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postgresql/src/backend/snowball/dict_snowball.c
Bruce Momjian 0239800893 Update copyright for the year 2010.
2010-01-02 16:58:17 +00:00

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/*-------------------------------------------------------------------------
*
* dict_snowball.c
* Snowball dictionary
*
* Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/snowball/dict_snowball.c,v 1.9 2010/01/02 16:57:51 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "commands/defrem.h"
#include "fmgr.h"
#include "tsearch/ts_locale.h"
#include "tsearch/ts_public.h"
#include "tsearch/ts_utils.h"
#include "utils/builtins.h"
/* Some platforms define MAXINT and/or MININT, causing conflicts */
#ifdef MAXINT
#undef MAXINT
#endif
#ifdef MININT
#undef MININT
#endif
/* Now we can include the original Snowball header.h */
#include "snowball/libstemmer/header.h"
#include "snowball/libstemmer/stem_ISO_8859_1_danish.h"
#include "snowball/libstemmer/stem_ISO_8859_1_dutch.h"
#include "snowball/libstemmer/stem_ISO_8859_1_english.h"
#include "snowball/libstemmer/stem_ISO_8859_1_finnish.h"
#include "snowball/libstemmer/stem_ISO_8859_1_french.h"
#include "snowball/libstemmer/stem_ISO_8859_1_german.h"
#include "snowball/libstemmer/stem_ISO_8859_1_hungarian.h"
#include "snowball/libstemmer/stem_ISO_8859_1_italian.h"
#include "snowball/libstemmer/stem_ISO_8859_1_norwegian.h"
#include "snowball/libstemmer/stem_ISO_8859_1_porter.h"
#include "snowball/libstemmer/stem_ISO_8859_1_portuguese.h"
#include "snowball/libstemmer/stem_ISO_8859_1_spanish.h"
#include "snowball/libstemmer/stem_ISO_8859_1_swedish.h"
#include "snowball/libstemmer/stem_ISO_8859_2_romanian.h"
#include "snowball/libstemmer/stem_KOI8_R_russian.h"
#include "snowball/libstemmer/stem_UTF_8_danish.h"
#include "snowball/libstemmer/stem_UTF_8_dutch.h"
#include "snowball/libstemmer/stem_UTF_8_english.h"
#include "snowball/libstemmer/stem_UTF_8_finnish.h"
#include "snowball/libstemmer/stem_UTF_8_french.h"
#include "snowball/libstemmer/stem_UTF_8_german.h"
#include "snowball/libstemmer/stem_UTF_8_hungarian.h"
#include "snowball/libstemmer/stem_UTF_8_italian.h"
#include "snowball/libstemmer/stem_UTF_8_norwegian.h"
#include "snowball/libstemmer/stem_UTF_8_porter.h"
#include "snowball/libstemmer/stem_UTF_8_portuguese.h"
#include "snowball/libstemmer/stem_UTF_8_romanian.h"
#include "snowball/libstemmer/stem_UTF_8_russian.h"
#include "snowball/libstemmer/stem_UTF_8_spanish.h"
#include "snowball/libstemmer/stem_UTF_8_swedish.h"
#include "snowball/libstemmer/stem_UTF_8_turkish.h"
PG_MODULE_MAGIC;
PG_FUNCTION_INFO_V1(dsnowball_init);
Datum dsnowball_init(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(dsnowball_lexize);
Datum dsnowball_lexize(PG_FUNCTION_ARGS);
/* List of supported modules */
typedef struct stemmer_module
{
const char *name;
pg_enc enc;
struct SN_env *(*create) (void);
void (*close) (struct SN_env *);
int (*stem) (struct SN_env *);
} stemmer_module;
static const stemmer_module stemmer_modules[] =
{
/*
* Stemmers list from Snowball distribution
*/
{"danish", PG_LATIN1, danish_ISO_8859_1_create_env, danish_ISO_8859_1_close_env, danish_ISO_8859_1_stem},
{"dutch", PG_LATIN1, dutch_ISO_8859_1_create_env, dutch_ISO_8859_1_close_env, dutch_ISO_8859_1_stem},
{"english", PG_LATIN1, english_ISO_8859_1_create_env, english_ISO_8859_1_close_env, english_ISO_8859_1_stem},
{"finnish", PG_LATIN1, finnish_ISO_8859_1_create_env, finnish_ISO_8859_1_close_env, finnish_ISO_8859_1_stem},
{"french", PG_LATIN1, french_ISO_8859_1_create_env, french_ISO_8859_1_close_env, french_ISO_8859_1_stem},
{"german", PG_LATIN1, german_ISO_8859_1_create_env, german_ISO_8859_1_close_env, german_ISO_8859_1_stem},
