    return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 0, ZSTD_dictMatchState);
}

Referenced by ZSTD_selectBlockCompressor().

ZSTD_compressBlock_greedy_extDict()

size_t ZSTD_compressBlock_greedy_extDict	(	ZSTD_matchState_t *	ms,
		seqStore_t *	seqStore,
		U32	rep[ZSTD_REP_NUM],
		void const *	src,
		size_t	srcSize
	)

Definition at line 1109 of file zstd_lazy.c.

{
    return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 0);
}

Referenced by ZSTD_selectBlockCompressor().

ZSTD_compressBlock_lazy()

size_t ZSTD_compressBlock_lazy	(	ZSTD_matchState_t *	ms,
		seqStore_t *	seqStore,
		U32	rep[ZSTD_REP_NUM],
		void const *	src,
		size_t	srcSize
	)

Definition at line 885 of file zstd_lazy.c.

{
    return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 1, ZSTD_noDict);
}

Referenced by ZSTD_selectBlockCompressor().

ZSTD_compressBlock_lazy2()

size_t ZSTD_compressBlock_lazy2	(	ZSTD_matchState_t *	ms,
		seqStore_t *	seqStore,
		U32	rep[ZSTD_REP_NUM],
		void const *	src,
		size_t	srcSize
	)

Definition at line 878 of file zstd_lazy.c.

{
    return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 2, ZSTD_noDict);
}

Referenced by ZSTD_selectBlockCompressor().

ZSTD_compressBlock_lazy2_dictMatchState()

size_t ZSTD_compressBlock_lazy2_dictMatchState	(	ZSTD_matchState_t *	ms,
		seqStore_t *	seqStore,
		U32	rep[ZSTD_REP_NUM],
		void const *	src,
		size_t	srcSize
	)

Definition at line 906 of file zstd_lazy.c.

{
    return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 2, ZSTD_dictMatchState);
}

Referenced by ZSTD_selectBlockCompressor().

ZSTD_compressBlock_lazy2_extDict()

size_t ZSTD_compressBlock_lazy2_extDict	(	ZSTD_matchState_t *	ms,
		seqStore_t *	seqStore,
		U32	rep[ZSTD_REP_NUM],
		void const *	src,
		size_t	srcSize
	)

Definition at line 1124 of file zstd_lazy.c.

{
    return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 2);
}

Referenced by ZSTD_selectBlockCompressor().

ZSTD_compressBlock_lazy_dictMatchState()

size_t ZSTD_compressBlock_lazy_dictMatchState	(	ZSTD_matchState_t *	ms,
		seqStore_t *	seqStore,
		U32	rep[ZSTD_REP_NUM],
		void const *	src,
		size_t	srcSize
	)

Definition at line 913 of file zstd_lazy.c.

{
    return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 1, ZSTD_dictMatchState);
}

Referenced by ZSTD_selectBlockCompressor().

ZSTD_compressBlock_lazy_extDict()

size_t ZSTD_compressBlock_lazy_extDict	(	ZSTD_matchState_t *	ms,
		seqStore_t *	seqStore,
		U32	rep[ZSTD_REP_NUM],
		void const *	src,
		size_t	srcSize
	)

Definition at line 1116 of file zstd_lazy.c.

{
    return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 1);
}

Referenced by ZSTD_selectBlockCompressor().

ZSTD_compressBlock_lazy_extDict_generic()

FORCE_INLINE_TEMPLATE size_t ZSTD_compressBlock_lazy_extDict_generic	(	ZSTD_matchState_t *	ms,
		seqStore_t *	seqStore,
		U32	rep[ZSTD_REP_NUM],
		const void *	src,
		size_t	srcSize,
		const searchMethod_e	searchMethod,
		const U32	depth
	)

Definition at line 929 of file zstd_lazy.c.

{
    const BYTE* const istart = (const BYTE*)src;
    const BYTE* ip = istart;
    const BYTE* anchor = istart;
    const BYTE* const iend = istart + srcSize;
    const BYTE* const ilimit = iend - 8;
    const BYTE* const base = ms->window.base;
    const U32 dictLimit = ms->window.dictLimit;
    const BYTE* const prefixStart = base + dictLimit;
    const BYTE* const dictBase = ms->window.dictBase;
    const BYTE* const dictEnd  = dictBase + dictLimit;
    const BYTE* const dictStart  = dictBase + ms->window.lowLimit;
    const U32 windowLog = ms->cParams.windowLog;
 
    typedef size_t (*searchMax_f)(
                        ZSTD_matchState_t* ms,
                        const BYTE* ip, const BYTE* iLimit, size_t* offsetPtr);
    searchMax_f searchMax = searchMethod==search_binaryTree ? ZSTD_BtFindBestMatch_extDict_selectMLS : ZSTD_HcFindBestMatch_extDict_selectMLS;
 
    U32 offset_1 = rep[0], offset_2 = rep[1];
 
    DEBUGLOG(5, "ZSTD_compressBlock_lazy_extDict_generic");
 
    /* init */
    ip += (ip == prefixStart);
 
    /* Match Loop */
#if defined(__GNUC__) && defined(__x86_64__)
    /* I've measured random a 5% speed loss on levels 5 & 6 (greedy) when the
     * code alignment is perturbed. To fix the instability align the loop on 32-bytes.
     */
    __asm__(".p2align 5");
#endif
    while (ip < ilimit) {
        size_t matchLength=0;
        size_t offset=0;
        const BYTE* start=ip+1;
        U32 current = (U32)(ip-base);
 
        /* check repCode */
        {   const U32 windowLow = ZSTD_getLowestMatchIndex(ms, current+1, windowLog);
            const U32 repIndex = (U32)(current+1 - offset_1);
            const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
            const BYTE* const repMatch = repBase + repIndex;
            if (((U32)((dictLimit-1) - repIndex) >= 3) & (repIndex > windowLow))   /* intentional overflow */
            if (MEM_read32(ip+1) == MEM_read32(repMatch)) {
                /* repcode detected we should take it */
                const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
                matchLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repEnd, prefixStart) + 4;
                if (depth==0) goto _storeSequence;
        }   }
 
        /* first search (depth 0) */
        {   size_t offsetFound = 999999999;
            size_t const ml2 = searchMax(ms, ip, iend, &offsetFound);
            if (ml2 > matchLength)
                matchLength = ml2, start = ip, offset=offsetFound;
        }
 
         if (matchLength < 4) {
            ip += ((ip-anchor) >> kSearchStrength) + 1;   /* jump faster over incompressible sections */
            continue;
        }
 
