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|
/*-
* Copyright 2017 Vsevolod Stakhov
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "lang_detection.h"
#include "libutil/logger.h"
#include "libcryptobox/cryptobox.h"
#include "libutil/multipattern.h"
#include "ucl.h"
#include "khash.h"
#include "libstemmer.h"
#include <glob.h>
#include <unicode/utf8.h>
#include <unicode/utf16.h>
#include <unicode/ucnv.h>
#include <unicode/uchar.h>
#include <unicode/ustring.h>
#include <math.h>
static const gsize default_short_text_limit = 20;
static const gsize default_words = 80;
static const gdouble update_prob = 0.6;
static const gchar *default_languages_path = RSPAMD_PLUGINSDIR "/languages";
#undef EXTRA_LANGDET_DEBUG
struct rspamd_language_unicode_match {
const gchar *lang;
gint unicode_code;
};
/*
* List of languages detected by unicode scripts
*/
static const struct rspamd_language_unicode_match unicode_langs[] = {
{"el", RSPAMD_UNICODE_GREEK},
{"ml", RSPAMD_UNICODE_MALAYALAM},
{"te", RSPAMD_UNICODE_TELUGU},
{"ta", RSPAMD_UNICODE_TAMIL},
{"gu", RSPAMD_UNICODE_GUJARATI},
{"th", RSPAMD_UNICODE_THAI},
{"ka", RSPAMD_UNICODE_GEORGIAN},
{"si", RSPAMD_UNICODE_SINHALA},
{"hy", RSPAMD_UNICODE_ARMENIAN},
{"ja", RSPAMD_UNICODE_JP},
{"ko", RSPAMD_UNICODE_HANGUL},
};
/*
* Top languages
*/
static const gchar *tier0_langs[] = {
"en",
};
static const gchar *tier1_langs[] = {
"fr", "it", "de", "es", "nl",
"pt", "ru", "pl", "tk", "th", "ar"
};
enum rspamd_language_elt_flags {
RS_LANGUAGE_DEFAULT = 0,
RS_LANGUAGE_LATIN = (1 << 0),
RS_LANGUAGE_TIER1 = (1 << 3),
RS_LANGUAGE_TIER0 = (1 << 4),
};
enum rspamd_language_category {
RSPAMD_LANGUAGE_LATIN = 0,
RSPAMD_LANGUAGE_CYRILLIC,
RSPAMD_LANGUAGE_DEVANAGARI,
RSPAMD_LANGUAGE_ARAB,
RSPAMD_LANGUAGE_MAX,
};
struct rspamd_language_elt {
const gchar *name; /* e.g. "en" or "ru" */
enum rspamd_language_elt_flags flags;
enum rspamd_language_category category;
guint trigramms_words;
guint stop_words;
gdouble mean;
gdouble std;
guint occurencies; /* total number of parts with this language */
};
struct rspamd_ngramm_elt {
struct rspamd_language_elt *elt;
gdouble prob;
};
struct rspamd_ngramm_chain {
GPtrArray *languages;
gdouble mean;
gdouble std;
gchar *utf;
};
struct rspamd_stop_word_range {
guint start;
guint stop;
struct rspamd_language_elt *elt;
};
struct rspamd_stop_word_elt {
struct rspamd_multipattern *mp;
GArray *ranges; /* of rspamd_stop_word_range */
};
#define msg_debug_lang_det(...) rspamd_conditional_debug_fast (NULL, NULL, \
rspamd_langdet_log_id, "langdet", task->task_pool->tag.uid, \
G_STRFUNC, \
__VA_ARGS__)
#define msg_debug_lang_det_cfg(...) rspamd_conditional_debug_fast (NULL, NULL, \
rspamd_langdet_log_id, "langdet", cfg->cfg_pool->tag.uid, \
G_STRFUNC, \
__VA_ARGS__)
INIT_LOG_MODULE(langdet)
static const struct rspamd_language_unicode_match *
rspamd_language_search_unicode_match (const gchar *key,
const struct rspamd_language_unicode_match *elts, size_t nelts)
{
size_t i;
for (i = 0; i < nelts; i++) {
if (strcmp (elts[i].lang, key) == 0) {
return &elts[i];
}
}
return NULL;
}
static gboolean
rspamd_language_search_str (const gchar *key, const gchar *elts[], size_t nelts)
{
size_t i;
for (i = 0; i < nelts; i++) {
if (strcmp (elts[i], key) == 0) {
return TRUE;
}
}
return FALSE;
}
static guint
rspamd_trigram_hash_func (gconstpointer key)
{
return rspamd_cryptobox_fast_hash (key, 3 * sizeof (UChar), rspamd_hash_seed ());
}
static gboolean
rspamd_trigram_equal_func (gconstpointer v, gconstpointer v2)
{
return memcmp (v, v2, 3 * sizeof (UChar)) == 0;
}
KHASH_INIT (rspamd_trigram_hash, const UChar *, struct rspamd_ngramm_chain, true,
rspamd_trigram_hash_func, rspamd_trigram_equal_func);
KHASH_INIT (rspamd_candidates_hash, const gchar *,
struct rspamd_lang_detector_res *, true,
rspamd_str_hash, rspamd_str_equal);
KHASH_INIT (rspamd_stopwords_hash, rspamd_ftok_t *,
char, false,
rspamd_ftok_hash, rspamd_ftok_equal);
struct rspamd_lang_detector {
GPtrArray *languages;
khash_t(rspamd_trigram_hash) *trigramms[RSPAMD_LANGUAGE_MAX]; /* trigramms frequencies */
struct rspamd_stop_word_elt stop_words[RSPAMD_LANGUAGE_MAX];
khash_t(rspamd_stopwords_hash) *stop_words_norm;
UConverter *uchar_converter;
gsize short_text_limit;
gsize total_occurencies; /* number of all languages found */
ref_entry_t ref;
};
static void
rspamd_language_detector_ucs_lowercase (UChar *s, gsize len)
{
gsize i;
for (i = 0; i < len; i ++) {
s[i] = u_tolower (s[i]);
}
}
static gboolean
rspamd_language_detector_ucs_is_latin (UChar *s, gsize len)
{
gsize i;
gboolean ret = TRUE;
for (i = 0; i < len; i ++) {
if (!((s[i] >= 'A' && s[i] <= 'Z') || (s[i] >= 'a' && s[i] <= 'z')
|| s[i] == ' ')) {
ret = FALSE;
break;
}
}
return ret;
}
struct rspamd_language_ucs_elt {
guint freq;
const gchar *utf;
UChar s[0];
};
static void
rspamd_language_detector_init_ngramm (struct rspamd_config *cfg,
struct rspamd_lang_detector *d,
struct rspamd_language_elt *lelt,
struct rspamd_language_ucs_elt *ucs,
guint len,
guint freq,
guint total,
khash_t (rspamd_trigram_hash) *htb)
