trgm.h File Reference

#include "access/gist.h"
#include "access/itup.h"
#include "storage/bufpage.h"

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Data Structures
struct	TRGM

Macros
#define	LPADDING   2
#define	RPADDING   1
#define	KEEPONLYALNUM
#define	IGNORECASE
#define	DIVUNION
#define	SimilarityStrategyNumber   1
#define	DistanceStrategyNumber   2
#define	LikeStrategyNumber   3
#define	ILikeStrategyNumber   4
#define	RegExpStrategyNumber   5
#define	RegExpICaseStrategyNumber   6
#define	WordSimilarityStrategyNumber   7
#define	WordDistanceStrategyNumber   8
#define	CMPCHAR(a, b)   ( ((a)==(b)) ? 0 : ( ((a)<(b)) ? -1 : 1 ) )
#define	CMPPCHAR(a, b, i)   CMPCHAR( *(((const char*)(a))+i), *(((const char*)(b))+i) )
#define	CMPTRGM(a, b)   ( CMPPCHAR(a,b,0) ? CMPPCHAR(a,b,0) : ( CMPPCHAR(a,b,1) ? CMPPCHAR(a,b,1) : CMPPCHAR(a,b,2) ) )
#define	CPTRGM(a, b)
#define	ISWORDCHR(c)   (t_isalpha(c) || t_isdigit(c))
#define	ISPRINTABLECHAR(a)   ( isascii( *(unsigned char*)(a) ) && (isalnum( *(unsigned char*)(a) ) || *(unsigned char*)(a)==' ') )
#define	ISPRINTABLETRGM(t)   ( ISPRINTABLECHAR( ((char*)(t)) ) && ISPRINTABLECHAR( ((char*)(t))+1 ) && ISPRINTABLECHAR( ((char*)(t))+2 ) )
#define	ISESCAPECHAR(x)   (*(x) == '\\') /* Wildcard escape character */
#define	ISWILDCARDCHAR(x)
#define	TRGMHDRSIZE   (VARHDRSZ + sizeof(uint8))
#define	BITBYTE   8
#define	SIGLENINT   3 /* >122 => key will toast, so very slow!!! */
#define	SIGLEN   ( sizeof(int)*SIGLENINT )
#define	SIGLENBIT   (SIGLEN*BITBYTE - 1) /* see makesign */
#define	LOOPBYTE   for(i=0;i<SIGLEN;i++)
#define	GETBYTE(x, i)   ( *( (BITVECP)(x) + (int)( (i) / BITBYTE ) ) )
#define	GETBITBYTE(x, i)   ( (((char)(x)) >> (i)) & 0x01 )
#define	CLRBIT(x, i)   GETBYTE(x,i) &= ~( 0x01 << ( (i) % BITBYTE ) )
#define	SETBIT(x, i)   GETBYTE(x,i) |= ( 0x01 << ( (i) % BITBYTE ) )
#define	GETBIT(x, i)   ( (GETBYTE(x,i) >> ( (i) % BITBYTE )) & 0x01 )
#define	HASHVAL(val)   (((unsigned int)(val)) % SIGLENBIT)
#define	HASH(sign, val)   SETBIT((sign), HASHVAL(val))
#define	ARRKEY   0x01
#define	SIGNKEY   0x02
#define	ALLISTRUE   0x04
#define	ISARRKEY(x)   ( ((TRGM*)x)->flag & ARRKEY )
#define	ISSIGNKEY(x)   ( ((TRGM*)x)->flag & SIGNKEY )
#define	ISALLTRUE(x)   ( ((TRGM*)x)->flag & ALLISTRUE )
#define	CALCGTSIZE(flag, len)   ( TRGMHDRSIZE + ( ( (flag) & ARRKEY ) ? ((len)*sizeof(trgm)) : (((flag) & ALLISTRUE) ? 0 : SIGLEN) ) )
#define	GETSIGN(x)   ( (BITVECP)( (char*)x+TRGMHDRSIZE ) )
#define	GETARR(x)   ( (trgm*)( (char*)x+TRGMHDRSIZE ) )
#define	ARRNELEM(x)   ( ( VARSIZE(x) - TRGMHDRSIZE )/sizeof(trgm) )
#define	CALCSML(count, len1, len2)   ((float4) (count)) / ((float4) ((len1) + (len2) - (count)))