        /* let's try to find a better solution */
        if (depth>=1)
        while (ip<ilimit) {
            ip ++;
            current++;
            /* check repCode */
            if (offset) {
                const U32 windowLow = ZSTD_getLowestMatchIndex(ms, current, windowLog);
                const U32 repIndex = (U32)(current - offset_1);
                const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
                const BYTE* const repMatch = repBase + repIndex;
                if (((U32)((dictLimit-1) - repIndex) >= 3) & (repIndex > windowLow))  /* intentional overflow */
                if (MEM_read32(ip) == MEM_read32(repMatch)) {
                    /* repcode detected */
                    const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
                    size_t const repLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd, prefixStart) + 4;
                    int const gain2 = (int)(repLength * 3);
                    int const gain1 = (int)(matchLength*3 - ZSTD_highbit32((U32)offset+1) + 1);
                    if ((repLength >= 4) && (gain2 > gain1))
                        matchLength = repLength, offset = 0, start = ip;
            }   }
 
            /* search match, depth 1 */
            {   size_t offset2=999999999;
                size_t const ml2 = searchMax(ms, ip, iend, &offset2);
                int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)offset2+1));   /* raw approx */
                int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 4);
                if ((ml2 >= 4) && (gain2 > gain1)) {
                    matchLength = ml2, offset = offset2, start = ip;
                    continue;   /* search a better one */
            }   }
 
            /* let's find an even better one */
            if ((depth==2) && (ip<ilimit)) {
                ip ++;
                current++;
                /* check repCode */
                if (offset) {
                    const U32 windowLow = ZSTD_getLowestMatchIndex(ms, current, windowLog);
                    const U32 repIndex = (U32)(current - offset_1);
                    const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
                    const BYTE* const repMatch = repBase + repIndex;
                    if (((U32)((dictLimit-1) - repIndex) >= 3) & (repIndex > windowLow))  /* intentional overflow */
                    if (MEM_read32(ip) == MEM_read32(repMatch)) {
                        /* repcode detected */
                        const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
                        size_t const repLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd, prefixStart) + 4;
                        int const gain2 = (int)(repLength * 4);
                        int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 1);
                        if ((repLength >= 4) && (gain2 > gain1))
                            matchLength = repLength, offset = 0, start = ip;
                }   }
 
                /* search match, depth 2 */
                {   size_t offset2=999999999;
                    size_t const ml2 = searchMax(ms, ip, iend, &offset2);
                    int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)offset2+1));   /* raw approx */
                    int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 7);
                    if ((ml2 >= 4) && (gain2 > gain1)) {
                        matchLength = ml2, offset = offset2, start = ip;
                        continue;
            }   }   }
            break;  /* nothing found : store previous solution */
        }
 
        /* catch up */
        if (offset) {
            U32 const matchIndex = (U32)((start-base) - (offset - ZSTD_REP_MOVE));
            const BYTE* match = (matchIndex < dictLimit) ? dictBase + matchIndex : base + matchIndex;
            const BYTE* const mStart = (matchIndex < dictLimit) ? dictStart : prefixStart;
            while ((start>anchor) && (match>mStart) && (start[-1] == match[-1])) { start--; match--; matchLength++; }  /* catch up */
            offset_2 = offset_1; offset_1 = (U32)(offset - ZSTD_REP_MOVE);
        }
 
        /* store sequence */
_storeSequence:
        {   size_t const litLength = start - anchor;
            ZSTD_storeSeq(seqStore, litLength, anchor, iend, (U32)offset, matchLength-MINMATCH);
            anchor = ip = start + matchLength;
        }
 
        /* check immediate repcode */
        while (ip <= ilimit) {
            const U32 repCurrent = (U32)(ip-base);
            const U32 windowLow = ZSTD_getLowestMatchIndex(ms, repCurrent, windowLog);
            const U32 repIndex = repCurrent - offset_2;
            const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
            const BYTE* const repMatch = repBase + repIndex;
            if (((U32)((dictLimit-1) - repIndex) >= 3) & (repIndex > windowLow))  /* intentional overflow */
            if (MEM_read32(ip) == MEM_read32(repMatch)) {
                /* repcode detected we should take it */
                const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
                matchLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd, prefixStart) + 4;
                offset = offset_2; offset_2 = offset_1; offset_1 = (U32)offset;   /* swap offset history */
                ZSTD_storeSeq(seqStore, 0, anchor, iend, 0, matchLength-MINMATCH);
                ip += matchLength;
                anchor = ip;
                continue;   /* faster when present ... (?) */
            }
            break;
    }   }
 
    /* Save reps for next block */
    rep[0] = offset_1;
    rep[1] = offset_2;
 
    /* Return the last literals size */
    return (size_t)(iend - anchor);
}

Referenced by ZSTD_compressBlock_btlazy2_extDict(), ZSTD_compressBlock_greedy_extDict(), ZSTD_compressBlock_lazy2_extDict(), and ZSTD_compressBlock_lazy_extDict().

ZSTD_compressBlock_lazy_generic()

size_t ZSTD_compressBlock_lazy_generic	(	ZSTD_matchState_t *	ms,
		seqStore_t *	seqStore,
		U32	rep[ZSTD_REP_NUM],
		const void *	src,
		size_t	srcSize,
		const searchMethod_e	searchMethod,
		const U32	depth,
		ZSTD_dictMode_e const	dictMode
	)

Definition at line 625 of file zstd_lazy.c.

{
    const BYTE* const istart = (const BYTE*)src;
    const BYTE* ip = istart;
    const BYTE* anchor = istart;
    const BYTE* const iend = istart + srcSize;
    const BYTE* const ilimit = iend - 8;
    const BYTE* const base = ms->window.base;
    const U32 prefixLowestIndex = ms->window.dictLimit;
    const BYTE* const prefixLowest = base + prefixLowestIndex;
 
    typedef size_t (*searchMax_f)(
                        ZSTD_matchState_t* ms,
                        const BYTE* ip, const BYTE* iLimit, size_t* offsetPtr);
    searchMax_f const searchMax = dictMode == ZSTD_dictMatchState ?
        (searchMethod==search_binaryTree ? ZSTD_BtFindBestMatch_dictMatchState_selectMLS
                                         : ZSTD_HcFindBestMatch_dictMatchState_selectMLS) :
        (searchMethod==search_binaryTree ? ZSTD_BtFindBestMatch_selectMLS
                                         : ZSTD_HcFindBestMatch_selectMLS);
    U32 offset_1 = rep[0], offset_2 = rep[1], savedOffset=0;
 
    const ZSTD_matchState_t* const dms = ms->dictMatchState;
    const U32 dictLowestIndex      = dictMode == ZSTD_dictMatchState ?
                                     dms->window.dictLimit : 0;
    const BYTE* const dictBase     = dictMode == ZSTD_dictMatchState ?
                                     dms->window.base : NULL;
    const BYTE* const dictLowest   = dictMode == ZSTD_dictMatchState ?
                                     dictBase + dictLowestIndex : NULL;
    const BYTE* const dictEnd      = dictMode == ZSTD_dictMatchState ?
                                     dms->window.nextSrc : NULL;
    const U32 dictIndexDelta       = dictMode == ZSTD_dictMatchState ?
                                     prefixLowestIndex - (U32)(dictEnd - dictBase) :
                                     0;
    const U32 dictAndPrefixLength = (U32)((ip - prefixLowest) + (dictEnd - dictLowest));
 