{
struct rspamd_ngramm_chain *chain = NULL, st_chain;
struct rspamd_ngramm_elt *elt;
khiter_t k;
guint i;
gboolean found;
switch (len) {
case 1:
case 2:
g_assert_not_reached ();
break;
case 3:
k = kh_get (rspamd_trigram_hash, htb, ucs->s);
if (k != kh_end (htb)) {
chain = &kh_value (htb, k);
}
break;
default:
g_assert_not_reached ();
break;
}
if (chain == NULL) {
/* New element */
chain = &st_chain;
memset (chain, 0, sizeof (st_chain));
chain->languages = g_ptr_array_sized_new (32);
rspamd_mempool_add_destructor (cfg->cfg_pool, rspamd_ptr_array_free_hard,
chain->languages);
chain->utf = rspamd_mempool_strdup (cfg->cfg_pool, ucs->utf);
elt = rspamd_mempool_alloc (cfg->cfg_pool, sizeof (*elt));
elt->elt = lelt;
elt->prob = ((gdouble)freq) / ((gdouble)total);
g_ptr_array_add (chain->languages, elt);
k = kh_put (rspamd_trigram_hash, htb, ucs->s, &i);
kh_value (htb, k) = *chain;
}
else {
/* Check sanity */
found = FALSE;
PTR_ARRAY_FOREACH (chain->languages, i, elt) {
if (strcmp (elt->elt->name, lelt->name) == 0) {
found = TRUE;
elt->prob += ((gdouble)freq) / ((gdouble)total);
break;
}
}
if (!found) {
elt = rspamd_mempool_alloc (cfg->cfg_pool, sizeof (*elt));
elt->elt = lelt;
elt->prob = ((gdouble)freq) / ((gdouble)total);
g_ptr_array_add (chain->languages, elt);
}
}
}
static inline enum rspamd_language_category
rspamd_language_detector_get_category (guint uflags)
{
enum rspamd_language_category cat = RSPAMD_LANGUAGE_LATIN;
if (uflags & RSPAMD_UNICODE_CYRILLIC) {
cat = RSPAMD_LANGUAGE_CYRILLIC;
}
else if (uflags & RSPAMD_UNICODE_DEVANAGARI) {
cat = RSPAMD_LANGUAGE_DEVANAGARI;
}
else if (uflags & RSPAMD_UNICODE_ARABIC) {
cat = RSPAMD_LANGUAGE_ARAB;
}
return cat;
}
static const gchar *
rspamd_language_detector_print_flags (struct rspamd_language_elt *elt)
{
static gchar flags_buf[256];
goffset r = 0;
if (elt->flags & RS_LANGUAGE_TIER1) {
r += rspamd_snprintf (flags_buf + r, sizeof (flags_buf) - r, "tier1,");
}
if (elt->flags & RS_LANGUAGE_TIER0) {
r += rspamd_snprintf (flags_buf + r, sizeof (flags_buf) - r, "tier0,");
}
if (elt->flags & RS_LANGUAGE_LATIN) {
r += rspamd_snprintf (flags_buf + r, sizeof (flags_buf) - r, "latin,");
}
if (r > 0) {
flags_buf[r - 1] = '\0';
}
else {
flags_buf[r] = '\0';
}
return flags_buf;
}
static gint
rspamd_language_detector_cmp_ngramm (gconstpointer a, gconstpointer b)
{
struct rspamd_language_ucs_elt *e1 = *(struct rspamd_language_ucs_elt **)a;
struct rspamd_language_ucs_elt *e2 = *(struct rspamd_language_ucs_elt **)b;
return (gint)e2->freq - (gint)e1->freq;
}
static void
rspamd_language_detector_read_file (struct rspamd_config *cfg,
struct rspamd_lang_detector *d,
const gchar *path,
const ucl_object_t *stop_words)
{
struct ucl_parser *parser;
ucl_object_t *top;
const ucl_object_t *freqs, *n_words, *cur, *type;
ucl_object_iter_t it = NULL;
UErrorCode uc_err = U_ZERO_ERROR;
struct rspamd_language_elt *nelt;
struct rspamd_language_ucs_elt *ucs_elt;
khash_t (rspamd_trigram_hash) *htb = NULL;
gchar *pos;
guint total = 0, total_latin = 0, total_ngramms = 0, i, skipped,
loaded, nstop = 0;
gdouble mean = 0, std = 0, delta = 0, delta2 = 0, m2 = 0;
enum rspamd_language_category cat = RSPAMD_LANGUAGE_MAX;
parser = ucl_parser_new (UCL_PARSER_NO_FILEVARS);
if (!ucl_parser_add_file (parser, path)) {
msg_warn_config ("cannot parse file %s: %s", path,
ucl_parser_get_error (parser));
ucl_parser_free (parser);
return;
}
top = ucl_parser_get_object (parser);
ucl_parser_free (parser);
freqs = ucl_object_lookup (top, "freq");
if (freqs == NULL) {
msg_warn_config ("file %s has no 'freq' key", path);
ucl_object_unref (top);
return;
}
pos = strrchr (path, '/');
g_assert (pos != NULL);
nelt = rspamd_mempool_alloc0 (cfg->cfg_pool, sizeof (*nelt));
nelt->name = rspamd_mempool_strdup (cfg->cfg_pool, pos + 1);
/* Remove extension */
pos = strchr (nelt->name, '.');
g_assert (pos != NULL);
*pos = '\0';
n_words = ucl_object_lookup (top, "n_words");
if (n_words == NULL || ucl_object_type (n_words) != UCL_ARRAY ||
n_words->len != 3) {
msg_warn_config ("cannot find n_words in language %s", nelt->name);
ucl_object_unref (top);
return;
}
else {
nelt->trigramms_words = ucl_object_toint (ucl_array_find_index (n_words,
2));
}
type = ucl_object_lookup (top, "type");
if (type == NULL || ucl_object_type (type) != UCL_STRING) {
msg_debug_config ("cannot find type in language %s", nelt->name);
ucl_object_unref (top);
return;
}
else {
const gchar *stype = ucl_object_tostring (type);
if (strcmp (stype, "latin") == 0) {
cat = RSPAMD_LANGUAGE_LATIN;
}
else if (strcmp (stype, "cyrillic") == 0) {
cat = RSPAMD_LANGUAGE_CYRILLIC;
}
else if (strcmp (stype, "arab") == 0) {
cat = RSPAMD_LANGUAGE_ARAB;
}
else if (strcmp (stype, "devanagari") == 0) {
cat = RSPAMD_LANGUAGE_DEVANAGARI;
}
else {
msg_debug_config ("unknown type %s of language %s", stype, nelt->name);
ucl_object_unref (top);
return;
}
}
if (stop_words) {
const ucl_object_t *specific_stop_words;
specific_stop_words = ucl_object_lookup (stop_words, nelt->name);
if (specific_stop_words) {
