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Obviously, in order to equality operator be satisfiable, target string must contain all the trigrams of the search string. On this base, we implement equality operator in GiST/GIN indexes with recheck. Discussion: https://postgr.es/m/CAOBaU_YWwtT7tdggtROacjdOdeYHCz-tmSwuC-j-TOG-g97J0w%40mail.gmail.com Author: Julien Rouhaud Reviewed-by: Tom Lane, Alexander Korotkov, Georgios Kokolatos, Erik Rijkers
141 lines
4.9 KiB
C
141 lines
4.9 KiB
C
/*
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* contrib/pg_trgm/trgm.h
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*/
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#ifndef __TRGM_H__
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#define __TRGM_H__
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#include "access/gist.h"
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#include "access/itup.h"
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#include "access/stratnum.h"
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#include "storage/bufpage.h"
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/*
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* Options ... but note that trgm_regexp.c effectively assumes these values
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* of LPADDING and RPADDING.
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*/
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#define LPADDING 2
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#define RPADDING 1
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#define KEEPONLYALNUM
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/*
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* Caution: IGNORECASE macro means that trigrams are case-insensitive.
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* If this macro is disabled, the ~* and ~~* operators must be removed from
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* the operator classes, because we can't handle case-insensitive wildcard
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* search with case-sensitive trigrams. Failure to do this will result in
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* "cannot handle ~*(~~*) with case-sensitive trigrams" errors.
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*/
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#define IGNORECASE
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#define DIVUNION
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/* operator strategy numbers */
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#define SimilarityStrategyNumber 1
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#define DistanceStrategyNumber 2
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#define LikeStrategyNumber 3
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#define ILikeStrategyNumber 4
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#define RegExpStrategyNumber 5
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#define RegExpICaseStrategyNumber 6
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#define WordSimilarityStrategyNumber 7
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#define WordDistanceStrategyNumber 8
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#define StrictWordSimilarityStrategyNumber 9
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#define StrictWordDistanceStrategyNumber 10
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#define EqualStrategyNumber 11
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typedef char trgm[3];
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#define CMPCHAR(a,b) ( ((a)==(b)) ? 0 : ( ((a)<(b)) ? -1 : 1 ) )
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#define CMPPCHAR(a,b,i) CMPCHAR( *(((const char*)(a))+i), *(((const char*)(b))+i) )
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#define CMPTRGM(a,b) ( CMPPCHAR(a,b,0) ? CMPPCHAR(a,b,0) : ( CMPPCHAR(a,b,1) ? CMPPCHAR(a,b,1) : CMPPCHAR(a,b,2) ) )
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#define CPTRGM(a,b) do { \
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*(((char*)(a))+0) = *(((char*)(b))+0); \
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*(((char*)(a))+1) = *(((char*)(b))+1); \
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*(((char*)(a))+2) = *(((char*)(b))+2); \
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} while(0)
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#ifdef KEEPONLYALNUM
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#define ISWORDCHR(c) (t_isalpha(c) || t_isdigit(c))
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#define ISPRINTABLECHAR(a) ( isascii( *(unsigned char*)(a) ) && (isalnum( *(unsigned char*)(a) ) || *(unsigned char*)(a)==' ') )
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#else
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#define ISWORDCHR(c) (!t_isspace(c))
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#define ISPRINTABLECHAR(a) ( isascii( *(unsigned char*)(a) ) && isprint( *(unsigned char*)(a) ) )
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#endif
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#define ISPRINTABLETRGM(t) ( ISPRINTABLECHAR( ((char*)(t)) ) && ISPRINTABLECHAR( ((char*)(t))+1 ) && ISPRINTABLECHAR( ((char*)(t))+2 ) )
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#define ISESCAPECHAR(x) (*(x) == '\\') /* Wildcard escape character */
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#define ISWILDCARDCHAR(x) (*(x) == '_' || *(x) == '%') /* Wildcard
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* meta-character */
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typedef struct