    DEBUGLOG(5, "ZSTD_compressBlock_lazy_generic (dictMode=%u)", (U32)dictMode);
 
    /* init */
    ip += (dictAndPrefixLength == 0);
    if (dictMode == ZSTD_noDict) {
        U32 const current = (U32)(ip - base);
        U32 const windowLow = ZSTD_getLowestPrefixIndex(ms, current, ms->cParams.windowLog);
        U32 const maxRep = current - windowLow;
        if (offset_2 > maxRep) savedOffset = offset_2, offset_2 = 0;
        if (offset_1 > maxRep) savedOffset = offset_1, offset_1 = 0;
    }
    if (dictMode == ZSTD_dictMatchState) {
        /* dictMatchState repCode checks don't currently handle repCode == 0
         * disabling. */
        assert(offset_1 <= dictAndPrefixLength);
        assert(offset_2 <= dictAndPrefixLength);
    }
 
    /* Match Loop */
#if defined(__GNUC__) && defined(__x86_64__)
    /* I've measured random a 5% speed loss on levels 5 & 6 (greedy) when the
     * code alignment is perturbed. To fix the instability align the loop on 32-bytes.
     */
    __asm__(".p2align 5");
#endif
    while (ip < ilimit) {
        size_t matchLength=0;
        size_t offset=0;
        const BYTE* start=ip+1;
 
        /* check repCode */
        if (dictMode == ZSTD_dictMatchState) {
            const U32 repIndex = (U32)(ip - base) + 1 - offset_1;
            const BYTE* repMatch = (dictMode == ZSTD_dictMatchState
                                && repIndex < prefixLowestIndex) ?
                                   dictBase + (repIndex - dictIndexDelta) :
                                   base + repIndex;
            if (((U32)((prefixLowestIndex-1) - repIndex) >= 3 /* intentional underflow */)
                && (MEM_read32(repMatch) == MEM_read32(ip+1)) ) {
                const BYTE* repMatchEnd = repIndex < prefixLowestIndex ? dictEnd : iend;
                matchLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repMatchEnd, prefixLowest) + 4;
                if (depth==0) goto _storeSequence;
            }
        }
        if ( dictMode == ZSTD_noDict
          && ((offset_1 > 0) & (MEM_read32(ip+1-offset_1) == MEM_read32(ip+1)))) {
            matchLength = ZSTD_count(ip+1+4, ip+1+4-offset_1, iend) + 4;
            if (depth==0) goto _storeSequence;
        }
 
        /* first search (depth 0) */
        {   size_t offsetFound = 999999999;
            size_t const ml2 = searchMax(ms, ip, iend, &offsetFound);
            if (ml2 > matchLength)
                matchLength = ml2, start = ip, offset=offsetFound;
        }
 
        if (matchLength < 4) {
            ip += ((ip-anchor) >> kSearchStrength) + 1;   /* jump faster over incompressible sections */
            continue;
        }
 
        /* let's try to find a better solution */
        if (depth>=1)
        while (ip<ilimit) {
            ip ++;
            if ( (dictMode == ZSTD_noDict)
              && (offset) && ((offset_1>0) & (MEM_read32(ip) == MEM_read32(ip - offset_1)))) {
                size_t const mlRep = ZSTD_count(ip+4, ip+4-offset_1, iend) + 4;
                int const gain2 = (int)(mlRep * 3);
                int const gain1 = (int)(matchLength*3 - ZSTD_highbit32((U32)offset+1) + 1);
                if ((mlRep >= 4) && (gain2 > gain1))
                    matchLength = mlRep, offset = 0, start = ip;
            }
            if (dictMode == ZSTD_dictMatchState) {
                const U32 repIndex = (U32)(ip - base) - offset_1;
                const BYTE* repMatch = repIndex < prefixLowestIndex ?
                               dictBase + (repIndex - dictIndexDelta) :
                               base + repIndex;
                if (((U32)((prefixLowestIndex-1) - repIndex) >= 3 /* intentional underflow */)
                    && (MEM_read32(repMatch) == MEM_read32(ip)) ) {
                    const BYTE* repMatchEnd = repIndex < prefixLowestIndex ? dictEnd : iend;
                    size_t const mlRep = ZSTD_count_2segments(ip+4, repMatch+4, iend, repMatchEnd, prefixLowest) + 4;
                    int const gain2 = (int)(mlRep * 3);
                    int const gain1 = (int)(matchLength*3 - ZSTD_highbit32((U32)offset+1) + 1);
                    if ((mlRep >= 4) && (gain2 > gain1))
                        matchLength = mlRep, offset = 0, start = ip;
                }
            }
            {   size_t offset2=999999999;
                size_t const ml2 = searchMax(ms, ip, iend, &offset2);
                int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)offset2+1));   /* raw approx */
                int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 4);
                if ((ml2 >= 4) && (gain2 > gain1)) {
                    matchLength = ml2, offset = offset2, start = ip;
                    continue;   /* search a better one */
            }   }
 
