--- /dev/null
+<?php
+
+/**
+ * Detects the language of a given piece of text.
+ *
+ * Attempts to detect the language of a sample of text by correlating ranked
+ * 3-gram frequencies to a table of 3-gram frequencies of known languages.
+ *
+ * Implements a version of a technique originally proposed by Cavnar & Trenkle
+ * (1994): "N-Gram-Based Text Categorization"
+ *
+ * PHP version 5
+ *
+ * @category Text
+ * @package Text_LanguageDetect
+ * @author Nicholas Pisarro <infinityminusnine+pear@gmail.com>
+ * @copyright 2005-2006 Nicholas Pisarro
+ * @license http://www.debian.org/misc/bsd.license BSD
+ * @version SVN: $Id: LanguageDetect.php 322353 2012-01-16 08:41:43Z cweiske $
+ * @link http://pear.php.net/package/Text_LanguageDetect/
+ * @link http://langdetect.blogspot.com/
+ */
+
+require_once 'lib/languagedetect/Text/LanguageDetect/Exception.php';
+require_once 'lib/languagedetect/Text/LanguageDetect/Parser.php';
+require_once 'lib/languagedetect/Text/LanguageDetect/ISO639.php';
+
+/**
+ * Language detection class
+ *
+ * Requires the langauge model database (lang.dat) that should have
+ * accompanied this class definition in order to be instantiated.
+ *
+ * Example usage:
+ *
+ * <code>
+ * require_once 'Text/LanguageDetect.php';
+ *
+ * $l = new Text_LanguageDetect;
+ *
+ * $stdin = fopen('php://stdin', 'r');
+ *
+ * echo "Supported languages:\n";
+ *
+ * try {
+ * $langs = $l->getLanguages();
+ * } catch (Text_LanguageDetect_Exception $e) {
+ * die($e->getMessage());
+ * }
+ *
+ * sort($langs);
+ * echo join(', ', $langs);
+ *
+ * while ($line = fgets($stdin)) {
+ * print_r($l->detect($line, 4));
+ * }
+ * </code>
+ *
+ * @category Text
+ * @package Text_LanguageDetect
+ * @author Nicholas Pisarro <infinityminusnine+pear@gmail.com>
+ * @copyright 2005 Nicholas Pisarro
+ * @license http://www.debian.org/misc/bsd.license BSD
+ * @version Release: @package_version@
+ * @link http://pear.php.net/package/Text_LanguageDetect/
+ * @todo allow users to generate their own language models
+ */
+class Text_LanguageDetect
+{
+ /**
+ * The filename that stores the trigram data for the detector
+ *
+ * If this value starts with a slash (/) or a dot (.) the value of
+ * $this->_data_dir will be ignored
+ *
+ * @var string
+ * @access private
+ */
+ var $_db_filename = 'lang.dat';
+
+ /**
+ * The filename that stores the unicode block definitions
+ *
+ * If this value starts with a slash (/) or a dot (.) the value of
+ * $this->_data_dir will be ignored
+ *
+ * @var string
+ * @access private
+ */
+ var $_unicode_db_filename = 'unicode_blocks.dat';
+
+ /**
+ * The data directory
+ *
+ * Should be set by PEAR installer
+ *
+ * @var string
+ * @access private
+ */
+ var $_data_dir = '@data_dir@';
+
+ /**
+ * The trigram data for comparison
+ *
+ * Will be loaded on start from $this->_db_filename
+ *
+ * @var array
+ * @access private
+ */
+ var $_lang_db = array();
+
+ /**
+ * stores the map of the trigram data to unicode characters
+ *
+ * @access private
+ * @var array
+ */
+ var $_unicode_map;
+
+ /**
+ * The size of the trigram data arrays
+ *
+ * @var int
+ * @access private
+ */
+ var $_threshold = 300;
+
+ /**
+ * the maximum possible score.
+ *
+ * needed for score normalization. Different depending on the
+ * perl compatibility setting
+ *
+ * @access private
+ * @var int
+ * @see setPerlCompatible()
+ */
+ var $_max_score = 0;
+
+ /**
+ * Whether or not to simulate perl's Language::Guess exactly
+ *
+ * @access private
+ * @var bool
+ * @see setPerlCompatible()
+ */
+ var $_perl_compatible = false;
+
+ /**
+ * Whether to use the unicode block detection to speed up processing
+ *
+ * @access private
+ * @var bool
+ */
+ var $_use_unicode_narrowing = true;
+
+ /**
+ * stores the result of the clustering operation
+ *
+ * @access private
+ * @var array
+ * @see clusterLanguages()
+ */
+ var $_clusters;
+
+ /**
+ * Which type of "language names" are accepted and returned:
+ *
+ * 0 - language name ("english")
+ * 2 - 2-letter ISO 639-1 code ("en")
+ * 3 - 3-letter ISO 639-2 code ("eng")
+ */
+ var $_name_mode = 0;
+
+ /**
+ * Constructor
+ *
+ * Will attempt to load the language database. If it fails, you will get
+ * an exception.
