Merge pull request #363 from inthepoche/dev1.3.0

poche 1.3.0

1 files changed, 1635 insertions, 0 deletions

diff --git a/inc/3rdparty/libraries/language-detect/LanguageDetect.php b/inc/3rdparty/libraries/language-detect/LanguageDetect.php
new file mode 100644
index 00000000..09b11546
--- /dev/null
+++ b/inc/3rdparty/libraries/language-detect/LanguageDetect.php
@@ -0,0 +1,1635 @@
+<?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 versions 4 and 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    CVS: $Id: LanguageDetect.php,v 1.20 2008/07/01 02:09:15 taak Exp $
+ * @link       http://pear.php.net/package/Text_LanguageDetect/
+ * @link       http://langdetect.blogspot.com/
+ */
+
+//require_once 'PEAR.php';
+require_once 'Parser.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";
+ *
+ * $langs = $l->getLanguages();
+ * if (PEAR::isError($langs)) {
+ *     die($langs->getMessage());
+ * }
+ *
+ * sort($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@
+ * @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
+     *
+     * May be set to a PEAR_Error object if there is an error during its 
+     * initialization
+     *
+     * @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 $_clusters;
+
+    /**
+     * Constructor
+     *
+     * Will attempt to load the language database. If it fails, you will get
+     * a PEAR_Error object returned when you try to use detect()
+     *
+     */
+    function Text_LanguageDetect($db=null, $unicode_db=null)
+    {
+                if (isset($db)) $this->_db_filename = $db;
+                if (isset($unicode_db)) $this->_unicode_db_filename = $unicode_db;
+                
+        $data = $this->_readdb($this->_db_filename);
+        $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 = $data['trigram-clusters'];
+        }               
+    }
+
+    /**
+     * Returns the path to the location of the database
+     *
+     * @access    private
+     * @return    string    expected path to the language model database
+     */
+    function _get_data_loc($fname)
+    {
+        return $fname;
+    }
+
+    /**
+     * Loads the language trigram database from filename
+     *
+     * Trigram datbase should be a serialize()'d array
+     * 
+     * @access    private
+     * @param     string      $fname   the filename where the data is stored
+     * @return    array                the language model data
+     * @throws    PEAR_Error
+     */
+    function _readdb($fname)
+    {
+        // finds the correct data dir
+        $fname = $this->_get_data_loc($fname);
+
+        // input check
+        if (!file_exists($fname)) {
+            throw new Exception('Language database does not exist.');
+        } elseif (!is_readable($fname)) {
+            throw new Exception('Language database is not readable.');
+        }
+
+        if (function_exists('file_get_contents')) {
+            return unserialize(file_get_contents($fname));
+        } else {
+            // if you don't have file_get_contents(), 
+            // then this is the next fastest way
+            ob_start();
+            readfile($fname);
+            $contents = ob_get_contents();
+            ob_end_clean();
+            return unserialize($contents);
+        }
+    }
+
+
+    /**
+     * Checks if this object is ready to detect languages
+     * 
+     * @access   private
+     * @param    mixed   &$err  error object to be returned by reference, if any
+     * @return   bool           true if no errors
+     */
+    function _setup_ok(&$err)
+    {
+        if (!is_array($this->_lang_db)) {
+            if (ini_get('magic_quotes_runtime')) {
+                throw new Exception('Error loading database. Try turning magic_quotes_runtime off.');
+            } else {
+                throw new Exception('Language database is not an array.');
+            }
+            return false;
+
+        } elseif (empty($this->_lang_db)) {
+            throw new Exception('Language database has no elements.');
+            return false;
+
+        } else {
+            return true;
+        }
+    }
+
+    /**
+     * 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
+     *
+     * @access   public
+     * @param    mixed  $omit_list      language name or array of names to omit
+     * @param    bool   $include_only   if true will include (rather than 
+     *                                  exclude) only those in the list
+     * @return   int                    number of languages successfully deleted
+     * @throws   PEAR_Error
+     */
+    function omitLanguages($omit_list, $include_only = false)
+    {
+
+        // setup check
+        if (!$this->_setup_ok($err)) {
+            return $err;
+        }
+
+        $deleted = 0;
+
+        // deleting the given languages
+        if (!$include_only) {
+            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]);
+                        $deleted++;
+                    } 
+                }
+            }
+
+        // deleting all except the given languages
+        } else {
+            if (!is_array($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) && $deleted > 0) {
