language detection library

1 files changed, 349 insertions, 0 deletions

diff --git a/library/langdet/Text/LanguageDetect/Parser.php b/library/langdet/Text/LanguageDetect/Parser.php
new file mode 100644
index 000000000..1c20c2657
--- /dev/null
+++ b/library/langdet/Text/LanguageDetect/Parser.php
@@ -0,0 +1,349 @@
+<?php
+
+/**
+ * This class represents a text sample to be parsed.
+ *
+ * @category    Text
+ * @package     Text_LanguageDetect
+ * @author      Nicholas Pisarro
+ * @copyright   2006
+ * @license     BSD
+ * @version     CVS: $Id: Parser.php 322327 2012-01-15 17:55:59Z cweiske $
+ * @link        http://pear.php.net/package/Text_LanguageDetect/
+ * @link        http://langdetect.blogspot.com/
+ */
+
+/**
+ * This class represents a text sample to be parsed.
+ *
+ * This separates the analysis of a text sample from the primary LanguageDetect
+ * class. After a new profile has been built, the data can be retrieved using
+ * the accessor functions.
+ *
+ * This class is intended to be used by the Text_LanguageDetect class, not 
+ * end-users.
+ *
+ * @category    Text
+ * @package     Text_LanguageDetect
+ * @author      Nicholas Pisarro
+ * @copyright   2006
+ * @license     BSD
+ * @version     release: 0.3.0
+ */
+class Text_LanguageDetect_Parser extends Text_LanguageDetect
+{
+    /**
+     * the piece of text being parsed
+     *
+     * @access  private
+     * @var     string
+     */
+    var $_string;
+
+    /**
+     * stores the trigram frequencies of the sample
+     *
+     * @access  private
+     * @var     string
+     */
+    var $_trigrams = array();
+
+    /**
+     * stores the trigram ranks of the sample
+     *
+     * @access  private
+     * @var     array
+     */
+    var $_trigram_ranks = array();
+
+    /**
+     * stores the unicode blocks of the sample
+     *
+     * @access  private
+     * @var     array
+     */
+    var $_unicode_blocks = array();
+    
+    /**
+     * Whether the parser should compile the unicode ranges
+     * 
+     * @access  private
+     * @var     bool
+     */
+    var $_compile_unicode = false;
+
+    /**
+     * Whether the parser should compile trigrams
+     *
+     * @access  private
+     * @var     bool
+     */
+    var $_compile_trigram = false;
+
+    /**
+     * Whether the trigram parser should pad the beginning of the string
+     *
+     * @access  private
+     * @var     bool
+     */
+    var $_trigram_pad_start = false;
+
+    /**
+     * Whether the unicode parser should skip non-alphabetical ascii chars
+     *
+     * @access  private
+     * @var     bool
+     */
+    var $_unicode_skip_symbols = true;
+
+    /**
+     * Constructor
+     *
+     * @access  private
+     * @param   string  $string     string to be parsed
+     */
+    function Text_LanguageDetect_Parser($string) {
+        $this->_string = $string;
+    }
+
+    /**
+     * Returns true if a string is suitable for parsing
+     *
+     * @param   string  $str    input string to test
+     * @return  bool            true if acceptable, false if not
+     */
+    public static function validateString($str) {
+        if (!empty($str) && strlen($str) > 3 && preg_match('/\S/', $str)) {
+            return true;
+        } else {
+            return false;
+        }
+    }
+
+    /**
+     * turn on/off trigram counting
+     *
+     * @access  public
+     * @param   bool    $bool true for on, false for off
+     */
+    function prepareTrigram($bool = true)
+    {
+        $this->_compile_trigram = $bool;
+    }
+
+    /**
+     * turn on/off unicode block counting
+     *
+     * @access  public
+     * @param   bool    $bool true for on, false for off
+     */
+    function prepareUnicode($bool = true)
+    {
+        $this->_compile_unicode = $bool;
+    }
+
+    /**
+     * turn on/off padding the beginning of the sample string
+     *
+     * @access  public
+     * @param   bool    $bool true for on, false for off
+     */
+    function setPadStart($bool = true)
+    {
+        $this->_trigram_pad_start = $bool;
+    }
+
+    /**
+     * Should the unicode block counter skip non-alphabetical ascii chars?