+ */
+ function __construct()
+ {
+ $data = $this->_readdb($this->_db_filename);
+ $this->_checkTrigram($data['trigram']);
+ $this->_lang_db = $data['trigram'];
+
+ if (isset($data['trigram-unicodemap'])) {
+ $this->_unicode_map = $data['trigram-unicodemap'];
+ }
+
+ // Not yet implemented:
+ if (isset($data['trigram-clusters'])) {
+ $this->_clusters = $data['trigram-clusters'];
+ }
+ }
+
+ /**
+ * Returns the path to the location of the database
+ *
+ * @param string $fname File name to load
+ *
+ * @return string expected path to the language model database
+ * @access private
+ */
+ function _get_data_loc($fname)
+ {
+ if ($fname{0} == '/' || $fname{0} == '.') {
+ // if filename starts with a slash, assume it's an absolute pathname
+ // and skip whatever is in $this->_data_dir
+ return $fname;
+
+ } elseif ($this->_data_dir != '@' . 'data_dir' . '@') {
+ // if the data dir was set by the PEAR installer, use that
+ return $this->_data_dir . '/Text_LanguageDetect/' . $fname;
+
+ } else {
+ // assume this was just unpacked somewhere
+ // try the local working directory if otherwise
+ return __DIR__ . '/data/' . $fname;
+ }
+ }
+
+ /**
+ * Loads the language trigram database from filename
+ *
+ * Trigram datbase should be a serialize()'d array
+ *
+ * @param string $fname the filename where the data is stored
+ *
+ * @return array the language model data
+ * @throws Text_LanguageDetect_Exception
+ * @access private
+ */
+ function _readdb($fname)
+ {
+ // finds the correct data dir
+ $fname = $this->_get_data_loc($fname);
+
+ // input check
+ if (!file_exists($fname)) {
+ throw new Text_LanguageDetect_Exception(
+ 'Language database does not exist: ' . $fname,
+ Text_LanguageDetect_Exception::DB_NOT_FOUND
+ );
+ } elseif (!is_readable($fname)) {
+ throw new Text_LanguageDetect_Exception(
+ 'Language database is not readable: ' . $fname,
+ Text_LanguageDetect_Exception::DB_NOT_READABLE
+ );
+ }
+
+ return unserialize(file_get_contents($fname));
+ }
+
+
+ /**
+ * Checks if this object is ready to detect languages
+ *
+ * @param array $trigram Trigram data from database
+ *
+ * @return void
+ * @access private
+ */
+ function _checkTrigram($trigram)
+ {
+ if (!is_array($trigram)) {
+ if (ini_get('magic_quotes_runtime')) {
+ throw new Text_LanguageDetect_Exception(
+ 'Error loading database. Try turning magic_quotes_runtime off.',
+ Text_LanguageDetect_Exception::MAGIC_QUOTES
+ );
+ }
+ throw new Text_LanguageDetect_Exception(
+ 'Language database is not an array.',
+ Text_LanguageDetect_Exception::DB_NOT_ARRAY
+ );
+ } elseif (empty($trigram)) {
+ throw new Text_LanguageDetect_Exception(
+ 'Language database has no elements.',
+ Text_LanguageDetect_Exception::DB_EMPTY
+ );
+ }
+ }
+
+ /**
+ * Omits languages
+ *
+ * Pass this function the name of or an array of names of
+ * languages that you don't want considered
+ *
+ * If you're only expecting a limited set of languages, this can greatly
+ * speed up processing
+ *
+ * @param mixed $omit_list language name or array of names to omit
+ * @param bool $include_only if true will include (rather than
+ * exclude) only those in the list
+ *
+ * @return int number of languages successfully deleted
+ * @throws Text_LanguageDetect_Exception
+ */
+ public function omitLanguages($omit_list, $include_only = false)
+ {
+ $deleted = 0;
+
+ $omit_list = $this->_convertFromNameMode($omit_list);
+
+ if (!$include_only) {
+ // deleting the given languages
+ if (!is_array($omit_list)) {
+ $omit_list = strtolower($omit_list); // case desensitize
+ if (isset($this->_lang_db[$omit_list])) {
+ unset($this->_lang_db[$omit_list]);
+ $deleted++;
+ }
+ } else {
+ foreach ($omit_list as $omit_lang) {
+ if (isset($this->_lang_db[$omit_lang])) {
+ unset($this->_lang_db[$omit_lang]);
+ $deleted++;
+ }
+ }
+ }
+
+ } else {
+ // deleting all except the given languages
+ if (!is_array($omit_list)) {
+ $omit_list = array($omit_list);
+ }
+
+ // case desensitize
+ foreach ($omit_list as $key => $omit_lang) {
+ $omit_list[$key] = strtolower($omit_lang);
+ }
+
+ foreach (array_keys($this->_lang_db) as $lang) {
+ if (!in_array($lang, $omit_list)) {
+ unset($this->_lang_db[$lang]);
+ $deleted++;
+ }
+ }
+ }
+
+ // reset the cluster cache if the number of languages changes
+ // this will then have to be recalculated
+ if (isset($this->_clusters) && $deleted > 0) {
+ $this->_clusters = null;
+ }
+
+ return $deleted;
+ }
+
+
+ /**
+ * Returns the number of languages that this object can detect
+ *
+ * @access public
+ * @return int the number of languages
+ * @throws Text_LanguageDetect_Exception
+ */
+ function getLanguageCount()
+ {
+ return count($this->_lang_db);
+ }
+
+ /**
+ * Checks if the language with the given name exists in the database
+ *
+ * @param mixed $lang Language name or array of language names
+ *
+ * @return bool true if language model exists
+ */
+ public function languageExists($lang)
+ {
+ $lang = $this->_convertFromNameMode($lang);
+
+ if (is_string($lang)) {
+ return isset($this->_lang_db[strtolower($lang)]);
+
+ } elseif (is_array($lang)) {
+ foreach ($lang as $test_lang) {
+ if (!isset($this->_lang_db[strtolower($test_lang)])) {
+ return false;
+ }
+ }
+ return true;
+
+ } else {
+ throw new Text_LanguageDetect_Exception(
+ 'Unsupported parameter type passed to languageExists()',
+ Text_LanguageDetect_Exception::PARAM_TYPE
+ );
+ }
+ }
+
+ /**
+ * Returns the list of detectable languages
+ *
+ * @access public
+ * @return array the names of the languages known to this object<<<<<<<
+ * @throws Text_LanguageDetect_Exception
+ */
+ function getLanguages()
+ {
+ return $this->_convertToNameMode(
+ array_keys($this->_lang_db)
+ );
+ }
+
+ /**
+ * Make this object behave like Language::Guess
+ *
+ * @param bool $setting false to turn off perl compatibility
+ *
+ * @return void
+ */
+ public function setPerlCompatible($setting = true)
+ {
+ if (is_bool($setting)) { // input check
+ $this->_perl_compatible = $setting;
+
+ if ($setting == true) {
+ $this->_max_score = $this->_threshold;
+ } else {
+ $this->_max_score = 0;
+ }
+ }
+
+ }
+
+ /**
+ * Sets the way how language names are accepted and returned.
+ *
+ * @param integer $name_mode One of the following modes:
+ * 0 - language name ("english")
+ * 2 - 2-letter ISO 639-1 code ("en")
+ * 3 - 3-letter ISO 639-2 code ("eng")
+ *
+ * @return void
+ */
+ function setNameMode($name_mode)
+ {
+ $this->_name_mode = $name_mode;
+ }
+
+ /**
+ * Whether to use unicode block ranges in detection
+ *
+ * Should speed up most detections if turned on (detault is on). In some
+ * circumstances it may be slower, such as for large text samples (> 10K)
+ * in languages that use latin scripts. In other cases it should speed up
+ * detection noticeably.