struct sb_stemmer *stem = NULL;
it = NULL;
const ucl_object_t *w;
guint start, stop;
stem = sb_stemmer_new (nelt->name, "UTF_8");
start = rspamd_multipattern_get_npatterns (d->stop_words[cat].mp);
while ((w = ucl_object_iterate (specific_stop_words, &it, true)) != NULL) {
gsize wlen;
const char *word = ucl_object_tolstring (w, &wlen);
const char *saved;
rspamd_multipattern_add_pattern_len (d->stop_words[cat].mp,
word, wlen,
RSPAMD_MULTIPATTERN_ICASE|RSPAMD_MULTIPATTERN_UTF8);
nelt->stop_words ++;
nstop ++;
/* Also lemmatise and store normalised */
if (stem) {
const char *nw = sb_stemmer_stem (stem, word, wlen);
if (nw) {
saved = nw;
wlen = strlen (nw);
}
else {
saved = word;
}
}
else {
saved = word;
}
if (saved) {
gint rc;
rspamd_ftok_t *tok;
gchar *dst;
tok = g_malloc (sizeof (*tok) + wlen + 1);
dst = ((gchar *)tok) + sizeof (*tok);
rspamd_strlcpy (dst, saved, wlen + 1);
tok->begin = dst;
tok->len = wlen;
kh_put (rspamd_stopwords_hash, d->stop_words_norm,
tok, &rc);
}
}
if (stem) {
sb_stemmer_delete (stem);
}
stop = rspamd_multipattern_get_npatterns (d->stop_words[cat].mp);
struct rspamd_stop_word_range r;
r.start = start;
r.stop = stop;
r.elt = nelt;
g_array_append_val (d->stop_words[cat].ranges, r);
it = NULL;
}
}
nelt->category = cat;
htb = d->trigramms[cat];
GPtrArray *ngramms;
guint nsym;
if (rspamd_language_search_str (nelt->name, tier1_langs,
G_N_ELEMENTS (tier1_langs))) {
nelt->flags |= RS_LANGUAGE_TIER1;
}
if (rspamd_language_search_str (nelt->name, tier0_langs,
G_N_ELEMENTS (tier0_langs))) {
nelt->flags |= RS_LANGUAGE_TIER0;
}
it = NULL;
ngramms = g_ptr_array_sized_new (freqs->len);
i = 0;
skipped = 0;
loaded = 0;
while ((cur = ucl_object_iterate (freqs, &it, true)) != NULL) {
const gchar *key;
gsize keylen;
guint freq;
key = ucl_object_keyl (cur, &keylen);
freq = ucl_object_toint (cur);
i ++;
delta = freq - mean;
mean += delta / i;
delta2 = freq - mean;
m2 += delta * delta2;
if (key != NULL) {
ucs_elt = rspamd_mempool_alloc (cfg->cfg_pool,
sizeof (*ucs_elt) + (keylen + 1) * sizeof (UChar));
nsym = ucnv_toUChars (d->uchar_converter,
ucs_elt->s, keylen + 1,
key,
keylen, &uc_err);
ucs_elt->utf = key;
if (uc_err != U_ZERO_ERROR) {
msg_warn_config ("cannot convert key to unicode: %s",
u_errorName (uc_err));
continue;
}
rspamd_language_detector_ucs_lowercase (ucs_elt->s, nsym);
if (nsym == 3) {
g_ptr_array_add (ngramms, ucs_elt);
}
else {
continue;
}
if (rspamd_language_detector_ucs_is_latin (ucs_elt->s, nsym)) {
total_latin++;
}
ucs_elt->freq = freq;
total_ngramms++;
}
}
std = sqrt (m2 / (i - 1));
if (total_latin >= total_ngramms / 3) {
nelt->flags |= RS_LANGUAGE_LATIN;
}
nsym = 3;
total = 0;
PTR_ARRAY_FOREACH (ngramms, i, ucs_elt) {
if (!(nelt->flags & RS_LANGUAGE_LATIN) &&
rspamd_language_detector_ucs_is_latin (ucs_elt->s, nsym)) {
ucs_elt->freq = 0;
/* Skip latin ngramm for non-latin language to avoid garbadge */
skipped ++;
continue;
}
/* Now, discriminate low frequency ngramms */
total += ucs_elt->freq;
loaded ++;
}
g_ptr_array_sort (ngramms, rspamd_language_detector_cmp_ngramm);
PTR_ARRAY_FOREACH (ngramms, i, ucs_elt) {
if (ucs_elt->freq > 0) {
rspamd_language_detector_init_ngramm (cfg, d,
nelt, ucs_elt, nsym,
ucs_elt->freq, total, htb);
}
}
#ifdef EXTRA_LANGDET_DEBUG
/* Useful for debug */
for (i = 0; i < 10; i ++) {
ucs_elt = g_ptr_array_index (ngramms, i);
msg_debug_lang_det_cfg ("%s -> %s: %d", nelt->name,
ucs_elt->utf, ucs_elt->freq);
}
#endif
g_ptr_array_free (ngramms, TRUE);
nelt->mean = mean;
nelt->std = std;
msg_debug_lang_det_cfg ("loaded %s language, %d trigramms, "
"%d ngramms loaded; "
"std=%.2f, mean=%.2f, skipped=%d, loaded=%d, stop_words=%d; "
"(%s)",
nelt->name,
(gint)nelt->trigramms_words,
total,
std, mean,
skipped, loaded, nelt->stop_words,
rspamd_language_detector_print_flags (nelt));
g_ptr_array_add (d->languages, nelt);
ucl_object_unref (top);
}
static gboolean
rspamd_ucl_array_find_str (const gchar *str, const ucl_object_t *ar)
{
ucl_object_iter_t it = NULL;
const ucl_object_t *cur;
if (ar == NULL || ar->len == 0) {
return FALSE;
}
while ((cur = ucl_object_iterate (ar, &it, true)) != NULL) {
if (ucl_object_type (cur) == UCL_STRING && rspamd_strcase_equal (
ucl_object_tostring (cur), str)) {
return TRUE;
}
}
return FALSE;
}
static void
rspamd_language_detector_process_chain (struct rspamd_config *cfg,
struct rspamd_ngramm_chain *chain)
{
struct rspamd_ngramm_elt *elt;
guint i;
gdouble delta, mean = 0, delta2, m2 = 0, std;
if (chain->languages->len > 3) {
PTR_ARRAY_FOREACH (chain->languages, i, elt) {
delta = elt->prob - mean;
mean += delta / (i + 1);
delta2 = elt->prob - mean;
m2 += delta * delta2;
}
std = sqrt (m2 / (i - 1));
chain->mean = mean;
chain->std = std;
/* Now, filter elements that are lower than mean */
PTR_ARRAY_FOREACH (chain->languages, i, elt) {
if (elt->prob < mean) {
g_ptr_array_remove_index_fast (chain->languages, i);
#ifdef EXTRA_LANGDET_DEBUG
msg_debug_lang_det_cfg ("remove %s from %s; prob: %.4f; mean: %.4f, std: %.4f",
elt->elt->name, chain->utf, elt->prob, mean, std);