Typedefs
typedef char	trgm [3]
typedef char	BITVEC [SIGLEN]
typedef char *	BITVECP
typedef struct TrgmPackedGraph	TrgmPackedGraph

Functions
uint32	trgm2int (trgm *ptr)
void	compact_trigram (trgm *tptr, char *str, int bytelen)
TRGM *	generate_trgm (char *str, int slen)
TRGM *	generate_wildcard_trgm (const char *str, int slen)
float4	cnt_sml (TRGM *trg1, TRGM *trg2, bool inexact)
bool	trgm_contained_by (TRGM *trg1, TRGM *trg2)
bool *	trgm_presence_map (TRGM *query, TRGM *key)
TRGM *	createTrgmNFA (text *text_re, Oid collation, TrgmPackedGraph **graph, MemoryContext rcontext)
bool	trigramsMatchGraph (TrgmPackedGraph *graph, bool *check)

Variables
double	similarity_threshold
double	word_similarity_threshold

Macro Definition Documentation

#define ALLISTRUE   0x04

Definition at line 96 of file trgm.h.

#define ARRKEY   0x01

Definition at line 94 of file trgm.h.

Referenced by expandColorTrigrams(), generate_trgm(), and generate_wildcard_trgm().

#define ARRNELEM

(

x

)

( ( VARSIZE(x) - TRGMHDRSIZE )/sizeof(trgm) )

Definition at line 105 of file trgm.h.

Referenced by cnt_sml(), cnt_sml_sign_common(), gin_extract_query_trgm(), gin_extract_value_trgm(), gtrgm_consistent(), gtrgm_distance(), gtrgm_same(), makesign(), show_trgm(), trgm_contained_by(), trgm_presence_map(), and unionkey().

#define BITBYTE   8

Definition at line 73 of file trgm.h.

#define CALCGTSIZE	(		flag,
			len
	)		( TRGMHDRSIZE + ( ( (flag) & ARRKEY ) ? ((len)*sizeof(trgm)) : (((flag) & ALLISTRUE) ? 0 : SIGLEN) ) )

Definition at line 102 of file trgm.h.

#define CALCSML	(		count,
			len1,
			len2
	)		((float4) (count)) / ((float4) ((len1) + (len2) - (count)))

Definition at line 114 of file trgm.h.

Referenced by cnt_sml(), and iterate_word_similarity().

#define CLRBIT	(		x,
			i
	)		GETBYTE(x,i) &= ~( 0x01 << ( (i) % BITBYTE ) )

Definition at line 87 of file trgm.h.

#define CMPCHAR	(		a,
			b
	)		( ((a)==(b)) ? 0 : ( ((a)<(b)) ? -1 : 1 ) )

Definition at line 40 of file trgm.h.

#define CMPPCHAR	(		a,
			b,
			i
	)		CMPCHAR( *(((const char*)(a))+i), *(((const char*)(b))+i) )

Definition at line 41 of file trgm.h.

#define CMPTRGM	(		a,
			b
	)		( CMPPCHAR(a,b,0) ? CMPPCHAR(a,b,0) : ( CMPPCHAR(a,b,1) ? CMPPCHAR(a,b,1) : CMPPCHAR(a,b,2) ) )

Definition at line 42 of file trgm.h.

Referenced by calc_word_similarity(), cnt_sml(), comp_ptrgm(), comp_trgm(), gtrgm_same(), trgm_contained_by(), trgm_presence_map(), and unique_array().

#define CPTRGM	(		a,
			b
	)

Value:

do {                \
    *(((char*)(a))+0) = *(((char*)(b))+0);  \
    *(((char*)(a))+1) = *(((char*)(b))+1);  \
    *(((char*)(a))+2) = *(((char*)(b))+2);  \
} while(0);

Definition at line 44 of file trgm.h.

Referenced by cnt_sml_sign_common(), compact_trigram(), gtrgm_consistent(), make_trigrams(), makesign(), show_trgm(), unionkey(), and unique_array().