+ *
+ * @param bool $setting false to turn off
+ *
+ * @return void
+ */
+ public function useUnicodeBlocks($setting = true)
+ {
+ if (is_bool($setting)) {
+ $this->_use_unicode_narrowing = $setting;
+ }
+ }
+
+ /**
+ * Converts a piece of text into trigrams
+ *
+ * @param string $text text to convert
+ *
+ * @return array array of trigram frequencies
+ * @access private
+ * @deprecated Superceded by the Text_LanguageDetect_Parser class
+ */
+ function _trigram($text)
+ {
+ $s = new Text_LanguageDetect_Parser($text);
+ $s->prepareTrigram();
+ $s->prepareUnicode(false);
+ $s->setPadStart(!$this->_perl_compatible);
+ $s->analyze();
+ return $s->getTrigramFreqs();
+ }
+
+ /**
+ * Converts a set of trigrams from frequencies to ranks
+ *
+ * Thresholds (cuts off) the list at $this->_threshold
+ *
+ * @param array $arr array of trigram
+ *
+ * @return array ranks of trigrams
+ * @access protected
+ */
+ function _arr_rank($arr)
+ {
+
+ // sorts alphabetically first as a standard way of breaking rank ties
+ $this->_bub_sort($arr);
+
+ // below might also work, but seemed to introduce errors in testing
+ //ksort($arr);
+ //asort($arr);
+
+ $rank = array();
+
+ $i = 0;
+ foreach ($arr as $key => $value) {
+ $rank[$key] = $i++;
+
+ // cut off at a standard threshold
+ if ($i >= $this->_threshold) {
+ break;
+ }
+ }
+
+ return $rank;
+ }
+
+ /**
+ * Sorts an array by value breaking ties alphabetically
+ *
+ * @param array &$arr the array to sort
+ *
+ * @return void
+ * @access private
+ */
+ function _bub_sort(&$arr)
+ {
+ // should do the same as this perl statement:
+ // sort { $trigrams{$b} == $trigrams{$a}
+ // ? $a cmp $b : $trigrams{$b} <=> $trigrams{$a} }
+
+ // needs to sort by both key and value at once
+ // using the key to break ties for the value
+
+ // converts array into an array of arrays of each key and value
+ // may be a better way of doing this
+ $combined = array();
+
+ foreach ($arr as $key => $value) {
+ $combined[] = array($key, $value);
+ }
+
+ usort($combined, array($this, '_sort_func'));
+
+ $replacement = array();
+ foreach ($combined as $key => $value) {
+ list($new_key, $new_value) = $value;
+ $replacement[$new_key] = $new_value;
+ }
+
+ $arr = $replacement;
+ }
+
+ /**
+ * Sort function used by bubble sort
+ *
+ * Callback function for usort().
+ *
+ * @param array $a first param passed by usort()
+ * @param array $b second param passed by usort()
+ *
+ * @return int 1 if $a is greater, -1 if not
+ * @see _bub_sort()
+ * @access private
+ */
+ function _sort_func($a, $b)
+ {
+ // each is actually a key/value pair, so that it can compare using both
+ list($a_key, $a_value) = $a;
+ list($b_key, $b_value) = $b;
+
+ if ($a_value == $b_value) {
+ // if the values are the same, break ties using the key
+ return strcmp($a_key, $b_key);
+
+ } else {
+ // if not, just sort normally
+ if ($a_value > $b_value) {
+ return -1;
+ } else {
+ return 1;
+ }
+ }
+
+ // 0 should not be possible because keys must be unique
+ }
+
+ /**
+ * Calculates a linear rank-order distance statistic between two sets of
+ * ranked trigrams
+ *
+ * Sums the differences in rank for each trigram. If the trigram does not
+ * appear in both, consider it a difference of $this->_threshold.
+ *
+ * This distance measure was proposed by Cavnar & Trenkle (1994). Despite
+ * its simplicity it has been shown to be highly accurate for language
+ * identification tasks.
+ *
+ * @param array $arr1 the reference set of trigram ranks
+ * @param array $arr2 the target set of trigram ranks
+ *
+ * @return int the sum of the differences between the ranks of
+ * the two trigram sets
+ * @access private
+ */
+ function _distance($arr1, $arr2)
+ {
+ $sumdist = 0;
+
+ foreach ($arr2 as $key => $value) {
+ if (isset($arr1[$key])) {
+ $distance = abs($value - $arr1[$key]);
+ } else {
+ // $this->_threshold sets the maximum possible distance value
+ // for any one pair of trigrams
+ $distance = $this->_threshold;
+ }
+ $sumdist += $distance;
+ }
+
+ return $sumdist;
+
+ // todo: there are other distance statistics to try, e.g. relative
+ // entropy, but they're probably more costly to compute
+ }
+
+ /**
+ * Normalizes the score returned by _distance()
+ *
+ * Different if perl compatible or not
+ *
+ * @param int $score the score from _distance()
+ * @param int $base_count the number of trigrams being considered
+ *
+ * @return float the normalized score
+ * @see _distance()
+ * @access private
+ */
+ function _normalize_score($score, $base_count = null)
+ {
+ if ($base_count === null) {
+ $base_count = $this->_threshold;
+ }
+
+ if (!$this->_perl_compatible) {
+ return 1 - ($score / $base_count / $this->_threshold);
+ } else {
+ return floor($score / $base_count);
+ }
+ }
+
+
+ /**
+ * Detects the closeness of a sample of text to the known languages
+ *
+ * Calculates the statistical difference between the text and
+ * the trigrams for each language, normalizes the score then
+ * returns results for all languages in sorted order
+ *
+ * If perl compatible, the score is 300-0, 0 being most similar.
+ * Otherwise, it's 0-1 with 1 being most similar.
+ *
+ * The $sample text should be at least a few sentences in length;
+ * should be ascii-7 or utf8 encoded, if another and the mbstring extension
+ * is present it will try to detect and convert. However, experience has
+ * shown that mb_detect_encoding() *does not work very well* with at least
+ * some types of encoding.
+ *
+ * @param string $sample a sample of text to compare.
+ * @param int $limit if specified, return an array of the most likely
+ * $limit languages and their scores.