            /* let's find an even better one */
            if ((depth==2) && (ip<ilimit)) {
                ip ++;
                if ( (dictMode == ZSTD_noDict)
                  && (offset) && ((offset_1>0) & (MEM_read32(ip) == MEM_read32(ip - offset_1)))) {
                    size_t const mlRep = ZSTD_count(ip+4, ip+4-offset_1, iend) + 4;
                    int const gain2 = (int)(mlRep * 4);
                    int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 1);
                    if ((mlRep >= 4) && (gain2 > gain1))
                        matchLength = mlRep, offset = 0, start = ip;
                }
                if (dictMode == ZSTD_dictMatchState) {
                    const U32 repIndex = (U32)(ip - base) - offset_1;
                    const BYTE* repMatch = repIndex < prefixLowestIndex ?
                                   dictBase + (repIndex - dictIndexDelta) :
                                   base + repIndex;
                    if (((U32)((prefixLowestIndex-1) - repIndex) >= 3 /* intentional underflow */)
                        && (MEM_read32(repMatch) == MEM_read32(ip)) ) {
                        const BYTE* repMatchEnd = repIndex < prefixLowestIndex ? dictEnd : iend;
                        size_t const mlRep = ZSTD_count_2segments(ip+4, repMatch+4, iend, repMatchEnd, prefixLowest) + 4;
                        int const gain2 = (int)(mlRep * 4);
                        int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 1);
                        if ((mlRep >= 4) && (gain2 > gain1))
                            matchLength = mlRep, offset = 0, start = ip;
                    }
                }
                {   size_t offset2=999999999;
                    size_t const ml2 = searchMax(ms, ip, iend, &offset2);
                    int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)offset2+1));   /* raw approx */
                    int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 7);
                    if ((ml2 >= 4) && (gain2 > gain1)) {
                        matchLength = ml2, offset = offset2, start = ip;
                        continue;
            }   }   }
            break;  /* nothing found : store previous solution */
        }
 
        /* NOTE:
         * start[-offset+ZSTD_REP_MOVE-1] is undefined behavior.
         * (-offset+ZSTD_REP_MOVE-1) is unsigned, and is added to start, which
         * overflows the pointer, which is undefined behavior.
         */
        /* catch up */
        if (offset) {
            if (dictMode == ZSTD_noDict) {
                while ( ((start > anchor) & (start - (offset-ZSTD_REP_MOVE) > prefixLowest))
                     && (start[-1] == (start-(offset-ZSTD_REP_MOVE))[-1]) )  /* only search for offset within prefix */
                    { start--; matchLength++; }
            }
            if (dictMode == ZSTD_dictMatchState) {
                U32 const matchIndex = (U32)((start-base) - (offset - ZSTD_REP_MOVE));
                const BYTE* match = (matchIndex < prefixLowestIndex) ? dictBase + matchIndex - dictIndexDelta : base + matchIndex;
                const BYTE* const mStart = (matchIndex < prefixLowestIndex) ? dictLowest : prefixLowest;
                while ((start>anchor) && (match>mStart) && (start[-1] == match[-1])) { start--; match--; matchLength++; }  /* catch up */
            }
            offset_2 = offset_1; offset_1 = (U32)(offset - ZSTD_REP_MOVE);
        }
        /* store sequence */
_storeSequence:
        {   size_t const litLength = start - anchor;
            ZSTD_storeSeq(seqStore, litLength, anchor, iend, (U32)offset, matchLength-MINMATCH);
            anchor = ip = start + matchLength;
        }
 
        /* check immediate repcode */
        if (dictMode == ZSTD_dictMatchState) {
            while (ip <= ilimit) {
                U32 const current2 = (U32)(ip-base);
                U32 const repIndex = current2 - offset_2;
                const BYTE* repMatch = dictMode == ZSTD_dictMatchState
                    && repIndex < prefixLowestIndex ?
                        dictBase - dictIndexDelta + repIndex :
                        base + repIndex;
                if ( ((U32)((prefixLowestIndex-1) - (U32)repIndex) >= 3 /* intentional overflow */)
                   && (MEM_read32(repMatch) == MEM_read32(ip)) ) {
                    const BYTE* const repEnd2 = repIndex < prefixLowestIndex ? dictEnd : iend;
                    matchLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd2, prefixLowest) + 4;
                    offset = offset_2; offset_2 = offset_1; offset_1 = (U32)offset;   /* swap offset_2 <=> offset_1 */
                    ZSTD_storeSeq(seqStore, 0, anchor, iend, 0, matchLength-MINMATCH);
                    ip += matchLength;
                    anchor = ip;
                    continue;
                }
                break;
            }
        }
 
        if (dictMode == ZSTD_noDict) {
            while ( ((ip <= ilimit) & (offset_2>0))
                 && (MEM_read32(ip) == MEM_read32(ip - offset_2)) ) {
                /* store sequence */
                matchLength = ZSTD_count(ip+4, ip+4-offset_2, iend) + 4;
                offset = offset_2; offset_2 = offset_1; offset_1 = (U32)offset; /* swap repcodes */
                ZSTD_storeSeq(seqStore, 0, anchor, iend, 0, matchLength-MINMATCH);
                ip += matchLength;
                anchor = ip;
                continue;   /* faster when present ... (?) */
    }   }   }
 
    /* Save reps for next block */
    rep[0] = offset_1 ? offset_1 : savedOffset;
    rep[1] = offset_2 ? offset_2 : savedOffset;
 
    /* Return the last literals size */
    return (size_t)(iend - anchor);
}

Referenced by ZSTD_compressBlock_btlazy2(), ZSTD_compressBlock_btlazy2_dictMatchState(), ZSTD_compressBlock_greedy(), ZSTD_compressBlock_greedy_dictMatchState(), ZSTD_compressBlock_lazy(), ZSTD_compressBlock_lazy2(), ZSTD_compressBlock_lazy2_dictMatchState(), and ZSTD_compressBlock_lazy_dictMatchState().

ZSTD_DUBT_findBestMatch()

static size_t ZSTD_DUBT_findBestMatch ( ZSTD_matchState_t *  ms, const BYTE *const  ip, const BYTE *const  iend, size_t *  offsetPtr, U32 const  mls, const ZSTD_dictMode_e  dictMode  )

static

Definition at line 231 of file zstd_lazy.c.

{
    const ZSTD_compressionParameters* const cParams = &ms->cParams;
    U32*   const hashTable = ms->hashTable;
    U32    const hashLog = cParams->hashLog;
    size_t const h  = ZSTD_hashPtr(ip, hashLog, mls);
    U32          matchIndex  = hashTable[h];
 
    const BYTE* const base = ms->window.base;
    U32    const current = (U32)(ip-base);
    U32    const windowLow = ZSTD_getLowestMatchIndex(ms, current, cParams->windowLog);
 
    U32*   const bt = ms->chainTable;
    U32    const btLog  = cParams->chainLog - 1;
    U32    const btMask = (1 << btLog) - 1;
    U32    const btLow = (btMask >= current) ? 0 : current - btMask;
    U32    const unsortLimit = MAX(btLow, windowLow);
 
    U32*         nextCandidate = bt + 2*(matchIndex&btMask);
    U32*         unsortedMark = bt + 2*(matchIndex&btMask) + 1;
    U32          nbCompares = 1U << cParams->searchLog;
    U32          nbCandidates = nbCompares;
    U32          previousCandidate = 0;
 