#define DistanceStrategyNumber   2

Definition at line 30 of file trgm.h.

Referenced by gtrgm_distance().

#define DIVUNION

Definition at line 26 of file trgm.h.

#define GETARR

(

x

)

( (trgm*)( (char*)x+TRGMHDRSIZE ) )

Definition at line 104 of file trgm.h.

Referenced by cnt_sml(), cnt_sml_sign_common(), expandColorTrigrams(), generate_trgm(), generate_wildcard_trgm(), gin_extract_query_trgm(), gin_extract_value_trgm(), gtrgm_consistent(), gtrgm_same(), makesign(), show_trgm(), trgm_contained_by(), trgm_presence_map(), and unionkey().

#define GETBIT	(		x,
			i
	)		( (GETBYTE(x,i) >> ( (i) % BITBYTE )) & 0x01 )

Definition at line 89 of file trgm.h.

#define GETBITBYTE	(		x,
			i
	)		( (((char)(x)) >> (i)) & 0x01 )

Definition at line 86 of file trgm.h.

#define GETBYTE	(		x,
			i
	)		( *( (BITVECP)(x) + (int)( (i) / BITBYTE ) ) )

Definition at line 85 of file trgm.h.

#define GETSIGN

(

x

)

( (BITVECP)( (char*)x+TRGMHDRSIZE ) )

Definition at line 103 of file trgm.h.

#define HASH	(		sign,
			val
	)		SETBIT((sign), HASHVAL(val))

Definition at line 92 of file trgm.h.

#define HASHVAL

(

val

)

(((unsigned int)(val)) % SIGLENBIT)

Definition at line 91 of file trgm.h.

#define IGNORECASE

Definition at line 25 of file trgm.h.

#define ILikeStrategyNumber   4

Definition at line 32 of file trgm.h.

Referenced by gin_extract_query_trgm(), gin_trgm_consistent(), gin_trgm_triconsistent(), and gtrgm_consistent().

#define ISALLTRUE

(

x

)

( ((TRGM*)x)->flag & ALLISTRUE )

Definition at line 100 of file trgm.h.

#define ISARRKEY

(

x

)

( ((TRGM*)x)->flag & ARRKEY )

Definition at line 98 of file trgm.h.

Referenced by fillcache(), and gtrgm_penalty().

#define ISESCAPECHAR

(

x

)

(*(x) == '\\') /* Wildcard escape character */

Definition at line 59 of file trgm.h.

Referenced by get_wildcard_part().

#define ISPRINTABLECHAR

(

a

)

( isascii( *(unsigned char*)(a) ) && (isalnum( *(unsigned char*)(a) ) || *(unsigned char*)(a)==' ') )

Definition at line 52 of file trgm.h.

#define ISPRINTABLETRGM

(

t

)

( ISPRINTABLECHAR( ((char*)(t)) ) && ISPRINTABLECHAR( ((char*)(t))+1 ) && ISPRINTABLECHAR( ((char*)(t))+2 ) )

Definition at line 57 of file trgm.h.

Referenced by show_trgm().

#define ISSIGNKEY

(

x

)

( ((TRGM*)x)->flag & SIGNKEY )

Definition at line 99 of file trgm.h.

Referenced by gtrgm_compress(), gtrgm_same(), and unionkey().

#define ISWILDCARDCHAR

(

x

)

Value:

(*(x) == '_' || *(x) == '%')    /* Wildcard
                                                         * meta-character */

Definition at line 60 of file trgm.h.

Referenced by get_wildcard_part().

#define ISWORDCHR

(

c

)

(t_isalpha(c) || t_isdigit(c))

Definition at line 51 of file trgm.h.

Referenced by find_word(), get_wildcard_part(), and getColorInfo().

#define KEEPONLYALNUM

Definition at line 17 of file trgm.h.

#define LikeStrategyNumber   3

Definition at line 31 of file trgm.h.

Referenced by gin_extract_query_trgm(), gin_trgm_consistent(), gin_trgm_triconsistent(), and gtrgm_consistent().

#define LOOPBYTE   for(i=0;i<SIGLEN;i++)

Definition at line 82 of file trgm.h.

#define LPADDING   2

Definition at line 15 of file trgm.h.