+ *
+ * @return mixed sorted array of language scores, blank array if no
+ * useable text was found
+ * @see _distance()
+ * @throws Text_LanguageDetect_Exception
+ */
+ public function detect($sample, $limit = 0)
+ {
+ // input check
+ if (!Text_LanguageDetect_Parser::validateString($sample)) {
+ return array();
+ }
+
+ // check char encoding
+ // (only if mbstring extension is compiled and PHP > 4.0.6)
+ if (function_exists('mb_detect_encoding')
+ && function_exists('mb_convert_encoding')
+ ) {
+ // mb_detect_encoding isn't very reliable, to say the least
+ // detection should still work with a sufficient sample
+ // of ascii characters
+ $encoding = mb_detect_encoding($sample);
+
+ // mb_detect_encoding() will return FALSE if detection fails
+ // don't attempt conversion if that's the case
+ if ($encoding != 'ASCII' && $encoding != 'UTF-8'
+ && $encoding !== false
+ ) {
+ // verify the encoding exists in mb_list_encodings
+ if (in_array($encoding, mb_list_encodings())) {
+ $sample = mb_convert_encoding($sample, 'UTF-8', $encoding);
+ }
+ }
+ }
+
+ $sample_obj = new Text_LanguageDetect_Parser($sample);
+ $sample_obj->prepareTrigram();
+ if ($this->_use_unicode_narrowing) {
+ $sample_obj->prepareUnicode();
+ }
+ $sample_obj->setPadStart(!$this->_perl_compatible);
+ $sample_obj->analyze();
+
+ $trigram_freqs =& $sample_obj->getTrigramRanks();
+ $trigram_count = count($trigram_freqs);
+
+ if ($trigram_count == 0) {
+ return array();
+ }
+
+ $scores = array();
+
+ // use unicode block detection to narrow down the possibilities
+ if ($this->_use_unicode_narrowing) {
+ $blocks =& $sample_obj->getUnicodeBlocks();
+
+ if (is_array($blocks)) {
+ $present_blocks = array_keys($blocks);
+ } else {
+ throw new Text_LanguageDetect_Exception(
+ 'Error during block detection',
+ Text_LanguageDetect_Exception::BLOCK_DETECTION
+ );
+ }
+
+ $possible_langs = array();
+
+ foreach ($present_blocks as $blockname) {
+ if (isset($this->_unicode_map[$blockname])) {
+
+ $possible_langs = array_merge(
+ $possible_langs,
+ array_keys($this->_unicode_map[$blockname])
+ );
+
+ // todo: faster way to do this?
+ }
+ }
+
+ // could also try an intersect operation rather than a union
+ // in other words, choose languages whose trigrams contain
+ // ALL of the unicode blocks found in this sample
+ // would improve speed but would be completely thrown off by an
+ // unexpected character, like an umlaut appearing in english text
+
+ $possible_langs = array_intersect(
+ array_keys($this->_lang_db),
+ array_unique($possible_langs)
+ );
+
+ // needs to intersect it with the keys of _lang_db in case
+ // languages have been omitted
+
+ } else {
+ // or just try 'em all
+ $possible_langs = array_keys($this->_lang_db);
+ }
+
+
+ foreach ($possible_langs as $lang) {
+ $scores[$lang] = $this->_normalize_score(
+ $this->_distance($this->_lang_db[$lang], $trigram_freqs),
+ $trigram_count
+ );
+ }
+
+ unset($sample_obj);
+
+ if ($this->_perl_compatible) {
+ asort($scores);
+ } else {
+ arsort($scores);
+ }
+
+ // todo: drop languages with a score of $this->_max_score?
+
+ // limit the number of returned scores
+ if ($limit && is_numeric($limit)) {
+ $limited_scores = array();
+
+ $i = 0;
+ foreach ($scores as $key => $value) {
+ if ($i++ >= $limit) {
+ break;
+ }
+
+ $limited_scores[$key] = $value;
+ }
+
+ return $this->_convertToNameMode($limited_scores, true);
+ } else {
+ return $this->_convertToNameMode($scores, true);
+ }
+ }
+
+ /**
+ * Returns only the most similar language to the text sample
+ *
+ * Calls $this->detect() and returns only the top result
+ *
+ * @param string $sample text to detect the language of
+ *
+ * @return string the name of the most likely language
+ * or null if no language is similar
+ * @see detect()
+ * @throws Text_LanguageDetect_Exception
+ */
+ public function detectSimple($sample)
+ {
+ $scores = $this->detect($sample, 1);
+
+ // if top language has the maximum possible score,
+ // then the top score will have been picked at random
+ if (!is_array($scores) || empty($scores)
+ || current($scores) == $this->_max_score
+ ) {
+ return null;
+ } else {
+ return key($scores);
+ }
+ }
+
+ /**
+ * Returns an array containing the most similar language and a confidence
+ * rating
+ *
+ * Confidence is a simple measure calculated from the similarity score
+ * minus the similarity score from the next most similar language
+ * divided by the highest possible score. Languages that have closely
+ * related cousins (e.g. Norwegian and Danish) should generally have lower
+ * confidence scores.
+ *
+ * The similarity score answers the question "How likely is the text the
+ * returned language regardless of the other languages considered?" The
+ * confidence score is one way of answering the question "how likely is the
+ * text the detected language relative to the rest of the language model
+ * set?"
+ *
+ * To see how similar languages are a priori, see languageSimilarity()
+ *
+ * @param string $sample text for which language will be detected
+ *
+ * @return array most similar language, score and confidence rating
+ * or null if no language is similar
+ * @see detect()
+ * @throws Text_LanguageDetect_Exception
+ */
+ public function detectConfidence($sample)
+ {
+ $scores = $this->detect($sample, 2);
+
+ // if most similar language has the max score, it
+ // will have been picked at random
+ if (!is_array($scores) || empty($scores)
+ || current($scores) == $this->_max_score
+ ) {
+ return null;
+ }
+
+ $arr['language'] = key($scores);
+ $arr['similarity'] = current($scores);
+ if (next($scores) !== false) { // if false then no next element
+ // the goal is to return a higher value if the distance between
+ // the similarity of the first score and the second score is high
+
+ if ($this->_perl_compatible) {
+ $arr['confidence'] = (current($scores) - $arr['similarity'])
+ / $this->_max_score;
+
+ } else {
+ $arr['confidence'] = $arr['similarity'] - current($scores);
+
+ }
+
+ } else {
+ $arr['confidence'] = null;
+ }
+
+ return $arr;
+ }
+
+ /**
+ * Returns the distribution of unicode blocks in a given utf8 string
+ *
+ * For the block name of a single char, use unicodeBlockName()
+ *
+ * @param string $str input string. Must be ascii or utf8
+ * @param bool $skip_symbols if true, skip ascii digits, symbols and
+ * non-printing characters. Includes spaces,
+ * newlines and common punctutation characters.