#endif
}
}
}
else {
/* We have a unique ngramm, increase its weight */
PTR_ARRAY_FOREACH (chain->languages, i, elt) {
elt->prob *= 4.0;
#ifdef EXTRA_LANGDET_DEBUG
msg_debug_lang_det_cfg ("increase weight of %s in %s; prob: %.4f",
elt->elt->name, chain->utf, elt->prob);
#endif
}
}
}
static void
rspamd_language_detector_dtor (struct rspamd_lang_detector *d)
{
if (d) {
rspamd_ftok_t *tok;
if (d->uchar_converter) {
ucnv_close (d->uchar_converter);
}
for (guint i = 0; i < RSPAMD_LANGUAGE_MAX; i ++) {
kh_destroy (rspamd_trigram_hash, d->trigramms[i]);
rspamd_multipattern_destroy (d->stop_words[i].mp);
g_array_free (d->stop_words[i].ranges, TRUE);
}
if (d->languages) {
g_ptr_array_free (d->languages, TRUE);
}
kh_foreach_key (d->stop_words_norm, tok, {
g_free (tok); /* String is embedded and freed automatically */
});
}
}
struct rspamd_lang_detector*
rspamd_language_detector_init (struct rspamd_config *cfg)
{
const ucl_object_t *section, *elt, *languages_enable = NULL,
*languages_disable = NULL;
const gchar *languages_path = default_languages_path;
glob_t gl;
size_t i, short_text_limit = default_short_text_limit, total = 0;
UErrorCode uc_err = U_ZERO_ERROR;
GString *languages_pattern;
struct rspamd_ngramm_chain *chain, schain;
gchar *fname;
struct rspamd_lang_detector *ret = NULL;
struct ucl_parser *parser;
ucl_object_t *stop_words;
section = ucl_object_lookup (cfg->rcl_obj, "lang_detection");
if (section != NULL) {
elt = ucl_object_lookup (section, "languages");
if (elt) {
languages_path = ucl_object_tostring (elt);
}
elt = ucl_object_lookup (section, "short_text_limit");
if (elt) {
short_text_limit = ucl_object_toint (elt);
}
languages_enable = ucl_object_lookup (section, "languages_enable");
languages_disable = ucl_object_lookup (section, "languages_disable");
}
languages_pattern = g_string_sized_new (PATH_MAX);
rspamd_printf_gstring (languages_pattern, "%s/stop_words", languages_path);
parser = ucl_parser_new (UCL_PARSER_DEFAULT);
if (ucl_parser_add_file (parser, languages_pattern->str)) {
stop_words = ucl_parser_get_object (parser);
}
else {
msg_err_config ("cannot read stop words from %s: %s",
languages_pattern->str,
ucl_parser_get_error (parser));
stop_words = NULL;
}
ucl_parser_free (parser);
languages_pattern->len = 0;
rspamd_printf_gstring (languages_pattern, "%s/*.json", languages_path);
memset (&gl, 0, sizeof (gl));
if (glob (languages_pattern->str, 0, NULL, &gl) != 0) {
msg_err_config ("cannot read any files matching %v", languages_pattern);
goto end;
}
ret = rspamd_mempool_alloc0 (cfg->cfg_pool, sizeof (*ret));
ret->languages = g_ptr_array_sized_new (gl.gl_pathc);
ret->uchar_converter = rspamd_get_utf8_converter ();
ret->short_text_limit = short_text_limit;
ret->stop_words_norm = kh_init (rspamd_stopwords_hash);
/* Map from ngramm in ucs32 to GPtrArray of rspamd_language_elt */
for (i = 0; i < RSPAMD_LANGUAGE_MAX; i ++) {
ret->trigramms[i] = kh_init (rspamd_trigram_hash);
ret->stop_words[i].mp = rspamd_multipattern_create (
RSPAMD_MULTIPATTERN_ICASE|RSPAMD_MULTIPATTERN_UTF8);
ret->stop_words[i].ranges = g_array_new (FALSE, FALSE,
sizeof (struct rspamd_stop_word_range));
}
g_assert (uc_err == U_ZERO_ERROR);
for (i = 0; i < gl.gl_pathc; i ++) {
fname = g_path_get_basename (gl.gl_pathv[i]);
if (!rspamd_ucl_array_find_str (fname, languages_disable) ||
(languages_enable == NULL ||
rspamd_ucl_array_find_str (fname, languages_enable))) {
rspamd_language_detector_read_file (cfg, ret, gl.gl_pathv[i],
stop_words);
}
else {
msg_info_config ("skip language file %s: disabled", fname);
}
g_free (fname);
}
for (i = 0; i < RSPAMD_LANGUAGE_MAX; i ++) {
GError *err = NULL;
kh_foreach_value (ret->trigramms[i], schain, {
chain = &schain;
rspamd_language_detector_process_chain (cfg, chain);
});
if (!rspamd_multipattern_compile (ret->stop_words[i].mp, &err)) {
msg_err_config ("cannot compile stop words for %z language group: %e",
i, err);
g_error_free (err);
}
total += kh_size (ret->trigramms[i]);
}
msg_info_config ("loaded %d languages, "
"%d trigramms",
(gint)ret->languages->len,
(gint)total);
if (stop_words) {
ucl_object_unref (stop_words);
}
REF_INIT_RETAIN (ret, rspamd_language_detector_dtor);
rspamd_mempool_add_destructor (cfg->cfg_pool,
(rspamd_mempool_destruct_t)rspamd_language_detector_unref,
ret);
end:
if (gl.gl_pathc > 0) {
globfree (&gl);
}
g_string_free (languages_pattern, TRUE);
return ret;
}
static void
rspamd_language_detector_random_select (GArray *ucs_tokens, guint nwords,
goffset *offsets_out)
{
guint step_len, remainder, i, out_idx;
guint64 coin, sel;
rspamd_stat_token_t *tok;
UChar32 first, last;
g_assert (nwords != 0);
g_assert (offsets_out != NULL);
g_assert (ucs_tokens->len >= nwords);
/*
* We split input array into `nwords` parts. For each part we randomly select
* an element from this particular split. Here is an example:
*
* nwords=2, input_len=5
*
* w1 w2 w3 w4 w5
* ^ ^
* part1 part2
* vv vv
* w2 w5
*
* So we have 2 output words from 5 input words selected randomly within
* their splits. It is not uniform distribution but it seems to be better