    DEBUGLOG(7, "ZSTD_DUBT_findBestMatch (%u) ", current);
    assert(ip <= iend-8);   /* required for h calculation */
 
    /* reach end of unsorted candidates list */
    while ( (matchIndex > unsortLimit)
         && (*unsortedMark == ZSTD_DUBT_UNSORTED_MARK)
         && (nbCandidates > 1) ) {
        DEBUGLOG(8, "ZSTD_DUBT_findBestMatch: candidate %u is unsorted",
                    matchIndex);
        *unsortedMark = previousCandidate;  /* the unsortedMark becomes a reversed chain, to move up back to original position */
        previousCandidate = matchIndex;
        matchIndex = *nextCandidate;
        nextCandidate = bt + 2*(matchIndex&btMask);
        unsortedMark = bt + 2*(matchIndex&btMask) + 1;
        nbCandidates --;
    }
 
    /* nullify last candidate if it's still unsorted
     * simplification, detrimental to compression ratio, beneficial for speed */
    if ( (matchIndex > unsortLimit)
      && (*unsortedMark==ZSTD_DUBT_UNSORTED_MARK) ) {
        DEBUGLOG(7, "ZSTD_DUBT_findBestMatch: nullify last unsorted candidate %u",
                    matchIndex);
        *nextCandidate = *unsortedMark = 0;
    }
 
    /* batch sort stacked candidates */
    matchIndex = previousCandidate;
    while (matchIndex) {  /* will end on matchIndex == 0 */
        U32* const nextCandidateIdxPtr = bt + 2*(matchIndex&btMask) + 1;
        U32 const nextCandidateIdx = *nextCandidateIdxPtr;
        ZSTD_insertDUBT1(ms, matchIndex, iend,
                         nbCandidates, unsortLimit, dictMode);
        matchIndex = nextCandidateIdx;
        nbCandidates++;
    }
 
    /* find longest match */
    {   size_t commonLengthSmaller = 0, commonLengthLarger = 0;
        const BYTE* const dictBase = ms->window.dictBase;
        const U32 dictLimit = ms->window.dictLimit;
        const BYTE* const dictEnd = dictBase + dictLimit;
        const BYTE* const prefixStart = base + dictLimit;
        U32* smallerPtr = bt + 2*(current&btMask);
        U32* largerPtr  = bt + 2*(current&btMask) + 1;
        U32 matchEndIdx = current + 8 + 1;
        U32 dummy32;   /* to be nullified at the end */
        size_t bestLength = 0;
 
        matchIndex  = hashTable[h];
        hashTable[h] = current;   /* Update Hash Table */
 
        while (nbCompares-- && (matchIndex > windowLow)) {
            U32* const nextPtr = bt + 2*(matchIndex & btMask);
            size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger);   /* guaranteed minimum nb of common bytes */
            const BYTE* match;
 
            if ((dictMode != ZSTD_extDict) || (matchIndex+matchLength >= dictLimit)) {
                match = base + matchIndex;
                matchLength += ZSTD_count(ip+matchLength, match+matchLength, iend);
            } else {
                match = dictBase + matchIndex;
                matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iend, dictEnd, prefixStart);
                if (matchIndex+matchLength >= dictLimit)
                    match = base + matchIndex;   /* to prepare for next usage of match[matchLength] */
            }
 
            if (matchLength > bestLength) {
                if (matchLength > matchEndIdx - matchIndex)
                    matchEndIdx = matchIndex + (U32)matchLength;
                if ( (4*(int)(matchLength-bestLength)) > (int)(ZSTD_highbit32(current-matchIndex+1) - ZSTD_highbit32((U32)offsetPtr[0]+1)) )
                    bestLength = matchLength, *offsetPtr = ZSTD_REP_MOVE + current - matchIndex;
                if (ip+matchLength == iend) {   /* equal : no way to know if inf or sup */
                    if (dictMode == ZSTD_dictMatchState) {
                        nbCompares = 0; /* in addition to avoiding checking any
                                         * further in this loop, make sure we
                                         * skip checking in the dictionary. */
                    }
                    break;   /* drop, to guarantee consistency (miss a little bit of compression) */
                }
            }
 
            if (match[matchLength] < ip[matchLength]) {
                /* match is smaller than current */
                *smallerPtr = matchIndex;             /* update smaller idx */
                commonLengthSmaller = matchLength;    /* all smaller will now have at least this guaranteed common length */
                if (matchIndex <= btLow) { smallerPtr=&dummy32; break; }   /* beyond tree size, stop the search */
                smallerPtr = nextPtr+1;               /* new "smaller" => larger of match */
                matchIndex = nextPtr[1];              /* new matchIndex larger than previous (closer to current) */
            } else {
                /* match is larger than current */
                *largerPtr = matchIndex;
                commonLengthLarger = matchLength;
                if (matchIndex <= btLow) { largerPtr=&dummy32; break; }   /* beyond tree size, stop the search */
                largerPtr = nextPtr;
                matchIndex = nextPtr[0];
        }   }
 
        *smallerPtr = *largerPtr = 0;
 
        if (dictMode == ZSTD_dictMatchState && nbCompares) {
            bestLength = ZSTD_DUBT_findBetterDictMatch(
                    ms, ip, iend,
                    offsetPtr, bestLength, nbCompares,
                    mls, dictMode);
        }
 
        assert(matchEndIdx > current+8); /* ensure nextToUpdate is increased */
        ms->nextToUpdate = matchEndIdx - 8;   /* skip repetitive patterns */
        if (bestLength >= MINMATCH) {
            U32 const mIndex = current - ((U32)*offsetPtr - ZSTD_REP_MOVE); (void)mIndex;
            DEBUGLOG(8, "ZSTD_DUBT_findBestMatch(%u) : found match of length %u and offsetCode %u (pos %u)",
                        current, (U32)bestLength, (U32)*offsetPtr, mIndex);
        }
        return bestLength;
    }
}

Referenced by ZSTD_BtFindBestMatch().

ZSTD_DUBT_findBetterDictMatch()

static size_t ZSTD_DUBT_findBetterDictMatch ( ZSTD_matchState_t *  ms, const BYTE *const  ip, const BYTE *const  iend, size_t *  offsetPtr, size_t  bestLength, U32  nbCompares, U32 const  mls, const ZSTD_dictMode_e  dictMode  )

static

Definition at line 153 of file zstd_lazy.c.

