Chris@0: <?php
Chris@0: 
Chris@0: namespace Drupal\Component\Transliteration;
Chris@0: 
Chris@0: /**
Chris@0:  * Implements transliteration without using the PECL extensions.
Chris@0:  *
Chris@0:  * Transliterations are done character-by-character, by looking up non-US-ASCII
Chris@0:  * characters in a transliteration database.
Chris@0:  *
Chris@0:  * The database comes from two types of files, both of which are searched for in
Chris@0:  * the PhpTransliteration::$dataDirectory directory. First, language-specific
Chris@0:  * overrides are searched (see PhpTransliteration::readLanguageOverrides()). If
Chris@0:  * there is no language-specific override for a character, the generic
Chris@0:  * transliteration character tables are searched (see
Chris@0:  * PhpTransliteration::readGenericData()). If looking up the character in the
Chris@0:  * generic table results in a NULL value, or an illegal character is
Chris@0:  * encountered, then a substitute character is returned.
Chris@0:  *
Chris@0:  * Some parts of this code were derived from the MediaWiki project's UtfNormal
Chris@0:  * class, Copyright © 2004 Brion Vibber <brion@pobox.com>,
Chris@0:  * http://www.mediawiki.org/
Chris@0:  */
Chris@0: class PhpTransliteration implements TransliterationInterface {
Chris@0: 
Chris@0:   /**
Chris@0:    * Directory where data for transliteration resides.
Chris@0:    *
Chris@0:    * The constructor sets this (by default) to subdirectory 'data' underneath
Chris@0:    * the directory where the class's PHP file resides.
Chris@0:    *
Chris@0:    * @var string
Chris@0:    */
Chris@0:   protected $dataDirectory;
Chris@0: 
Chris@0:   /**
Chris@0:    * Associative array of language-specific character transliteration tables.
Chris@0:    *
Chris@0:    * The outermost array keys are language codes. For each language code key,
Chris@0:    * the value is an array whose keys are Unicode character codes, and whose
Chris@0:    * values are the transliterations of those characters to US-ASCII. This is
Chris@0:    * set up as needed in PhpTransliteration::replace() by calling
Chris@0:    * PhpTransliteration::readLanguageOverrides().
Chris@0:    *
Chris@0:    * @var array
Chris@0:    */
Chris@0:   protected $languageOverrides = [];
Chris@0: 
Chris@0:   /**
Chris@0:    * Non-language-specific transliteration tables.
Chris@0:    *
Chris@0:    * Array whose keys are the upper two bytes of the Unicode character, and
Chris@0:    * whose values are an array of transliterations for each lower-two bytes
Chris@0:    * character code. This is set up as needed in PhpTransliteration::replace()
Chris@0:    * by calling PhpTransliteration::readGenericData().
Chris@0:    *
Chris@0:    * @var array
Chris@0:    */
Chris@0:   protected $genericMap = [];
Chris@0: 
Chris@0:   /**
Chris@0:    * Constructs a transliteration object.
Chris@0:    *
Chris@0:    * @param string $data_directory
Chris@0:    *   (optional) The directory where data files reside. If omitted, defaults
Chris@0:    *   to subdirectory 'data' underneath the directory where the class's PHP
Chris@0:    *   file resides.
Chris@0:    */
Chris@0:   public function __construct($data_directory = NULL) {
Chris@0:     $this->dataDirectory = (isset($data_directory)) ? $data_directory : __DIR__ . '/data';
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function removeDiacritics($string) {
Chris@0:     $result = '';
Chris@0: 
Chris@0:     foreach (preg_split('//u', $string, 0, PREG_SPLIT_NO_EMPTY) as $character) {
Chris@0:       $code = self::ordUTF8($character);
Chris@0: 
Chris@0:       // These two Unicode ranges include the accented US-ASCII letters, with a
Chris@0:       // few characters that aren't accented letters mixed in. So define the
Chris@0:       // ranges and the excluded characters.
Chris@0:       $range1 = $code > 0x00bf && $code < 0x017f;
Chris@0:       $exclusions_range1 = [0x00d0, 0x00d7, 0x00f0, 0x00f7, 0x0138, 0x014a, 0x014b];
Chris@0:       $range2 = $code > 0x01cc && $code < 0x0250;
Chris@0:       $exclusions_range2 = [0x01DD, 0x01f7, 0x021c, 0x021d, 0x0220, 0x0221, 0x0241, 0x0242, 0x0245];
Chris@0: 
Chris@0:       $replacement = $character;
Chris@0:       if (($range1 && !in_array($code, $exclusions_range1)) || ($range2 && !in_array($code, $exclusions_range2))) {
Chris@0:         $to_add = $this->lookupReplacement($code, 'xyz');
Chris@0:         if (strlen($to_add) === 1) {
Chris@0:           $replacement = $to_add;
Chris@0:         }
Chris@0:       }
Chris@0: 
Chris@0:       $result .= $replacement;
Chris@0:     }
Chris@0: 
Chris@0:     return $result;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function transliterate($string, $langcode = 'en', $unknown_character = '?', $max_length = NULL) {
Chris@0:     $result = '';
Chris@0:     $length = 0;
Chris@17:     $hash = FALSE;
Chris@17: 
Chris@17:     // Replace question marks with a unique hash if necessary. This because
Chris@17:     // mb_convert_encoding() replaces all invalid characters with a question
Chris@17:     // mark.
