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/* Part of SWI-Prolog
Author: Jan Wielemaker
E-mail: J.Wielemaker@vu.nl
WWW: http://www.swi-prolog.org
Copyright (c) 2010-2017, VU University Amsterdam
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in
the documentation and/or other materials provided with the
distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
*/
#include <config.h>
#include <SWI-Prolog.h>
#include <SWI-Stream.h>
#include "libstemmer_c/include/libstemmer.h"
#include <pthread.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#define STEMMER_BUCKETS (32) /* cache CACHE_SIZE languages */
typedef struct stemmer
{ atom_t language;
struct stemmer *next;
struct sb_stemmer *stemmer;
} stemmer;
typedef struct
{ stemmer *stemmers[STEMMER_BUCKETS];
} stem_cache;
static pthread_key_t stem_key;
#ifndef __WINDOWS__
static pthread_once_t stem_key_once = PTHREAD_ONCE_INIT;
#endif
static void
stem_destroy_cache(void *buf)
{ stem_cache *cache = buf;
int i;
for(i=0; i<STEMMER_BUCKETS; i++)
{ stemmer *s = cache->stemmers[i];
stemmer *n;
for( ; s; s = n)
{ n = s->next;
PL_unregister_atom(s->language);
sb_stemmer_delete(s->stemmer);
PL_free(s);
}
}
PL_free(cache);
}
static void
stem_key_alloc(void)
{ pthread_key_create(&stem_key, stem_destroy_cache);
}
static stem_cache *
get_cache(void)
{ stem_cache *cache;
#ifndef __WINDOWS__
pthread_once(&stem_key_once, stem_key_alloc);
#endif
if ( (cache=(stem_cache*)pthread_getspecific(stem_key)) )
return cache;
if ( (cache = PL_malloc(sizeof(stem_cache))) )
memset(cache, 0, sizeof(*cache));
pthread_setspecific(stem_key, cache);
return cache;
}
#define ATOM_HASH(a) ((unsigned int)(a>>7) & (STEMMER_BUCKETS-1))
static int
get_lang_stemmer(term_t t, struct sb_stemmer **stemmerp)
{ stem_cache *cache = get_cache();
atom_t lang;
int k;
stemmer *s;
struct sb_stemmer *st;
const char *lname;
if ( !PL_get_atom(t, &lang) )
return PL_type_error("atom", t);
k = ATOM_HASH(lang);
for(s=cache->stemmers[k]; s; s=s->next)
{ if ( s->language == lang )
{ *stemmerp = s->stemmer;
return TRUE;
}
}
if ( !(lname=PL_atom_chars(lang)) ||
!(st=sb_stemmer_new(lname, NULL)) )
{ if ( errno == ENOMEM )
return PL_resource_error("memory");
else
return PL_domain_error("snowball_algorithm", t);
}
s = PL_malloc(sizeof(*s));
s->language = lang;
s->stemmer = st;
PL_register_atom(lang);
s->next = cache->stemmers[k];
cache->stemmers[k] = s;
*stemmerp = st;
return TRUE;
}
static foreign_t
snowball(term_t lang, term_t in, term_t out)
{ struct sb_stemmer *stemmer = NULL;
char *s;
size_t len, olen;
const sb_symbol *stemmed;
if ( !get_lang_stemmer(lang, &stemmer) )
return FALSE;
if ( !PL_get_nchars(in, &len, &s,
CVT_ATOM|CVT_STRING|CVT_LIST|REP_UTF8|CVT_EXCEPTION) )
return FALSE;
if ( !(stemmed = sb_stemmer_stem(stemmer, (const sb_symbol*)s, (int)len)) )
return PL_resource_error("memory");
olen = sb_stemmer_length(stemmer);
return PL_unify_chars(out, PL_ATOM|REP_UTF8, olen, (const char*)stemmed);
}
static foreign_t
snowball_algorithms(term_t list)
{ term_t tail = PL_copy_term_ref(list);
term_t head = PL_new_term_ref();
const char **algos = sb_stemmer_list();
int i;
for(i=0; algos[i]; i++)
{ if ( !PL_unify_list(tail, head, tail) ||
!PL_unify_atom_chars(head, algos[i]) )
return FALSE;
}
return PL_unify_nil(tail);
}
install_t
install_snowball(void)
{ assert(sizeof(sb_symbol) == sizeof(char));
PL_register_foreign("snowball", 3, snowball, 0);
PL_register_foreign("snowball_algorithms", 1, snowball_algorithms, 0);
#ifdef __WINDOWS__
stem_key_alloc();
#endif
}
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