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{
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int32 vl_len_; /* varlena header (do not touch directly!) */
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uint8 flag;
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char data[FLEXIBLE_ARRAY_MEMBER];
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} TRGM;
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#define TRGMHDRSIZE (VARHDRSZ + sizeof(uint8))
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/* gist */
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#define SIGLEN_DEFAULT (sizeof(int) * 3)
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#define SIGLEN_MAX GISTMaxIndexKeySize
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#define BITBYTE 8
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#define SIGLENBIT(siglen) ((siglen) * BITBYTE - 1) /* see makesign */
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typedef char *BITVECP;
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#define LOOPBYTE(siglen) \
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for (i = 0; i < (siglen); i++)
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#define GETBYTE(x,i) ( *( (BITVECP)(x) + (int)( (i) / BITBYTE ) ) )
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#define GETBITBYTE(x,i) ( (((char)(x)) >> (i)) & 0x01 )
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#define CLRBIT(x,i) GETBYTE(x,i) &= ~( 0x01 << ( (i) % BITBYTE ) )
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#define SETBIT(x,i) GETBYTE(x,i) |= ( 0x01 << ( (i) % BITBYTE ) )
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#define GETBIT(x,i) ( (GETBYTE(x,i) >> ( (i) % BITBYTE )) & 0x01 )
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#define HASHVAL(val, siglen) (((unsigned int)(val)) % SIGLENBIT(siglen))
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#define HASH(sign, val, siglen) SETBIT((sign), HASHVAL(val, siglen))
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#define ARRKEY 0x01
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#define SIGNKEY 0x02
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#define ALLISTRUE 0x04
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#define ISARRKEY(x) ( ((TRGM*)x)->flag & ARRKEY )
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#define ISSIGNKEY(x) ( ((TRGM*)x)->flag & SIGNKEY )
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#define ISALLTRUE(x) ( ((TRGM*)x)->flag & ALLISTRUE )
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#define CALCGTSIZE(flag, len) ( TRGMHDRSIZE + ( ( (flag) & ARRKEY ) ? ((len)*sizeof(trgm)) : (((flag) & ALLISTRUE) ? 0 : (len)) ) )
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#define GETSIGN(x) ( (BITVECP)( (char*)x+TRGMHDRSIZE ) )
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#define GETARR(x) ( (trgm*)( (char*)x+TRGMHDRSIZE ) )
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#define ARRNELEM(x) ( ( VARSIZE(x) - TRGMHDRSIZE )/sizeof(trgm) )
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/*
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* If DIVUNION is defined then similarity formula is:
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* count / (len1 + len2 - count)
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* else if DIVUNION is not defined then similarity formula is:
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* count / max(len1, len2)
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*/
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#ifdef DIVUNION
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#define CALCSML(count, len1, len2) ((float4) (count)) / ((float4) ((len1) + (len2) - (count)))
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#else
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#define CALCSML(count, len1, len2) ((float4) (count)) / ((float4) (((len1) > (len2)) ? (len1) : (len2)))
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#endif
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typedef struct TrgmPackedGraph TrgmPackedGraph;
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extern double similarity_threshold;
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extern double word_similarity_threshold;
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extern double strict_word_similarity_threshold;
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extern double index_strategy_get_limit(StrategyNumber strategy);
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extern uint32 trgm2int(trgm *ptr);
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extern void compact_trigram(trgm *tptr, char *str, int bytelen);
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extern TRGM *generate_trgm(char *str, int slen);
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extern TRGM *generate_wildcard_trgm(const char *str, int slen);
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extern float4 cnt_sml(TRGM *trg1, TRGM *trg2, bool inexact);
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extern bool trgm_contained_by(TRGM *trg1, TRGM *trg2);
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extern bool *trgm_presence_map(TRGM *query, TRGM *key);
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extern TRGM *createTrgmNFA(text *text_re, Oid collation,
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TrgmPackedGraph **graph, MemoryContext rcontext);
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extern bool trigramsMatchGraph(TrgmPackedGraph *graph, bool *check);
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#endif /* __TRGM_H__ */
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