* to include words from different text parts
*/
step_len = ucs_tokens->len / nwords;
remainder = ucs_tokens->len % nwords;
out_idx = 0;
coin = rspamd_random_uint64_fast ();
sel = coin % (step_len + remainder);
offsets_out[out_idx] = sel;
for (i = step_len + remainder; i < ucs_tokens->len;
i += step_len, out_idx ++) {
guint ntries = 0;
coin = rspamd_random_uint64_fast ();
sel = (coin % step_len) + i;
for (;;) {
tok = &g_array_index (ucs_tokens, rspamd_stat_token_t, sel);
/* Filter bad tokens */
if (tok->normalized.len >= 2) {
U16_GET_OR_FFFD (tok->normalized.begin, 0, 0, tok->normalized.len,
first);
U16_GET_OR_FFFD (tok->normalized.begin, 0, tok->normalized.len - 1,
tok->normalized.len,
last);
if (u_isalpha (first) && u_isalpha (last)) {
offsets_out[out_idx] = sel;
break;
}
}
else {
ntries ++;
coin = rspamd_random_uint64_fast ();
if (ntries < step_len) {
sel = (coin % step_len) + i;
}
else if (ntries < ucs_tokens->len) {
sel = coin % ucs_tokens->len;
}
else {
offsets_out[out_idx] = sel;
break;
}
}
}
}
/*
* Fisher-Yates algorithm:
* for i from 0 to n−2 do
* j ← random integer such that i ≤ j < n
* exchange a[i] and a[j]
*/
#if 0
if (out_idx > 2) {
for (i = 0; i < out_idx - 2; i++) {
coin = rspamd_random_uint64_fast ();
sel = (coin % (out_idx - i)) + i;
/* swap */
tmp = offsets_out[i];
offsets_out[i] = offsets_out[sel];
offsets_out[sel] = tmp;
}
}
#endif
}
static goffset
rspamd_language_detector_next_ngramm (rspamd_stat_token_t *tok, UChar *window,
guint wlen, goffset cur_off)
{
guint i;
if (wlen > 1) {
/* Deal with spaces at the beginning and ending */
if (cur_off == 0) {
window[0] = (UChar)' ';
for (i = 0; i < wlen - 1; i ++) {
window[i + 1] = tok->unicode.begin[i];
}
}
else if (cur_off + wlen == tok->normalized.len + 1) {
/* Add trailing space */
for (i = 0; i < wlen - 1; i ++) {
window[i] = tok->unicode.begin[cur_off + i];
}
window[wlen - 1] = (UChar)' ';
}
else if (cur_off + wlen > tok->normalized.len + 1) {
/* No more fun */
return -1;
}
else {
/* Normal case */
for (i = 0; i < wlen; i++) {
window[i] = tok->unicode.begin[cur_off + i];
}
}
}
else {
if (tok->normalized.len <= cur_off) {
return -1;
}
window[0] = tok->unicode.begin[cur_off];
}
return cur_off + 1;
}
/*
* Do full guess for a specific ngramm, checking all languages defined
*/
static void
rspamd_language_detector_process_ngramm_full (struct rspamd_task *task,
struct rspamd_lang_detector *d,
UChar *window,
khash_t(rspamd_candidates_hash) *candidates,
khash_t(rspamd_trigram_hash) *trigramms)
{
guint i;
gint ret;
struct rspamd_ngramm_chain *chain = NULL;
struct rspamd_ngramm_elt *elt;
struct rspamd_lang_detector_res *cand;
khiter_t k;
gdouble prob;
k = kh_get (rspamd_trigram_hash, trigramms, window);
if (k != kh_end (trigramms)) {
chain = &kh_value (trigramms, k);
}
if (chain) {
PTR_ARRAY_FOREACH (chain->languages, i, elt) {
prob = elt->prob;
if (prob < chain->mean) {
continue;
}
k = kh_get (rspamd_candidates_hash, candidates, elt->elt->name);
if (k != kh_end (candidates)) {
cand = kh_value (candidates, k);
}
else {
cand = NULL;
}
#ifdef NGRAMMS_DEBUG
msg_err ("gramm: %s, lang: %s, prob: %.3f", chain->utf,
elt->elt->name, log2 (elt->prob));
#endif
if (cand == NULL) {
cand = rspamd_mempool_alloc (task->task_pool, sizeof (*cand));
cand->elt = elt->elt;
cand->lang = elt->elt->name;
cand->prob = prob;
k = kh_put (rspamd_candidates_hash, candidates, elt->elt->name,
&ret);
kh_value (candidates, k) = cand;
} else {
/* Update guess */
cand->prob += prob;
}
}
}
}
static void
rspamd_language_detector_detect_word (struct rspamd_task *task,
struct rspamd_lang_detector *d,
rspamd_stat_token_t *tok,
khash_t(rspamd_candidates_hash) *candidates,
khash_t(rspamd_trigram_hash) *trigramms)
{
const guint wlen = 3;
UChar window[3];
goffset cur = 0;
/* Split words */
while ((cur = rspamd_language_detector_next_ngramm (tok, window, wlen, cur))
!= -1) {
rspamd_language_detector_process_ngramm_full (task,
d, window, candidates, trigramms);
}
}
static const gdouble cutoff_limit = -8.0;
/*
* Converts frequencies to log probabilities, filter those candidates who
* has the lowest probabilities
*/
static inline void
rspamd_language_detector_filter_step1 (struct rspamd_task *task,
struct rspamd_lang_detector_res *cand,
gdouble *max_prob, guint *filtered)
{
if (!isnan (cand->prob)) {
if (cand->prob == 0) {
cand->prob = NAN;
msg_debug_lang_det (
"exclude language %s",
cand->lang);
(*filtered)++;
}
else {
cand->prob = log2 (cand->prob);
if (cand->prob < cutoff_limit) {
msg_debug_lang_det (
"exclude language %s: %.3f, cutoff limit: %.3f",
cand->lang, cand->prob, cutoff_limit);
cand->prob = NAN;
(*filtered)++;
}
else if (cand->prob > *max_prob) {
*max_prob = cand->prob;
}
}
}
}
static inline void
rspamd_language_detector_filter_step2 (struct rspamd_task *task,
struct rspamd_lang_detector_res *cand,
gdouble max_prob, guint *filtered)
{
/*
* Probabilities are logarithmic, so if prob1 - prob2 > 4, it means that
* prob2 is 2^4 less than prob1
*/
if (!isnan (cand->prob) && max_prob - cand->prob > 1) {