Referenced by generate_trgm_only(), generate_wildcard_trgm(), and get_wildcard_part().

#define RegExpICaseStrategyNumber   6

Definition at line 34 of file trgm.h.

Referenced by gin_extract_query_trgm(), gin_trgm_consistent(), gin_trgm_triconsistent(), and gtrgm_consistent().

#define RegExpStrategyNumber   5

Definition at line 33 of file trgm.h.

Referenced by gin_extract_query_trgm(), gin_trgm_consistent(), gin_trgm_triconsistent(), and gtrgm_consistent().

#define RPADDING   1

Definition at line 16 of file trgm.h.

Referenced by generate_trgm_only(), generate_wildcard_trgm(), and get_wildcard_part().

#define SETBIT	(		x,
			i
	)		GETBYTE(x,i) |= ( 0x01 << ( (i) % BITBYTE ) )

Definition at line 88 of file trgm.h.

#define SIGLEN   ( sizeof(int)*SIGLENINT )

Definition at line 75 of file trgm.h.

#define SIGLENBIT   (SIGLEN*BITBYTE - 1) /* see makesign */

Definition at line 77 of file trgm.h.

#define SIGLENINT   3 /* >122 => key will toast, so very slow!!! */

Definition at line 74 of file trgm.h.

#define SIGNKEY   0x02

Definition at line 95 of file trgm.h.

Referenced by gtrgm_compress(), gtrgm_picksplit(), and gtrgm_union().

#define SimilarityStrategyNumber   1

Definition at line 29 of file trgm.h.

Referenced by gin_extract_query_trgm(), gin_trgm_consistent(), gin_trgm_triconsistent(), and gtrgm_consistent().

#define TRGMHDRSIZE   (VARHDRSZ + sizeof(uint8))

Definition at line 70 of file trgm.h.

Referenced by expandColorTrigrams(), generate_trgm(), and generate_wildcard_trgm().

#define WordDistanceStrategyNumber   8

Definition at line 36 of file trgm.h.

Referenced by gtrgm_distance().

#define WordSimilarityStrategyNumber   7

Definition at line 35 of file trgm.h.

Referenced by gin_extract_query_trgm(), gin_trgm_consistent(), gin_trgm_triconsistent(), and gtrgm_consistent().

Typedef Documentation

typedef char BITVEC[SIGLEN]

Definition at line 79 of file trgm.h.

typedef char* BITVECP

Definition at line 80 of file trgm.h.

typedef char trgm[3]

Definition at line 38 of file trgm.h.

typedef struct TrgmPackedGraph TrgmPackedGraph

Definition at line 119 of file trgm.h.

Function Documentation

float4 cnt_sml	(	TRGM *	trg1,
		TRGM *	trg2,
		bool	inexact
	)

Definition at line 928 of file trgm_op.c.

References ARRNELEM, CALCSML, CMPTRGM, and GETARR.

Referenced by gtrgm_consistent(), gtrgm_distance(), and similarity().

{
    trgm       *ptr1,
               *ptr2;
    int         count = 0;
    int         len1,
                len2;

    ptr1 = GETARR(trg1);
    ptr2 = GETARR(trg2);

    len1 = ARRNELEM(trg1);
    len2 = ARRNELEM(trg2);

    /* explicit test is needed to avoid 0/0 division when both lengths are 0 */
    if (len1 <= 0 || len2 <= 0)
        return (float4) 0.0;

    while (ptr1 - GETARR(trg1) < len1 && ptr2 - GETARR(trg2) < len2)
    {
        int         res = CMPTRGM(ptr1, ptr2);

        if (res < 0)
            ptr1++;
        else if (res > 0)
            ptr2++;
        else
        {
            ptr1++;
            ptr2++;
            count++;
        }
    }

    /*
     * If inexact then len2 is equal to count, because we don't know actual
     * length of second string in inexact search and we can assume that count
     * is a lower bound of len2.
     */
    return CALCSML(count, len1, inexact ? count : len2);
}

void compact_trigram	(	trgm *	tptr,
		char *	str,
		int	bytelen
	)

Definition at line 166 of file trgm_op.c.