+ *
+ * @return array
+ * @throws Text_LanguageDetect_Exception
+ */
+ public function detectUnicodeBlocks($str, $skip_symbols)
+ {
+ $skip_symbols = (bool)$skip_symbols;
+ $str = (string)$str;
+
+ $sample_obj = new Text_LanguageDetect_Parser($str);
+ $sample_obj->prepareUnicode();
+ $sample_obj->prepareTrigram(false);
+ $sample_obj->setUnicodeSkipSymbols($skip_symbols);
+ $sample_obj->analyze();
+ $blocks = $sample_obj->getUnicodeBlocks();
+ unset($sample_obj);
+ return $blocks;
+ }
+
+ /**
+ * Returns the block name for a given unicode value
+ *
+ * If passed a string, will assume it is being passed a UTF8-formatted
+ * character and will automatically convert. Otherwise it will assume it
+ * is being passed a numeric unicode value.
+ *
+ * Make sure input is of the correct type!
+ *
+ * @param mixed $unicode unicode value or utf8 char
+ *
+ * @return mixed the block name string or false if not found
+ * @throws Text_LanguageDetect_Exception
+ */
+ public function unicodeBlockName($unicode)
+ {
+ if (is_string($unicode)) {
+ // assume it is being passed a utf8 char, so convert it
+ if (self::utf8strlen($unicode) > 1) {
+ throw new Text_LanguageDetect_Exception(
+ 'Pass a single char only to this method',
+ Text_LanguageDetect_Exception::PARAM_TYPE
+ );
+ }
+ $unicode = $this->_utf8char2unicode($unicode);
+
+ } elseif (!is_int($unicode)) {
+ throw new Text_LanguageDetect_Exception(
+ 'Input must be of type string or int.',
+ Text_LanguageDetect_Exception::PARAM_TYPE
+ );
+ }
+
+ $blocks = $this->_read_unicode_block_db();
+
+ $result = $this->_unicode_block_name($unicode, $blocks);
+
+ if ($result == -1) {
+ return false;
+ } else {
+ return $result[2];
+ }
+ }
+
+ /**
+ * Searches the unicode block database
+ *
+ * Returns the block name for a given unicode value. unicodeBlockName() is
+ * the public interface for this function, which does input checks which
+ * this function omits for speed.
+ *
+ * @param int $unicode the unicode value
+ * @param array $blocks the block database
+ * @param int $block_count the number of defined blocks in the database
+ *
+ * @return mixed Block name, -1 if it failed
+ * @see unicodeBlockName()
+ * @access protected
+ */
+ function _unicode_block_name($unicode, $blocks, $block_count = -1)
+ {
+ // for a reference, see
+ // http://www.unicode.org/Public/UNIDATA/Blocks.txt
+
+ // assume that ascii characters are the most common
+ // so try it first for efficiency
+ if ($unicode <= $blocks[0][1]) {
+ return $blocks[0];
+ }
+
+ // the optional $block_count param is for efficiency
+ // so we this function doesn't have to run count() every time
+ if ($block_count != -1) {
+ $high = $block_count - 1;
+ } else {
+ $high = count($blocks) - 1;
+ }
+
+ $low = 1; // start with 1 because ascii was 0
+
+ // your average binary search algorithm
+ while ($low <= $high) {
+ $mid = floor(($low + $high) / 2);
+
+ if ($unicode < $blocks[$mid][0]) {
+ // if it's lower than the lower bound
+ $high = $mid - 1;
+
+ } elseif ($unicode > $blocks[$mid][1]) {
+ // if it's higher than the upper bound
+ $low = $mid + 1;
+
+ } else {
+ // found it
+ return $blocks[$mid];
+ }
+ }
+
+ // failed to find the block
+ return -1;
+
+ // todo: differentiate when it's out of range or when it falls
+ // into an unassigned range?
+ }
+
+ /**
+ * Brings up the unicode block database
+ *
+ * @return array the database of unicode block definitions
+ * @throws Text_LanguageDetect_Exception
+ * @access protected
+ */
+ function _read_unicode_block_db()
+ {
+ // since the unicode definitions are always going to be the same,
+ // might as well share the memory for the db with all other instances
+ // of this class
+ static $data;
+
+ if (!isset($data)) {
+ $data = $this->_readdb($this->_unicode_db_filename);
+ }
+
+ return $data;
+ }
+
+ /**
+ * Calculate the similarities between the language models
+ *
+ * Use this function to see how similar languages are to each other.
+ *
+ * If passed 2 language names, will return just those languages compared.
+ * If passed 1 language name, will return that language compared to
+ * all others.
+ * If passed none, will return an array of every language model compared
+ * to every other one.
+ *
+ * @param string $lang1 the name of the first language to be compared
+ * @param string $lang2 the name of the second language to be compared
+ *
+ * @return array scores of every language compared
+ * or the score of just the provided languages
+ * or null if one of the supplied languages does not exist
+ * @throws Text_LanguageDetect_Exception
+ */
+ public function languageSimilarity($lang1 = null, $lang2 = null)
+ {
+ $lang1 = $this->_convertFromNameMode($lang1);
+ $lang2 = $this->_convertFromNameMode($lang2);
+ if ($lang1 != null) {
+ $lang1 = strtolower($lang1);
+
+ // check if language model exists
+ if (!isset($this->_lang_db[$lang1])) {
+ return null;
+ }
+
+ if ($lang2 != null) {
+ if (!isset($this->_lang_db[$lang2])) {
+ // check if language model exists
+ return null;
+ }
+
+ $lang2 = strtolower($lang2);
+
+ // compare just these two languages
+ return $this->_normalize_score(
+ $this->_distance(
+ $this->_lang_db[$lang1],
+ $this->_lang_db[$lang2]
+ )
+ );
+
+ } else {
+ // compare just $lang1 to all languages
+ $return_arr = array();
+ foreach ($this->_lang_db as $key => $value) {
+ if ($key != $lang1) {
+ // don't compare a language to itself
+ $return_arr[$key] = $this->_normalize_score(
+ $this->_distance($this->_lang_db[$lang1], $value)
+ );
+ }
+ }
+ asort($return_arr);
+
+ return $return_arr;
+ }
+
+
+ } else {
+ // compare all languages to each other
+ $return_arr = array();
+ foreach (array_keys($this->_lang_db) as $lang1) {
+ foreach (array_keys($this->_lang_db) as $lang2) {
+ // skip comparing languages to themselves
+ if ($lang1 != $lang2) {
+
+ if (isset($return_arr[$lang2][$lang1])) {
+ // don't re-calculate what's already been done
+ $return_arr[$lang1][$lang2]
+ = $return_arr[$lang2][$lang1];
+
+ } else {
+ // calculate
+ $return_arr[$lang1][$lang2]
+ = $this->_normalize_score(
+ $this->_distance(
+ $this->_lang_db[$lang1],
+ $this->_lang_db[$lang2]
+ )
+ );
+
+ }
+ }
+ }
+ }
+ return $return_arr;
+ }
+ }
+
+ /**
+ * Cluster known languages according to languageSimilarity()
+ *
+ * WARNING: this method is EXPERIMENTAL. It is not recommended for common
+ * use, and it may disappear or its functionality may change in future
+ * releases without notice.
