postgresql/contrib/pg_trgm/trgm.h
Alexander Korotkov 935f666650 Handle equality operator in contrib/pg_trgm
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
2020-11-15 08:52:35 +03:00

141 lines
4.9 KiB
C

/*
* contrib/pg_trgm/trgm.h
*/
#ifndef __TRGM_H__
#define __TRGM_H__
#include "access/gist.h"
#include "access/itup.h"
#include "access/stratnum.h"
#include "storage/bufpage.h"
/*
* Options ... but note that trgm_regexp.c effectively assumes these values
* of LPADDING and RPADDING.
*/
#define LPADDING 2
#define RPADDING 1
#define KEEPONLYALNUM
/*
* Caution: IGNORECASE macro means that trigrams are case-insensitive.
* If this macro is disabled, the ~* and ~~* operators must be removed from
* the operator classes, because we can't handle case-insensitive wildcard
* search with case-sensitive trigrams. Failure to do this will result in
* "cannot handle ~*(~~*) with case-sensitive trigrams" errors.
*/
#define IGNORECASE
#define DIVUNION
/* operator strategy numbers */
#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 StrictWordSimilarityStrategyNumber 9
#define StrictWordDistanceStrategyNumber 10
#define EqualStrategyNumber 11
typedef char trgm[3];
#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) do { \
*(((char*)(a))+0) = *(((char*)(b))+0); \
*(((char*)(a))+1) = *(((char*)(b))+1); \
*(((char*)(a))+2) = *(((char*)(b))+2); \
} while(0)
#ifdef KEEPONLYALNUM
#define ISWORDCHR(c) (t_isalpha(c) || t_isdigit(c))
#define ISPRINTABLECHAR(a) ( isascii( *(unsigned char*)(a) ) && (isalnum( *(unsigned char*)(a) ) || *(unsigned char*)(a)==' ') )
#else
#define ISWORDCHR(c) (!t_isspace(c))
#define ISPRINTABLECHAR(a) ( isascii( *(unsigned char*)(a) ) && isprint( *(unsigned char*)(a) ) )
#endif
#define ISPRINTABLETRGM(t) ( ISPRINTABLECHAR( ((char*)(t)) ) && ISPRINTABLECHAR( ((char*)(t))+1 ) && ISPRINTABLECHAR( ((char*)(t))+2 ) )
#define ISESCAPECHAR(x) (*(x) == '\\') /* Wildcard escape character */
#define ISWILDCARDCHAR(x) (*(x) == '_' || *(x) == '%') /* Wildcard
* meta-character */
typedef struct
{
int32 vl_len_; /* varlena header (do not touch directly!) */
uint8 flag;
char data[FLEXIBLE_ARRAY_MEMBER];
} TRGM;
#define TRGMHDRSIZE (VARHDRSZ + sizeof(uint8))
/* gist */
#define SIGLEN_DEFAULT (sizeof(int) * 3)
#define SIGLEN_MAX GISTMaxIndexKeySize
#define BITBYTE 8
#define SIGLENBIT(siglen) ((siglen) * BITBYTE - 1) /* see makesign */
typedef char *BITVECP;
#define LOOPBYTE(siglen) \
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, siglen) (((unsigned int)(val)) % SIGLENBIT(siglen))
#define HASH(sign, val, siglen) SETBIT((sign), HASHVAL(val, siglen))
#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 : (len)) ) )
#define GETSIGN(x) ( (BITVECP)( (char*)x+TRGMHDRSIZE ) )
#define GETARR(x) ( (trgm*)( (char*)x+TRGMHDRSIZE ) )
#define ARRNELEM(x) ( ( VARSIZE(x) - TRGMHDRSIZE )/sizeof(trgm) )
/*
* If DIVUNION is defined then similarity formula is:
* count / (len1 + len2 - count)
* else if DIVUNION is not defined then similarity formula is:
* count / max(len1, len2)
*/
#ifdef DIVUNION
#define CALCSML(count, len1, len2) ((float4) (count)) / ((float4) ((len1) + (len2) - (count)))
#else
#define CALCSML(count, len1, len2) ((float4) (count)) / ((float4) (((len1) > (len2)) ? (len1) : (len2)))
#endif
typedef struct TrgmPackedGraph TrgmPackedGraph;
extern double similarity_threshold;
extern double word_similarity_threshold;
extern double strict_word_similarity_threshold;
extern double index_strategy_get_limit(StrategyNumber strategy);
extern uint32 trgm2int(trgm *ptr);
extern void compact_trigram(trgm *tptr, char *str, int bytelen);
extern TRGM *generate_trgm(char *str, int slen);
extern TRGM *generate_wildcard_trgm(const char *str, int slen);
extern float4 cnt_sml(TRGM *trg1, TRGM *trg2, bool inexact);
extern bool trgm_contained_by(TRGM *trg1, TRGM *trg2);
extern bool *trgm_presence_map(TRGM *query, TRGM *key);
extern TRGM *createTrgmNFA(text *text_re, Oid collation,
TrgmPackedGraph **graph, MemoryContext rcontext);
extern bool trigramsMatchGraph(TrgmPackedGraph *graph, bool *check);
#endif /* __TRGM_H__ */