+            unset($this->_clusters);
+        }
+
+        return $deleted;
+    }
+
+
+    /**
+     * Returns the number of languages that this object can detect
+     *
+     * @access public
+     * @return int            the number of languages
+     * @throws PEAR_Error
+     */
+    function getLanguageCount()
+    {
+        if (!$this->_setup_ok($err)) {
+            return $err;
+        } else {
+            return count($this->_lang_db);
+        }
+    }
+
+    /**
+     * Returns true if a given language exists
+     *
+     * If passed an array of names, will return true only if all exist
+     *
+     * @access    public
+     * @param     mixed       $lang    language name or array of language names
+     * @return    bool                 true if language model exists
+     * @throws    PEAR_Error
+     */
+    function languageExists($lang)
+    {
+        if (!$this->_setup_ok($err)) {
+            return $err;
+        } else {
+            // string
+            if (is_string($lang)) {
+                return isset($this->_lang_db[strtolower($lang)]);
+
+            // array
+            } elseif (is_array($lang)) {
+                foreach ($lang as $test_lang) {
+                    if (!isset($this->_lang_db[strtolower($test_lang)])) {
+                        return false;
+                    } 
+                }
+                return true;
+
+            // other (error)
+            } else {
+                throw new Exception('Unknown type passed to languageExists()');
+            }
+        }
+    }
+
+    /**
+     * Returns the list of detectable languages
+     *
+     * @access public
+     * @return array        the names of the languages known to this object
+     * @throws PEAR_Error
+     */
+    function getLanguages()
+    {
+        if (!$this->_setup_ok($err)) {
+            return $err;
+        } else {
+            return array_keys($this->_lang_db);
+        }
+    }
+
+    /**
+     * Make this object behave like Language::Guess
+     * 
+     * @access    public
+     * @param     bool     $setting     false to turn off perl compatibility
+     */
+    function setPerlCompatible($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;
+            }
+        }
+
+    }
+
+    /**
+     * 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.
+     *
+     * @access  public
+     * @param   bool    $setting    false to turn off
+     */
+    function useUnicodeBlocks($setting = true)
+    {
+        if (is_bool($setting)) {
+            $this->_use_unicode_narrowing = $setting;
+        }
+    }
+
+    /**
+     * Converts a piece of text into trigrams
+     *
+     * Superceded by the Text_LanguageDetect_Parser class 
+     *
+     * @access    private
+     * @param     string    $text    text to convert
+     * @return    array              array of trigram frequencies
+     */
+    function _trigram($text)
+    {
+        $s = new Text_LanguageDetect_Parser($text, $this->_db_filename, $this->_unicode_db_filename);
+        $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
+     *
+     * @access    protected
+     * @param     array     $arr     array of trgram 
+     * @return    array              ranks of trigrams
+     */
+    function _arr_rank(&$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 $rank;
+    }
+
+    /**
+     * Sorts an array by value breaking ties alphabetically
+     * 
+     * @access   private
+     * @param    array     &$arr     the array to sort
+     */
+    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(). 
+     *
+     * @access   private
+     * @param    array        first param passed by usort()
+     * @param    array        second param passed by usort()
+     * @return   int          1 if $a is greater, -1 if not
+     * @see      _bub_sort()
+     */
+    function _sort_func($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) = $b;
+
+        // if the values are the same, break ties using the key
+        if ($a_value == $b_value) {
+            return strcmp($a_key, $b_key);
+
+        // if not, just sort normally
+        } else {
+            if ($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.
+     *
+     * @access  private
+     * @param   array    $arr1  the reference set of trigram ranks
+     * @param   array    $arr2  the target set of trigram ranks
+     * @return  int             the sum of the differences between the ranks of
+     *                          the two trigram sets
+     */
+    function _distance(&$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
+     *
+     * @access    private
+     * @param     int    $score          the score from _distance()
+     * @param     int    $base_count     the number of trigrams being considered
+     * @return    float                  the normalized score
+     * @see       _distance()
+     */
+    function _normalize_score($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.
+     *
+     * @access  public
+     * @param   string  $sample a sample of text to compare.
+     * @param   int     $limit  if specified, return an array of the most likely
+     *                           $limit languages and their scores.