+ *
+ * Uses a nearest neighbor technique to generate the maximum possible
+ * number of dendograms from the similarity data.
+ *
+ * @access public
+ * @return array language cluster data
+ * @throws Text_LanguageDetect_Exception
+ * @see languageSimilarity()
+ * @deprecated this function will eventually be removed and placed into
+ * the model generation class
+ */
+ function clusterLanguages()
+ {
+ // todo: set the maximum number of clusters
+ // return cached result, if any
+ if (isset($this->_clusters)) {
+ return $this->_clusters;
+ }
+
+ $langs = array_keys($this->_lang_db);
+
+ $arr = $this->languageSimilarity();
+
+ sort($langs);
+
+ foreach ($langs as $lang) {
+ if (!isset($this->_lang_db[$lang])) {
+ throw new Text_LanguageDetect_Exception(
+ "missing $lang!",
+ Text_LanguageDetect_Exception::UNKNOWN_LANGUAGE
+ );
+ }
+ }
+
+ // http://www.psychstat.missouristate.edu/multibook/mlt04m.html
+ foreach ($langs as $old_key => $lang1) {
+ $langs[$lang1] = $lang1;
+ unset($langs[$old_key]);
+ }
+
+ $result_data = $really_map = array();
+
+ $i = 0;
+ while (count($langs) > 2 && $i++ < 200) {
+ $highest_score = -1;
+ $highest_key1 = '';
+ $highest_key2 = '';
+ foreach ($langs as $lang1) {
+ foreach ($langs as $lang2) {
+ if ($lang1 != $lang2
+ && $arr[$lang1][$lang2] > $highest_score
+ ) {
+ $highest_score = $arr[$lang1][$lang2];
+ $highest_key1 = $lang1;
+ $highest_key2 = $lang2;
+ }
+ }
+ }
+
+ if (!$highest_key1) {
+ // should not ever happen
+ throw new Text_LanguageDetect_Exception(
+ "no highest key? (step: $i)",
+ Text_LanguageDetect_Exception::NO_HIGHEST_KEY
+ );
+ }
+
+ if ($highest_score == 0) {
+ // languages are perfectly dissimilar
+ break;
+ }
+
+ // $highest_key1 and $highest_key2 are most similar
+ $sum1 = array_sum($arr[$highest_key1]);
+ $sum2 = array_sum($arr[$highest_key2]);
+
+ // use the score for the one that is most similar to the rest of
+ // the field as the score for the group
+ // todo: could try averaging or "centroid" method instead
+ // seems like that might make more sense
+ // actually nearest neighbor may be better for binary searching
+
+
+ // for "Complete Linkage"/"furthest neighbor"
+ // sign should be <
+ // for "Single Linkage"/"nearest neighbor" method
+ // should should be >
+ // results seem to be pretty much the same with either method
+
+ // figure out which to delete and which to replace
+ if ($sum1 > $sum2) {
+ $replaceme = $highest_key1;
+ $deleteme = $highest_key2;
+ } else {
+ $replaceme = $highest_key2;
+ $deleteme = $highest_key1;
+ }
+
+ $newkey = $replaceme . ':' . $deleteme;
+
+ // $replaceme is most similar to remaining languages
+ // replace $replaceme with '$newkey', deleting $deleteme
+
+ // keep a record of which fork is really which language
+ $really_lang = $replaceme;
+ while (isset($really_map[$really_lang])) {
+ $really_lang = $really_map[$really_lang];
+ }
+ $really_map[$newkey] = $really_lang;
+
+
+ // replace the best fitting key, delete the other
+ foreach ($arr as $key1 => $arr2) {
+ foreach ($arr2 as $key2 => $value2) {
+ if ($key2 == $replaceme) {
+ $arr[$key1][$newkey] = $arr[$key1][$key2];
+ unset($arr[$key1][$key2]);
+ // replacing $arr[$key1][$key2] with $arr[$key1][$newkey]
+ }
+
+ if ($key1 == $replaceme) {
+ $arr[$newkey][$key2] = $arr[$key1][$key2];
+ unset($arr[$key1][$key2]);
+ // replacing $arr[$key1][$key2] with $arr[$newkey][$key2]
+ }
+
+ if ($key1 == $deleteme || $key2 == $deleteme) {
+ // deleting $arr[$key1][$key2]
+ unset($arr[$key1][$key2]);
+ }
+ }
+ }
+
+
+ unset($langs[$highest_key1]);
+ unset($langs[$highest_key2]);
+ $langs[$newkey] = $newkey;
+
+
+ // some of these may be overkill
+ $result_data[$newkey] = array(
+ 'newkey' => $newkey,
+ 'count' => $i,
+ 'diff' => abs($sum1 - $sum2),
+ 'score' => $highest_score,
+ 'bestfit' => $replaceme,
+ 'otherfit' => $deleteme,
+ 'really' => $really_lang,
+ );
+ }
+
+ $return_val = array(
+ 'open_forks' => $langs,
+ // the top level of clusters
+ // clusters that are mutually exclusive
+ // or specified by a specific maximum
+
+ 'fork_data' => $result_data,
+ // data for each split
+
+ 'name_map' => $really_map,
+ // which cluster is really which language
+ // using the nearest neighbor technique, the cluster
+ // inherits all of the properties of its most-similar member
+ // this keeps track
+ );
+
+
+ // saves the result in the object
+ $this->_clusters = $return_val;
+
+ return $return_val;
+ }
+
+
+ /**
+ * Perform an intelligent detection based on clusterLanguages()
+ *
+ * WARNING: this method is EXPERIMENTAL. It is not recommended for common
+ * use, and it may disappear or its functionality may change in future
+ * releases without notice.