References COMP_LEGACY_CRC32, CPTRGM, FIN_LEGACY_CRC32, and INIT_LEGACY_CRC32.

Referenced by fillTrgm(), and make_trigrams().

{
    if (bytelen == 3)
    {
        CPTRGM(tptr, str);
    }
    else
    {
        pg_crc32    crc;

        INIT_LEGACY_CRC32(crc);
        COMP_LEGACY_CRC32(crc, str, bytelen);
        FIN_LEGACY_CRC32(crc);

        /*
         * use only 3 upper bytes from crc, hope, it's good enough hashing
         */
        CPTRGM(tptr, &crc);
    }
}

TRGM* createTrgmNFA	(	text *	text_re,
		Oid	collation,
		TrgmPackedGraph **	graph,
		MemoryContext	rcontext
	)

Definition at line 523 of file trgm_regexp.c.

References ALLOCSET_DEFAULT_SIZES, AllocSetContextCreate(), createTrgmNFAInternal(), CurrentMemoryContext, MemoryContextDelete(), MemoryContextSwitchTo(), PG_CATCH, PG_END_TRY, PG_RE_THROW, pg_regfree(), PG_TRY, RE_compile(), REG_ADVANCED, and REG_ICASE.

Referenced by gin_extract_query_trgm(), and gtrgm_consistent().

{
    TRGM       *trg;
    regex_t     regex;
    MemoryContext tmpcontext;
    MemoryContext oldcontext;

    /*
     * This processing generates a great deal of cruft, which we'd like to
     * clean up before returning (since this function may be called in a
     * query-lifespan memory context).  Make a temp context we can work in so
     * that cleanup is easy.
     */
    tmpcontext = AllocSetContextCreate(CurrentMemoryContext,
                                       "createTrgmNFA temporary context",
                                       ALLOCSET_DEFAULT_SIZES);
    oldcontext = MemoryContextSwitchTo(tmpcontext);

    /*
     * Stage 1: Compile the regexp into a NFA, using the regexp library.
     */
#ifdef IGNORECASE
    RE_compile(&regex, text_re, REG_ADVANCED | REG_ICASE, collation);
#else
    RE_compile(&regex, text_re, REG_ADVANCED, collation);
#endif

    /*
     * Since the regexp library allocates its internal data structures with
     * malloc, we need to use a PG_TRY block to ensure that pg_regfree() gets
     * done even if there's an error.
     */
    PG_TRY();
    {
        trg = createTrgmNFAInternal(&regex, graph, rcontext);
    }
    PG_CATCH();
    {
        pg_regfree(&regex);
        PG_RE_THROW();
    }
    PG_END_TRY();

    pg_regfree(&regex);

    /* Clean up all the cruft we created */
    MemoryContextSwitchTo(oldcontext);
    MemoryContextDelete(tmpcontext);

    return trg;
}

TRGM* generate_trgm	(	char *	str,
		int	slen
	)

Definition at line 321 of file trgm_op.c.

References ARRKEY, CALCGTSIZE, comp_trgm(), TRGM::flag, generate_trgm_only(), GETARR, palloc(), protect_out_of_mem(), qsort, SET_VARSIZE, TRGMHDRSIZE, and unique_array().

Referenced by gin_extract_query_trgm(), gin_extract_value_trgm(), gtrgm_compress(), gtrgm_consistent(), gtrgm_distance(), show_trgm(), and similarity().

{
    TRGM       *trg;
    int         len;

    protect_out_of_mem(slen);

    trg = (TRGM *) palloc(TRGMHDRSIZE + sizeof(trgm) * (slen / 2 + 1) * 3);
    trg->flag = ARRKEY;

    len = generate_trgm_only(GETARR(trg), str, slen);
    SET_VARSIZE(trg, CALCGTSIZE(ARRKEY, len));

    if (len == 0)
        return trg;

    /*
     * Make trigrams unique.
     */
    if (len > 1)
    {
        qsort((void *) GETARR(trg), len, sizeof(trgm), comp_trgm);
        len = unique_array(GETARR(trg), len);
    }

    SET_VARSIZE(trg, CALCGTSIZE(ARRKEY, len));

    return trg;
}

TRGM* generate_wildcard_trgm	(	const char *	str,
		int	slen
	)

Definition at line 796 of file trgm_op.c.

