src/backend/tsearch/dict_simple.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * dict_simple.c
   4  *              Simple dictionary: just lowercase and check for stopword
   5  *
   6  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
   7  *
   8  *
   9  * IDENTIFICATION
  10  *        $PostgreSQL$
  11  *
  12  *-------------------------------------------------------------------------
  13  */
  14 #include "postgres.h"
  15
  16 #include "commands/defrem.h"
  17 #include "tsearch/ts_locale.h"
  18 #include "tsearch/ts_public.h"
  19 #include "tsearch/ts_utils.h"
  20 #include "utils/builtins.h"
  21
  22
  23 typedef struct
  24 {
  25         StopList        stoplist;
  26         bool            accept;
  27 } DictSimple;
  28
  29
  30 Datum
  31 dsimple_init(PG_FUNCTION_ARGS)
  32 {
  33         List       *dictoptions = (List *) PG_GETARG_POINTER(0);
  34         DictSimple *d = (DictSimple *) palloc0(sizeof(DictSimple));
  35         bool            stoploaded = false,
  36                                 acceptloaded = false;
  37         ListCell   *l;
  38
  39         d->accept = true;                       /* default */
  40
  41         foreach(l, dictoptions)
  42         {
  43                 DefElem    *defel = (DefElem *) lfirst(l);
  44
  45                 if (pg_strcasecmp("StopWords", defel->defname) == 0)
  46                 {
  47                         if (stoploaded)
  48                                 ereport(ERROR,
  49                                                 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
  50                                                  errmsg("multiple StopWords parameters")));
  51                         readstoplist(defGetString(defel), &d->stoplist, lowerstr);
  52                         stoploaded = true;
  53                 }
  54                 else if (pg_strcasecmp("Accept", defel->defname) == 0)
  55                 {
  56                         if (acceptloaded)
  57                                 ereport(ERROR,
  58                                                 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
  59                                                  errmsg("multiple Accept parameters")));
  60                         d->accept = defGetBoolean(defel);
  61                         acceptloaded = true;
  62                 }
  63                 else
  64                 {
  65                         ereport(ERROR,
  66                                         (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
  67                                    errmsg("unrecognized simple dictionary parameter: \"%s\"",
  68                                                   defel->defname)));
  69                 }
  70         }
  71
  72         PG_RETURN_POINTER(d);
  73 }
  74
  75 Datum
  76 dsimple_lexize(PG_FUNCTION_ARGS)
  77 {
  78         DictSimple *d = (DictSimple *) PG_GETARG_POINTER(0);
  79         char       *in = (char *) PG_GETARG_POINTER(1);
  80         int32           len = PG_GETARG_INT32(2);
  81         char       *txt;
  82         TSLexeme   *res;
  83
  84         txt = lowerstr_with_len(in, len);
  85
  86         if (*txt == '\0' || searchstoplist(&(d->stoplist), txt))
  87         {
  88                 /* reject as stopword */
  89                 pfree(txt);
  90                 res = palloc0(sizeof(TSLexeme) * 2);
  91                 PG_RETURN_POINTER(res);
  92         }
  93         else if (d->accept)
  94         {
  95                 /* accept */
  96                 res = palloc0(sizeof(TSLexeme) * 2);
  97                 res[0].lexeme = txt;
  98                 PG_RETURN_POINTER(res);
  99         }
 100         else
 101         {
 102                 /* report as unrecognized */
 103                 pfree(txt);
 104                 PG_RETURN_POINTER(NULL);
 105         }
 106 }