+ *
+ * This compares the sample text to top the top level of clusters. If the
+ * sample is similar to the cluster it will drop down and compare it to the
+ * languages in the cluster, and so on until it hits a leaf node.
+ *
+ * this should find the language in considerably fewer compares
+ * (the equivalent of a binary search), however clusterLanguages() is costly
+ * and the loss of accuracy from this technique is significant.
+ *
+ * This method may need to be 'fuzzier' in order to become more accurate.
+ *
+ * This function could be more useful if the universe of possible languages
+ * was very large, however in such cases some method of Bayesian inference
+ * might be more helpful.
+ *
+ * @param string $str input string
+ *
+ * @return array language scores (only those compared)
+ * @throws Text_LanguageDetect_Exception
+ * @see clusterLanguages()
+ */
+ public function clusteredSearch($str)
+ {
+ // input check
+ if (!Text_LanguageDetect_Parser::validateString($str)) {
+ return array();
+ }
+
+ // clusterLanguages() will return a cached result if possible
+ // so it's safe to call it every time
+ $result = $this->clusterLanguages();
+
+ $dendogram_start = $result['open_forks'];
+ $dendogram_data = $result['fork_data'];
+ $dendogram_alias = $result['name_map'];
+
+ $sample_obj = new Text_LanguageDetect_Parser($str);
+ $sample_obj->prepareTrigram();
+ $sample_obj->setPadStart(!$this->_perl_compatible);
+ $sample_obj->analyze();
+ $sample_result = $sample_obj->getTrigramRanks();
+ $sample_count = count($sample_result);
+
+ // input check
+ if ($sample_count == 0) {
+ return array();
+ }
+
+ $i = 0; // counts the number of steps
+
+ foreach ($dendogram_start as $lang) {
+ if (isset($dendogram_alias[$lang])) {
+ $lang_key = $dendogram_alias[$lang];
+ } else {
+ $lang_key = $lang;
+ }
+
+ $scores[$lang] = $this->_normalize_score(
+ $this->_distance($this->_lang_db[$lang_key], $sample_result),
+ $sample_count
+ );
+
+ $i++;
+ }
+
+ if ($this->_perl_compatible) {
+ asort($scores);
+ } else {
+ arsort($scores);
+ }
+
+ $top_score = current($scores);
+ $top_key = key($scores);
+
+ // of starting forks, $top_key is the most similar to the sample
+
+ $cur_key = $top_key;
+ while (isset($dendogram_data[$cur_key])) {
+ $lang1 = $dendogram_data[$cur_key]['bestfit'];
+ $lang2 = $dendogram_data[$cur_key]['otherfit'];
+ foreach (array($lang1, $lang2) as $lang) {
+ if (isset($dendogram_alias[$lang])) {
+ $lang_key = $dendogram_alias[$lang];
+ } else {
+ $lang_key = $lang;
+ }
+
+ $scores[$lang] = $this->_normalize_score(
+ $this->_distance($this->_lang_db[$lang_key], $sample_result),
+ $sample_count
+ );
+
+ //todo: does not need to do same comparison again
+ }
+
+ $i++;
+
+ if ($scores[$lang1] > $scores[$lang2]) {
+ $cur_key = $lang1;
+ $loser_key = $lang2;
+ } else {
+ $cur_key = $lang2;
+ $loser_key = $lang1;
+ }
+
+ $diff = $scores[$cur_key] - $scores[$loser_key];
+
+ // $cur_key ({$dendogram_alias[$cur_key]}) wins
+ // over $loser_key ({$dendogram_alias[$loser_key]})
+ // with a difference of $diff
+ }
+
+ // found result in $i compares
+
+ // rather than sorting the result, preserve it so that you can see
+ // which paths the algorithm decided to take along the tree
+
+ // but sometimes the last item is only the second highest
+ if (($this->_perl_compatible && (end($scores) > prev($scores)))
+ || (!$this->_perl_compatible && (end($scores) < prev($scores)))
+ ) {
+ $real_last_score = current($scores);
+ $real_last_key = key($scores);
+
+ // swaps the 2nd-to-last item for the last item
+ unset($scores[$real_last_key]);
+ $scores[$real_last_key] = $real_last_score;
+ }
+
+
+ if (!$this->_perl_compatible) {
+ $scores = array_reverse($scores, true);
+ // second param requires php > 4.0.3
+ }
+
+ return $scores;
+ }
+
+ /**
+ * ut8-safe strlen()
+ *
+ * Returns the numbers of characters (not bytes) in a utf8 string
+ *
+ * @param string $str string to get the length of
+ *
+ * @return int number of chars
+ */
+ public static function utf8strlen($str)
+ {
+ // utf8_decode() will convert unknown chars to '?', which is actually
+ // ideal for counting.