msg_debug_lang_det ("exclude language %s: %.3f (%.3f max)",
cand->lang, cand->prob, max_prob);
cand->prob = NAN;
(*filtered) ++;
}
}
static void
rspamd_language_detector_filter_negligible (struct rspamd_task *task,
khash_t(rspamd_candidates_hash) *candidates)
{
struct rspamd_lang_detector_res *cand;
guint filtered = 0;
gdouble max_prob = -(G_MAXDOUBLE);
kh_foreach_value (candidates, cand,
rspamd_language_detector_filter_step1 (task, cand, &max_prob, &filtered));
kh_foreach_value (candidates, cand,
rspamd_language_detector_filter_step2 (task, cand, max_prob, &filtered));
msg_debug_lang_det ("removed %d languages", filtered);
}
static void
rspamd_language_detector_detect_type (struct rspamd_task *task,
guint nwords,
struct rspamd_lang_detector *d,
GArray *words,
enum rspamd_language_category cat,
khash_t(rspamd_candidates_hash) *candidates)
{
guint nparts = MIN (words->len, nwords);
goffset *selected_words;
rspamd_stat_token_t *tok, ucs_w;
guint i;
selected_words = g_new0 (goffset, nparts);
rspamd_language_detector_random_select (words, nparts, selected_words);
msg_debug_lang_det ("randomly selected %d words", nparts);
for (i = 0; i < nparts; i++) {
tok = &g_array_index (words, rspamd_stat_token_t,
selected_words[i]);
rspamd_language_detector_detect_word (task, d, tok, candidates,
d->trigramms[cat]);
}
/* Filter negligible candidates */
rspamd_language_detector_filter_negligible (task, candidates);
g_free (selected_words);
}
static gint
rspamd_language_detector_cmp (gconstpointer a, gconstpointer b)
{
const struct rspamd_lang_detector_res
*canda = *(const struct rspamd_lang_detector_res **)a,
*candb = *(const struct rspamd_lang_detector_res **)b;
if (canda->prob > candb->prob) {
return -1;
}
else if (candb->prob > canda->prob) {
return 1;
}
return 0;
}
enum rspamd_language_detected_type {
rs_detect_none = 0,
rs_detect_single,
rs_detect_multiple,
};
static enum rspamd_language_detected_type
rspamd_language_detector_try_ngramm (struct rspamd_task *task,
guint nwords,
struct rspamd_lang_detector *d,
GArray *ucs_tokens,
enum rspamd_language_category cat,
khash_t(rspamd_candidates_hash) *candidates)
{
guint cand_len = 0;
struct rspamd_lang_detector_res *cand;
rspamd_language_detector_detect_type (task,
nwords,
d,
ucs_tokens,
cat,
candidates);
kh_foreach_value (candidates, cand, {
if (!isnan (cand->prob)) {
cand_len ++;
}
});
if (cand_len == 0) {
return rs_detect_none;
}
else if (cand_len == 1) {
return rs_detect_single;
}
return rs_detect_multiple;
}
enum rspamd_language_sort_flags {
RSPAMD_LANG_FLAG_DEFAULT = 0,
RSPAMD_LANG_FLAG_SHORT = 1 << 0,
};
struct rspamd_frequency_sort_cbdata {
struct rspamd_lang_detector *d;
enum rspamd_language_sort_flags flags;
gdouble std;
gdouble mean;
};
static const gdouble tier0_adjustment = 1.2;
static const gdouble tier1_adjustment = 0.8;
static const gdouble frequency_adjustment = 0.8;
static gint
rspamd_language_detector_cmp_heuristic (gconstpointer a, gconstpointer b,
gpointer ud)
{
struct rspamd_frequency_sort_cbdata *cbd = ud;
const struct rspamd_lang_detector_res
*canda = *(const struct rspamd_lang_detector_res **)a,
*candb = *(const struct rspamd_lang_detector_res **)b;
gdouble adj;
gdouble proba_adjusted, probb_adjusted, freqa, freqb;
freqa = ((gdouble)canda->elt->occurencies) /
(gdouble)cbd->d->total_occurencies;
freqb = ((gdouble)candb->elt->occurencies) /
(gdouble)cbd->d->total_occurencies;
proba_adjusted = canda->prob;
probb_adjusted = candb->prob;
if (isnormal (freqa) && isnormal (freqb)) {
proba_adjusted += cbd->std * (frequency_adjustment * freqa);
probb_adjusted += cbd->std * (frequency_adjustment * freqb);
}
if (cbd->flags & RSPAMD_LANG_FLAG_SHORT) {
adj = tier1_adjustment * 2.0;
}
else {
adj = tier1_adjustment;
}
if (canda->elt->flags & RS_LANGUAGE_TIER1) {
proba_adjusted += cbd->std * adj;
}
if (candb->elt->flags & RS_LANGUAGE_TIER1) {
probb_adjusted += cbd->std * adj;
}
if (cbd->flags & RSPAMD_LANG_FLAG_SHORT) {
adj = tier0_adjustment * 16.0;
}
else {
adj = tier0_adjustment;
}
if (canda->elt->flags & RS_LANGUAGE_TIER0) {
proba_adjusted += cbd->std * adj;
}
if (candb->elt->flags & RS_LANGUAGE_TIER0) {
probb_adjusted += cbd->std * adj;
}
if (proba_adjusted > probb_adjusted) {
return -1;
}
else if (probb_adjusted > proba_adjusted) {
return 1;
}
return 0;
}
static void
rspamd_language_detector_unicode_scripts (struct rspamd_task *task,
struct rspamd_mime_text_part *part)
{
const gchar *p = part->utf_stripped_content->data, *end;
guint i = 0;
end = p + part->utf_stripped_content->len;
gint32 uc, sc;
guint nlatin = 0, nchinese = 0, nspecial = 0;
while (p + i < end) {
U8_NEXT (p, i, part->utf_stripped_content->len, uc);
if (((gint32) uc) < 0) {
break;
}
if (u_isalpha (uc)) {
sc = ublock_getCode (uc);
switch (sc) {
case UBLOCK_BASIC_LATIN:
case UBLOCK_LATIN_1_SUPPLEMENT:
part->unicode_scripts |= RSPAMD_UNICODE_LATIN;
nlatin ++;
break;
case UBLOCK_HEBREW:
part->unicode_scripts |= RSPAMD_UNICODE_HEBREW;
nspecial ++;
break;
case UBLOCK_GREEK:
part->unicode_scripts |= RSPAMD_UNICODE_GREEK;
