contrib/pg_trgm/trgm_gin.c

   1 /*
   2  * $PostgreSQL$
   3  */
   4 #include "trgm.h"
   5
   6 #include "access/gin.h"
   7 #include "access/itup.h"
   8 #include "access/tuptoaster.h"
   9 #include "storage/bufpage.h"
  10 #include "utils/array.h"
  11 #include "utils/builtins.h"
  12
  13 PG_FUNCTION_INFO_V1(gin_extract_trgm);
  14 Datum           gin_extract_trgm(PG_FUNCTION_ARGS);
  15
  16 PG_FUNCTION_INFO_V1(gin_trgm_consistent);
  17 Datum           gin_trgm_consistent(PG_FUNCTION_ARGS);
  18
  19 Datum
  20 gin_extract_trgm(PG_FUNCTION_ARGS)
  21 {
  22         text       *val = (text *) PG_GETARG_TEXT_P(0);
  23         int32      *nentries = (int32 *) PG_GETARG_POINTER(1);
  24         Datum      *entries = NULL;
  25         TRGM       *trg;
  26         int4            trglen;
  27
  28         *nentries = 0;
  29
  30         trg = generate_trgm(VARDATA(val), VARSIZE(val) - VARHDRSZ);
  31         trglen = ARRNELEM(trg);
  32
  33         if (trglen > 0)
  34         {
  35                 trgm       *ptr;
  36                 int4            i = 0,
  37                                         item;
  38
  39                 *nentries = (int32) trglen;
  40                 entries = (Datum *) palloc(sizeof(Datum) * trglen);
  41
  42                 ptr = GETARR(trg);
  43                 while (ptr - GETARR(trg) < ARRNELEM(trg))
  44                 {
  45                         item = trgm2int(ptr);
  46                         entries[i++] = Int32GetDatum(item);
  47
  48                         ptr++;
  49                 }
  50         }
  51
  52         PG_RETURN_POINTER(entries);
  53 }
  54
  55 /*
  56  * Per call strage for consistent functions to
  57  * cache computed value from query
  58  */
  59 typedef struct PerCallConsistentStorage {
  60         int             trglen;
  61         text    data[1]; /* query */
  62 } PerCallConsistentStorage;
  63 #define PCCSHDR_SZ  offsetof(PerCallConsistentStorage, data)
  64
  65 Datum
  66 gin_trgm_consistent(PG_FUNCTION_ARGS)
  67 {
  68         bool       *check = (bool *) PG_GETARG_POINTER(0);
  69         /* StrategyNumber strategy = PG_GETARG_UINT16(1); */
  70         text       *query = PG_GETARG_TEXT_P(2);
  71         bool       *recheck = (bool *) PG_GETARG_POINTER(3);
  72         bool            res = FALSE;
  73         int4            i,
  74                                 trglen,
  75                                 ntrue = 0;
  76         PerCallConsistentStorage  *pccs = (PerCallConsistentStorage*) fcinfo->flinfo->fn_extra;
  77
  78         /* All cases served by this function are inexact */
  79         *recheck = true;
  80
  81         if ( pccs == NULL || VARSIZE(pccs->data) != VARSIZE(query) || memcmp( pccs->data, query, VARSIZE(query) ) !=0  )
  82         {
  83                 TRGM       *trg = generate_trgm(VARDATA(query), VARSIZE(query) - VARHDRSZ);
  84
  85                 if ( pccs )
  86                         pfree(pccs);
  87
  88                 fcinfo->flinfo->fn_extra = MemoryContextAlloc(fcinfo->flinfo->fn_mcxt,
  89                                                                         VARSIZE(query) + PCCSHDR_SZ);
  90                 pccs = (PerCallConsistentStorage*) fcinfo->flinfo->fn_extra;
  91
  92                 pccs->trglen = ARRNELEM(trg);
  93                 memcpy( pccs->data, query, VARSIZE(query) );
  94         }
  95
  96         trglen = pccs->trglen;
  97
  98         for (i = 0; i < trglen; i++)
  99                 if (check[i])
 100                         ntrue++;
 101
 102 #ifdef DIVUNION
 103         res = (trglen == ntrue) ? true : ((((((float4) ntrue) / ((float4) (trglen - ntrue)))) >= trgm_limit) ? true : false);
 104 #else
 105         res = (trglen == 0) ? false : ((((((float4) ntrue) / ((float4) trglen))) >= trgm_limit) ? true : false);
 106 #endif
 107
 108         PG_RETURN_BOOL(res);
 109 }