bigm.h

   1 /*-------------------------------------------------------------------------
   2  *
   3  * Portions Copyright (c) 2004-2012, PostgreSQL Global Development Group
   4  * Portions Copyright (c) 2013-2015, NTT DATA Corporation
   5  *
   6  * Changelog:
   7  *       2013/01/09
   8  *       Support full text search using bigrams.
   9  *       Author: NTT DATA Corporation
  10  *
  11  *-------------------------------------------------------------------------
  12  */
  13 #ifndef __BIGM_H__
  14 #define __BIGM_H__
  15
  16 #include "access/itup.h"
  17 #include "storage/bufpage.h"
  18 #include "utils/builtins.h"
  19
  20 /* GUC variable */
  21 extern bool bigm_enable_recheck;
  22 extern int      bigm_gin_key_limit;
  23 extern double bigm_similarity_limit;
  24 extern char     *bigm_last_update;
  25
  26 /* options */
  27 #define LPADDING                1
  28 #define RPADDING                1
  29
  30 /* operator strategy numbers */
  31 #define LikeStrategyNumber                      1
  32 #define SimilarityStrategyNumber        2
  33
  34 typedef struct
  35 {
  36         bool            pmatch;                 /* partial match is required? */
  37         int8            bytelen;                /* byte length of bi-gram string */
  38
  39         /*
  40          * Bi-gram string; we assume here that the maximum bytes for a character
  41          * are four.
  42          */
  43         char            str[8];
  44 }       bigm;
  45
  46 #define BIGMSIZE        sizeof(bigm)
  47
  48 extern inline int       bigmstrcmp(char *arg1, int len1, char *arg2, int len2);
  49 #define CMPBIGM(a,b) ( bigmstrcmp(((bigm *)a)->str, ((bigm *)a)->bytelen, ((bigm *)b)->str, ((bigm *)b)->bytelen) )
  50
  51 #define CPBIGM(bptr, s, len) do {               \
  52         Assert(len <= 8);                               \
  53         memcpy(bptr->str, s, len);              \
  54         bptr->bytelen = len;                    \
  55         bptr->pmatch = false;                   \
  56 } while(0);
  57
  58 #define ISESCAPECHAR(x) (*(x) == '\\')  /* Wildcard escape character */
  59 #define ISWILDCARDCHAR(x) (*(x) == '%' || *(x) == '_')  /* Wildcard
  60                                                                                                                  * meta-character */
  61 typedef struct
  62 {
  63         int32           vl_len_;                /* varlena header (do not touch directly!) */
  64         char            data[1];
  65 }       BIGM;
  66
  67 #define CALCGTSIZE(len) (VARHDRSZ + len * sizeof(bigm))
  68 #define GETARR(x)               ( (bigm *)( (char*)x + VARHDRSZ ) )
  69 #define ARRNELEM(x) ( ( VARSIZE(x) - VARHDRSZ )/sizeof(bigm) )
  70
  71 extern BIGM *generate_bigm(char *str, int slen);
  72 extern BIGM *generate_wildcard_bigm(const char *str, int slen, bool *removeDups);
  73
  74 #endif   /* __BIGM_H__ */