+     * @return  mixed       sorted array of language scores, blank array if no 
+     *                      useable text was found, or PEAR_Error if error 
+     *                      with the object setup
+     * @see     _distance()
+     * @throws  PEAR_Error
+     */
+    function detect($sample, $limit = 0)
+    {
+        if (!$this->_setup_ok($err)) {
+            return $err;
+        }
+
+        // input check
+        if (!Text_LanguageDetect_Parser::validateString($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' && $encoding !== false) {
+            
+                if (function_exists('mb_list_encodings')) {
+ 
+                    // verify the encoding exists in mb_list_encodings
+                    if (in_array($encoding, mb_list_encodings())) {
+                        $sample = mb_convert_encoding($sample, 'UTF-8', $encoding);
+                    }
+
+                    // if the previous condition failed:
+                    // somehow we detected an encoding that also we don't support
+
+                } else {
+                    // php 4 doesnt have mb_list_encodings()
+                    // so attempt with error suppression
+                    $sample = @mb_convert_encoding($sample, 'UTF-8', $encoding);
+                }
+            }
+        }
+
+        $sample_obj = new Text_LanguageDetect_Parser($sample, $this->_db_filename, $this->_unicode_db_filename);
+        $sample_obj->prepareTrigram();
+        if ($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 Exception('Error during 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
+
+        // or just try 'em all
+        } else {
+            $possible_langs = array_keys($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 $limited_scores;
+        } else {
+            return $scores;
+        }
+    }
+
+    /**
+     * Returns only the most similar language to the text sample
+     *
+     * Calls $this->detect() and returns only the top result
+     * 
+     * @access   public
+     * @param    string    $sample    text to detect the language of
+     * @return   string               the name of the most likely language
+     *                                or null if no language is similar
+     * @see      detect()
+     * @throws   PEAR_Error
+     */
+    function detectSimple($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) == $this->_max_score) {
+
+            return null;
+
+        } else {
+            return ucfirst(key($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()
+     * 
+     * @access   public
+     * @param    string    $sample    text for which language will be detected
+     * @return   array     most similar language, score and confidence rating
+     *                     or null if no language is similar
+     * @see      detect()
+     * @throws   PEAR_Error
+     */
+    function detectConfidence($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;
+        }
+
+        $arr['language'] = ucfirst(key($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()
+     * 
+     * @access public
+     * @param string $str input string. Must be ascii or utf8
+     * @param bool $skip_symbols if true, skip ascii digits, symbols and 
+     *                           non-printing characters. Includes spaces,
+     *                           newlines and common punctutation characters.
+     * @return array
+     * @throws PEAR_Error
+     */
+    function detectUnicodeBlocks($str, $skip_symbols)
+    {
+        // input check
+        if (!is_bool($skip_symbols)) {
+            throw new Exception('Second parameter must be boolean');
+        } 
+
+        if (!is_string($str)) {
+            throw new Exception('First parameter was not a string');
+        }
+
+        $sample_obj = new Text_LanguageDetect_Parser($str, $this->_db_filename, $this->_unicode_db_filename);
+        $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!
+     *
+     * @access public
+     * @param mixed $unicode unicode value or utf8 char
+     * @return mixed the block name string or false if not found
+     * @throws PEAR_Error
+     */
+    function unicodeBlockName($unicode) {
+        if (is_string($unicode)) {
+            // assume it is being passed a utf8 char, so convert it
+
+            // input check
+            if ($this->utf8strlen($unicode) > 1) {
+                throw new Exception('Pass this function only a single char');
+            }
+
+            $unicode = $this->_utf8char2unicode($unicode);
+
+            if ($unicode == -1) {
+                throw new Exception('Malformatted char');
+            }
+
+        // input check
+        } elseif (!is_int($unicode)) {
+            throw new Exception('Input must be of type string or int.');
+        }
+
+        $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.
+     *
+     * @access  protected
+     * @param   int     $unicode the unicode value
+     * @param   array   &$blocks the block database
+     * @param   int     $block_count the number of defined blocks in the database
+     * @see     unicodeBlockName()
+     */
+    function _unicode_block_name($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 + $high) / 2);
+
+            // if it's lower than the lower bound
+            if ($unicode < $blocks[$mid][0]) {
+                $high = $mid - 1;
+
+            // if it's higher than the upper bound
+            } elseif ($unicode > $blocks[$mid][1]) {
+                $low = $mid + 1;
+
+            // found it
+            } else {
+                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
+     *
+     * @access protected
+     * @return array the database of unicode block definitions
+     * @throws PEAR_Error
+     */
+    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.