References ARRKEY, buf, CALCGTSIZE, comp_trgm(), TRGM::flag, get_wildcard_part(), GETARR, lowerstr_with_len(), LPADDING, make_trigrams(), NULL, palloc(), pfree(), protect_out_of_mem(), qsort, RPADDING, SET_VARSIZE, TRGMHDRSIZE, and unique_array().

Referenced by gin_extract_query_trgm(), and gtrgm_consistent().

{
    TRGM       *trg;
    char       *buf,
               *buf2;
    trgm       *tptr;
    int         len,
                charlen,
                bytelen;
    const char *eword;

    protect_out_of_mem(slen);

    trg = (TRGM *) palloc(TRGMHDRSIZE + sizeof(trgm) * (slen / 2 + 1) * 3);
    trg->flag = ARRKEY;
    SET_VARSIZE(trg, TRGMHDRSIZE);

    if (slen + LPADDING + RPADDING < 3 || slen == 0)
        return trg;

    tptr = GETARR(trg);

    /* Allocate a buffer for blank-padded, but not yet case-folded, words */
    buf = palloc(sizeof(char) * (slen + 4));

    /*
     * Extract trigrams from each substring extracted by get_wildcard_part.
     */
    eword = str;
    while ((eword = get_wildcard_part(eword, slen - (eword - str),
                                      buf, &bytelen, &charlen)) != NULL)
    {
#ifdef IGNORECASE
        buf2 = lowerstr_with_len(buf, bytelen);
        bytelen = strlen(buf2);
#else
        buf2 = buf;
#endif

        /*
         * count trigrams
         */
        tptr = make_trigrams(tptr, buf2, bytelen, charlen);

#ifdef IGNORECASE
        pfree(buf2);
#endif
    }

    pfree(buf);

    if ((len = tptr - GETARR(trg)) == 0)
        return trg;

    /*
     * Make trigrams unique.
     */
    if (len > 1)
    {
        qsort((void *) GETARR(trg), len, sizeof(trgm), comp_trgm);
        len = unique_array(GETARR(trg), len);
    }

    SET_VARSIZE(trg, CALCGTSIZE(ARRKEY, len));

    return trg;
}

uint32 trgm2int

(

trgm *

ptr

)

Definition at line 865 of file trgm_op.c.

References val.

Referenced by gin_extract_query_trgm(), gin_extract_value_trgm(), and show_trgm().

{
    uint32      val = 0;

    val |= *(((unsigned char *) ptr));
    val <<= 8;
    val |= *(((unsigned char *) ptr) + 1);
    val <<= 8;
    val |= *(((unsigned char *) ptr) + 2);

    return val;
}

bool trgm_contained_by	(	TRGM *	trg1,
		TRGM *	trg2
	)

Definition at line 976 of file trgm_op.c.

References ARRNELEM, CMPTRGM, and GETARR.

Referenced by gtrgm_consistent().

{
    trgm       *ptr1,
               *ptr2;
    int         len1,
                len2;

    ptr1 = GETARR(trg1);
    ptr2 = GETARR(trg2);

    len1 = ARRNELEM(trg1);
    len2 = ARRNELEM(trg2);

    while (ptr1 - GETARR(trg1) < len1 && ptr2 - GETARR(trg2) < len2)
    {
        int         res = CMPTRGM(ptr1, ptr2);

        if (res < 0)
            return false;
        else if (res > 0)
            ptr2++;
        else
        {
            ptr1++;
            ptr2++;
        }
    }
    if (ptr1 - GETARR(trg1) < len1)
        return false;
    else
        return true;
}

bool* trgm_presence_map	(	TRGM *	query,
		TRGM *	key
	)

Definition at line 1015 of file trgm_op.c.

References ARRNELEM, CMPTRGM, GETARR, i, palloc0(), and result.

Referenced by gtrgm_consistent().