nspecial ++;
break;
case UBLOCK_CYRILLIC:
part->unicode_scripts |= RSPAMD_UNICODE_CYRILLIC;
nspecial ++;
break;
case UBLOCK_CJK_UNIFIED_IDEOGRAPHS:
case UBLOCK_CJK_COMPATIBILITY:
case UBLOCK_CJK_RADICALS_SUPPLEMENT:
case UBLOCK_CJK_UNIFIED_IDEOGRAPHS_EXTENSION_A:
case UBLOCK_CJK_UNIFIED_IDEOGRAPHS_EXTENSION_B:
part->unicode_scripts |= RSPAMD_UNICODE_CJK;
nchinese ++;
break;
case UBLOCK_HIRAGANA:
case UBLOCK_KATAKANA:
part->unicode_scripts |= RSPAMD_UNICODE_JP;
nspecial ++;
break;
case UBLOCK_HANGUL_JAMO:
case UBLOCK_HANGUL_COMPATIBILITY_JAMO:
part->unicode_scripts |= RSPAMD_UNICODE_HANGUL;
nspecial ++;
break;
case UBLOCK_ARABIC:
part->unicode_scripts |= RSPAMD_UNICODE_ARABIC;
nspecial ++;
break;
case UBLOCK_DEVANAGARI:
part->unicode_scripts |= RSPAMD_UNICODE_DEVANAGARI;
nspecial ++;
break;
case UBLOCK_ARMENIAN:
part->unicode_scripts |= RSPAMD_UNICODE_ARMENIAN;
nspecial ++;
break;
case UBLOCK_GEORGIAN:
part->unicode_scripts |= RSPAMD_UNICODE_GEORGIAN;
nspecial ++;
break;
case UBLOCK_GUJARATI:
part->unicode_scripts |= RSPAMD_UNICODE_GUJARATI;
nspecial ++;
break;
case UBLOCK_TELUGU:
part->unicode_scripts |= RSPAMD_UNICODE_TELUGU;
nspecial ++;
break;
case UBLOCK_TAMIL:
part->unicode_scripts |= RSPAMD_UNICODE_TAMIL;
nspecial ++;
break;
case UBLOCK_THAI:
part->unicode_scripts |= RSPAMD_UNICODE_THAI;
nspecial ++;
break;
case RSPAMD_UNICODE_MALAYALAM:
part->unicode_scripts |= RSPAMD_UNICODE_MALAYALAM;
nspecial ++;
break;
case RSPAMD_UNICODE_SINHALA:
part->unicode_scripts |= RSPAMD_UNICODE_SINHALA;
nspecial ++;
break;
}
}
if (nspecial > 6 && nspecial > nlatin) {
break;
}
else if (nchinese > 6 && nchinese > nlatin) {
if (nspecial > 0) {
/* Likely japanese */
break;
}
}
}
msg_debug_lang_det ("stop after checking %d characters, "
"%d latin, %d special, %d chinese",
i, nlatin, nspecial, nchinese);
}
static inline void
rspamd_language_detector_set_language (struct rspamd_task *task,
struct rspamd_mime_text_part *part,
const gchar *code)
{
struct rspamd_lang_detector_res *r;
r = rspamd_mempool_alloc0 (task->task_pool, sizeof (*r));
r->prob = 1.0;
r->lang = code;
part->languages = g_ptr_array_sized_new (1);
g_ptr_array_add (part->languages, r);
part->language = code;
}
static gboolean
rspamd_language_detector_try_uniscript (struct rspamd_task *task,
struct rspamd_mime_text_part *part)
{
guint i;
for (i = 0; i < G_N_ELEMENTS (unicode_langs); i ++) {
if (unicode_langs[i].unicode_code & part->unicode_scripts) {
msg_debug_lang_det ("set language based on unicode script %s",
unicode_langs[i].lang);
rspamd_language_detector_set_language (task, part,
unicode_langs[i].lang);
return TRUE;
}
}
if (part->unicode_scripts & RSPAMD_UNICODE_CJK) {
rspamd_language_detector_set_language (task, part,
"zh-CN");
return TRUE;
}
return FALSE;
}
static guint
rspamd_langelt_hash_func (gconstpointer key)
{
const struct rspamd_language_elt *elt = (const struct rspamd_language_elt *)key;
return rspamd_cryptobox_fast_hash (elt->name, strlen (elt->name),
rspamd_hash_seed ());
}
static gboolean
rspamd_langelt_equal_func (gconstpointer v, gconstpointer v2)
{
const struct rspamd_language_elt *elt1 = (const struct rspamd_language_elt *)v,
*elt2 = (const struct rspamd_language_elt *)v2;
return strcmp (elt1->name, elt2->name) == 0;
}
KHASH_INIT (rspamd_sw_hash, struct rspamd_language_elt *, int, 1,
rspamd_langelt_hash_func, rspamd_langelt_equal_func);
struct rspamd_sw_cbdata {
khash_t (rspamd_sw_hash) *res;
GArray *ranges;
};
static gint
rspamd_ranges_cmp (const void *k, const void *memb)
{
gint pos = GPOINTER_TO_INT (k);
const struct rspamd_stop_word_range *r = (struct rspamd_stop_word_range *)memb;
if (pos >= r->start && pos < r->stop) {
return 0;
}
else if (pos < r->start) {
return -1;
}
return 1;
}
static gint
rspamd_language_detector_sw_cb (struct rspamd_multipattern *mp,
guint strnum,
gint match_start,
gint match_pos,
const gchar *text,
gsize len,
void *context)
{
/* Check if boundary */
const gchar *prev = text, *next = text + len;
struct rspamd_stop_word_range *r;
struct rspamd_sw_cbdata *cbdata = (struct rspamd_sw_cbdata *)context;
khiter_t k;
if (match_start > 0) {
prev = text + match_start - 1;
if (!(g_ascii_isspace (*prev) || g_ascii_ispunct (*prev))) {
return 0;
}
}
if (match_pos < len) {
next = text + match_pos;
if (!(g_ascii_isspace (*next) || g_ascii_ispunct (*next))) {
return 0;
}
}
/* We have a word on the boundary, check range */
r = bsearch (GINT_TO_POINTER (strnum), cbdata->ranges->data,
cbdata->ranges->len, sizeof (*r), rspamd_ranges_cmp);
g_assert (r != NULL);
k = kh_get (rspamd_sw_hash, cbdata->res, r->elt);
if (k != kh_end (cbdata->res)) {
kh_value (cbdata->res, k) ++;
}
else {
gint tt;
k = kh_put (rspamd_sw_hash, cbdata->res, r->elt, &tt);
kh_value (cbdata->res, k) = 1;
}
return 0;
}
static gboolean
rspamd_language_detector_try_stop_words (struct rspamd_task *task,
struct rspamd_lang_detector *d,
struct rspamd_mime_text_part *part,
enum rspamd_language_category cat)
{
struct rspamd_stop_word_elt *elt;
struct rspamd_sw_cbdata cbdata;