{
    const ZSTD_matchState_t * const dms = ms->dictMatchState;
    const ZSTD_compressionParameters* const dmsCParams = &dms->cParams;
    const U32 * const dictHashTable = dms->hashTable;
    U32         const hashLog = dmsCParams->hashLog;
    size_t      const h  = ZSTD_hashPtr(ip, hashLog, mls);
    U32               dictMatchIndex = dictHashTable[h];
 
    const BYTE* const base = ms->window.base;
    const BYTE* const prefixStart = base + ms->window.dictLimit;
    U32         const current = (U32)(ip-base);
    const BYTE* const dictBase = dms->window.base;
    const BYTE* const dictEnd = dms->window.nextSrc;
    U32         const dictHighLimit = (U32)(dms->window.nextSrc - dms->window.base);
    U32         const dictLowLimit = dms->window.lowLimit;
    U32         const dictIndexDelta = ms->window.lowLimit - dictHighLimit;
 
    U32*        const dictBt = dms->chainTable;
    U32         const btLog  = dmsCParams->chainLog - 1;
    U32         const btMask = (1 << btLog) - 1;
    U32         const btLow = (btMask >= dictHighLimit - dictLowLimit) ? dictLowLimit : dictHighLimit - btMask;
 
    size_t commonLengthSmaller=0, commonLengthLarger=0;
 
    (void)dictMode;
    assert(dictMode == ZSTD_dictMatchState);
 
    while (nbCompares-- && (dictMatchIndex > dictLowLimit)) {
        U32* const nextPtr = dictBt + 2*(dictMatchIndex & btMask);
        size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger);   /* guaranteed minimum nb of common bytes */
        const BYTE* match = dictBase + dictMatchIndex;
        matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iend, dictEnd, prefixStart);
        if (dictMatchIndex+matchLength >= dictHighLimit)
            match = base + dictMatchIndex + dictIndexDelta;   /* to prepare for next usage of match[matchLength] */
 
        if (matchLength > bestLength) {
            U32 matchIndex = dictMatchIndex + dictIndexDelta;
            if ( (4*(int)(matchLength-bestLength)) > (int)(ZSTD_highbit32(current-matchIndex+1) - ZSTD_highbit32((U32)offsetPtr[0]+1)) ) {
                DEBUGLOG(9, "ZSTD_DUBT_findBetterDictMatch(%u) : found better match length %u -> %u and offsetCode %u -> %u (dictMatchIndex %u, matchIndex %u)",
                    current, (U32)bestLength, (U32)matchLength, (U32)*offsetPtr, ZSTD_REP_MOVE + current - matchIndex, dictMatchIndex, matchIndex);
                bestLength = matchLength, *offsetPtr = ZSTD_REP_MOVE + current - matchIndex;
            }
            if (ip+matchLength == iend) {   /* reached end of input : ip[matchLength] is not valid, no way to know if it's larger or smaller than match */
                break;   /* drop, to guarantee consistency (miss a little bit of compression) */
            }
        }
 
        if (match[matchLength] < ip[matchLength]) {
            if (dictMatchIndex <= btLow) { break; }   /* beyond tree size, stop the search */
            commonLengthSmaller = matchLength;    /* all smaller will now have at least this guaranteed common length */
            dictMatchIndex = nextPtr[1];              /* new matchIndex larger than previous (closer to current) */
        } else {
            /* match is larger than current */
            if (dictMatchIndex <= btLow) { break; }   /* beyond tree size, stop the search */
            commonLengthLarger = matchLength;
            dictMatchIndex = nextPtr[0];
        }
    }
 
    if (bestLength >= MINMATCH) {
        U32 const mIndex = current - ((U32)*offsetPtr - ZSTD_REP_MOVE); (void)mIndex;
        DEBUGLOG(8, "ZSTD_DUBT_findBetterDictMatch(%u) : found match of length %u and offsetCode %u (pos %u)",
                    current, (U32)bestLength, (U32)*offsetPtr, mIndex);
    }
    return bestLength;
 
}

Referenced by ZSTD_DUBT_findBestMatch().

ZSTD_HcFindBestMatch_dictMatchState_selectMLS()

static size_t ZSTD_HcFindBestMatch_dictMatchState_selectMLS ( ZSTD_matchState_t *  ms, const BYTE *  ip, const BYTE *const  iLimit, size_t *  offsetPtr  )

static

Definition at line 587 of file zstd_lazy.c.

{
    switch(ms->cParams.minMatch)
    {
    default : /* includes case 3 */
    case 4 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 4, ZSTD_dictMatchState);
    case 5 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 5, ZSTD_dictMatchState);
    case 7 :
    case 6 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 6, ZSTD_dictMatchState);
    }
}

Referenced by ZSTD_compressBlock_lazy_generic().

ZSTD_HcFindBestMatch_extDict_selectMLS()

FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_extDict_selectMLS	(	ZSTD_matchState_t *	ms,
		const BYTE *	ip,
		const BYTE *const	iLimit,
		size_t *	offsetPtr
	)

Definition at line 603 of file zstd_lazy.c.

{
    switch(ms->cParams.minMatch)
    {
    default : /* includes case 3 */
    case 4 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 4, ZSTD_extDict);
    case 5 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 5, ZSTD_extDict);
    case 7 :
    case 6 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 6, ZSTD_extDict);
    }
}

Referenced by ZSTD_compressBlock_lazy_extDict_generic().

ZSTD_HcFindBestMatch_generic()

FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_generic	(	ZSTD_matchState_t *	ms,
		const BYTE *const	ip,
		const BYTE *const	iLimit,
		size_t *	offsetPtr,
		const U32	mls,
		const ZSTD_dictMode_e	dictMode
	)

Definition at line 481 of file zstd_lazy.c.