+
+ return strlen(utf8_decode($str));
+
+ // idea stolen from dokuwiki
+ }
+
+ /**
+ * Returns the unicode value of a utf8 char
+ *
+ * @param string $char a utf8 (possibly multi-byte) char
+ *
+ * @return int unicode value
+ * @access protected
+ * @link http://en.wikipedia.org/wiki/UTF-8
+ */
+ function _utf8char2unicode($char)
+ {
+ // strlen() here will actually get the binary length of a single char
+ switch (strlen($char)) {
+ case 1:
+ // normal ASCII-7 byte
+ // 0xxxxxxx --> 0xxxxxxx
+ return ord($char{0});
+
+ case 2:
+ // 2 byte unicode
+ // 110zzzzx 10xxxxxx --> 00000zzz zxxxxxxx
+ $z = (ord($char{0}) & 0x000001F) << 6;
+ $x = (ord($char{1}) & 0x0000003F);
+ return ($z | $x);
+
+ case 3:
+ // 3 byte unicode
+ // 1110zzzz 10zxxxxx 10xxxxxx --> zzzzzxxx xxxxxxxx
+ $z = (ord($char{0}) & 0x0000000F) << 12;
+ $x1 = (ord($char{1}) & 0x0000003F) << 6;
+ $x2 = (ord($char{2}) & 0x0000003F);
+ return ($z | $x1 | $x2);
+
+ case 4:
+ // 4 byte unicode
+ // 11110zzz 10zzxxxx 10xxxxxx 10xxxxxx -->
+ // 000zzzzz xxxxxxxx xxxxxxxx
+ $z1 = (ord($char{0}) & 0x00000007) << 18;
+ $z2 = (ord($char{1}) & 0x0000003F) << 12;
+ $x1 = (ord($char{2}) & 0x0000003F) << 6;
+ $x2 = (ord($char{3}) & 0x0000003F);
+ return ($z1 | $z2 | $x1 | $x2);
+ }
+ }
+
+ /**
+ * utf8-safe fast character iterator
+ *
+ * Will get the next character starting from $counter, which will then be
+ * incremented. If a multi-byte char the bytes will be concatenated and
+ * $counter will be incremeted by the number of bytes in the char.
+ *
+ * @param string $str the string being iterated over
+ * @param int &$counter the iterator, will increment by reference
+ * @param bool $special_convert whether to do special conversions
+ *
+ * @return char the next (possibly multi-byte) char from $counter
+ * @access private
+ */
+ static function _next_char($str, &$counter, $special_convert = false)
+ {
+ $char = $str{$counter++};
+ $ord = ord($char);
+
+ // for a description of the utf8 system see
+ // http://www.phpclasses.org/browse/file/5131.html
+
+ // normal ascii one byte char
+ if ($ord <= 127) {
+ // special conversions needed for this package
+ // (that only apply to regular ascii characters)
+ // lower case, and convert all non-alphanumeric characters
+ // other than "'" to space
+ if ($special_convert && $char != ' ' && $char != "'") {
+ if ($ord >= 65 && $ord <= 90) { // A-Z
+ $char = chr($ord + 32); // lower case
+ } elseif ($ord < 97 || $ord > 122) { // NOT a-z
+ $char = ' '; // convert to space
+ }
+ }
+
+ return $char;
+
+ } elseif ($ord >> 5 == 6) { // two-byte char
+ // multi-byte chars
+ $nextchar = $str{$counter++}; // get next byte
+
+ // lower-casing of non-ascii characters is still incomplete
+
+ if ($special_convert) {
+ // lower case latin accented characters
+ if ($ord == 195) {
+ $nextord = ord($nextchar);
+ $nextord_adj = $nextord + 64;
+ // for a reference, see
+ // http://www.ramsch.org/martin/uni/fmi-hp/iso8859-1.html
+
+ // À - Þ but not ×
+ if ($nextord_adj >= 192
+ && $nextord_adj <= 222
+ && $nextord_adj != 215
+ ) {
+ $nextchar = chr($nextord + 32);
+ }
+
+ } elseif ($ord == 208) {
+ // lower case cyrillic alphabet
+ $nextord = ord($nextchar);
+ // if A - Pe
+ if ($nextord >= 144 && $nextord <= 159) {
+ // lower case
+ $nextchar = chr($nextord + 32);
+
+ } elseif ($nextord >= 160 && $nextord <= 175) {
+ // if Er - Ya
+ // lower case
+ $char = chr(209); // == $ord++
+ $nextchar = chr($nextord - 32);
+ }
+ }
+ }
+
+ // tag on next byte
+ return $char . $nextchar;
+ } elseif ($ord >> 4 == 14) { // three-byte char
+
+ // tag on next 2 bytes
+ return $char . $str{$counter++} . $str{$counter++};
+
+ } elseif ($ord >> 3 == 30) { // four-byte char
+
+ // tag on next 3 bytes
+ return $char . $str{$counter++} . $str{$counter++} . $str{$counter++};
+
+ } else {
+ // error?
+ }
+ }
+
+ /**
+ * Converts an $language input parameter from the configured mode
+ * to the language name that is used internally.
+ *
+ * Works for strings and arrays.
+ *
+ * @param string|array $lang A language description ("english"/"en"/"eng")
+ * @param boolean $convertKey If $lang is an array, setting $key
+ * converts the keys to the language name.
+ *
+ * @return string|array Language name
+ */
+ function _convertFromNameMode($lang, $convertKey = false)
+ {
+ if ($this->_name_mode == 0) {
+ return $lang;
+ }
+
+ if ($this->_name_mode == 2) {
+ $method = 'code2ToName';
+ } else {
+ $method = 'code3ToName';
+ }
+
+ if (is_string($lang)) {
+ return (string)Text_LanguageDetect_ISO639::$method($lang);
+ }
+
+ $newlang = array();
+ foreach ($lang as $key => $val) {
+ if ($convertKey) {
+ $newkey = (string)Text_LanguageDetect_ISO639::$method($key);
+ $newlang[$newkey] = $val;
+ } else {
+ $newlang[$key] = (string)Text_LanguageDetect_ISO639::$method($val);
+ }
+ }
+ return $newlang;
+ }
+
+ /**
+ * Converts an $language output parameter from the language name that is
+ * used internally to the configured mode.
+ *
+ * Works for strings and arrays.
+ *
+ * @param string|array $lang A language description ("english"/"en"/"eng")
+ * @param boolean $convertKey If $lang is an array, setting $key
+ * converts the keys to the language name.
+ *
+ * @return string|array Language name
+ */
+ function _convertToNameMode($lang, $convertKey = false)
+ {
+ if ($this->_name_mode == 0) {
+ return $lang;
+ }
+
+ if ($this->_name_mode == 2) {
+ $method = 'nameToCode2';
+ } else {
+ $method = 'nameToCode3';
+ }
+
+ if (is_string($lang)) {
+ return Text_LanguageDetect_ISO639::$method($lang);
+ }
+
+ $newlang = array();
+ foreach ($lang as $key => $val) {
+ if ($convertKey) {
+ $newkey = Text_LanguageDetect_ISO639::$method($key);
+ $newlang[$newkey] = $val;
+ } else {
+ $newlang[$key] = Text_LanguageDetect_ISO639::$method($val);
+ }
+ }
+ return $newlang;
+ }
+}
+
+/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
+
+?>
projects / tt-rss.git / commitdiff