Chris@17:     if ($unknown_character != '?' && strpos($string, '?') !== FALSE) {
Chris@17:       $hash = hash('sha256', $string);
Chris@17:       $string = str_replace('?', $hash, $string);
Chris@17:     }
Chris@17: 
Chris@17:     // Ensure the string is valid UTF8 for preg_split(). Unknown characters will
Chris@17:     // be replaced by a question mark.
Chris@17:     $string = mb_convert_encoding($string, 'UTF-8', 'UTF-8');
Chris@17: 
Chris@17:     // Use the provided unknown character instead of a question mark.
Chris@17:     if ($unknown_character != '?') {
Chris@17:       $string = str_replace('?', $unknown_character, $string);
Chris@17:       // Restore original question marks if necessary.
Chris@17:       if ($hash !== FALSE) {
Chris@17:         $string = str_replace($hash, '?', $string);
Chris@17:       }
Chris@17:     }
Chris@17: 
Chris@0:     // Split into Unicode characters and transliterate each one.
Chris@0:     foreach (preg_split('//u', $string, 0, PREG_SPLIT_NO_EMPTY) as $character) {
Chris@0:       $code = self::ordUTF8($character);
Chris@0:       if ($code == -1) {
Chris@0:         $to_add = $unknown_character;
Chris@0:       }
Chris@0:       else {
Chris@0:         $to_add = $this->replace($code, $langcode, $unknown_character);
Chris@0:       }
Chris@0: 
Chris@0:       // Check if this exceeds the maximum allowed length.
Chris@0:       if (isset($max_length)) {
Chris@0:         $length += strlen($to_add);
Chris@0:         if ($length > $max_length) {
Chris@0:           // There is no more space.
Chris@0:           return $result;
Chris@0:         }
Chris@0:       }
Chris@0: 
Chris@0:       $result .= $to_add;
Chris@0:     }
Chris@0: 
Chris@0:     return $result;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Finds the character code for a UTF-8 character: like ord() but for UTF-8.
Chris@0:    *
Chris@0:    * @param string $character
Chris@0:    *   A single UTF-8 character.
Chris@0:    *
Chris@0:    * @return int
Chris@0:    *   The character code, or -1 if an illegal character is found.
Chris@0:    */
Chris@0:   protected static function ordUTF8($character) {
Chris@0:     $first_byte = ord($character[0]);
Chris@0: 
Chris@0:     if (($first_byte & 0x80) == 0) {
Chris@0:       // Single-byte form: 0xxxxxxxx.
Chris@0:       return $first_byte;
Chris@0:     }
Chris@0:     if (($first_byte & 0xe0) == 0xc0) {
Chris@0:       // Two-byte form: 110xxxxx 10xxxxxx.
Chris@0:       return (($first_byte & 0x1f) << 6) + (ord($character[1]) & 0x3f);
Chris@0:     }
Chris@0:     if (($first_byte & 0xf0) == 0xe0) {
Chris@0:       // Three-byte form: 1110xxxx 10xxxxxx 10xxxxxx.
Chris@0:       return (($first_byte & 0x0f) << 12) + ((ord($character[1]) & 0x3f) << 6) + (ord($character[2]) & 0x3f);
Chris@0:     }
Chris@0:     if (($first_byte & 0xf8) == 0xf0) {
Chris@0:       // Four-byte form: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx.
Chris@0:       return (($first_byte & 0x07) << 18) + ((ord($character[1]) & 0x3f) << 12) + ((ord($character[2]) & 0x3f) << 6) + (ord($character[3]) & 0x3f);
Chris@0:     }
Chris@0: 
Chris@0:     // Other forms are not legal.
Chris@0:     return -1;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Replaces a single Unicode character using the transliteration database.
Chris@0:    *
Chris@0:    * @param int $code
Chris@0:    *   The character code of a Unicode character.
Chris@0:    * @param string $langcode
Chris@0:    *   The language code of the language the character is in.
Chris@0:    * @param string $unknown_character
Chris@0:    *   The character to substitute for characters without transliterated
Chris@0:    *   equivalents.
Chris@0:    *
Chris@0:    * @return string
Chris@0:    *   US-ASCII replacement character. If it has a mapping, it is returned;
Chris@0:    *   otherwise, $unknown_character is returned. The replacement can contain
Chris@0:    *   multiple characters.