+     *
+     * @access  public
+     * @param   bool    $bool true for on, false for off
+     */
+    function setUnicodeSkipSymbols($bool = true)
+    {
+        $this->_unicode_skip_symbols = $bool;
+    }
+
+    /**
+     * Returns the trigram ranks for the text sample
+     *
+     * @access  public
+     * @return  array    trigram ranks in the text sample
+     */
+    function &getTrigramRanks()
+    {
+        return $this->_trigram_ranks;
+    }
+
+    /**
+     * Return the trigram freqency table
+     *
+     * only used in testing to make sure the parser is working
+     *
+     * @access  public
+     * @return  array    trigram freqencies in the text sample
+     */
+    function &getTrigramFreqs()
+    {
+        return $this->_trigram;
+    }
+
+    /**
+     * returns the array of unicode blocks
+     *
+     * @access  public
+     * @return  array   unicode blocks in the text sample
+     */
+    function &getUnicodeBlocks()
+    {
+        return $this->_unicode_blocks;
+    }
+
+    /**
+     * Executes the parsing operation
+     * 
+     * Be sure to call the set*() functions to set options and the 
+     * prepare*() functions first to tell it what kind of data to compute
+     *
+     * Afterwards the get*() functions can be used to access the compiled
+     * information.
+     *
+     * @access public
+     */
+    function analyze()
+    {
+        $len = strlen($this->_string);
+        $byte_counter = 0;
+
+
+        // unicode startup
+        if ($this->_compile_unicode) {
+            $blocks = $this->_read_unicode_block_db();
+            $block_count = count($blocks);
+
+            $skipped_count = 0;
+            $unicode_chars = array();
+        }
+
+        // trigram startup
+        if ($this->_compile_trigram) {
+            // initialize them as blank so the parser will skip the first two
+            // (since it skips trigrams with more than  2 contiguous spaces)
+            $a = ' ';
+            $b = ' ';
+
+            // kludge
+            // if it finds a valid trigram to start and the start pad option is
+            // off, then set a variable that will be used to reduce this
+            // trigram after parsing has finished
+            if (!$this->_trigram_pad_start) {
+                $a = $this->_next_char($this->_string, $byte_counter, true);
+
+                if ($a != ' ') {
+                    $b = $this->_next_char($this->_string, $byte_counter, true);
+                    $dropone = " $a$b";
+                }
+
+                $byte_counter = 0;
+                $a = ' ';
+                $b = ' ';
+            }
+        }
+
+        while ($byte_counter < $len) {
+            $char = $this->_next_char($this->_string, $byte_counter, true);
+
+
+            // language trigram detection
+            if ($this->_compile_trigram) {
+                if (!($b == ' ' && ($a == ' ' || $char == ' '))) {
+                    if (!isset($this->_trigram[$a . $b . $char])) {
+                       $this->_trigram[$a . $b . $char] = 1;
+                    } else {
+                       $this->_trigram[$a . $b . $char]++;
+                    }
+                }
+
+                $a = $b;
+                $b = $char;
+            }
+
+            // unicode block detection
+            if ($this->_compile_unicode) {
+                if ($this->_unicode_skip_symbols
+                        && strlen($char) == 1
+                        && ($char < 'A' || $char > 'z'
+                        || ($char > 'Z' && $char < 'a'))
+                        && $char != "'") {  // does not skip the apostrophe
+                                            // since it's included in the language
+                                            // models
+
+                    $skipped_count++;
+                    continue;
+                }
+
+                // build an array of all the characters
+                if (isset($unicode_chars[$char])) {
+                    $unicode_chars[$char]++;
+                } else {
+                    $unicode_chars[$char] = 1;
+                }
+            }
+
+            // todo: add byte detection here
+        }
+
+        // unicode cleanup
+        if ($this->_compile_unicode) {
+            foreach ($unicode_chars as $utf8_char => $count) {
+                $search_result = $this->_unicode_block_name(
+                        $this->_utf8char2unicode($utf8_char), $blocks, $block_count);
+
+                if ($search_result != -1) {
+                    $block_name = $search_result[2];
+                } else {
+                    $block_name = '[Malformatted]';
+                }
+
+                if (isset($this->_unicode_blocks[$block_name])) {
+                    $this->_unicode_blocks[$block_name] += $count;
+                } else {
+                    $this->_unicode_blocks[$block_name] = $count;
+                }
+            }
+        }
+
+
+        // trigram cleanup
+        if ($this->_compile_trigram) {
+            // pad the end
+            if ($b != ' ') {
+                if (!isset($this->_trigram["$a$b "])) {
+                    $this->_trigram["$a$b "] = 1;
+                } else {
+                    $this->_trigram["$a$b "]++;
+                }
+            }
+
+            // perl compatibility; Language::Guess does not pad the beginning
+            // kludge
+            if (isset($dropone)) {
+                if ($this->_trigram[$dropone] == 1) {
+                    unset($this->_trigram[$dropone]);
+                } else {
+                    $this->_trigram[$dropone]--;
+                }
+            }
+
+            if (!empty($this->_trigram)) {
+                $this->_trigram_ranks = $this->_arr_rank($this->_trigram);
+            } else {
+                $this->_trigram_ranks = array();
+            }
+        }
+    }
+}
+
+/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
+
+?>