{
    const ZSTD_compressionParameters* const cParams = &ms->cParams;
    U32* const chainTable = ms->chainTable;
    const U32 chainSize = (1 << cParams->chainLog);
    const U32 chainMask = chainSize-1;
    const BYTE* const base = ms->window.base;
    const BYTE* const dictBase = ms->window.dictBase;
    const U32 dictLimit = ms->window.dictLimit;
    const BYTE* const prefixStart = base + dictLimit;
    const BYTE* const dictEnd = dictBase + dictLimit;
    const U32 current = (U32)(ip-base);
    const U32 maxDistance = 1U << cParams->windowLog;
    const U32 lowestValid = ms->window.lowLimit;
    const U32 withinMaxDistance = (current - lowestValid > maxDistance) ? current - maxDistance : lowestValid;
    const U32 isDictionary = (ms->loadedDictEnd != 0);
    const U32 lowLimit = isDictionary ? lowestValid : withinMaxDistance;
    const U32 minChain = current > chainSize ? current - chainSize : 0;
    U32 nbAttempts = 1U << cParams->searchLog;
    size_t ml=4-1;
 
    /* HC4 match finder */
    U32 matchIndex = ZSTD_insertAndFindFirstIndex_internal(ms, cParams, ip, mls);
 
    for ( ; (matchIndex>lowLimit) & (nbAttempts>0) ; nbAttempts--) {
        size_t currentMl=0;
        if ((dictMode != ZSTD_extDict) || matchIndex >= dictLimit) {
            const BYTE* const match = base + matchIndex;
            assert(matchIndex >= dictLimit);   /* ensures this is true if dictMode != ZSTD_extDict */
            if (match[ml] == ip[ml])   /* potentially better */
                currentMl = ZSTD_count(ip, match, iLimit);
        } else {
            const BYTE* const match = dictBase + matchIndex;
            assert(match+4 <= dictEnd);
            if (MEM_read32(match) == MEM_read32(ip))   /* assumption : matchIndex <= dictLimit-4 (by table construction) */
                currentMl = ZSTD_count_2segments(ip+4, match+4, iLimit, dictEnd, prefixStart) + 4;
        }
 
        /* save best solution */
        if (currentMl > ml) {
            ml = currentMl;
            *offsetPtr = current - matchIndex + ZSTD_REP_MOVE;
            if (ip+currentMl == iLimit) break; /* best possible, avoids read overflow on next attempt */
        }
 
        if (matchIndex <= minChain) break;
        matchIndex = NEXT_IN_CHAIN(matchIndex, chainMask);
    }
 
    if (dictMode == ZSTD_dictMatchState) {
        const ZSTD_matchState_t* const dms = ms->dictMatchState;
        const U32* const dmsChainTable = dms->chainTable;
        const U32 dmsChainSize         = (1 << dms->cParams.chainLog);
        const U32 dmsChainMask         = dmsChainSize - 1;
        const U32 dmsLowestIndex       = dms->window.dictLimit;
        const BYTE* const dmsBase      = dms->window.base;
        const BYTE* const dmsEnd       = dms->window.nextSrc;
        const U32 dmsSize              = (U32)(dmsEnd - dmsBase);
        const U32 dmsIndexDelta        = dictLimit - dmsSize;
        const U32 dmsMinChain = dmsSize > dmsChainSize ? dmsSize - dmsChainSize : 0;
 
        matchIndex = dms->hashTable[ZSTD_hashPtr(ip, dms->cParams.hashLog, mls)];
 
        for ( ; (matchIndex>dmsLowestIndex) & (nbAttempts>0) ; nbAttempts--) {
            size_t currentMl=0;
            const BYTE* const match = dmsBase + matchIndex;
            assert(match+4 <= dmsEnd);
            if (MEM_read32(match) == MEM_read32(ip))   /* assumption : matchIndex <= dictLimit-4 (by table construction) */
                currentMl = ZSTD_count_2segments(ip+4, match+4, iLimit, dmsEnd, prefixStart) + 4;
 
            /* save best solution */
            if (currentMl > ml) {
                ml = currentMl;
                *offsetPtr = current - (matchIndex + dmsIndexDelta) + ZSTD_REP_MOVE;
                if (ip+currentMl == iLimit) break; /* best possible, avoids read overflow on next attempt */
            }
 
            if (matchIndex <= dmsMinChain) break;
            matchIndex = dmsChainTable[matchIndex & dmsChainMask];
        }
    }
 
    return ml;
}

Referenced by ZSTD_HcFindBestMatch_dictMatchState_selectMLS(), ZSTD_HcFindBestMatch_extDict_selectMLS(), and ZSTD_HcFindBestMatch_selectMLS().

ZSTD_HcFindBestMatch_selectMLS()

FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_selectMLS	(	ZSTD_matchState_t *	ms,
		const BYTE *	ip,
		const BYTE *const	iLimit,
		size_t *	offsetPtr
	)

Definition at line 571 of file zstd_lazy.c.

{
    switch(ms->cParams.minMatch)
    {
    default : /* includes case 3 */
    case 4 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 4, ZSTD_noDict);
    case 5 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 5, ZSTD_noDict);
    case 7 :
    case 6 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 6, ZSTD_noDict);
    }
}

Referenced by ZSTD_compressBlock_lazy_generic().

ZSTD_insertAndFindFirstIndex()

U32 ZSTD_insertAndFindFirstIndex	(	ZSTD_matchState_t *	ms,
		const BYTE *	ip
	)

Definition at line 473 of file zstd_lazy.c.

                                                                        {
    const ZSTD_compressionParameters* const cParams = &ms->cParams;
    return ZSTD_insertAndFindFirstIndex_internal(ms, cParams, ip, ms->cParams.minMatch);
}

Referenced by ZSTD_loadDictionaryContent().

ZSTD_insertAndFindFirstIndex_internal()

static U32 ZSTD_insertAndFindFirstIndex_internal ( ZSTD_matchState_t *  ms, const ZSTD_compressionParameters *const  cParams, const BYTE *  ip, U32 const  mls  )

static

Definition at line 449 of file zstd_lazy.c.

{
    U32* const hashTable  = ms->hashTable;
    const U32 hashLog = cParams->hashLog;
    U32* const chainTable = ms->chainTable;
    const U32 chainMask = (1 << cParams->chainLog) - 1;
    const BYTE* const base = ms->window.base;
    const U32 target = (U32)(ip - base);
    U32 idx = ms->nextToUpdate;
 
    while(idx < target) { /* catch up */
        size_t const h = ZSTD_hashPtr(base+idx, hashLog, mls);
        NEXT_IN_CHAIN(idx, chainMask) = hashTable[h];
        hashTable[h] = idx;
        idx++;
    }
 
    ms->nextToUpdate = target;
    return hashTable[ZSTD_hashPtr(ip, hashLog, mls)];
}

Referenced by ZSTD_HcFindBestMatch_generic(), and ZSTD_insertAndFindFirstIndex().

ZSTD_insertDUBT1()

static void ZSTD_insertDUBT1 ( ZSTD_matchState_t *  ms, U32  current, const BYTE *  inputEnd, U32  nbCompares, U32  btLow, const ZSTD_dictMode_e  dictMode  )

static

ZSTD_insertDUBT1() : sort one already inserted but unsorted position assumption : current >= btlow == (current - btmask) doesn't fail

Definition at line 64 of file zstd_lazy.c.