Chris@0:    */
Chris@0:   protected function replace($code, $langcode, $unknown_character) {
Chris@0:     if ($code < 0x80) {
Chris@0:       // Already lower ASCII.
Chris@0:       return chr($code);
Chris@0:     }
Chris@0: 
Chris@0:     // See if there is a language-specific override for this character.
Chris@0:     if (!isset($this->languageOverrides[$langcode])) {
Chris@0:       $this->readLanguageOverrides($langcode);
Chris@0:     }
Chris@0:     if (isset($this->languageOverrides[$langcode][$code])) {
Chris@0:       return $this->languageOverrides[$langcode][$code];
Chris@0:     }
Chris@0: 
Chris@0:     return $this->lookupReplacement($code, $unknown_character);
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Look up the generic replacement for a UTF-8 character code.
Chris@0:    *
Chris@0:    * @param $code
Chris@0:    *   The UTF-8 character code.
Chris@0:    * @param string $unknown_character
Chris@0:    *   (optional) The character to substitute for characters without entries in
Chris@0:    *   the replacement tables.
Chris@0:    *
Chris@0:    * @return string
Chris@0:    *   US-ASCII replacement characters. If it has a mapping, it is returned;
Chris@0:    *   otherwise, $unknown_character is returned. The replacement can contain
Chris@0:    *   multiple characters.
Chris@0:    */
Chris@0:   protected function lookupReplacement($code, $unknown_character = '?') {
Chris@0:     // See if there is a generic mapping for this character.
Chris@0:     $bank = $code >> 8;
Chris@0:     if (!isset($this->genericMap[$bank])) {
Chris@0:       $this->readGenericData($bank);
Chris@0:     }
Chris@0:     $code = $code & 0xff;
Chris@0:     return isset($this->genericMap[$bank][$code]) ? $this->genericMap[$bank][$code] : $unknown_character;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Reads in language overrides for a language code.
Chris@0:    *
Chris@0:    * The data is read from files named "$langcode.php" in
Chris@0:    * PhpTransliteration::$dataDirectory. These files should set up an array
Chris@0:    * variable $overrides with an element whose key is $langcode and whose value
Chris@0:    * is an array whose keys are character codes, and whose values are their
Chris@0:    * transliterations in this language. The character codes can be for any valid
Chris@0:    * Unicode character, independent of the number of bytes.
Chris@0:    *
Chris@0:    * @param $langcode
Chris@0:    *   Code for the language to read.
Chris@0:    */
Chris@0:   protected function readLanguageOverrides($langcode) {
Chris@0:     // Figure out the file name to use by sanitizing the language code,
Chris@0:     // just in case.
Chris@0:     $file = $this->dataDirectory . '/' . preg_replace('/[^a-zA-Z\-]/', '', $langcode) . '.php';
Chris@0: 
Chris@0:     // Read in this file, which should set up a variable called $overrides,
Chris@0:     // which will be local to this function.
Chris@0:     if (is_file($file)) {
Chris@0:       include $file;
Chris@0:     }
Chris@0:     if (!isset($overrides) || !is_array($overrides)) {
Chris@0:       $overrides = [$langcode => []];
Chris@0:     }
Chris@0:     $this->languageOverrides[$langcode] = $overrides[$langcode];
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Reads in generic transliteration data for a bank of characters.
Chris@0:    *
Chris@0:    * The data is read in from a file named "x$bank.php" (with $bank in
Chris@0:    * hexadecimal notation) in PhpTransliteration::$dataDirectory. These files
Chris@0:    * should set up a variable $bank containing an array whose numerical indices
Chris@0:    * are the remaining two bytes of the character code, and whose values are the
Chris@0:    * transliterations of these characters into US-ASCII. Note that the maximum
Chris@0:    * Unicode character that can be encoded in this way is 4 bytes.
Chris@0:    *
Chris@0:    * @param $bank
Chris@0:    *   First two bytes of the Unicode character, or 0 for the ASCII range.
Chris@0:    */
Chris@0:   protected function readGenericData($bank) {
Chris@0:     // Figure out the file name.
Chris@0:     $file = $this->dataDirectory . '/x' . sprintf('%02x', $bank) . '.php';
Chris@0: 
Chris@0:     // Read in this file, which should set up a variable called $base, which
Chris@0:     // will be local to this function.
Chris@0:     if (is_file($file)) {
Chris@0:       include $file;
Chris@0:     }
Chris@0:     if (!isset($base) || !is_array($base)) {
Chris@0:       $base = [];
Chris@0:     }
Chris@0: 
Chris@0:     // Save this data.
Chris@0:     $this->genericMap[$bank] = $base;
Chris@0:   }
Chris@0: 
Chris@0: }