+     *
+     * @access  public
+     * @param   string   $lang1   the name of the first language to be compared
+     * @param   string   $lang2   the name of the second language to be compared
+     * @return  array    scores of every language compared
+     *                   or the score of just the provided languages
+     *                   or null if one of the supplied languages does not exist
+     * @throws  PEAR_Error
+     */
+    function languageSimilarity($lang1 = null, $lang2 = null)
+    {
+        if (!$this->_setup_ok($err)) {
+            return $err;
+        }
+
+        if ($lang1 != null) {
+            $lang1 = strtolower($lang1);
+
+            // check if language model exists
+            if (!isset($this->_lang_db[$lang1])) {
+                return null;
+            }
+
+            if ($lang2 != null) {
+
+                // can't only set the second param
+                if ($lang1 == null) {
+                    return null;
+                // check if language model exists
+                } elseif (!isset($this->_lang_db[$lang2])) {
+                    return null;
+                }
+
+                $lang2 = strtolower($lang2);
+
+                // compare just these two languages
+                return $this->_normalize_score(
+                    $this->_distance(
+                        $this->_lang_db[$lang1],
+                        $this->_lang_db[$lang2]
+                    )
+                );
+
+
+            // compare just $lang1 to all languages
+            } else {
+                $return_arr = array();
+                foreach ($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;
+            }
+
+
+        // compare all languages to each other
+        } else {
+            $return_arr = array();
+            foreach (array_keys($this->_lang_db) as $lang1) {
+                foreach (array_keys($this->_lang_db) as $lang2) {
+
+                    // skip comparing languages to themselves
+                    if ($lang1 != $lang2) { 
+                    
+                        // don't re-calculate what's already been done
+                        if (isset($return_arr[$lang2][$lang1])) {
+
+                            $return_arr[$lang1][$lang2] =
+                                $return_arr[$lang2][$lang1];
+
+                        // calculate
+                        } else {
+
+                            $return_arr[$lang1][$lang2] = 
+                                $this->_normalize_score(
+                                        $this->_distance(
+                                            $this->_lang_db[$lang1],
+                                            $this->_lang_db[$lang2]
+                                        )
+                                );
+
+                        }
+                    }
+                }
+            }
+            return $return_arr;
+        }
+    }
+
+    /**
+     * Cluster known languages according to languageSimilarity()
+     *
+     * WARNING: this method is EXPERIMENTAL. It is not recommended for common
+     * use, and it may disappear or its functionality may change in future
+     * releases without notice.
+     *
+     * Uses a nearest neighbor technique to generate the maximum possible
+     * number of dendograms from the similarity data.
+     *
+     * @access      public
+     * @return      array language cluster data
+     * @throws      PEAR_Error
+     * @see         languageSimilarity()
+     * @deprecated  this function will eventually be removed and placed into 
+     *              the model generation class
+     */
+    function clusterLanguages()
+    {
+        // todo: set the maximum number of clusters
+
+        // setup check
+        if (!$this->_setup_ok($err)) {
+            return $err;
+        }
+
+        // return cached result, if any
+        if (isset($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 Exception("missing $lang!\n");
+            }
+        }
+
+        // http://www.psychstat.missouristate.edu/multibook/mlt04m.html
+        foreach ($langs as $old_key => $lang1) {
+            $langs[$lang1] = $lang1;
+            unset($langs[$old_key]);
+        }
+        
+        $i = 0;
+        while (count($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 Exception("no highest key? (step: $i)");
+            }
+
+            if ($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.
+     *
+     * @see     clusterLanguages()
+     * @access  public
+     * @param   string $str input string
+     * @return  array language scores (only those compared)
+     * @throws  PEAR_Error
+     */
+    function clusteredSearch($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, $this->_db_filename, $this->_unicode_db_filename);
+        $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
+     *
+     * @static
+     * @access  public
+     * @param   string $str string to get the length of
+     * @return  int         number of chars
+     */
+    function utf8strlen($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
+     *
+     * @access  protected
+     * @param   string $char a utf8 (possibly multi-byte) char
+     * @return  int          unicode value or -1 if malformatted
+     */
+    function _utf8char2unicode($char) {
+
+        // strlen() here will actually get the binary length of a single char
+        switch (strlen($char)) {
+
+            // for a reference, see http://en.wikipedia.org/wiki/UTF-8
+
+            case 1:
+                // normal ASCII-7 byte
+                // 0xxxxxxx -->  0xxxxxxx
+                return ord($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);
+
+            default:
+                // error: malformatted char?
+                return -1;
+        }
+    }
+
+    /**
+     * 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 
+     * $counter will be incremeted by the number of bytes in the char.
+     *
+     * @access  private
+     * @param   string  &$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 $counter
+     */
+    function _next_char(&$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 $char;
+
+        // multi-byte chars
+        } elseif ($ord >> 5 == 6) { // two-byte char
+            $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
+
+                    // &Agrave; - &THORN; but not &times;
+                    if (    $nextord_adj >= 192
+                            && $nextord_adj <= 222 
+                            && $nextord_adj != 215) {
+
+                        $nextchar = chr($nextord + 32); 
+                    }
+
+                // lower case cyrillic alphabet
+                } elseif ($ord == 208) {
+                    $nextord = ord($nextchar);
+                    // if A - Pe
+                    if ($nextord >= 144 && $nextord <= 159) {
+                        // lower case
+                        $nextchar = chr($nextord + 32);
+
+                    // if Er - Ya
+                    } elseif ($nextord >= 160 && $nextord <= 175) {
+                        // 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?
+        }
+    }
+
+}
+
+/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
+
+?>