{"hungarian", PG_LATIN1, hungarian_ISO_8859_1_create_env, hungarian_ISO_8859_1_close_env, hungarian_ISO_8859_1_stem},
{"italian", PG_LATIN1, italian_ISO_8859_1_create_env, italian_ISO_8859_1_close_env, italian_ISO_8859_1_stem},
{"norwegian", PG_LATIN1, norwegian_ISO_8859_1_create_env, norwegian_ISO_8859_1_close_env, norwegian_ISO_8859_1_stem},
{"porter", PG_LATIN1, porter_ISO_8859_1_create_env, porter_ISO_8859_1_close_env, porter_ISO_8859_1_stem},
{"portuguese", PG_LATIN1, portuguese_ISO_8859_1_create_env, portuguese_ISO_8859_1_close_env, portuguese_ISO_8859_1_stem},
{"spanish", PG_LATIN1, spanish_ISO_8859_1_create_env, spanish_ISO_8859_1_close_env, spanish_ISO_8859_1_stem},
{"swedish", PG_LATIN1, swedish_ISO_8859_1_create_env, swedish_ISO_8859_1_close_env, swedish_ISO_8859_1_stem},
{"romanian", PG_LATIN2, romanian_ISO_8859_2_create_env, romanian_ISO_8859_2_close_env, romanian_ISO_8859_2_stem},
{"russian", PG_KOI8R, russian_KOI8_R_create_env, russian_KOI8_R_close_env, russian_KOI8_R_stem},
{"danish", PG_UTF8, danish_UTF_8_create_env, danish_UTF_8_close_env, danish_UTF_8_stem},
{"dutch", PG_UTF8, dutch_UTF_8_create_env, dutch_UTF_8_close_env, dutch_UTF_8_stem},
{"english", PG_UTF8, english_UTF_8_create_env, english_UTF_8_close_env, english_UTF_8_stem},
{"finnish", PG_UTF8, finnish_UTF_8_create_env, finnish_UTF_8_close_env, finnish_UTF_8_stem},
{"french", PG_UTF8, french_UTF_8_create_env, french_UTF_8_close_env, french_UTF_8_stem},
{"german", PG_UTF8, german_UTF_8_create_env, german_UTF_8_close_env, german_UTF_8_stem},
{"hungarian", PG_UTF8, hungarian_UTF_8_create_env, hungarian_UTF_8_close_env, hungarian_UTF_8_stem},
{"italian", PG_UTF8, italian_UTF_8_create_env, italian_UTF_8_close_env, italian_UTF_8_stem},
{"norwegian", PG_UTF8, norwegian_UTF_8_create_env, norwegian_UTF_8_close_env, norwegian_UTF_8_stem},
{"porter", PG_UTF8, porter_UTF_8_create_env, porter_UTF_8_close_env, porter_UTF_8_stem},
{"portuguese", PG_UTF8, portuguese_UTF_8_create_env, portuguese_UTF_8_close_env, portuguese_UTF_8_stem},
{"romanian", PG_UTF8, romanian_UTF_8_create_env, romanian_UTF_8_close_env, romanian_UTF_8_stem},
{"russian", PG_UTF8, russian_UTF_8_create_env, russian_UTF_8_close_env, russian_UTF_8_stem},
{"spanish", PG_UTF8, spanish_UTF_8_create_env, spanish_UTF_8_close_env, spanish_UTF_8_stem},
{"swedish", PG_UTF8, swedish_UTF_8_create_env, swedish_UTF_8_close_env, swedish_UTF_8_stem},
{"turkish", PG_UTF8, turkish_UTF_8_create_env, turkish_UTF_8_close_env, turkish_UTF_8_stem},
/*
* Stemmer with PG_SQL_ASCII encoding should be valid for any server
* encoding
*/
{"english", PG_SQL_ASCII, english_ISO_8859_1_create_env, english_ISO_8859_1_close_env, english_ISO_8859_1_stem},
{NULL, 0, NULL, NULL, NULL} /* list end marker */
};
typedef struct DictSnowball
{
struct SN_env *z;
StopList stoplist;
bool needrecode; /* needs recoding before/after call stem */
int (*stem) (struct SN_env * z);
/*
* snowball saves alloced memory between calls, so we should run it in our
* private memory context. Note, init function is executed in long lived
* context, so we just remember CurrentMemoryContext
*/
MemoryContext dictCtx;
} DictSnowball;
static void
locate_stem_module(DictSnowball *d, char *lang)
{
const stemmer_module *m;
/*
* First, try to find exact match of stemmer module. Stemmer with
* PG_SQL_ASCII encoding is treated as working with any server encoding
*/
for (m = stemmer_modules; m->name; m++)
{
if ((m->enc == PG_SQL_ASCII || m->enc == GetDatabaseEncoding()) &&
pg_strcasecmp(m->name, lang) == 0)
{
d->stem = m->stem;
d->z = m->create();
d->needrecode = false;
return;
}
}
/*
* Second, try to find stemmer for needed language for UTF8 encoding.