{
    bool       *result;
    trgm       *ptrq = GETARR(query),
               *ptrk = GETARR(key);
    int         lenq = ARRNELEM(query),
                lenk = ARRNELEM(key),
                i;

    result = (bool *) palloc0(lenq * sizeof(bool));

    /* for each query trigram, do a binary search in the key array */
    for (i = 0; i < lenq; i++)
    {
        int         lo = 0;
        int         hi = lenk;

        while (lo < hi)
        {
            int         mid = (lo + hi) / 2;
            int         res = CMPTRGM(ptrq, ptrk + mid);

            if (res < 0)
                hi = mid;
            else if (res > 0)
                lo = mid + 1;
            else
            {
                result[i] = true;
                break;
            }
        }
        ptrq++;
    }

    return result;
}

bool trigramsMatchGraph	(	TrgmPackedGraph *	graph,
		bool *	check
	)

Definition at line 641 of file trgm_regexp.c.

References TrgmPackedState::arcs, TrgmPackedState::arcsCount, TrgmPackedArc::colorTrgm, TrgmPackedGraph::colorTrigramGroups, TrgmPackedGraph::colorTrigramsActive, TrgmPackedGraph::colorTrigramsCount, i, TrgmPackedGraph::states, TrgmPackedGraph::statesActive, TrgmPackedGraph::statesCount, TrgmPackedGraph::statesQueue, and TrgmPackedArc::targetState.

Referenced by gin_trgm_consistent(), gin_trgm_triconsistent(), and gtrgm_consistent().

{
    int         i,
                j,
                k,
                queueIn,
                queueOut;

    /*
     * Reset temporary working areas.
     */
    memset(graph->colorTrigramsActive, 0,
           sizeof(bool) * graph->colorTrigramsCount);
    memset(graph->statesActive, 0, sizeof(bool) * graph->statesCount);

    /*
     * Check which color trigrams were matched.  A match for any simple
     * trigram associated with a color trigram counts as a match of the color
     * trigram.
     */
    j = 0;
    for (i = 0; i < graph->colorTrigramsCount; i++)
    {
        int         cnt = graph->colorTrigramGroups[i];

        for (k = j; k < j + cnt; k++)
        {
            if (check[k])
            {
                /*
                 * Found one matched trigram in the group. Can skip the rest
                 * of them and go to the next group.
                 */
                graph->colorTrigramsActive[i] = true;
                break;
            }
        }
        j = j + cnt;
    }

    /*
     * Initialize the statesQueue to hold just the initial state.  Note:
     * statesQueue has room for statesCount entries, which is certainly enough
     * since no state will be put in the queue more than once. The
     * statesActive array marks which states have been queued.
     */
    graph->statesActive[0] = true;
    graph->statesQueue[0] = 0;
    queueIn = 0;
    queueOut = 1;

    /* Process queued states as long as there are any. */
    while (queueIn < queueOut)
    {
        int         stateno = graph->statesQueue[queueIn++];
        TrgmPackedState *state = &graph->states[stateno];
        int         cnt = state->arcsCount;

        /* Loop over state's out-arcs */
        for (i = 0; i < cnt; i++)
        {
            TrgmPackedArc *arc = &state->arcs[i];

            /*
             * If corresponding color trigram is present then activate the
             * corresponding state.  We're done if that's the final state,
             * otherwise queue the state if it's not been queued already.
             */
            if (graph->colorTrigramsActive[arc->colorTrgm])
            {
                int         nextstate = arc->targetState;

                if (nextstate == 1)
                    return true;    /* success: final state is reachable */

                if (!graph->statesActive[nextstate])
                {
                    graph->statesActive[nextstate] = true;
                    graph->statesQueue[queueOut++] = nextstate;
                }
            }
        }
    }

    /* Queue is empty, so match fails. */
    return false;
}

Variable Documentation

double similarity_threshold

Definition at line 19 of file trgm_op.c.

Referenced by _PG_init(), gin_trgm_consistent(), gin_trgm_triconsistent(), gtrgm_consistent(), set_limit(), show_limit(), and similarity_op().

double word_similarity_threshold

Definition at line 20 of file trgm_op.c.

Referenced by _PG_init(), gin_trgm_consistent(), gin_trgm_triconsistent(), gtrgm_consistent(), iterate_word_similarity(), word_similarity_commutator_op(), and word_similarity_op().