gboolean ret = FALSE;
elt = &d->stop_words[cat];
cbdata.res = kh_init (rspamd_sw_hash);
cbdata.ranges = elt->ranges;
rspamd_multipattern_lookup (elt->mp, part->utf_stripped_content->data,
part->utf_stripped_content->len, rspamd_language_detector_sw_cb,
&cbdata, NULL);
if (kh_size (cbdata.res) > 0) {
gint cur_matches;
double max_rate = G_MINDOUBLE;
const gchar *sel = NULL;
struct rspamd_language_elt *cur_lang;
kh_foreach (cbdata.res, cur_lang, cur_matches, {
double rate = (double)cur_matches / (double)cur_lang->stop_words;
if (rate > max_rate) {
max_rate = rate;
sel = cur_lang->name;
}
msg_debug_lang_det ("found %d stop words from %s: %3f rate",
cur_matches, cur_lang->name, rate);
});
if (max_rate > 0 && sel) {
msg_debug_lang_det ("set language based on stop words script %s, %.3f found",
sel, max_rate);
rspamd_language_detector_set_language (task, part,
sel);
ret = TRUE;
}
}
kh_destroy (rspamd_sw_hash, cbdata.res);
return ret;
}
gboolean
rspamd_language_detector_detect (struct rspamd_task *task,
struct rspamd_lang_detector *d,
struct rspamd_mime_text_part *part)
{
khash_t(rspamd_candidates_hash) *candidates;
GPtrArray *result;
gdouble mean, std, start_ticks, end_ticks;
guint cand_len;
enum rspamd_language_category cat;
struct rspamd_lang_detector_res *cand;
enum rspamd_language_detected_type r;
struct rspamd_frequency_sort_cbdata cbd;
/* Check if we have sorted candidates based on frequency */
gboolean frequency_heuristic_applied = FALSE, ret = FALSE;
if (!part->utf_stripped_content) {
return FALSE;
}
start_ticks = rspamd_get_ticks (TRUE);
rspamd_language_detector_unicode_scripts (task, part);
/* Apply unicode scripts heuristic */
if (rspamd_language_detector_try_uniscript (task, part)) {
ret = TRUE;
}
cat = rspamd_language_detector_get_category (part->unicode_scripts);
if (!ret && rspamd_language_detector_try_stop_words (task, d, part, cat)) {
ret = TRUE;
}
if (!ret) {
if (part->utf_words->len < default_short_text_limit) {
r = rs_detect_none;
msg_debug_lang_det ("text is too short for trigramms detection: "
"%d words; at least %d words required",
(int)part->utf_words->len,
(int)default_short_text_limit);
rspamd_language_detector_set_language (task, part, "en");
candidates = kh_init (rspamd_candidates_hash);
}
else {
candidates = kh_init (rspamd_candidates_hash);
kh_resize (rspamd_candidates_hash, candidates, 32);
r = rspamd_language_detector_try_ngramm (task,
default_words,
d,
part->utf_words,
cat,
candidates);
if (r == rs_detect_none) {
msg_debug_lang_det ("no trigramms found, fallback to english");
rspamd_language_detector_set_language (task, part, "en");
} else if (r == rs_detect_multiple) {
/* Check our guess */
mean = 0.0;
std = 0.0;
cand_len = 0;
/* Check distirbution */
kh_foreach_value (candidates, cand, {
if (!isnan (cand->prob)) {
mean += cand->prob;
cand_len++;
}
});
if (cand_len > 0) {
mean /= cand_len;
kh_foreach_value (candidates, cand, {
gdouble err;
if (!isnan (cand->prob)) {
err = cand->prob - mean;
std += fabs (err);
}
});
std /= cand_len;
}
msg_debug_lang_det ("trigramms checked, %d candidates, %.3f mean, %.4f stddev",
cand_len, mean, std);
if (cand_len > 0 && std / fabs (mean) < 0.25) {
msg_debug_lang_det ("apply frequency heuristic sorting");
frequency_heuristic_applied = TRUE;
cbd.d = d;
cbd.mean = mean;
cbd.std = std;
cbd.flags = RSPAMD_LANG_FLAG_DEFAULT;
if (part->utf_words->len < default_words / 2) {
cbd.flags |= RSPAMD_LANG_FLAG_SHORT;
}
}
}
}
/* Now, convert hash to array and sort it */
if (r != rs_detect_none && kh_size (candidates) > 0) {
result = g_ptr_array_sized_new (kh_size (candidates));
kh_foreach_value (candidates, cand, {
if (!isnan (cand->prob)) {
msg_debug_lang_det ("final probability %s -> %.2f", cand->lang,
cand->prob);
g_ptr_array_add (result, cand);
}
});
if (frequency_heuristic_applied) {
g_ptr_array_sort_with_data (result,
rspamd_language_detector_cmp_heuristic, (gpointer) &cbd);
} else {
g_ptr_array_sort (result, rspamd_language_detector_cmp);
}
if (result->len > 0 && !frequency_heuristic_applied) {
cand = g_ptr_array_index (result, 0);
cand->elt->occurencies++;
d->total_occurencies++;
}
part->languages = result;
ret = TRUE;
}
else if (part->languages == NULL) {
rspamd_language_detector_set_language (task, part, "en");
}
kh_destroy (rspamd_candidates_hash, candidates);
}
end_ticks = rspamd_get_ticks (TRUE);
msg_debug_lang_det ("detected languages in %.0f ticks",
(end_ticks - start_ticks));
return ret;
}
struct rspamd_lang_detector*
rspamd_language_detector_ref (struct rspamd_lang_detector* d)
{
REF_RETAIN (d);
return d;
}
void
rspamd_language_detector_unref (struct rspamd_lang_detector* d)
{
REF_RELEASE (d);
}
gboolean
rspamd_language_detector_is_stop_word (struct rspamd_lang_detector *d,
const gchar *word, gsize wlen)
{
khiter_t k;
rspamd_ftok_t search;
search.begin = word;
search.len = wlen;
k = kh_get (rspamd_stopwords_hash, d->stop_words_norm, &search);
if (k != kh_end (d->stop_words_norm)) {
return TRUE;
}
return FALSE;
}
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