{
    const ZSTD_compressionParameters* const cParams = &ms->cParams;
    U32* const bt = ms->chainTable;
    U32  const btLog  = cParams->chainLog - 1;
    U32  const btMask = (1 << btLog) - 1;
    size_t commonLengthSmaller=0, commonLengthLarger=0;
    const BYTE* const base = ms->window.base;
    const BYTE* const dictBase = ms->window.dictBase;
    const U32 dictLimit = ms->window.dictLimit;
    const BYTE* const ip = (current>=dictLimit) ? base + current : dictBase + current;
    const BYTE* const iend = (current>=dictLimit) ? inputEnd : dictBase + dictLimit;
    const BYTE* const dictEnd = dictBase + dictLimit;
    const BYTE* const prefixStart = base + dictLimit;
    const BYTE* match;
    U32* smallerPtr = bt + 2*(current&btMask);
    U32* largerPtr  = smallerPtr + 1;
    U32 matchIndex = *smallerPtr;   /* this candidate is unsorted : next sorted candidate is reached through *smallerPtr, while *largerPtr contains previous unsorted candidate (which is already saved and can be overwritten) */
    U32 dummy32;   /* to be nullified at the end */
    U32 const windowValid = ms->window.lowLimit;
    U32 const maxDistance = 1U << cParams->windowLog;
    U32 const windowLow = (current - windowValid > maxDistance) ? current - maxDistance : windowValid;
 
 
    DEBUGLOG(8, "ZSTD_insertDUBT1(%u) (dictLimit=%u, lowLimit=%u)",
                current, dictLimit, windowLow);
    assert(current >= btLow);
    assert(ip < iend);   /* condition for ZSTD_count */
 
    while (nbCompares-- && (matchIndex > windowLow)) {
        U32* const nextPtr = bt + 2*(matchIndex & btMask);
        size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger);   /* guaranteed minimum nb of common bytes */
        assert(matchIndex < current);
        /* note : all candidates are now supposed sorted,
         * but it's still possible to have nextPtr[1] == ZSTD_DUBT_UNSORTED_MARK
         * when a real index has the same value as ZSTD_DUBT_UNSORTED_MARK */
 
        if ( (dictMode != ZSTD_extDict)
          || (matchIndex+matchLength >= dictLimit)  /* both in current segment*/
          || (current < dictLimit) /* both in extDict */) {
            const BYTE* const mBase = ( (dictMode != ZSTD_extDict)
                                     || (matchIndex+matchLength >= dictLimit)) ?
                                        base : dictBase;
            assert( (matchIndex+matchLength >= dictLimit)   /* might be wrong if extDict is incorrectly set to 0 */
                 || (current < dictLimit) );
            match = mBase + matchIndex;
            matchLength += ZSTD_count(ip+matchLength, match+matchLength, iend);
        } else {
            match = dictBase + matchIndex;
            matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iend, dictEnd, prefixStart);
            if (matchIndex+matchLength >= dictLimit)
                match = base + matchIndex;   /* preparation for next read of match[matchLength] */
        }
 
        DEBUGLOG(8, "ZSTD_insertDUBT1: comparing %u with %u : found %u common bytes ",
                    current, matchIndex, (U32)matchLength);
 
        if (ip+matchLength == iend) {   /* equal : no way to know if inf or sup */
            break;   /* drop , to guarantee consistency ; miss a bit of compression, but other solutions can corrupt tree */
        }
 
        if (match[matchLength] < ip[matchLength]) {  /* necessarily within buffer */
            /* match is smaller than current */
            *smallerPtr = matchIndex;             /* update smaller idx */
            commonLengthSmaller = matchLength;    /* all smaller will now have at least this guaranteed common length */
            if (matchIndex <= btLow) { smallerPtr=&dummy32; break; }   /* beyond tree size, stop searching */
            DEBUGLOG(8, "ZSTD_insertDUBT1: %u (>btLow=%u) is smaller : next => %u",
                        matchIndex, btLow, nextPtr[1]);
            smallerPtr = nextPtr+1;               /* new "candidate" => larger than match, which was smaller than target */
            matchIndex = nextPtr[1];              /* new matchIndex, larger than previous and closer to current */
        } else {
            /* match is larger than current */
            *largerPtr = matchIndex;
            commonLengthLarger = matchLength;
            if (matchIndex <= btLow) { largerPtr=&dummy32; break; }   /* beyond tree size, stop searching */
            DEBUGLOG(8, "ZSTD_insertDUBT1: %u (>btLow=%u) is larger => %u",
                        matchIndex, btLow, nextPtr[0]);
            largerPtr = nextPtr;
            matchIndex = nextPtr[0];
    }   }
 
    *smallerPtr = *largerPtr = 0;
}

Referenced by ZSTD_DUBT_findBestMatch().

ZSTD_updateDUBT()

static void ZSTD_updateDUBT ( ZSTD_matchState_t *  ms, const BYTE *  ip, const BYTE *  iend, U32  mls  )

static

Definition at line 20 of file zstd_lazy.c.

{
    const ZSTD_compressionParameters* const cParams = &ms->cParams;
    U32* const hashTable = ms->hashTable;
    U32  const hashLog = cParams->hashLog;
 
    U32* const bt = ms->chainTable;
    U32  const btLog  = cParams->chainLog - 1;
    U32  const btMask = (1 << btLog) - 1;
 
    const BYTE* const base = ms->window.base;
    U32 const target = (U32)(ip - base);
    U32 idx = ms->nextToUpdate;
 
    if (idx != target)
        DEBUGLOG(7, "ZSTD_updateDUBT, from %u to %u (dictLimit:%u)",
                    idx, target, ms->window.dictLimit);
    assert(ip + 8 <= iend);   /* condition for ZSTD_hashPtr */
    (void)iend;
 
    assert(idx >= ms->window.dictLimit);   /* condition for valid base+idx */
    for ( ; idx < target ; idx++) {
        size_t const h  = ZSTD_hashPtr(base + idx, hashLog, mls);   /* assumption : ip + 8 <= iend */
        U32    const matchIndex = hashTable[h];
 
        U32*   const nextCandidatePtr = bt + 2*(idx&btMask);
        U32*   const sortMarkPtr  = nextCandidatePtr + 1;
 
        DEBUGLOG(8, "ZSTD_updateDUBT: insert %u", idx);
        hashTable[h] = idx;   /* Update Hash Table */
        *nextCandidatePtr = matchIndex;   /* update BT like a chain */
        *sortMarkPtr = ZSTD_DUBT_UNSORTED_MARK;
    }
    ms->nextToUpdate = target;
}

Referenced by ZSTD_BtFindBestMatch().