*/
for (m = stemmer_modules; m->name; m++)
{
if (m->enc == PG_UTF8 && pg_strcasecmp(m->name, lang) == 0)
{
d->stem = m->stem;
d->z = m->create();
d->needrecode = true;
return;
}
}
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("no Snowball stemmer available for language \"%s\" and encoding \"%s\"",
lang, GetDatabaseEncodingName())));
}
Datum
dsnowball_init(PG_FUNCTION_ARGS)
{
List *dictoptions = (List *) PG_GETARG_POINTER(0);
DictSnowball *d;
bool stoploaded = false;
ListCell *l;
d = (DictSnowball *) palloc0(sizeof(DictSnowball));
foreach(l, dictoptions)
{
DefElem *defel = (DefElem *) lfirst(l);
if (pg_strcasecmp("StopWords", defel->defname) == 0)
{
if (stoploaded)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("multiple StopWords parameters")));
readstoplist(defGetString(defel), &d->stoplist, lowerstr);
stoploaded = true;
}
else if (pg_strcasecmp("Language", defel->defname) == 0)
{
if (d->stem)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("multiple Language parameters")));
locate_stem_module(d, defGetString(defel));
}
else
{
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("unrecognized Snowball parameter: \"%s\"",
defel->defname)));
}
}
if (!d->stem)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("missing Language parameter")));
d->dictCtx = CurrentMemoryContext;
PG_RETURN_POINTER(d);
}
Datum
dsnowball_lexize(PG_FUNCTION_ARGS)
{
DictSnowball *d = (DictSnowball *) PG_GETARG_POINTER(0);
char *in = (char *) PG_GETARG_POINTER(1);
int32 len = PG_GETARG_INT32(2);
char *txt = lowerstr_with_len(in, len);
TSLexeme *res = palloc0(sizeof(TSLexeme) * 2);
if (*txt == '\0' || searchstoplist(&(d->stoplist), txt))
{
pfree(txt);
}
else
{
MemoryContext saveCtx;
/*
* recode to utf8 if stemmer is utf8 and doesn't match server encoding
*/
if (d->needrecode)
{
char *recoded;
recoded = (char *) pg_do_encoding_conversion((unsigned char *) txt,
strlen(txt),
GetDatabaseEncoding(),
PG_UTF8);
if (recoded != txt)
{
pfree(txt);
txt = recoded;
}
}
/* see comment about d->dictCtx */
saveCtx = MemoryContextSwitchTo(d->dictCtx);
SN_set_current(d->z, strlen(txt), (symbol *) txt);
d->stem(d->z);
MemoryContextSwitchTo(saveCtx);
if (d->z->p && d->z->l)
{
txt = repalloc(txt, d->z->l + 1);
memcpy(txt, d->z->p, d->z->l);
txt[d->z->l] = '\0';
}
/* back recode if needed */
if (d->needrecode)
{
char *recoded;
recoded = (char *) pg_do_encoding_conversion((unsigned char *) txt,
strlen(txt),
PG_UTF8,
GetDatabaseEncoding());
if (recoded != txt)
{
pfree(txt);
txt = recoded;
}
}
res->lexeme = txt;
}
PG_RETURN_POINTER(res);
}
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