+++ /dev/null
-<?php
-/**
- * Part of Text_LanguageDetect
- *
- * PHP version 5
- *
- * @category Text
- * @package Text_LanguageDetect
- * @author Nicholas Pisarro <infinityminusnine+pear@gmail.com>
- * @copyright 2005-2006 Nicholas Pisarro
- * @license BSD http://www.opensource.org/licenses/bsd-license.php
- * @link http://pear.php.net/package/Text_LanguageDetect/
- */
-
-require_once __DIR__ . '/LanguageDetect/Exception.php';
-require_once __DIR__ . '/LanguageDetect/Parser.php';
-require_once __DIR__ . '/LanguageDetect/ISO639.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"
- *
- * Requires the language 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 BSD http://www.opensource.org/licenses/bsd-license.php
- * @version Release: @package_version@
- * @link http://pear.php.net/package/Text_LanguageDetect/
- *
- * @SuppressWarnings(PHPMD)
- */
-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
- */
- protected $_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
- */
- protected $_unicode_db_filename = 'unicode_blocks.dat';
-
- /**
- * The data directory
- *
- * Should be set by PEAR installer
- *
- * @var string
- */
- protected $_data_dir = '@data_dir@';
-
- /**
- * The trigram data for comparison
- *
- * Will be loaded on start from $this->_db_filename
- *
- * @var array
- */
- protected $_lang_db = array();
-
- /**
- * Stores the map of the trigram data to unicode characters
- *
- * @var array
- */
- protected $_unicode_map;
-
- /**
- * The size of the trigram data arrays
- *
- * @var int
- */
- protected $_threshold = 300;
-
- /**
- * The maximum possible score.
- *
- * Needed for score normalization. Different depending on the
- * perl compatibility setting
- *
- * @var int
- * @see setPerlCompatible()
- */
- protected $_max_score = 0;
-
- /**
- * Whether or not to simulate perl's Language::Guess exactly
- *
- * @var bool
- * @see setPerlCompatible()
- */
- protected $_perl_compatible = false;
-
- /**
- * Whether to use the unicode block detection to speed up processing
- *
- * @var bool
- */
- protected $_use_unicode_narrowing = true;
-
- /**
- * Stores the result of the clustering operation
- *
- * @var array
- * @see clusterLanguages()
- */
- protected $_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")
- */
- protected $_name_mode = 0;
-
- /**
- * Constructor
- *
- * Will attempt to load the language database. If it fails, you will get
- * an exception.
- */
- public 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 $fname File name to load
- *
- * @return string expected path to the language model database
- */
- protected function _get_data_loc($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 $fname the filename where the data is stored
- *
- * @return array the language model data
- * @throws Text_LanguageDetect_Exception
- */
- protected function _readdb($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 $trigram Trigram data from database
- *
- * @return void
- */
- protected function _checkTrigram($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 $deleted;
- }
-
-
- /**
- * Returns the number of languages that this object can detect
- *
- * @return int the number of languages
- * @throws Text_LanguageDetect_Exception
- */
- public function getLanguageCount()
- {
- return count($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
- *
- * @return array the names of the languages known to this object<<<<<<<
- * @throws Text_LanguageDetect_Exception
- */
- public 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 $name_mode One of the following modes:
- * 0 - language name ("english")
- * 2 - 2-letter ISO 639-1 code ("en")
- * 3 - 3-letter ISO 639-2 code ("eng")
- *
- * @return void
- */
- public function setNameMode($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 $text text to convert
- *
- * @return array array of trigram frequencies
- * @deprecated Superceded by the Text_LanguageDetect_Parser class
- */
- protected function _trigram($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 $arr array of trigram
- *
- * @return array ranks of trigrams
- */
- protected function _arr_rank($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 $arr the array to sort
- *
- * @return void
- */
- protected function _bub_sort(&$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 $a is greater, -1 if not
- * @see _bub_sort()
- */
- protected function _sort_func($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 $arr2 the target set of trigram ranks
- *
- * @return int the sum of the differences between the ranks of
- * the two trigram sets
- */
- protected function _distance($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 $base_count the number of trigrams being considered
- *
- * @return float the normalized score
- * @see _distance()
- */
- protected function _normalize_score($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 $block_count the number of defined blocks in the database
- *
- * @return mixed Block name, -1 if it failed
- * @see unicodeBlockName()
- */
- protected function _unicode_block_name($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
- */
- 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 $return_arr;
- }
- }
-
- /**
- * Cluster known languages according to languageSimilarity()
- *
- * WARNING: this method is EXPERIMENTAL. It is not recommended for common
- * use, and it may disappear or its functionality may change in future
- * releases without notice.
- *
- * Uses a nearest neighbor technique to generate the maximum possible
- * number of dendograms from the similarity data.
- *
- * @return array language cluster data
- * @throws Text_LanguageDetect_Exception
- * @see languageSimilarity()
- * @deprecated this function will eventually be removed and placed into
- * the model generation class
- */
- public function clusterLanguages()
- {
- // todo: set the maximum number of clusters
- // return cached result, if any
- if (isset($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;
- }
-
- /**
- * UTF8-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 $char a utf8 (possibly multi-byte) char
- *
- * @return int unicode value
- * @link http://en.wikipedia.org/wiki/UTF-8
- */
- protected function _utf8char2unicode($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 $counter
- */
- protected static function _next_char($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 $key
- * converts the keys to the language name.
- *
- * @return string|array Language name
- */
- protected function _convertFromNameMode($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 $key
- * converts the keys to the language name.
- *
- * @return string|array Language name
- */
- protected function _convertToNameMode($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: */
git.wh0rd.org / tt-rss.git / commitdiff
