/**
*
* The value $max_delta = 80000 is good enough for speed and detection accuracy.
* If you set the value of $max_delta too low, no language will be recognized.
* $max_delta = 400 * 350 = 140000 is the best detection with lowest speed.
*/
function &_api_compare_n_grams(&$n_grams, $encoding, $max_delta = LANGUAGE_DETECT_MAX_DELTA)
{
static $language_profiles;
if (!isset($language_profiles)) {
// Reading the language profile files from the internationalization database.
$exceptions = array('.', '..', 'CVS', '.htaccess', '.svn', '_svn', 'index.html');
$path = str_replace("\\", '/', dirname(__FILE__) . '/internationalization_database/language_detection/language_profiles/');
$non_utf8_encodings =& _api_non_utf8_encodings();
if (is_dir($path)) {
if ($handle = @opendir($path)) {
while (($dir_entry = @readdir($handle)) !== false) {
if (api_in_array_nocase($dir_entry, $exceptions)) {
continue;
}
if (strpos($dir_entry, '.txt') === false) {
continue;
}
$dir_entry_full_path = $path . '/' . $dir_entry;
if (@filetype($dir_entry_full_path) != 'dir') {
if (false !== ($data = @file_get_contents($dir_entry_full_path))) {
$language = basename($dir_entry_full_path, '.txt');
$encodings = array('UTF-8');
if (!empty($non_utf8_encodings[$language])) {
$encodings = array_merge($encodings, $non_utf8_encodings[$language]);
}
foreach ($encodings as $enc) {
$data_enc = api_utf8_decode($data, $enc);
if (empty($data_enc)) {
continue;
}
$key = $language . ':' . $enc;
$language_profiles[$key]['data'] = array_flip(explode("\n", $data_enc));
$language_profiles[$key]['language'] = $language;
$language_profiles[$key]['encoding'] = $enc;
}
}
}
}
}
}
@closedir($handle);
ksort($language_profiles);
}
if (!is_array($n_grams) || empty($n_grams)) {
return array();
}
// Comparison between the input n-grams and the lanuage profiles.
foreach ($language_profiles as $key => &$language_profile) {
if (!api_is_language_supported($language_profile['language']) || !api_equal_encodings($encoding, $language_profile['encoding'])) {
continue;
}
$delta = 0;
// This is a summary measurment for matching between the input text and the current language profile.
// Searching each n-gram from the input text into the language profile.
foreach ($n_grams as $rank => &$n_gram) {
if (isset($language_profile['data'][$n_gram])) {
// The n-gram has been found, the difference between places in both
// arrays is calculated (so called delta-points are adopted for
// measuring distances between n-gram ranks.
$delta += abs($rank - $language_profile['data'][$n_gram]);
} else {
// The n-gram has not been found in the profile. We add then
// a large enough "distance" in delta-points.
$delta += 400;
}
// Abort: This language already differs too much.
if ($delta > $max_delta) {
break;
}
}
// Include only non-aborted languages in result array.
if ($delta < $max_delta - 400) {
$result[$key] = $delta;
}
}
if (!isset($result)) {
return array();
}
asort($result);
return $result;
}
/**
* Returns in an array the most-probably used non-UTF-8 encoding for the given language.
* The first (leading) value is actually used by the system at the moment.
* @param string $language (optional) The specified language, the default value is the user intrface language.
* @return string The correspondent encoding to the specified language.
* Note: See the file chamilo/main/inc/lib/internationalization_database/non_utf8_encodings.php
* if you wish to revise the leading non-UTF-8 encoding for your language.
*/
function api_get_non_utf8_encoding($language = null)
{
$language_is_supported = api_is_language_supported($language);
if (!$language_is_supported || empty($language)) {
$language = api_get_interface_language(false, true);
}
$language = api_purify_language_id($language);
$encodings =& _api_non_utf8_encodings();
if (is_array($encodings[$language])) {
if (!empty($encodings[$language][0])) {
return $encodings[$language][0];
}
return null;
}
return null;
}